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Australske forskere forstår ikke hva som skjer med havskilpaddene.
Del 9. juli 2016 kl. 17.49(Dagbladet): Flere verdensledende havforskere har slått alarm: Naturperlen og verdensarvområdet Great Barrier Reef i Australia står i fare for å dø ut. Kanskje for godt. Nær én fjerdedel av korallene i det enorme revet er allerede døde, og mange eksperter har varslet at det allerede kan være for seint å redde resten.
Nå får en pågående herpesepidemi, som rammer skilpadder i det store barriererevet, forskere ved James Cook-universitetet til å klø seg i hodet.
Syksdommen, som på engelsk har fått navnet fibropapillomatosis, fører til at havskilpaddene utvikler store svulster over hele kroppen. Svulstene angriper også i enkelte tilfeller indre organer, som hjerte og lunger.
Bildene av Great Barrier Reef er tatt med én måneds mellomrom. - Knapt mulig å fatte
- Svulstene er godartede. Men de kan bli 30 centimeter i omkrets, og blokkere skilpaddenes syn. Dermed klarer de ikke å finne mat, eller se farlige rovdyr og båter, sier forsker Karina Jones ved James Cook-universitetet til New Scientist.
En stort antall av skilpaddene dør fordi de ikke klarer å se eller spise. Det har ført Jones og hennes forskerkolleger ut på jakt etter ledetråder, i havet utenfor Magnetic Island, Nord-Øst i Australia.
- Åpenbart ille
Til tross for at de har studert og fulgt med på de rammede havskilpaddene lenge, har de ikke kommet noe nærmere et svar på hvorfor herpesviruset utvikler seg til store svulster. Men lokal forurensning i havet er foreløpig på toppen av lista over mistenkte.
- Vi ser at disse svulstene dukker opp i begrensede områder, over hele verden, der det er betydelig menneskelig aktivitet, sier Jones til New Scientist.
Tilsynelatende friske skilpadder, i havområder som ikke er plaget av kraftig forurensning, kan også være bærere av herpesviruset, men de får ofte ikke synlige symptomer.
- Det er antatt at forurensningen kan svekke skilpaddenes immunsystem, som dermed gjør de mer utsatt for sykdom, sier veterinær Doug Mader ved The Turtle Hospital i Florida til New Scientist.
Sykdommen har også dukket opp stadig hyppigere blant havskilpadder i Florida og Hawaii i USA, ifølge New Scientist. I Australia mener forskerne dette er nok et tegn på at Great Barrier Reef sliter motstrøms.
Great Barrier Reef ligger i Korallhavet utenfor nordkysten av Queensland i Australia. Det er over 2300 kilometer langt, dekker et område på 344 400 km² og kan sees fra verdensrommet. Nå mener forskere at revet er alvorlig truet av korallbleking.- Jeg er bekymret, for vi begynner å se stadig mer av denne sykdommen. Det er åpenbart ille for skilpaddene, men vi må også spørre oss selv: hva betyr dette for revet? sier Jones til nyhetsbyrået AP.
Flere skilpadder skal ha blitt funnet døde, som følge av underernæring.
- I den største delen av revet er skilpaddene friske, men i dette området er de ikke det, sier professor Ellen Ariel ved James Cook-universitetet til nyhetsbyrået AP.
93 prosent bleket
Professor og korallrevekspert Terry Hughes ledet en undersøkelse som tidligere i år påviste korallbleking på 93 prosent av revene i den nordlige delen av barriererevet, og at rundt 22 prosent av korallene i hele revet har dødd ut.
- Det er dessverre minst like ille som det høres ut. Kanskje også verre. Jeg vil nesten ikke gå ut i vannet lenger, fordi ødeleggelsene er så omfattende. Det er knapt mulig å fatte at det har skjedd så fort, sa Lyle Vail til Dagbladet i slutten av juni.
Vail er, sammen med kona Anne Hoggett, sjef ved forskningsstasjonen Lizard Island, som drives av Australia Museum, nordøst i landet. De siste 26 årene har paret fulgt utviklingen i revet så godt som hver eneste dag, men nå orker Vail altså nesten ikke lenger.
Allerede i 2006 ble det varslet en dyster framtid for Great Barrier Reef. Men det var først i fjor høst forskerne trykket på den store røde knappen, da det ble klart at ekstreme vanntemperaturer kunne komme til å bleke store deler av korallrevet. Gjennom vinteren forverret situasjonen seg raskt, og i vår konkluderte flere forskere med at det allerede kan være for seint å redde store deler av revet.
Great Barrier Reef
- Great Barrier Reef er verdens største korallrev.
- Navnet på revet har ikke kommet ved en tilfeldighet. Det store barriererevet er omtrent 2300 kilometer langt, og dekker et arial på 344 000 kvadratkilometer, som nesten måler seg med Norges (385 156 kvadratkilometer).
- Over 360 korallarter, 1500 fiskearter og 4000 bløtdyrarter holder til i revet, som er blant verdens mest komplekse økosystem.
- Habitat for dugong (Dugong dugong) sjøkuer og grønn havskilpadde, som er utrydningstruet.
- Listet opp av Unesco som et verdensarvsted siden 1981.
- Revet starter utenfor Hervey Bay i Queensland i sør, og strekker seg 2300 kilometer langs Australias østkyst før det tar slutt like ved Papua Ny-Guinea i nord.
- Den britiske eventyreren og kapteinen James Cook har i moderne tid blitt anerkjent for å ha «oppdaget» revet, da seilskuta Endeavour gikk på grunn i 1770. Cook ga også navn til Lizard Island på grunn av alle de store øglene på øya.
(Kilder: SNL, The Guardian, NTB, Dagbladet)
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Biggest ever die-off of ocean forests triggered by warming seas
Warmer seas mean tough times for kelpJoan Costa, University of Western Australia
By Alice Klein
Help the kelp. Rising sea temperatures have already wiped out 100 kilometres of kelp forest along the south coast of Western Australia – and this unprecedented loss looks set to worsen.
The Indian Ocean off Western Australia experienced record summer temperatures between 2011 and 2013 caused by a double whammy of global warming and a La Niña weather phase. At their peak, in 2011, sea surface temperatures reached more than 6 °C above average in some areas.
By the end of the heatwave, declines in kelp cover were observed along more than 500 kilometres of the south coast, with complete extinction in the northernmost 100 kilometres.
This rate of kelp loss is the most rapid and extensive ever documented in the world, says Thomas Wernberg at the University of Western Australia in Perth, who led the survey.
“It was quite a shock to come back to these diving locations and all of a sudden realise: ‘Wow – this is completely different’,” he says. “When we went up to the northern regions and saw that everything was gone, it was devastating.”
Tropical takeover
The most recent surveying expedition in 2015 found no signs of kelp recovery. Instead of lush temperate-water forests, tropical turf-forming seaweed carpeted the ocean floor, and tropical fish, corals and invertebrates from the north coast of Western Australia had spread south into the newly warmed waters (move the slider below to see the difference).
As sea temperatures continue to rise, kelp forests will retreat further south until they have no more coastline to cling to, while tropical species will take over the old kelp heartlands, says Wernberg.
However, this does not mean that the heat-stressed tropical reefs of the north, such as the Great Barrier Reef, will be able to relocate to cooler climes in the south, he says. Only some species will be able to make the leap.
A kelpless future?
Unpublished research by Alexandra Campbell at the University of New South Wales, Sydney, and her colleagues shows that kelp forests are dying off at similar latitudes on the east coast of Australia.
The parallel findings provide robust evidence that rising sea temperatures are to blame, says Campbell: “Warming waters may have a direct physiological effect on kelp or increase their natural enemies, like pathogens and herbivores.”
The loss of kelp forests is as catastrophic as the demise of the Great Barrier Reef, she adds.
“Underwater kelp forests are like forests on land: they produce oxygen, they capture and sequester atmospheric carbon dioxide, and they provide food and shelter to a huge diversity of fish and other marine organisms,” she says. “Kelp forests receive far less attention than coral reefs, but that needs to change because they are extremely important – we all rely on them.”
Journal Reference: Science, DOI: 10.1126/science.aad8745
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Brugde er den nest største haiarten, og den anses å være en helnorsk haiart. Foto: Wikimedia Commons.Hai
Disse haiene er mest vanlige i norske farvann
Det er faktisk registret et haiangrep på mennesker i norske farvann.Publisert: for 13 timer sidenSist oppdatert: for 11 timer sidenBadesesongen i Norge er godt i gang, og de gamle Haisommer-filmene ruller på norske TV-skjermer. Svært mange mennesker har en irrasjonell frykt for hai, til og med når de bader i farvann hvor det knapt finnes noen store fisk.
I norske farvann finnes det rundt 20 forskjellige haiarter. Den minste er noen titalls centimeter lang, mens den største kan bli over ti meter lang og veie fire tonn. Og i nyere tid er det registrert ett haiangrep i norske farvann.
Nettavisen har snakket med en haiekspert som ramser opp de vanligste haiartene i Norge.
ANNONSEPigghå (Squalus acanthias):
- Det som tradisjonelt blir ansett som en av de mest vanlige haiartene i Norge, er pigghå. Dette er en sterkt utrydningstruet art som følge av kraftig overfiske i det nordøstlige Atlanterhavet på 1950-tallet. Norge var da verdens største pigghåfiskenasjon. Denne arten tåler dårlig fiskepress, sier haiekspert og marinebiologi Fredrik Myhre, som står bak organisasjonen Hjelp Havets Haier, til Nettavisen.
- Pigghåen er en art som blir maksimum to meter lang. Den er fredet for både fritidsfiske og kommersiell fiske.
- Den er ikke farlig, men du skal være forsiktig når du håndterer den hvis du får den på line eller i garn. Den har to giftpigger på ryggfinnene. Og hvis du stikker deg, får du litt ubehag. Piggene er en forsvarsmekanisme for større fisk og andre større haier. Så vær forsiktig når du slipper fanget pigghå ut i vannet igjen.
(Artikkelen fortsetter under bildet).
Bildet ble tatt under organisasjonen Hjelp Havets Haiers årlige dykking med pigghå på Reve ved Jæren i begynnelsen av juli.
Fredrik Myhre / Hjelp Havets HaierSmåflekket rødhai (Scyliorhnius canicula):
- Småflekket rødhai er en litt mindre art som blir maksimalt rundt en meter lang og to kilo tung. Det er en hai som lever hovedsakelig på bunnen. Småflekket rødhai er ganske vanlig å få på kroken i Sør-Norge. Det er også en hai man kan påtreffe når man dykker. Haiarten er kanskje den mest fotogene haien vi har. Den er lang og slank med rød farge og svarte flekker på kroppen, og ansiktet ser nærmest ut som en liten hundevalp.
- Småflekket rødhai spiser krepsdyr, som krabbe og hummer, og små fisk. Den er heller ikke farlig for mennesker, men man skal være forsiktig med å håndtere dem. Faktisk er det eneste haiangrepet som er registrert i Norge, fra en småflekket rødhai. Det var en dykker i Oslofjorden som for ti år siden tok på en småflekket rødhai og ble bitt.
- Det er en påminnelse om at dette er ville dyr, og at man ikke skal plage ville dyr unødvendig. Siden den da spiser krepsdyr, så har den ganske kraftige kjever. Hvis man har fått den på kroken, skal man være litt forsiktig.
- Men den kommer ikke opp og biter deg når du bader.
Marinebiolog Fredrik MyhreFredrik Myhre / Hjelp Havets HaierBrugde (Cetorhinus maximus):
- Brugden er verdens nest største hai. Dette er en ganske formidabel kjempe, og absolutt ikke alle forunt å få se. Brugden er utrydningstruet og fredet mot kommersiell fiske.
Myhre sier at det var mye kommersiell fiske av brugden før i tiden, fordi leveren var så ettertraktet.
- Leveren kan være så mye som en tredjedel av hele dyret. Den ble brukt til å utvinne olje til oljelamper og den ble smurt på skroget til høyhastighetsfly. Så den hadde mange bruksområder.
Myhre sier brugden er i all hovedsak en planktonspiser som kan bli mellom ti og elleve meter lang og veier godt over fire tonn.
Håbrann (Lamna nasus):
- Den som kanskje blir sett på som den mest spektakulære haien, er håbrannen. Den er da et medlem av samme familie som hvithaien, nemlig makrellhaifamilien. Den ser ut som en miniatyr-hvithai.
- Den er også utryddingstuet som følge av overfiske, og er fredet i norske farvann.
Myhre sier håbrannen kan bli opptil tre meter lang og opptil 300 kilo tung. De som havner i fiskegarnet, er som regel mellom én og to meter lange.
- Ser man en miniatyr-hvithai på to meter, er det mange som blir litt foruroligede.
Myhre sier håbrannen ikke er farlig for mennesker. Dessuten er det vanskelige å påtreffe.
- Man skal være veldig heldig hvis man ser en håbrann i levende live. De lever langt ute til havs og ofte på forholdsvis dypt vann, men er på overflaten når de jakter. De beveger seg over store områder. Når man ser den i Norge, er det som regel enten ved oljeplattformer eller så er de døde i garnet.
(Artikkelen fortsetter under bildet).
Håbrann (Lamna nasus).Wikimedia COmmons/NOAAHågjel (Galeus melastomus):
- Hågjel er kanskje den som har finest skinn av alle haiene. Den har en fin marmorering i skinnet sitt. Det er en fisk som lever på forholdvis dypt vann. Det er en fisk både fiskere og dykkere kan påtreffe om natten i norske fjordsystemer, fordi den går grunnere der enn på åpent hav.
Svarthå (Etmopterus spinax):
- Svarthåen er ganske vanlig og er den minste arten vi har i norsk farvann.
Myhre sier at svarthåen er besatt med små selvlysende organ.
- Dette gjør at de kan produsere lys selv og kan lyse opp i mørket. Lysene brukes til kommunikasjon og jakt nede i dybden. Denne arten går også opp på ganske grunt vann i norske fjorder.
Haien er mellom 30 til 40 centimeter lang, med en maksstørrelse på 60 centimeter.
(Artikkelen fortsetter under bildet).
Håkjerring (Somniosus microcephalus).Wikimedia Commons/NOAAHåkjerring (Somniosus microcephalus):
- Håkjerring er en art som det tidligere er drevet en del fiske på. Den kan bli syv meter lang. Håkjerringa spiser sel og er en hai som kan potensielt spise store byttedyr. Den lever veldig dypt på ned til over 600 meter. Oppe ved Svalbard kan den dukke opp på 30 meters dyp, men der er det ikke så mange badegjester. Det er en utpreget dorsk bunnfisk som ikke er farlig for mennesker.
- Det er en art man har liten kunnskap om. Den kan bli i hvert fall 200 år gammel, og kanskje det dobbelte. Det er nok den eldste fisken vi har i norske farvann.
Rundt 20 haiarter i norske farvann
Myhre sier det er opptil 20 haiarter som lever i norske farvann.- Vi har ni arter som vi anser som helnorske og ni-ti arter som vi anser som gjester. De kommer inn på sensommeren eller høsten fra eksotiske farvann. I den forbindelse er både blåhai og makrellhaien blitt nevnt.
(Artikkelen fortsetter under bildet).
Hvithai finnes ikke i norske farvann, men ingen vet hva global oppvarming vil føre til.Wikimedia CommonsHvithai (Carcharodon carcharias):
Det har også blitt spekulert på om den beryktede hvithaien har kunnet ta veien fra tropiske farvann til norske farvann på denne årstiden, men Myhre beroliger med at det ikke finnes noe vitenskapelig bevis for at hvithaien noensinne har vært i norske farvann.
- Men med økte havtemperaturer vet man aldri hva evolusjonen vil bringe med seg. Vi har en del selkolonier langs kysten, og vi har en del økt tilstrømming av blåfinntunfisk. Begge to er normal føde for hvithaien.
Myhre sier at det har blitt gjort observasjoner i Norge hvor man har trodd at det var hvithai.
- Men da har det vært håbrann, sier han.
Blåhai har blitt observert flere ganger i norske farvann.Wikimedia CommonsBlåhai (Prionace glauca):
Blåhaien, imidlertid, har blitt påvist flere ganger i norske farvann. Blant annet ute ved oljeplattformer.
- Kan blåhaien være potensielt farlig, Myhre?
- Ja, men det er vel ikke så mange som svømmer der ute ved oljeplattformene. Den blir ikke ansett som veldig farlig. Angrep fra blåhaien skyldes som regel at mennesker har gjort noe dumt, for eksempel ved å mate hai ved dykking. Andre historier som går ut på angrep fra blåhai, er enten skipsforlis eller flyulykker ute til havs, hvor blodet og andre kroppsvæsker kan framprovosere haiangrep.
- Det er ingen farlige hai i Norge. Det eneste som kan være farlig med hai i norske farvann, er at det er fare for at de forsvinner.
- Man har veldig lite forskning på hai her i Norge, så man har ikke noe gode estimat på noen av artene. Man vet svært lite konkret om hvordan bestandene har utviklet seg de siste ti åre. Hjelp Havets Haier etterlyser forskningsmidler til haiforskning på statsbudsjettet, som må prioriteres av Nærings- og fiskedepartementet og minister Per Sandberg, avslutter Myhre.
Brugden er enorm, men helt ufarlig for mennesker.
Småflekket rødhai (Scyliorhnius canicula).Wikimedia COmmons/Hans Hillewaert
Hågjel (Galeus melastomus)Wikimedia Commons -
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Rising temperatures, Suez Canal widening open the door to invasive species
- Date:
- June 28, 2016
- Source:
- University of Plymouth
- Summary:
- Rising sea temperatures in the Mediterranean are encouraging alien lionfish species to invade and colonize new territories with potentially serious ecological and socioeconomic impacts.
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FULL STORY
A lionfish specimen photographed in the Mediterranean.Credit: Maria PapinikolaRising sea temperatures in the Mediterranean are encouraging alien lionfish species to invade and colonise new territories with potentially serious ecological and socioeconomic impacts.
Evidence collated from divers and fishermen reveals that in the space of a year, the poisonous predators have colonised Cyprus -- and these may be at the vanguard of a pan-Atlantic Ocean invasion following the widening and deepening of the Suez Canal.
The report, published in Marine Biodiversity Records, was written by Mr Demetris Kletou, of the Environmental Research Lab, in Limassol, Cyprus; and Professor Jason Hall Spencer, of the School of Marine Science and Engineering at Plymouth University.
"Until now, few sightings of the alien lionfish Pterois miles have been reported in the Mediterranean and it was questionable whether the species could invade this region like it has in the western Atlantic," says Mr Kletou. "But we've found that lionfish have recently increased in abundance, and within a year have colonised almost the entire south eastern coast of Cyprus, assisted by sea surface warming."
Lionfish are generalist carnivores and can feed on a variety of fish and crustaceans, with large individuals preying almost exclusively on fish. They spawn every four days, year-round, producing around two million buoyant gelatinous eggs per year, which can ride the ocean currents and cover large distances for about a month before they settle.
Their success at invading new territories stems from a combination of factors such as early maturation and reproduction, and venomous spines that deter predators, and they can quickly colonise reefs and reduce biodiversity in the area.
The research team collated information on reported encounters in coastal waters from divers, spearfishers and fishermen, and conducted interviews, gathering photographic and video evidence, and recording the date of the sighting, and the location. In addition, governmental officers of the Department of Fisheries and Marine Research (DFMR) of the Ministry of Agriculture, Rural Development and Environment, in Cyprus, shared information and specimens captured in nets by local coastal fishermen.
The results show that the lionfish P. miles has colonised almost the entire south eastern coast of Cyprus, from Limassol to Protaras in just one year. At least 24 new and confirmed sightings of 19 individuals were recorded, such as three pairs found on a wreck near Cape Kiti.
Professor Jason Hall Spencer said: "Groups of lionfish exhibiting mating behaviour have been noted for the first time in the Mediterranean. By publishing this information, we can help stakeholders plan mitigating action, such as offering incentives for divers and fishermen to run lionfish removal programmes, which have worked well at shallow depths in the Caribbean, and restoring populations of potential predators, such as the dusky grouper. Given that the Suez Canal has recently been widened and deepened, measures will need to be put in place to help prevent further invasion."
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- Date:
- June 8, 2016
- Source:
- Pensoft Publishers
- Summary:
- A new goby fish species was discovered in the southern Caribbean. Living at depths greater than conventional SCUBA divers can access, yet too shallow to interest deep-diving submersibles, the fish will now be known under the common name of the Godzilla goby, referring to its reptilian appearance and proportions.
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Live male specimen of the new Godzilla goby fish (holotype).Credit: Barry Brown; CC-BY 4.0As part of the Deep Reef Observation Project (DROP), initiated by the Smithsonian Institution, a new goby fish species was discovered in the southern Caribbean. Living at depths greater than conventional SCUBA divers can access, yet too shallow to be of interest for deep-diving submersibles, the fish will now be known under the common name of the Godzilla goby.
Its discoverers Drs Luke Tornabene, Ross Robertson and Carole C. Baldwin, all affiliated with the Smithsonian Institution, have described the species in the open access journal ZooKeys.
Formally called Varicus lacerta, the species name translates to 'lizard' in Latin and refers to the reptilian appearance of the fish. Its prime colors are bright yellow and orange, while the eyes are green.
The new goby also has a disproportionately large head and multiple rows of recurved canine teeth in each jaw. This is also why the research team has chosen the common name of the Godzilla goby.
Apart from its lovely coloration, the new fish stands out with its branched, feather-like pelvic-fin rays and the absence of scales.
The scientists caught the Godzilla goby thanks to the manned submersible Curasub, which had already helped in discovering several species over the course of the project. Last year, Drs Ross Robertson and Carole Baldwin had another new goby published in ZooKeys. That time, they even named it after the submersible. Earlier this year, the DROP team also described nine additional new species, many of which were collected by the Curasub.
The manned submersible Curasub reaches depths up to 300 m in search of tropical marine fishes and invertebrates. As a result, it provides new information on the fauna that inhabits poorly studied deep-reef ecosystems.
The sub relies on two hydraulic arms, one equipped with a suction hose, and the other designed to immobilize the fish with an anaesthetizing chemical. That way, not only do the researchers gather live specimens, which once collected, are deposited into a vented acrylic cylinder attached to the outside of the sub, but also individuals suitable for critical DNA analyses.
Story Source:
The above post is reprinted from materials provided by Pensoft Publishers. The original story is licensed under a Creative Commons License. Note: Materials may be edited for content and length.
Journal Reference:
- Luke Tornabene, D. Ross Robertson, Carole C. Baldwin. Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean. ZooKeys, 2016; 596: 143 DOI: 10.3897/zookeys.596.8217
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FULL STORY
These Mexican blindcats were discovered in an underwater cave in Texas.Credit: Danté FenolioAn extremely rare eyeless catfish species previously known to exist only in Mexico has been discovered in Texas.
Dean Hendrickson, curator of ichthyology at The University of Texas at Austin, identified the live fish, discovered in a deep limestone cave at Amistad National Recreation Area near Del Rio, Texas, as the endangered Mexican blindcat (Prietella phreatophila). The pair of small catfish, collected by a team in May, have been relocated to the San Antonio Zoo.
The Mexican blindcat, a species that grows to no more than 3 inches in length, is known to dwell only in areas supported by the Edwards-Trinity Aquifer that underlies the Rio Grande basin in Texas and Coahuila. The new blindcat finding lends additional weight to a theory that water-filled caves below the Rio Grande may connect the Texas and Mexico portions of the aquifer.
"Since the 1960s there have been rumors of sightings of blind, white catfishes in that area, but this is the first confirmation," Hendrickson said. "I've seen more of these things than anybody, and these specimens look just like the ones from Mexico."
Jack Johnson, a caver and National Park Service resource manager at Amistad, first spotted some of the slow-moving, pinkish-white fish with no eyes in April 2015. After several attempts to relocate the species, Johnson and biologist Peter Sprouse of Zara Environmental LLC led the team that found the fish again last month. Mexican blindcats are a pale pink color because their blood can be seen through the translucent skin, and they dwell exclusively in groundwater.
"Cave-dwelling animals are fascinating in that they have lost many of the characteristics we are familiar with in surface animals, such as eyes, pigmentation for camouflage, and speed," Sprouse said. "They have found an ecological niche where none of those things are needed, and in there they have evolved extra-sensory abilities to succeed in total darkness."
The Mexican blindcat was originally described in 1954 when found in wells and springs near Melchor Múzquiz in the northern Mexican state of Coahuila. It was subsequently listed as an endangered species by the Mexican government, and as a foreign endangered species by the U.S. Fish and Wildlife Service. Hendrickson led efforts to locate additional blindcat sites in Mexico and Texas for years but only located them in Mexico on previous expeditions.
"Aquifer systems like the one that supports this rare fish are also the lifeblood of human populations and face threats from contamination and over-pumping of groundwater," Johnson said. "The health of rare and endangered species like this fish at Amistad can help indicate the overall health of the aquifer and water resources upon which many people depend."
The fish are not yet on public display. They will be maintained alive in a special facility designed to accommodate cave and aquifer species at the San Antonio Zoo's Department of Conservation and Research.
"The San Antonio Zoo has a series of labs specially designed to keep subterranean wildlife safe and healthy," said Danté Fenolio, vice president of conservation and research at the San Antonio Zoo. "The fact that the zoo can participate now and house these very special catfish demonstrates the zoo's commitment to the conservation of creatures that live in groundwater."
Others involved in the discovery were Andy Gluesenkamp and Ben Hutchins of Texas Parks and Wildlife, Gary Garrett and Adam Cohen of UT Austin and Jean Krejca of Zara Environmental.
The finding brings the number of blind catfish species within the U.S. to three, all found only in Texas. The two other species of blind catfish in Texas, the toothless blindcat (Trogloglanis pattersoni) and the widemouth blindcat (sat** eurystomus), live in part of the Edwards Aquifer complex, the deep Edwards pool below the city of San Antonio.
Story Source:
The above post is reprinted from materials provided by University of Texas at Austin. The original item was written by Christine S Sinatra. Note: Materials may be edited for content and length.
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Ved å studere hjernen hos oppdrettslaks, har forskere funnet ut at en stor gruppe fisk best kan beskrives som kronisk stresset og deprimert.
Normal fisk (øverst) og såkalt «taperfisk» nederst.
Foto: Marco Antonio Vindas- Mer om Oppdrett i Norge
- Publisert i dag, for 55 minutter siden
Enkelte oppdrettsanlegg opplever at 20–25 prosent av laksefiskene blir såkalt «taperfisk». Dette er fisk som spiser lite og som gjerne svømmer til utkanten av merden, med hodet opp og halen ned.
Forsker Marco Vindas forteller at dette er en studie som ikke har blitt gjort tidligere.
Foto: PrivatTaperfisken vokser dårlig, blir forkrøplet, og dør som regel av seg selv innen et par måneder, eller ved at oppdretterne fjerner fisken fra karene.
Den merkelige oppførselen har blitt registeret og rapportert i veterinærrapporter, men fisken har aldri blitt undersøkt fysiologisk i et forsøk på å forstå hva det egentlig er som skjer. Før nå.
– Vi som står bak studien jobber med stressbiologi og nevrobiologi, og har ønsket å forstå noen av mekanismene bak, sier førsteforfatter Marco Vindas, som er tilknyttet universitetet i Göteborg og Uni Research AS i Bergen.
Analyserte hjernen
Ida Beitnes Johansen ved Institutt for Biovitenskap ved Universitetet i Oslo.
Foto: PrivatStudien, som nylig ble publisert i journalen Royal Society Open Science, ble gjennomført under autentiske forhold på et oppdrettsanlegg vest i landet.
«Taperfisk» og normal fisk ble hentet opp, før hjernene deres ble tatt ut og analysert.
– Det vi fant ut var at taperfiskene hadde kronisk forhøyde nivåer av kortisol og serotonin i hjernen, sier Ida Beitnes Johansen ved Institutt for Biovitenskap ved Universitetet i Oslo, som er medforfatter av studien.
- Kortisol er et stresshormon som finnes hos både fisk og mennesker, mens serotonin er en annen vanlig signalsubstans i hjernen.
- Serotonin har mange viktige roller, og regulerer blant annet appetitt og humør. Hos mennesker er serotoninforstyrrelser gjerne forbundet med depresjon.
– Hos oss mennesker ville denne profilen minne om det man finner hos deprimerte mennesker, sier Johansen.
Ida Beitnes Johansen / ForskerFisken virket kronisk stresset og var lite aktiv, nesten deprimert - i den grad fisk kan oppleve depresjon. De samme signalsystemene er forstyrret hos fisken som hos deprimerte mennesker.
Kan være genetisk
Årsaken til at inntil hver fjerde fisk i et oppdrettsanlegg havner i denne tilstanden, er noe som krever videre forskning. Det er likevel nærliggende å tro at forholdene i anlegget spiller inn fordi fisken utsettes for mange unaturlige stressfaktorer i et oppdrettsanlegg.
– Fisken må håndteres, vaksineres og transporteres fra ferskvann til saltvann. Alt dette skjer innenfor et tidsrom på et par måneder. Stresset kan trigge oppførselen hos noen av dem, sier Johansen.
På samme måte som vi mennesker er forskjellig, er også fisken forskjellig. Noen av oss håndterer stress bedre enn andre. Det samme kan gjelde fisken.
– Hvis dette er genetisk betinget, så er det mulig å avle taperfisken bort. Da får man bedre fiskevelferd og et bedre produkt, bemerker Marco Vindas.
Kan ha evolusjonær forklaring
Forsker Ida Beitnes Johansen tror adferden kan ha en evolusjonær forklaring.
– Det blir vår egen spekulasjon, men man kan tenke seg at det i naturen kan være lurt å innta denne adferden for en periode hvis individet utsettes for mye stress eller hvis det er mange predatorer rundt, sier Johansen.
I en oppdrettssituasjon, derimot, er dette ingen gunstig strategi.
Marco Vindas tror videre studier kan bidra til bedre medisiner hos mennesker.
– Dette fordi den fysiologisk profilen er såpass lik den man finner hos deprimerte mennesker.
Har gjennomført tiltak
Informasjonssjef Øyvind André Haram i Sjømat Norge er glad for at dette er noe som det forskes på, og forteller at taperfisk er en utfordring som de har jobbet med i mange år.
– Vi har gjort mange tiltak, og ser at antallet slike fisk har gått nedover i anleggene. Samtidig er det sånn at vi jobber med levende vesener. I naturen overlever ikke alle, og slik vil det nok alltid være.
Hvor stort problemet med taperfisk er hos det enkelte anlegg varierer. Hos noen anlegg er problemet nærmest fraværende. Illustrasjonsfoto.
Foto: Marøy, Terje / SCANPIX
https://www.nrk.no/nordland/den-ene-laksen-er-frisk_-den-andre-er-_stresset-og-deprimert_-1.13014970
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Flytter på seg og så digert at lyden lager bølger i jordens gravitasjonsfelt.
Vitenskapsmenn og -kvinner liker et spennende mysterium like godt som oss andre. Og på oppdrag for å studere strømmene i Det karibiske hav, snublet en ekspedisjon fra Universitetet i Livepool over et virkelig gigantisk ett.
Det karibiske hav dekker om lag 2,8 millioner kvadratkilometer og er 7500 meter på det dypeste.
Teamet fra Liverpool skriver i Geophysical Research Letters at instrumentene deres registrerte noe helt utenom det vanlige, en slags fløytelyd med svært lav tonehøyde - langt utenfor hva det menneskelige øret fanger opp.
I realiteten var lyden så kraftig at den skapte bølger i jordens gravitasjonsfelt.
I tillegg beveget den på seg.
Det var klart at noe av gigantisk størrelse ga seg til å kjenne i havdypet. Spørsmålet var om lyden kom fra noe levende eller om den skyldtes et annet naturlig fenomen, skriver IFL Science.
Godziiiiiiiiilla!
Forskerne fant ut av det.
Og, dessverre, er det ikke krakens verste mareritt som svømmer rundt i havet.
Ved hjelp av en rekke målinger av alt fra trykkforskjeller i havet på grunn av tidevann til satelittmålinger av gravitasjonsvariasjoner fant forskerne ut at lyden kom fra havet selv.
Nærmere bestemt bølgene.
Bølgemønstre i bassenget flater ut i enkelte områder og perioder og forsterkes i andre, avhengig av hvilken retning de går i og hvordan de påvirkes av havbunnen. Resultatet av alt vannet i bevegelse gir et bølgemønster som altså skaper en dyp, dyp lyd i ass (a♭).
- Vi kan sammenlikne aktivitetene i Det karibiske hav med å blåse i en fløyte, sier havforsker Chris Hughes ved Universitetet i Livepool i en pressemelding.
Lyden er en nyoppdagelse, og har fått navnet "Rossby Whistle" etter Rossby-strømmen i Karibhavet.
Her er lyden skrudd opp flere oktaver så den skal være mulig å høre for mennesker:
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(ble guffen cut'n'paste)
Slik gikk lak-risen fem på for Guro (8)
Den fiskemetoden hadde ikke far tro på.
Del torsdag 23. juni 2016(Dagbladet): Guro (8) har vært med far Bjørn Ivar Haugen på fisketurer siden hun var så liten at hun satt i meis på ryggen.
Men det var ikke pappas lærdom som ga en lakserugg på kroken i Gaula nå tirsdag. Snarere tvert i mot.
DET FUNKET:Det tok ikke lang tid før far måtte legge skepsisen til side. Foto: Bjørn Ivar Haugen.
- Vi bor like ved elva, og koser oss stadig med å jakte etter laksen. Og denne ettermiddagen skulle Guro trene med ny snelle og sluk for første gang. Det skulle jo ikke være agn på den. Men hun insisterte på å sette på noe hun trodde fisken likte, sier Bjørn Ivar Haugen til Dagbladet.
Og dermed måtte de ned i godteposen og fiske opp en lakrisbit de egentlig hadde tatt med til seg selv.
- Det hadde jeg ingen tro på. Men da det nappet etter ti minutter og vi dro opp en laks på fem kilo, kom det noen gledeshyl, forteller far.
LIKE FØR LAKRISNAPPET: Guro testet både nytt utstyr og nye agn. Foto: Bjørn Ivar Haugen.
Da var det rett hjem til fryseboksen.
Blåhval neste
- Hun sier hun skal spise den selv. Så kanskje vi andre blir invitert på en smak, sier den rutinerte fiskefaren, som aldri har fått en lakris-laks for egen del.
For Guro var det «bare» den nest største fisken hun har fått.
Hun skal fortsette å agne med lakris utover sommeren. Og er klar på hva som er neste mål:
- Neste gang håper jeg at jeg får en blåhval, sier hun til Adresseavisen, som først omtalte den godtgode fiskehistorie.
Da må hun nok nærmere havet enn fiskeplassen rett for hjemmet.
http://www.dagbladet.no/nyheter/slik-gikk-lak-risen-fem-pa-for-guro-8/60249250
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HAI PÅ DEG: En gjeng mannfolk oppå en hai imponerer verken dyrevenner eller karenes arbeidsgiver. Foto: Facebook/Gary Stokes
Internett raser etter at en gjeng turister dro en hai på land for å ta bilder av den.
LarsBarth-Heyerdahl
17 timer siden
Men i likhet med de fleste andre fisker, klarer ikke haier seg så godt på landjorda. Haien var nemlig død da bildene var tatt og fisken ble returnert til sitt rette element.
Hendelsen skjedde i Den dominikanske republikk i forrige uke. En video som ble postet på Youtube og senere fjernet, viser hvordan en gruppe menn løper ut på stranden før de drar blåhaien på land ved hjelp av tau. Det skriver avisen Independent.
Tommel opp
En badevakt kommer til og trer en livbøye over haiens hode og dytter på den med en planke.
Haien strever febrilsk for å komme seg løs, men med en hel haug staute mannfolk over seg er overmakten for stor. Enkelte av karene løfter halen og viser tommel opp til kamera.
@SeaShepSeattle Hard Rock does not condone this behavior and is taking the situation seriously. Staff involved will face appropriate action.
— Hard Rock Hotels (@HardRockHotels) June 16, 2016Flere av de som er med på bildet, skal være tilknyttet Hard Rock Hotel & Casino i Punta Cana. Bilder av hendelse er lagt ut på Facebook-kontoen til dyrevennen Gary Stokes.
– Fokastelig oppførsel for å underholde turister! Samtidig pågår det et intenst arbeid andre steder i Karibia for å bevare haien, skriver Stokes.
– Tar saken alvorlig
I kommentarfeltene hagler det med kritikk mot Hard Rock og de som poserer på bildene.
– Hva i helvete er det som feiler disse folkene??? Boikott Hard Rock til de gjør det godt igjen, skriver en opprørt Facebook-bruker.
I en Twitter-post understreker Hard Rock Hotels at de ikke støtter slik oppførsel og vil følge opp saken med de involverte.
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Fant nok en liten videosnutt med nye arter fra forskjellige deler i verdens dype hav. Alltid artig å se hvilke overraskelser naturen kaster til oss.
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Til nå i år har Statens Naturoppsyn beslaglagt i overkant av 100 ulovlige garn som er satt ut i norske elver.
Det tilsvarer over 3000 meter med garn, og er en ganske markant økning sammenlignet med samme periode i fjor. Verst står det til i Nordland, Troms og Hordaland.
Seksjonssjef Arnstein Johnsen i Statens naturoppsyn fortviler over at folk setter ulovlige garn.
FOTO: JØTE TOFTAKER / NRK– I verste fall risikerer vi at hele årganger, som skal til en elv som er sårbar, blir tatt ut. Dette kan ikke fortsatte sånn som det er nå i enkelte regioner. Folk bør tenke seg litt om, sier Arnstein Johnsen til NRK.
Han er seksjonssjef for Tilsyn kyst i Statens naturoppsyn og gjør jevnlig inndragninger av ulovlige garn langs kysten.
Selve hovedinnsiget av laks skjer på denne tiden av året, og utviklingen av garntjuvfiske bekymrer.
– Det er et tildels stort antall ulovlig garn som blir inndratt. Samtidig er det forholdsvis store mørketall, påpeker han.
Må stenge elver
I Norge er det forbudt å fiske etter villaks, sjøørret eller sjørøye. Ifølge Johnsen i SNO er antall anmeldelsen for brudd på lakseloven økende.
– Villaksen er en verdifull art som vi alle ønsker å ta vare på, men det irreggulerte fisket ødelegger ganske mye, forklarer Geir Håkon Olsen i Statens Naturoppsyn i Nordland.
Nylig var de ute på en innbringende tokt i Lofoten. 14 ulovlige garn ble beslaglagt i Nappstraumen i Vestvågøy, et område kjent for mye fisk.
(artikkelen fortsetter under bildet)
Geir Håkon Olsen i Statens Naturoppsyn etter en innbringende tokt i Lofoten. På landsbasis er det blitt beslaglagt 40 prosent flere ulovlige garn i år enn på samme tid i fjor.
FOTO: STATENS NATUROPPSYN– På det meste er det opp mot ti laks i garnet når vi beslaglegger det. Ingen av garnene er merket, så de som setter dem ut vet hva de holder på med.
Over halvparten av de rundt 100 lakseelvene i Nordland er for tiden stengt for laksefiske, blant annet som følge av den ulovlige virksomheten, opplyser Miljøvernavdelinga hos Fylkesmannen i Nordland
– Det kommer for lite laks tilbake til disse elvene med tanke på å opprettholde en god gytebestand. Årsaken er selvsagt sammensatt, men ulovlig fiske er helt klart en del av forklaringen, sier seksjonsleder Tore Vatne.
– Hører skrekkhistorier
John Davy Oddekalv i Vestvågøy Jeger og Fiskerforbund peker på gamle tradisjoner som henger igjen.
Vestvågøy Jeger og Fiskerforbunds John Davy Oddekalv tror gamle tradisjoner er noe av forklaringen.
FOTO: PRIVAT– Fra gammelt av hadde mange rett til fiske med både garn og not, og føler at de fremdeles burde ha rett til det. Samtidig er sjansen for å bli tatt liten.
Han hevder ulovlig garnfiske er et utbredt problem i Lofoten.
– Det er flere som fisker for salg, får hundretalls laks og har fryserne fulle. Mange er irriterte, sånn sett er det bra at myndighetene følger med.
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Usually an accidental infection, Australia wants to make the herpes virus into a bioweapon against fish. But they may have good reasons for it.
Australia is famously protective of its impressive biodiversity, and for good reason. The continent is the home of many species of plant and animal that cannot be found anywhere else in the world, and a fair share of them are under threat from outside influences. One of those is European immigrants – of the fish variety.
European carp are not native to Australia, but were brought in by us humans in order to farm the fish. Apart from being a popular ornamental fish, carp can be used as food, hence the efforts to bring the species into Australian fish farms. If they had just stayed there, there wouldn't even be a problem. It just so happens that – through accident and other other means – European carp came to be released into Australian rivers. And there, they thrived.
The BBC reports that the Australian government has had enough of the carp overpopulation damaging the water quality in the Murray-Darling Basin, which estimates say are costing up to AUSD $500 million a year to compensate for. Their solution is to enact a plan they call "Carpageddon", and it involves releasing a strain of the herpes virus into the carp-infested waters.
If that sounds like a mad plan to you, I certainly wouldn't blame you. However:
Science Minister Christopher Pyne said the virus would have no impact on humans, but the clean-up would be costly. Thousands of carp are expected to die after the virus is released.
So on the one hand, there's likely no danger to humans in terms of catching herpes from Australian water. Well, that's good news. On the other, though, there'll be hundreds of thousands of dead fish floating in the water shortly after the plan is enacted. Give and take, I suppose?
http://www.sciencedump.com/content/australia-wants-give-carp-herpes
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By Sandrine Ceurstemont
Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world
Species: the electric eel, Electrophorus electricus. Despite its name, it’s a knifefish not an eel
Habitat: the waters of South AmericaMore than 200 years ago naturalist Alexander von Humboldt recounted seeing electric eels leaping out of the water to attack horses in the Amazon. The locals herded some 30 horses and mules into a small pool provoking the eels to attack – and kill some of the – horses.
The method, he wrote, was used to “fish with horses”, because locals could pick up the exhausted eels safely after the mayhem. But it was thought to be an exaggeration because nobody else had witnessed a similar assault.
Until now, that is. They’ve been filmed leaping out of the water and delivering massive shocks to powerful predators.
Kenneth Catania from Vanderbilt University in Nashville, Tennessee, saw the jumps when he used a metal-rimmed net to transfer eels in his lab. “I was definitely surprised,” he says. “This isn’t something electric eels typically do.”
Electric eels emit electric pulses in water, where they have the choice of two different settings. Using three electric organs that fire at the same time, they release a low voltage to sense their environment but can switch to high power to stun prey or defend themselves.
Batteries included
The electrical organs extend from the rear of the fish’s body up most of its length, leaving a little room in the front for the stomach and other organs. “They are like giant flashlights with a lot of battery packed into their back end,” says Catania.
When the eels lunged at Catania’s net, he initially thought they were simply trying to avoid it. “Sometimes up to half of their body rises out of the water,” he says. “They don’t seem like dexterous animals but they are good at it.”
However he noticed that the eels would deliver high-voltage blasts while keeping their chin in contact with the net during a leap. So he set up an experiment to record the electric pulses by placing a conductive rod in an aquarium.
He then dunked a fake alligator head laced with LEDs into a tank, which would light up if the eels attacked (see video below).
When the eels jumped onto a mock predator, the current it received increased as the eels slithered higher up. Slowing down the videos revealed that the tip of their electric organ always touched their target during a leap.
Off or on
The eels have only a single high-voltage setting, so can’t tweak its power output so instead it seems to be using a trick: delivering the shock directly to a threat, instead of distributing it through water.
The recordings show both voltage and current increasing the higher up the eel slithered.
“It seems clear that the eels are actively keeping contact with their chin to try to target the object they see as a threat,” says Catania.
Catania has previously found that the eels have complex hunting tactics. Emitting a specific pattern of electric pulses can uncover hidden, motionless prey by making muscles twitch involuntarily. Another type of shock hijacks the muscles and blasts the prey to death. The targeted leaping is another example of their sophistication.
“It is a beautiful example of how the eel has evolved a fairly simple behaviour that exploits the basic physics of electricity,” says Bruce Carlson from Washington University in St Louis, who studies how electric fish use sensory information.
Catania thinks the behaviour is an evolved adaption to life in the Amazon, where water retreats during the dry season and leaves eels trapped in small bodies of water and exposed to predators.
Journal reference: PNAS, DOI: 10.1073/pnas.1604009113
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Fant en liten YouTube snutt med 15 forskjellige "farlige" fisker. Ingen spesielt ukjente, men de er samlet i en video.
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By Laura Geggel, Senior Writer | April 18, 2016 10:02am ET
No necks here!Credit: Alex Bruce | Shutterstock.comFish have fins and gills, but they don't have necks. That's partly because it would be difficult to swim quickly with a neck that wagged back and forth in the water.
What's more, anything called a fish, by definition, can't have a neck. The moment a fish-like creature developed a neck, it became classified as another type of animal, experts told Live Science.
The oldest neck on record belongs to Tiktaalik roseae, a creature that lived about 375 million years ago, during the Devonian period. Scientists describe T. roseae as part fish, part tetrapod (a four-limbed animal), said Ted Daeschler, the curator of paleontology at the Academy of Natural Sciences of Drexel University in Philadelphia. [See Images of the Weird Ancient Fish-Like Fossil, Titktaalik]
Instead of necks, fish have a series of bones that connect the skull to the shoulder girdle, which attaches to the fins, Daeschler said.
"The shoulder girdles are those bony elements, like the clavicle and the scapula, that support the front appendage, whether it's a fin or a limb," Daeschler told Live Science. "[In fish] they're connected not always terribly tightly, but it's one solid surface of bone."
Over time, some fish began to change shape. Take, for instance, the lobe-finned fish, which includes the coelacanth — an ancient group thought to be extinct until fishermen rediscovered them off the South African coast in 1938. According to the fossil record, the lobe-finned fishes, over time, lost some of the bones that connected the shoulders to the skull.
Researchers consider the 9-foot-long (2.7 meters) T. roseae a lobe-finned fish, Daeschler said. But it completely lost the bones that connected the skull to the shoulder girdles, and instead developed a neck. This neck likely helped it hunt in shallow, freshwater environments, he said. [Photos: The Freakiest-Looking Fish]
The earliest known neck belongs to Tiktaalik roseae, a transitional animal that's part fish, part four-limbed animal. T. roseae was discovered in 2004 in northern Canada's Ellesmere Island.Credit: Flick Ford Academy of Natural Sciences of Drexel University"[Its neck] allowed the head to move independently from the body," Daeschler said. "That's great if you live in in shallow, swampy areas, where you might need to turn your head quickly to grab prey or to reach up to breathe."
In contrast, without a neck, fish have to move their entire bodies to aim their head in a certain direction.
One fish, two fish
Was Tiktaalik strictly a fish or a tetrapod? "It's in the gray area, which is what's so cool about evolution," Daeschler said.
This gray area lasted about 20 million years as that lineage evolved from lobe-finned fishes to four-limbed amphibians, he said. Scientists call this gray area — when some parts of an animal evolve, but other parts remain in their primitive forms — "mosaic evolution."
Animals with necks had a unique advantage; they could quickly steer their mouth without having to move their entire bodies. In fact, "all of theseearly tetrapods were predators, no doubt about it," Daeschler said.
But many fish are predators, too, and they have been very successful without necks, he said. Moreover, whales and dolphins are thought to have once lived on land before they moved back into the water. Once they became marine animals again, whales and dolphins greatly shortened their neck vertebrae, so that the entire neck is short and rigid instead of being long and flexible.
"The idea there was that long and flexible necks are not great if you'rejetting though the water," Daeschler said. "Your head gets thrown to the side by the pressure. It's better not to have a neck and just be a torpedo and swim forward."
http://www.livescience.com/54430-why-fish-do-not-have-necks.html
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By Mindy Weisberger, Senior Writer | May 4, 2016 02:11pm ET
Australia plans to resort to "viral warfare" to combat invasive European carp.Credit: Dmitrij SkorobogatovThe Australian government recently announced an unusual initiative to eradicate a long-standing animal pest problem.
To rid their streams and rivers of invasive European carp crowding out native freshwater species, officials plan to begin introducing a strain of the herpes virus — Cyprinid herpesvirus 3 (CyHV-3), or "carp herpes" — into fish populations.
In a statement released May 1, Australian Department of Agriculture and Water Resources (DAWR) officials described their National Carp Control Plan, which will be developed over the next two and a half years at a cost of approximately AU$15 million (about US$11.2 million) and potentially deployed by 2018. [Alien Invaders: Photos of Destructive Invasive Species]
Research by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has already determined that the virus kills European carp quickly, and that it does not develop in native fish, in other introduced fish species or in other animals — including humans.
Also known as Koi herpes virus (KHV), this viral infection has only ever been observed as naturally occurring in carp, according to a diagnostic manual published online by the European Union Reference Laboratory for Fish Diseases (EURLFD).
The virus progresses quickly, with the rate of mortality in carp increasing during an outbreak, the EURLFD explained. Inflammation of the organs and gills, and secondary bacterial infection are the primary causes of death in infected fish.
European carp (Cyprinus carpio) are also called common carp or koi. They originated in central Asia but have been introduced in other countries so successfully that they are currently the most widely distributed freshwater fish species on Earth. Carp have been known to reach lengths of 3.9 feet (1.2 meters) and can weigh up to 132 lbs. (60 kilograms). However, on average, they're much smaller and lighter — 1 to 3 feet (0.3 to 0.9 m) and 9 to 11 lbs. (4 to 5 kg).
Carp were first brought to Australia over a century ago, and were designated as a notable aquatic pest species in the 1960s, the DAWR said in a statement. Under the right conditions, carp can breed very rapidly, and their ability to tolerate a range of freshwater conditions — including rivers that are briny or low in oxygen — allowed them to increase dramatically in Australian waters, outcompeting native fish and gaining a presence in every Australian state except the Northern Territory.
In fact, the DAWR estimated that in one freshwater region — the Murray-Darling Basin — carp make up approximately 80 to 90 percent of the resident fish.
But carp herpes could provide an effective means to target the invasive species, according to the DAWR.
"Under optimal conditions, carp herpes virus will kill up to 95 percent of individual carp," DAWR officials said in a statement.
The Australian government considered using carp herpes to combat the invasive fish over a decade ago; years of testing went into determining whether this could be done safely. But before launching the initiative, much more research will be required to test how the virus would be managed, the level of risk involved to amphibians and other animal species, and other possible ecological impacts.
To that end, government officials will collaborate with representatives from environmental groups and the local industry, as well as residential communities that might be affected, DAWR officials said.
http://www.livescience.com/54643-eradicating-australian-carp-using-herpes.html
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By Mindy Weisberger, Senior Writer | May 23, 2016 03:09pm ET
A still frame from drone footage of tiger sharks feeding on a humpback whale carcass, shot by Australian tour company Eco Abrolhos on May 20.Credit: Eco AbrolhosOn May 20, tourists on an Australian cruise witnessed an incredible but gruesome sight: approximately 70 tiger sharks tearing apart the carcass of a humpback whale in Shark Bay.
The tour company, Eco Abrolhos, encountered the bloody scene during the fourth day of a 14-day cruise, as the group traveled near Steep Point, Dirk Hartog Island, according to a post on the company's Facebook page. They used an aerial drone to capture footage of the carnage and shared the video on Facebook, showing scores of tiger sharks circling and ripping into the dead whale, as clouds of gore stained the turquoise water.
The sharks were described as having "a whale of a time."
In an earlier image that Eco Abrolhos shared on Facebook before posting the video, a group of sharks clustered around the whale carcass, close enough to the boat — and the photographer — that they appear no more than an arm's length away.
The video has accrued more than 850,000 views since it was shared on May 21.
Shark Bay is a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site on the western coast of Australia. Its waters, islands and peninsulas cover approximately 5.4 million acres (2.2 million hectares) and host diverse communities of plants, amphibians, land mammals and marine life.
Shark Bay earned its name in 1699, after English explorer William Dampier visited the region and was deeply impressed by the number of sharks he observed there. He also pronounced those sharks to be delicious, according to Australia's Department of Parks and Wildlife.
But in the May 21 video, it was whale that was on the menu. Increasingly, humpback whales and southern right whales have been using Shark Bay as a stopping point along their migratory routes, UNESCO explained in a site description. While the tour guides were unable to tell how the whale got there or describe the circumstances surrounding its death, the sight of the feeding frenzy likely will not be forgotten anytime soon — by the tourists who witnessed it firsthand, or by the hundreds of thousands of people who glimpsed it on video.
http://www.livescience.com/54842-shark-feeding-frenzy-whale.html
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By Charles Q. Choi, Live Science Contributor | May 25, 2016 07:23am ET
On Oct. 1, 2013, a 30-foot-long giant squid washed ashore in the Spanish community of Cantabria.Credit: Enrique Talledo, www.enriquetalledo.comSteeped in mystery, the elusive, deep-sea-dwelling giant squid, with eyes the size of basketballs, may be larger than it has gotten credit for. In fact, the monster cephalopod may grow to be longer than a school bus, researchers say.
Specimens recognizable as giant squid (Architeuthis dux) have been found washed up onshore since at least 1639. However, these sea monsters — which some people say inspired the legend of the giant kraken, though not all scientists agree — are so elusive that they were largely thought to be mythical until they were first photographed alive in their natural environment in 2004.
Ever since giant squid were discovered, there has been considerable speculation as to how large they can get. In a previous analysis of more than 130 specimens, scientists said that none exceeded 42 feet (13 meters) in length. Suggesting that giant squid could grow larger was "a disservice to science," they said. [Release the Kraken! See Photos of Giant Squid]
In 1954, two men in Norway inspected a 30.2-foot-long (9.2 meters) giant squid.Credit: NTNU Museum of Natural History and Archeaology, via Wikimedia CommonsStill, prior studies estimated that hundreds of thousands of giant squid may live in the ocean, which would suggest that there are plenty of chances for giant squid to grow larger than previously suggested, said Charles Paxton, a fisheries ecologist and statistician at the University of St Andrews in Scotland.
Now, a statistical analysis from Paxton suggests that giant squid may plausibly reach 65 feet (20 m) in total length. This new study extrapolated the maximum sizes this species might reach by both examining a variety of categories of data and examining as much data taken directly from specimens of the creature as was available.
"I've been interested in the last few years about investigating the hard science behind sea monsters," Paxton said.
The data Paxton analyzed included 164 measures of mantle (body) length; 39 measures of standard length, which included the lengths of their bodies as well as the lengths of the longest of their arms; and 47 measures of total length, which included the lengths of their bodies as well as the lengths of the tentacles. (Tentacles are squid limbs that often end in teeth and hooks, and are usually significantly longer than squid arms.)
Paxton also examined 46 instances where beak, or mouth, size was measured along with mantle length. He found that beak size could help predict mantle length, confirming previous studies.
All in all, Paxton found that it was statistically plausible that giant squid could have mantle lengths of about 10 feet (3 m) and total lengths of 65 feet, "and that's a conservative analysis," he said.
"I am extrapolating here, and extrapolation can sometimes be a bit sketchy," Paxton said. "But I think these are fairly safe extrapolations. I genuinely think that giant-squid size has been underestimated."
Paxton noted that there are claims that giant squid can grow to be 100 feet (30 m) long. "I don't think giant squid can get that big, but while a measurement of a giant squid total length of 19 meters [62 feet] can be questioned, I'd say it certainly wasn't impossible," Paxton said.
Some scientists have suggested that squid parts may stretch over time, leading to overestimates of the animal's size.
To help resolve that question, "there are people in New Zealand and Spain who fairly regularly collect specimens of giant squid, and I'd like them to see just how stretchy they are postmortem," Paxton said.
Another study, reported in 2015 in the journal PeerJ, suggested that it's human nature to exaggerate the sizes of the ocean's giants. The study found that people overestimate measurements for whales, sharks and squid.
As to why giant squid might grow as large as they do, "perhaps it makes them less likely to be eaten by sperm whales," Paxton said. "It'd be interesting to find out if they do ever reach a size where they cannot ever be eaten by sperm whales."
Paxtondetailed his findings online May 17 in the Journal of Zoology.
http://www.livescience.com/54870-giant-squid-may-be-school-bus-size.html
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Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world
NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana
By Agata Blaszczak-Boxe
Species: Sponge of the Rossellidae family
Habitat: Deep waters off Hawaii, USDeep in the waters off the Northwestern Hawaiian Islands lurks a 3.5-metre-long behemoth – the world’s largest known sponge that could be hundreds, if not thousands, of years old.
Sponges are some of the simplest and most ancient of animals, though they don’t look like animals as we usually know them.
Large ones provide ecosystem services such as filtering seawater, recycling nutrients on reefs and providing habitat for other species, and are estimated to be able to live for more than 2300 years.
Daniel Wagner of the NOAA Papahānaumokuākea Marine National Monument and his colleague spotted the giant, a member of the Rossellidae family, during an expedition to the islands last year.
The sponge was filmed from two remotely operated vehicles during a dive on a ridge at the Papahānaumokuākea site– one of the world’s largest marine conservation areas, containing coral reefs that host more than 7000 marine species.
Images of the sponge taken at a depth of just over 2100 metres revealed that it was 3.5 metres long, 2 metres high and 1.5 metres wide (see video below).
Its huge size trumps the dimensions of the sponge previously recognised as the largest – a colony of Aphrocallistes vastus with respective measurements of 3.4, 1.1 and 0.5 metres found in shallow waters off western Canada.
Rise of a giant
The stable, relatively undisturbed habitat of the conservation site has probably been conducive to the sponge’s unfettered growth.
“A lot of organisms in deep seas grow very slowly, so they need their habitats to remain stable over a long time to be able to grow larger and larger,” Wagner says.
We don’t know exactly how old it is. “Sponges don’t have things like growth rings that can be used to estimate age,” Wagner says. “We do know, however, that several coral species that live at those depths can live to multiple hundred to even a few thousand years: the oldest one is 4500 years. Thus, my best guess is that this is likely a very old sponge on the order of century to millennia.”
The discovery of the sponge at the site underscores the need to protect the area with strict conservation measures, says the team.
Sponges are thought to be some of the earliest animals to have evolved on Earth – perhaps even ancestors of all complex animals. They are also thought to have helped aerate ancient seas, boosting life in the oceans some 750 million years ago.
Most sea sponges feed on single-celled organisms, which they filter from water, but some are more voracious, catching small crustaceans. Dolphins use sponges as tools to help them uncover food on the seabed.
Journal reference: Marine Biodiversity, DOI: 10.1007/s12526-016-0508-z
Read more: Sponge larvae: Your unlikely ancestors
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By Brian Owens
On the march: cuttlefish are masters of all they surveyDavid Wiltshire
Octopuses and their tentacled brethren are taking over the seas, as ocean temperatures climb and humans snaffle up their natural predators.
Zoe Doubleday, a marine biologist at the University of Adelaide in Australia, and her colleagues were studying an iconic local species, the giant Australian cuttlefish, which had been in decline for several years.
Doubleday wanted to see whether it was part of a larger cyclical trend in global populations, so she looked at data from surveys and from cephalopod fisheries and cephalopod bycatch in finfish fisheries between 1953 and 2013.
To her surprise she found a consistent increase in cephalopod populations over the past six decades, in species from all over the world and in every habitat, from the deep ocean to the near-shore shallows.
“When we looked at the data from around the world, it was a different story,” she says. “It wasn’t just about cuttlefish any more.”
Since 2013, the giant Australian cuttlefish has also recovered, and Doubleday thinks the previous drop was part of a natural fluctuation.
The exact cause of the global increase still needs to be pinned down, but there are a couple of strong contenders.
One is that as overfishing reduces the number of fish in the sea and cephalopods benefit from the removal of predators and competitors. Cephalopods are able to adapt quickly to take advantage of new opportunities. “When you clear a garden, the first things that start to grow are weeds. Cephalopods are like that,” Doubleday says.
Rigoberto Rosas-Luis, a biologist at the Laica Eloy Alfaro de Manabí university in Manta, Ecuador, agrees. He says that the huge numbers of juveniles produced by cephalopods, their short life cycle, and the fact that they aren’t very picky eaters make it easy for them to colonise new areas. “A generalist organism is more capable of facing variations in the ecosystem,” he says.
Rising ocean temperatures could also be to their advantage, because higher temperatures are thought to accelerate their life cycle, making it even easier to adapt to changing environmental conditions – as long as the temperatures don’t rise beyond their maximum tolerance, and they can still find enough to eat.
Eat, prey, love
Is the rise of the cephalopods a good thing? No one knows yet. They are voracious predators so their rise could hamper prey species. But they also fall prey to many marine animals themselves as well as providing food for humans, who could benefit from the higher abundance.
Doubleday hopes that this research will be a starting point to begin looking at cephalopod population trends in more detail, and how they relate to the global environment.
“Cephalopods are a bit of a research underdog, compared with other marine animals,” she says. “So I hope we can use this as a springboard to do some more work.”
“It is a good example of how the ecological changes in the world’s oceans are being driven by humans through the long-term effects of fisheries and probably global climate change but to date the latter is less well established,” saysPaul Rodhouse, a biological oceanographer at the British Antarctic Survey. But he adds that the global cephalopod fishery catches seem to have levelled off recently, so it may be premature to declare they are taking over the seas.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.04.002
Read more: Magical morphing jumbo squid are taking over the eastern Pacific
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Okenia rosacea, marching northwardsGary McDonald
By Brian Owens
Unusually warm waters in the Pacific Ocean are driving dozens of species of nudibranch – a photogenic type of sea slug – northward at a surprising pace.
This could signal the beginning of a major climate shift in the region, says Jeffrey Goddard, a marine biologist at the University of California, Santa Barbara.
His team tracked the northernmost sightings of 30 species of nudibranch along the US coast during 2014, when a large portion of the eastern Pacific Ocean was unusually warm – a phenomenon that came to be known as “the blob”.
Nine species were found further north than they had ever been seen before, such as Okenia rosacea – which usually lives south of San Francisco but was seen as far north as Oregon. The rest were spotted at or near the northernmost limits of their known range.Nudibranchs are excellent indicators of shifts in ocean temperatures and currents, Goddard says. They have long-lived planktonic larvae that are easily transported by currents, but fast-growing and short-lived adults. So when you see adults in a new place, you know they arrived recently.
“It’s like they’re waving little semaphore flags, saying ‘hey, we just got here from southern California’,” he says.
Hey, we just got here from southern California!Jeff Goddard
The next question is whether they will stay in their new homes, or retreat as waters cool and currents slow.
Goddard thinks that at least some will stick around, and even move further north during the strong El Niño, which drives powerful northward currents along the coast.
“If the nudibranchs get into those currents they can go for a real ride,” he says – and he has already received “remarkable” reports from as far north as Vancouver Island.
The more important issue is what the nudibranchs could be telling us about the wider climate in the region. Goddard thinks it may be an early indication of a big shift in the Pacific Decadal Oscillation (PDO), a kind of long-term El Niño-like pattern of climate variability. The last time this happened was in 1977.
That shift caused warmer temperatures in the north-west US, fewer storms in the south-east, and reduced precipitation in the west – conditions that persisted for about a decade.
“The last time I saw such an explosion of nudibranchs was in 1977,” Goddard says.
Tamsin Edwards, a climatologist at the Open University in the UK, says it is too early to tell, since changes in the PDO can only be detected through statistical analysis of large amounts of data on ocean surface temperatures.
But she agrees that marine species like nudibranchs are important and sensitive indicators of climate change.
“This is clearly an important piece of evidence for the puzzle of trying to detect and predict global weather and climate patterns like the PDO,” she says.
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Zoologger is our weekly column highlighting extraordinary animals - and occasionally other organisms - from around the world
Shrimp
Shrimp from the dark
Luis Espinasa et al.
Species: Stygobromus allegheniensis
Habitat: Caves throughout the north-eastern US
Deep in the ice caves of the Shawangunk Ridge in New York state lives a tiny crustacean with unique abilities.
Despite being eyeless, it can still detect some wavelengths of visible light. And it has no problem with being frozen solid during the frigid winters.
Luis Espinasa, a cave biologist at nearby Marist College in Poughkeepsie, New York, first came across the 2-centimetre-long shrimp while hiking with his young son Jordi shortly after moving to the area. I was looking for critters in the caves, like I always do, when he called out Hey dad, look at these! recalls Espinasa.
Years later, Jordi decided to study the creatures further for a high-school science class. He wanted to know how the little shrimps survived in the icy home over the winter.
Although there are examples of animals that can survive being frozen solid, few, if any, have been found in caves. Cave dwellers are typically not adapted to freezing, says Espinasa.
They dont usually need to be: most caves, such as the limestone caves where S. allegheniensis is more commonly found, maintain a fairly steady temperature throughout the year.
Life in the freezer
The ice caves, however, are different. They are tectonic, having been formed by faults and cracks in the rock. Snow and cold air enter the caves through openings at the top and are then unable to escape, creating a refrigerated environment in which some of the walls and floors become covered in solid ice.
Experiments in both the field and lab showed that the shrimp were able to survive and return to swimming normally after being frozen in solid blocks of ice for several hours.
Espinasa believes they can probably survive much longer in natural conditions, given that they would have weeks to adjust their physiology in preparation for winter.
Its still not clear how the creature deals with being frozen, but that will be one of the next research steps for the students in Espinasas lab.
Animals generally survive a deep freeze by filling their body with substances such as glycerol, a variety of sugars or amino acids that lower the freezing point of the water inside them, and prevent ice crystals from forming and destroying their cells.
My guess is it is one of the above, says Espinasa. I dont expect well find new physiological chemicals, but you never know.
Frozen solid
Frozen solid
Luis Espinasa et al.
His team also found in tests that the eyeless shrimp could distinguish between light and dark, with the creatures being drawn to the dark a feature known as scotophilia.
Espinasa doesnt know what they use instead of eyes, but early results suggest that the light-detecting structures may be on their heads.
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Sharks survive in the deep seaNOAA Office of Ocean Exploration and Research, Hohonu Moana 2016
Eight dives into the deep waters of the Papahanaumokuakea Marine National Monument of north-west Hawaii have resulted in thousands of samples and images of never-before-seen life and landforms.
In general, the deeper you go in the ocean, the fewer living organisms you find. But during a 4000-metre-deep dive this month, shipboard scientists came across a large aggregation of corals and sponges.
“It was surprising to see a lot of life that deep. It was almost twice as deep as any other high density community in the region,” says Dan Wagner, the biology science lead for this year’s NOAA expedition, part of a three-year project to look at this region that began in 2015. This was the final dive of the expedition, and is only the third below 4000 metres in the region, he says.
Surprises have come with every dive, including the discovery of a previously unknown deep-sea octopus (see video, below). “Because this is the last unexplored place in the world in a way, it’s so common that the creatures we see are new to science,” says expedition coordinator Brian Kennedy.
The 225,000 square kilometre marine monument is one of the most geologically active areas on the planet. This year’s expedition mapped the topography of an unnamed 1400-metre-tall seamount that had never been surveyed.
Sea cucumber spotted swimmingNOAA Office of Ocean Exploration and Research, 2016 Hohonu Moana
Most seamounts are made up of one volcano with a cone or star shape, says geology science lead Johnathan Tree. But this one had a unique structure with several complex ridges buried by two previous underwater eruptions.
“We saw lava flows that were active 100 million years ago, and then we bring a loose rock to the surface,” says Tree. “When it comes up on deck, I’m the very first human to ever touch it.”
The samples are key to determining the geochemistry that leads to the formation of volcanoes like those in the Hawaiian chain, he says.
To explore the deep regions of the marine monument the NOAA team used two remotely operated vehicles tethered together. Each had high-definition cameras with lenses ground to operate under water. “If you try to look at them on deck, they’re a little off. They’re expecting the refraction of the water,” Kennedy says.
Rolling in the deepThe video taken by these cameras has been so spectacular, Wagner says, that close up images reveal features that can only be seen in the laboratory with microscopes.
“Even with the species that are already known to science, we’re seeing them alive in their habitat for the first time,” says Kennedy. “For many deep-sea organisms, as soon as they get warm, they change colour or degrade. These are really dramatic finds and scientists are excited to see them because they have only seen them dead or in distress.”
As expeditions like this are rare, the team streamed the video live from the submersibles to shore-based scientists, who were helping direct the team’s focus while on each dive. “It ensures that we won’t blow by something that might rewrite textbooks just because we didn’t have the right set of eyes watching from the ship,” Tree says.
Find out more about the deep sea: Springtime in the abyss
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World octopus and squid populations are booming
i Artikler & eksterne nyheter
Skrevet
By Patrick MonahanMay. 23, 2016 , 12:00 PM
Wherever humans have changed the environment—and you’d be hard-pressed to find a place we haven’t—there are winners and losers. Cities around the world shelter pigeons, naturally adapted to life on rock ledges. Farms allow weedy plants to thrive between their fields. Oceans—plagued by rising temperatures, depleted fish populations, and acidifying waters brought on by human activity—are no exception. New research shows that these changes to marine environments are leading to a surge of cephalopods, the invertebrate group that includes octopuses, squid, and cuttlefish.
Scientists have noticed a growth in cephalopod catches around the world since the late 1990s. But drawing conclusions from national fisheries data can be tricky. Not only can catch numbers be misreported, but changes in catch amounts can also be influenced by factors that change the amount of time people spend fishing—like the price of fish and the cost of fuel—or by technological advances that allow fishers to catch more. So an increase in cephalopod catch doesn’t necessarily mean there are more cephalopods in the ocean.
To solve this problem, researchers looked for data that would allow them to calculate how much fishers catch over a given time period—a more reliable metric of actual cephalopod population numbers. But finding the data wasn’t easy. Zoe Doubleday, a marine biologist at the University of Adelaide in Australia and lead author of the study, spent months with her team poring over the available literature, persuading international colleagues to track down hard-to-get national fisheries records, and then getting those records translated into English. Combined with 32 scientific surveys, the records gave the researchers 60 years of reliable data.
The conclusion was clear: Cephalopod populations—from New England to Japan—have boomed since the 1950s. And the numbers aren’t limited to species that live in the open ocean, like the Humboldt squid (Dosidicus gigas). Species that live closer to shore, like the elegant cuttlefish (Sepia elegans), have also seen a steady rise in numbers, the researchers report today in Current Biology. Crucially, the increase was seen in both scientific survey data and fisheries records—so it wasn’t just an artifact of technological advances or a growing global hunger for calamari and sushi.
So why are cephalopods, of all things, thriving? Like rodents, cephalopods are highly adaptable to changes in their environment, researchers say—in large part because most species live just 1 or 2 years, dying as soon as they give birth. That allows them to respond rapidly to disturbance. “We refer to them as the weeds of the sea,” jokes Gretta Pecl, a marine biologist at the University of Tasmania in Australia who wasn’t involved with the study.
Pegging the increase in cephalopod numbers to any one factor is tough, although the 60-year timescale points to human influence: Natural ocean cycles are shorter, and so can’t be responsible. But there are many avenues by which humans could tip the balance. Fishing is one potential culprit: By catching fish that eat cephalopods or compete with them for food, humans create gaps in the food chain for these adaptable creatures to fill. Climate change is another: Rising temperatures can speed up cephalopods’ already rapid growth rates, making them have babies more quickly, which in turn speeds up the growth of populations. But until more research is done, Doubleday says, “it’s all speculation, what’s causing them to increase.”
No matter what the cause, the change could have far-reaching effects on the ocean. Faster growth rates also mean that cephalopods will eat more—and they’re already voracious eaters, with some species eating 30% of their body weight each day as adults, according to Pecl.
“This is not a sensational ‘cephalopods are taking over the world’s oceans’ story,” says Paul Rodhouse, a biological oceanographer with the British Antarctic Survey in Cambridge, U.K. Further climate change could have unpredictable effects, squeezing generation times to less than a year and throwing off some species’ annual mating gatherings in the process. And along with the threat of continued fishing by humans, Doubleday notes that many cephalopods are cannibals. “There’s always competition stabilizing things,” she says. “I don’t know whether we’ll eat them first or they’ll start eating each other.”