Fish and aquatic news

The Zoological Society of London (ZSL) has announced their plans to create a cryobank for corals. Corals will be collected from tropical areas and placed in liquid nitrogen at the Whipsnade zoo in Bedfordshire.

“Carbon dioxide emissions are rising fast and are already above the safe level for corals,” said Dr Alex Rogers, head of marine biodiversity at the ZSL. “Some reefs are already beginning to fail and many will die within a few decades. We need a plan B, and freezing them is the best option.”

The idea of creating a coral cryobank stems from similar projects concerning seeds, such as the Svalbard Global Seed Vault where seeds from all over the world are preserved inside a cool cavern on Spitsbergen, north of mainland Norway.

Storing coral for prolonged periods of time without killing them was made possible quite recently thanks to a new method developed by researcher Craig Downs of the Haereticus Environmental Laboratory.

“We can take 1mm-2mm biopsies from coral, freeze them at -200C and thaw them out to regenerate back into a polyp,” says Downs, who is now working with the ZSL. “We are proposing to do this for every species of coral on the planet.”

Roughly 3,350 cold-water corals and about 1,800 tropical coral species are currently know to science. Downs proposes keeping 1,000 samples of each at the zoo.

The Smithsonian Institution in Washington is now discussing setting up their own coral sample facility to alleviate the risks of having just one coral sample storage in the world.

Charlie Veron, former chief scientist of the Australian Institute of Marine Science, said he supported the efforts but warned it was no consolation for the eradication of reefs. According to Veron, endeavours such as cryobanks, genetic make-up preservation, and coral aquariums aren’t meaningful.

“These are not solutions,” says Veron. “Because Australia is home to the biggest coral reef in the world, it should concentrate all its efforts into helping the Great Barrier Reef survive. Personally, I feel it’s no compensation to know that the genetic information of corals is kept in machines.”

An algae bloom stretching from the Olympic Peninsula in Washington state to the northern parts of Oregon has killed thousands of seabirds by stripping them of the natural oils that keep them waterproof. Without these oils, seabirds quickly get wet and succumb to hypothermia.

“This is huge,” says Professor Julia Parrish, a marine biologist who leads a seabird monitoring group at the University of Washington. “It’s the largest mortality event of its kind on the West Coast that we know of.”

Similar mass-deaths have taken place along the coast of California before, but this is the first time it is reported from the states of Oregon and Washington. Also, as far as we know, the California die-offs affected hundreds of seabirds, not thousands.

The so called algae “bloom” consists of tiny single-celled algae of the species Akashiwo sanguinea.

Marine biologists have not been able to determine the reason for the sudden appearance of up to a million Akashiwo sanguinea cells per litre seawater, but recent storms in the area may have contributed to the severity of the problem by breaking up the algae.

When the algae get whipped, it turns into what can best be described as a bubbly soap which sticks to the seabirds.

“It looks like they’re [the seabirds] lying in a sea of bubble bath,” said Greg Schirato, regional wildlife program manager for the Washington Department of Fish and Wildlife.

The Indonesian Navy (TNI AL) has officially announced that they are deploying five warships and one reconnaissance plane to protect the Natuna waters from illegal fishing and poaching.

“The five warships and reconnaissance plane have conducted routine patrols in the Natuna waters as part of efforts to reduce the number of fish thefts,” S.M. Darojatim, Commander of the Main Naval Base IV Commodore, announced Tuesday.

He also stated that the Natuna waters and the South China Sea were vulnerable to a number of criminal offences, including fish and coral thefts.

“The Pontianak naval base has so far secured the West Kalimantan waters well so that it sets a good example to other naval bases to safeguard the Indonesian waters,” said the commander.

Natuna Sea Facts

The Natuna Sea is a part of the South China Sea and home to an archipelago of 272 islands, located between east and west Malaysia and the Kalimantan (the Indonesian portion of the island Borneo). The islands form a part of the Indonesian Riau province and is the northernmost non-disputed island group in Indonesia.

The islands are populated with roughly 100,000 people, most of them farmers and fishermen. The beaches are important nesting sites for sea turtles and the surrounding waters are filled with biodiverse coral reefs. The archipelago is also famous for its rich avifauna with over 70 different described species of bird, including rare ones like the Natuna Serpent-eagle and the Lesser Fish-eagle. The islands are also home to primates, such as the Natuna Banded Leaf Monkey which is considered one of the 25 most endangered primates in the world.

According to geologist James W. Castle and ecotoxicologist John H. Rodgers, both of the Clemson University in South Carolina, toxin-producing algae caused or contributed to the mass extinction of dinosaurs.

After spending two years analyzing data from ancient algal deposits, so called stromatolite structures, the researchers have found evidence that blue-green algae where present in sufficient quantities to kill off countless numbers of plants and animals living in the ocean or on land at the time. Blue-green algae may not seem very harmful, but they produce toxins and deplete oxygen.

Other researchers have suggested that phenomena such as volcanic activity, climate change, sea level changes or asteroids are responsible for the five major extinctions and a number of other significant die-offs during the part of Earths history during which life with skeletons or shells have existed. According to Castle and Rodgers, all these phenomena contributed to the mass deaths but algae was the most important factor.

“The fossil record indicates that mass extinctions… occurred in response to environmental changes at the end of the Cretaceous; however, these extinctions occurred more gradually than expected if caused solely by a catastrophic event,” Castle and Roger argue in their work.

The part of the study that has caused the most debate so far is the warning that current global warming may cause similar die-offs, since our current environmental conditions show significant similarity to times when mass die-offs have occurred.

“This hypothesis gives us cause for concern and underscores the importance of careful and strategic monitoring as we move into an era of global climate change,” Castle and Roger writes, adding that the level of “modern toxin-producing algae is presently increasing, and their geographic distribution is expanding… “

The paper has already gained a lot of attention within the scientific community.

“Scientists from around the world have been sending us data that support our hypothesis and our concern about the future,” says Rodgers. “I look forward to the debate this work will generate. I hope it helps focus attention on climate change and the consequences we may face.”

You can download the entire “Hypothesis for the role of toxin-producing algae in Phanerozoic mass extinctions based on evidence from the geologic record and modern environments” from Clemson University.

http://www.clemson.edu/media-relations/files/articles/2009/2336_295_mass_extinctions.pdf

The work has also been published in the March 2009 issue of the journal Environmental Geosciences.

In order to survive until it becomes a skilled hunter, a shark pups is born with an enlarged “super liver” that functions as a food source for several months.

This new finding have surprised marine scientists, because shark pups were believed to suffer from a high mortality rate because they had to find food immediately after being born.

“They’re much more likely to survive when they’re born than we previously thought,” says Australian Institute of Marine Science researcher Aaron MacNeil.

Unlike live-bearing sea mammals like dolphins and whales, live-bearing shark mothers do not produce milk for their offspring. Until know, researchers assumed that the shark mothers didn’t invest much energy into keeping the offspring alive once it was born, but the new finding changes this perception radically. The shark mother is effectively sending her young off with a liver so packed with energy and nutrients that it keeps the baby fed for several months.

“It is likely that the liver reserves enable the newborn sharks to acclimatize themselves to their environment and to develop their foraging skills,” says lead researcher Nigel Hussey, “We know that large sharks use their livers as an energy store, but we had no idea that the mother provisions her young with additional liver reserves to enhance their survival.”

The research that led to the discovery was carried out by an international team of researchers headed by the Bangor University in Wales.

The annual whale expedition off the Japanese port city of Kushiro ended this weekend after having caught 59 minke whales, the Japanese Fisheries Agency said in a statement.

The whales where caught as a part of a research program that whaling opponents claim is just a cover for commercial whaling. A maximum capture of 60 whales is allowed under this research program, which is authorised by the International Whaling Commission (IWC).

The Fisheries Agency says the goal of the hunt was to study the feeding patterns of the whales and their effect on fish stocks. Initial examination of the stomach contents of the killed mink whales revealed mostly pollack, krill and anchovy. The complete results of the study will be presented at next year’s IWC meeting.

Japan also catches about 1,000 whales in the Antarctic Ocean and the northwest Pacific Ocean each year under another IWC research programme.

Minke Whale Facts

· Once perceived as asingle species, the minke whale population has quite recently been recognized as consisting of two distinct species: the Northern Mink Whale, Balaenoptera acutorostrata, and the Southern Mink Whale, Balaenoptera bonaerensis.

· Also known as Little Piked Whales or Lesser Rorquals, Mink Whales prefer icy waters but are found world-wide.

· Balaenoptera acutorostrata is listed as Least Concern on the IUCN Red List of Threatened Species, while Balaenoptera bonaerensi is listed as Data Deficient since it was recognized as a separate species so recently.

· Together, the two species are believed to form a population of over 1 million Minke Whales world-wide.

Researchers from Emory University have identified the first fish to have switched from ultraviolet vision to violet vision, i.e. the ability to see blue light. This fish in question – a type of scabbardfish – is also the first example of an animal where a deleted molecule has resulted in a change in visual spectrum.

Many species, including humans, have violet vision but our common vertebrate ancestor had UV-vision and could not sense the blue colour spectrum.

All fish studied before the scabbardfish have been found to have UV vision. The scabbardfish is believed to have switched from UV vision to violet vision by deleting the molecule at site 86 in the chain of amino acids that makes up the opsin protein.

“Normally, amino acid changes cause small structure changes, but in this case, a critical amino acid was deleted,” Yokoyama explains.

Vision is of particular interest to evolutionary geneticists since it is a comparatively straight-forward sensory system with a low number of genes involved. Human vision is for instance made possible by no more than four genes.

“It’s amazing, but you can mix together this small number of genes and detect a whole color spectrum,” says evolutionary geneticist and research team leader Shozo Yokoyama. “It’s just like a painting.”

In their study, the Emory researchers linked molecular evolution to functional changes and the possible environmental factors driving them.

“This multi-dimensional approach strengthens the case for the importance of adaptive evolution,” says Yokoyama. “Building on this framework will take studies of natural selection to the next level.”

The Scabbardfish spends most of its life at a depth of 25-100 meters and at these depths UV light is less intense then violet light, something which may have prompted the change in vision. Living deep down in the ocean will however not necessarily make you benefit from a vision switch; the Lampfish has for instance retained its UV vision – most likely because it swims up to the surface at night to feed on translucent crustaceans that are easier to locate if you have UV vision.

“The finding implies that we can find more examples of a similar switch to violet vision in different fish lineages,” says Yokoyama. “Comparing violet and UV pigments in fish living in different habitats will open an unprecedented opportunity to clarify the molecular basis of phenotypic adaptations, along with the genetics of UV and violet vision.”

The article has been published in the October 13 issue of Proceedings of the National Academy of Sciences.

http://www.pnas.org

In addition to evolutionary geneticist Shozo Yokoyama, the research team also included post-doctoral fellow in biology Takashi Tada and post-doctoral fellow in biology and computational chemistry Ahmet Altun.

A research team from the National University of Singapore announced this week that they have created the world’s first semi-cloned fish – a female medaka fish named Holly.

Holly is the result of so called semi-cloning; an approach that leads to the formation of a new and unpredictable combination of genetic traits from both parents, similar to normal fertilization.

The research team also announced that Holly has produced normal offspring that carry a genetic marker also found in her and her parents. According to the team, this indicates that the new technique retains genetic stability.

Holly may aid researchers working with reproductive medicine and technology to find new ways of helping people with infertility problems.

The findings will be published in the October 16 issue of Science Journal.

www.sciencemag.org

Barnacles are capable of attaching themselves to virtually any underwater surface; from whale skin and turtle shells to ship hulls and pier structures. Just how they manage to keep themselves anchored has remained a mystery; a multimillion mystery since barnacles increase fuel consumption by adding additional drag to the submerged parts of marine vessels. Scientists knew that the barnacles used a type of glue, but they didn’t understand how it worked and why it was so strong.

Traditionally, toxic paint has been used to keep the barnacles away but dry-docking huge cargo ships every so often to have them repainted is naturally expensive. Also, the toxic paint is not only affecting the barnacles; it is causing problems for entire ecosystems and many countries have therefore decided to ban or limit the use of some of the most harmful ones.

Using modern techniques such as force microscopy and mass spectrometry, a team of scientists from Duke University’s Marine Laboratory in Durham has now managed to find out how barnacles stick to surfaces; a discovery which they hope will lead to the development of more environmentally friendly anti-barnacle remedies.

The research team unveiled that barnacle glue from the species Amphibalanus amphitrite binds together much the same way as red blood cells bind together when our blood clots. When our blood clot, several different enzymes work together to form protein fibres that bind the cells together. In barnacle glue, similar enzymes - known as trypsin-like serine proteases – do the same thing. Interestingly enough, one of these enzymes are remarkably similar to Factor XIII, and essential blood clotting agent present in human blood.

“We’ve found homologous enzymes in barnacles and humans, which serve the same function of clotting proteins underwater, despite roughly a billion years of evolutionary separation,” says research team member Dr Gary Dickinson.

Another team member, Professor Dan Rittschof, explains that this similarity does make evolutionary sense.

“Virtually no biochemical pathway is brand new. Everything is related and really important pathways are used over and over,” says Rittschof. “Really key parts of those pathways can’t change because if they do, the pathway fails and the animal dies.”

According to Dickinson, it wouldn’t be surprising to find this glue in other organisms besides the barnacles.

“The enzymes are highly conserved because they are very effective at what they do, ” says Dickinson. “There are bound to be a number of other organisms that use the same enzymes for the same purpose.”

For more information, read the article in The Journal of Experimental Biology.

http://jeb.biologists.org

A 10-year study of Rockefeller Wildlife Refuge alligators has yielded some surprising results. Despite having plenty of suitable males to choose among, up to 70 percent of the female gators in this Louisiana refuge preferred to mate with the same male year after another. Also, females who mated with more than one male per breeding season and produced young from multiple fathers usually continued to mate with their select group of males year after year, thus displaying a form of polygamous fidelity.

“Given how incredibly open and dense the alligator population is at RWR, we didn’t expect to find fidelity,” biologist Stacey Lance of the Savannah River Ecology Laboratory in South Carolina said in a press release. “To actually find that 70 percent of our re-trapped females showed mate fidelity was really incredible. I don’t think any of us expected that the same pair of alligators that bred together in 1997 would still be breeding together in 2005 and may still be producing nests together to this day.”

Most reptiles are polygamous and will choose a new mate or mates each breeding season, and only a few reptilian species are known to actively choose the same mate or mates over and over again.

Since the Rockefeller Wildlife Refuge is so densely populated with alligators, researchers don’t think that the repeated pairings are the result of chance.

The study has been published in the journal Molecular Ecology.

http://www3.interscience.wiley.com/journal/117989598/home

According to a new UN report, marine plants take 2 billion tonnes of carbon dioxide away from the atmosphere each year as they use the carbon dioxide for photosynthesis. Most of these plants are plankton, but planktons rarely form a permanent carbon store on the seabed. Instead, mangrove forests, salt marshes and seagrass beds are responsible for locking away well over 50 percent of all carbon that is buried in the sea – an amazing feat when you consider that these types of habitat only comprise 1 percent of the world’s seabed.

“The carbon burial capacity of marine vegetated habitats is phenomenal, 180 times greater than the average burial rate in the open ocean,” say the authors of the UN report.

Mangrove forests, salt marshes and seagrass beds are the most intense carbon sinks on our planet and they store away an estimated 1,650 million tonnes of carbon dioxide per year.

Unfortunately, these habitats are being ruined or damaged worldwide and a third of them are believed to have been lost already, although it is difficult to obtain accurate figures regarding the extent of these types of habitats worldwide. What we do know is that half of the world’s population lives within 65 miles of the ocean and that vegetated ocean near habitats are often under severe pressure.

“On current trends they may be all largely lost within a couple of decades”, said Christian Nellemann, the editor of the report.”

To help developing nations protect the remaining marine vegetated habitats the authors of the report suggest that a fund should be launched. They also wish to have a market place created where oceanic carbon sinks are traded in the same fashion as terrestrial forests.

The report, which has been named Blue Carbon, is a collaboration between the United Nations Environment Programme, the Food and Agriculture Organisation and Unesco.

The National Marine Aquarium in Plymouth, UK has received some attention in the press after chartering a Boeing 767 to fly in a 42-tonne cargo of Caribbean fish for a new exhibition.

The fish – 100 specimens from 18 different species – was purchased from the Ocean World aquarium in Barbados and will arrive to the UK in 19 purpose-built tanks. The sharks, rays and other fish will then be escorted by the police to their new homes in the National Marine Aquarium.

Chartering a Boeing 767 for this type of tropical import costs roughly £100,000, which is almost 160,000 USD.

In most species, a male specimen will usually don’t invest a lot of time or energy in caring for young when there is a good chance that he is not their father. There are how ever exceptions to this rule, such as the Ocellated wrasse.

Yale University researchers studying the breeding behaviour of this Mediterranean fish have found that a male Ocellated wrasse is more likely to care for the offspring when there is grave doubt about who actually fathered them.

The study also showed that female Ocellated wrasse will deposit more eggs in a nest where the nesting male is surrounded by non-nesting “sneaker males”; males who are keen to fertilize the eggs but have no plans ever caring for the offspring. Females will also deposit more eggs in nests where there are already large numbers of offspring.

“Parental male oscellated wrasse are more likely to care for offspring in this sperm-filled  environment than in nests in which there is less sexual competition”, said Suzanne H. Alonzo, assistant professor of ecology and evolutionary biology and co-author of the study.

Even though the caring male has a greater chance of ending up taking care of someone else’s offspring if he allow other males to hang around, he still benefits from having a lot of “sneaker males” near his nest since it will make the females deposit more eggs.

“While our simpler theories have trouble explaining the diversity of what we observe in nature, these patterns do have explanations,” Alonzo said. “The paper suggests we may have oversimplified the evolutionary dynamics of how these things work.”

The paper has been published in the edition of the journal Proceedings of the Royal Society of London. The study was carried out by Suzanne H. Alonzo, assistant professor of ecology and evolutionary biology and Kellie L. Heckman, a postdoctoral fellow in the department.

The Jordanian government has announced its plans to extract over 10 billion cubic feet of water per year from the Red Sea and send most of it to a desalination plant to produce drinking water. The salty wastewater will then be sent from the desalination plant to the Dead Sea by tunnel. Jordanian Water Minister Maysoun Zu’bi says the project will begin as soon as funding has been arranged.

Environmentalists warn that the endeavour could damage the ecosystem of both seas. Mixing two types of saltwater could produce algae blooms in the Dead Sea, and some environmentalists also fear that the extraction of saltwater will increase the Salinity of the Red Sea.

Dead Sea info

The Dead Sea is a salt lake shared by Jordan and Israel. Its surface and shores are 422 meters below sea level, which is the lowest elevation on the Earth’s surface on dry land. With almost 34% salinity, the Dead Sea is one of the saltiest bodies of water in the world and 8.6 times as salty as the ocean.

During recent decades, the Dead Sea as shrunk rapidly, chiefly due to the diversion of incoming water from the Jordan River. The diverted water is used for households, agriculture and industry. In 1970, the Dead Sea was 395 meters below sea level. In 2006, that number had increased to 418 meters.

The Dead Sea level drop has been followed by a drop in groundwater level and large sinkholes have begun to appear along the western shore.

In the ocean, krill live together in swarms, some of them stretching for tens of kilometres. Krill swarms are some of the largest gatherings of life on the planet and this naturally poses some puzzling questions to science: Why are krill living together? How do they find each other? Why are some swarms enormous when others are more moderately sized?

In an effort to shed some light on the mystery, a team of British Antarctic Survey (BAS) researchers headed by Dr Geraint Tarling set out to study the composition and structure of 4525 separate krill swarms in the Scotia Sea. Despite its name, the Scotia Sea is not located close to home for these British scientists – it is a vast expanse of water situated partly in the Southern Ocean and partly in the Atlantic; between Argentina and the Antarctic Peninsula.

Using echo-sounding equipment, the Tarling team tracked down the krill living in this 900,000 km² area and what they found surprised them. According to this new research, krill normally gather into two different types of swarms. The first type is relatively small, typically not exceeding a length of 50 meters and a depth of 4 meters. In this comparatively small type of swarm, the density of krill isn’t very high – you will just find an average of ten krill per cubic meter.

The other type of swarm – dubbed “superswarm” by the researchers – is on the other hand a very densely packed group with up to 100 krill per cubic meter. These dense congregations are the ones that grow really big, often stretching over one kilometre in length and averaging almost 30 meter in depth.

“I was coming at it thinking there might be small swarms tightly packed, and then large swarms that were a bit more diffuse,” says Dr Tarling. “But what we actually found was the opposite. There were small swarms that were quite diffuse and large swarms that were tightly packed.”

This means that a majority of the krill living in the Scotia Sea at any one time will be found within one of just a few enormous superswarms.

“We talking trillions of krill in one aggregation,” explains Dr Tarling. “Ten or 12 swarms could explain 60 or 70% of the biomass in an area the size of the eastern Atlantic. It was astonishing how much biomass could be concentrated into such a small area.”

A fishing flee scooping up a whole swarm of krill may therefore be removing the majority of krill from the Southern Ocean in just one short fishing trip if they happen to target one of the superswarms instead of a small swarm.

How does a superswarm come about?

Although they weren’t able to fully answer this question, Tarling and his colleagues managed to pinpoint certain factors that make superswarms more likely to appear.

“The factors we identified included whether there was more likely to be a lot of food around or not, and when there wasn’t that much food around, they tended to form larger swarms,” says Dr Tarling.

Age is also of importance. The smaller, diffuse swarms typically contained adult krill, while the enormous superswarms consisted of densely packed juvenile individuals.

“Where the animals were less mature, they were more likely to form the larger swarms,” says Dr Tarling, adding that he doesn’t know why.

It might be a question of safety in numbers; it is common among prey animals to live in large groups to reduce the risk of getting eaten, and krill is after all a favoured meal by a long row of sea living creatures.

“All types of swarms are probably to a greater or lesser extent an antipredator response,” Dr Tarling says.

But although living in a swarm reduces the risk of being eaten, it also means having to compete with all the other members of the group for food. Juvenile krill are more buoyant than adults, which mean that they spend less energy swimming. Perhaps this is why adult krill prefers to live in smaller congregations; their negative buoyancy forces them to eat more so they can’t afford living in a huge swarm densely surrounded by competitors.

On the other hand, being in a swarm has been shown to be more energetically efficient than being isolated.

“For a juvenile that wants to grow very quickly, saving energy could be a bonus for them,” says Dr Tarling.

Night-time mystery

As a scientist, you often find yourself in a situation where new findings answer one question but simultaneously create three new ones. One of the new conundrums that Dr Tarling has brought back home from his research trip is the following: Why are superswarms more likely to form at night?

“That is more puzzling for us to explain,” says Dr Tarling. “Up until this point, most polar biologists believed that the swarms dispersed [at night], because that’s the time they feed. When daylight comes they get back into the swarm again for the antipredator benefit. But we found the opposite to that.”

The research has been published in the journal Deep Sea Research I.