NEWSLETTER 5/2010 19. Mai 2010
- · Dr. Susan Turner, School of Geosciences, Monash University, Clayton, Victoria, Australia (Homepage)
- · Dr. Dimitrios Damalas, Hellenic Center for Marine Research, Institute of Marine Biological Resources, Athens, Greece, e-mail: firstname.lastname@example.org
- · Dr. Tristan Guttridge, University of Leeds, Leeds, United Kingdom (Homepage)
- · K.V. Akhilesh, Central Marine Fisheries Research Institute, Kochi, Kerala, India (Homepage)
- · Dr. Christine Dudgeon, Cetacean Ecology and Acoustics Laboratory, School of Veterinary Sciences, University of Queensland, Brisbane, Australia
- · Ana Verissimo, Department of Fisheries Science, Virginia Institute of Marine Science, Gloucester Point, USA
- · Dott. Alessandro De Maddalena, President of the Italian Ichthyological Society, Milano, Italy (Homepage)
- · Julia Spät, Boston University/Woods Hole Oceanographic Institution joint program, Shark Sensory Lab, Woods Hole Oceanographic Institution, Woods Hole, USA
- · Dr. Cristina Rodríguez-Cabello, Centro Oceanográfico de Santander, Santander-Cantabria, Espanna (Homepage)
- · Dr. Alexandre Aires-da-Silva, Inter-American Tropical Tuna Commission, La Jolla, California, USA
- · Dr. E. Vivekanandan, Principal Scientist & Head Demersal Fisheries Division, Central Marine Fisheries Research Institute, Cochin, India (Homepage)
15.15.2010: 721 new data, 201 new analysed papers
01.05.2010: 86 new data, 176 new analysed papers
Currently this database contains 8.131 papers (5.677 about recent sharks, rays and chimaeras, 2.454 about fossil sharks, rays and chimaeras). Out of this 8.131 papers, 4.062 papers had been evaluated, and there is the possibility of free downloading 1.092 papers.
ICES Annual Science Conference 2010
Elasmobranch Fisheries: Developments in stock assessment, technical mitigation and management measures
All abstracts must be received on or before Thursday 15 April 2010
Early registration opens March 2010
Early registration deadline Tuesday 31 August 2010
The II Colombian Meeting on Chondrichthyans
16-20 August 2010
The deadline for abstracts is May 14, 2010.
Further information on the Meeting is on the SQUALUS FOUNDATION website (www.squalus.org).
The IEG is pleased to announce that it will be hosting the 14th Annual European Elasmobranch Association Conference in Galway, 10th-13th November 2010. This international conference is a key feature on the EEA calendar and an opportunity to showcase the elasmobranch research currrently being undertaken in Ireland, Europe and further afield.
This is the first time the EEA conference has been held in Ireland and we look forward to giving you a warm welcome to Galway. For further information check out EEA 2010. More information will be added regularly.
EEA 2010 – Abstract submission open
Abstract submission is now open for the EEA 2010 scientific conference. Abstract submission closes 31st May so don’t delay and get your abstracts submitted today.
Click here for the abstract submission page.
NEW FUNCTION OF THE WEBSITE:
Now it is possible to use only the check-boxes (e.g.: use only the box “only download” or use the box “select year”)
HAMM, S.A. (2010); The Late Cretaceous shark Ptychodus marginalis in the Western Interior Seaway.; Journal of Paleontology, 84 (3): 537-547
HAMM, S.A. (2010); The Late Cretaceous shark, Ptychodus rugosus, (Ptychodontidae) in the Western Interior Sea.; Transactions of the Kansas Academy of Science, 113 (1/2): 45-55
FISCHER, J. & SCHNEIDER, J.W. & RONCHI, A. (2010); New hybondontoid shark from the Permocarboniferous (Gzhelian–Asselian) of Guardia Pisano (Sardinia, Italy).; Acta Palaeontologica Polonica, 55 (2): 241-264
SHIMADA, K. & TSUIHIJI, T. & SATO, T. & HASEGAWA, Y. (2010); A Remarkable Case of a Shark-Bitten Elasmosaurid Plesiosaur.; Journal of Vertebrate Paleontology, 30 (2): 592-597
KUBA, M.J. & BYRNE, R.A. & BURGHARDT, G.M. (2010); A new method for studying problem solving and tool use in stingrays (Potamotrygon castexi).; Animal Cognition: 13 (3): 507-513
McCAULEY, D.J. & PAPASTAMATIOU, Y.P. & YOUNG, H.S. (2010); An Observation of Mating in Free-Ranging Blacktip Reef Sharks, Carcharhinus melanopterus.; Pacific Science, 64 (2): 349-352
BARBUTO, M. & GALIMBERTI, A. & FERRI, E. & LABRA, M. & MALANDRA, R. & GALLI, P. & CASIRAGHI, M. (2010); DNA barcoding reveals fraudulent substitutions in shark seafood products: The Italian case of “palombo” (Mustelus spp.).; Food Research International, 43 (1): 376-381
WILGA, C.D. (2010); Hyoid and pharyngeal arch function during ventilation and feeding in elasmobranchs: Conservation and modification in function.; Journal of Applied Ichthyology, 26 (2): 162-166
DAMALAS, D. & MEGALOFONO, P. (2010); Environmental effects on blue shark (Prionace glauca) and oilfish (Ruvettus pretiosus) distribution based on fishery-dependent data from the eastern Mediterranean Sea.; Journal of the Marine Biological Association of the United Kingdom, 90: 467-480
GUTTRIDGE, T.L. & GRUBER, S.H. & KRAUSE, J. & SIMS, D.W. (2010); Novel Acoustic Technology for Studying Free-Ranging Shark Social Behaviour by Recording Individuals’ Interactions.; PLoS ONE, 5 (2): e9324
SAWADA, T. & INOUE, S. (2010); Ultrastructure of irregular collagen fibrils of shark mandible.; Acta Zoologica (Stockholm), in press
VERÍSSIMO,A. & McDOWELL, J.R. & GRAVES, J.E. (2010); Global population structure of the spiny dogfish Squalus acanthias, a temperate shark with an antitropical distribution.; Molecular Ecology, 19 (8): 1651-1662
PORTNOY, D.S. & McDOWELL, J.R. & HEIST, E.J. & MUSICK, J.A. & GRAVES, J.E. (2010); World phylogeography and male-mediated gene flow in the sandbar shark, Carcharhinus plumbeus.; Molecular Ecology, 19 (10): 1994-2010
ALLEN, G.R. & DUDGEON, C.L. (2010); Hemiscyllium michaeli, a new species of Bamboo Shark (Hemiscyllidae) from Papua New Guinea.; Aqua, International Journal of Ichyology, 16 (1): 19-30
LAST, P.R. & WHITE, W.T. & PUCKRIDGE, M. (2010); Neotrygon ningalooensis n. sp. (Myliobatoidei: Dasyatidae), a new maskray from Australia.; Aqua, International Journal of Ichyology, 16 (2): 37-50
SPAET, J.L.Y. & KESSEL, S.T. & GRUBER, S.H. (2010); Learned hook avoidance of lemon sharks (Negaprion brevirostris) based on electroreception and shock treatment.; Marine Biology Research: in press
MURADO, M.A. & FRAGUAS, J. & MONTEMAYOR, M.I. & VAZQUEZ, J.A. & GONZALEZ, P. (2010); Preparation of highly purified chondroitin sulphate from skate (Raja clavata) cartilage by-products. Process.; Biochemical Engineering Journal, 49 (1): 126-132
PIOVANO, S. & CLO, S. & GIACOMA, C. (2010); Reducing longline bycatch: The larger the hook, the fewer the stingrays.; Biological Conservation, 143 (1): 261-264
PADILLA-MORALES, L.F. & MORALES-PEREZ, C.L. & DE LA CRUZ-RIVERA, P. & LOPEZ-CRUZ, L.M. & ASMAR-ROVIRA, G. & STEVENS, R. & QUESADA, O. & LASALDE-DOMINICCI, J.A. (2010); Efficient Isolation and Characterization of Nicotinic Acetylcholine Receptor from Torpedo Californica using Lipid Analog.; Biophysical Journal, 98 (3): 132a-133a
SPRINGAUF, A. & GRUNDER, S. (2010); Characterization of Shark ASIC1b, an Ancient Form of an Acid-Sensing Ion Channel.; Biophysical Journal, 98 (3): 702a-702a
WILLIAMS, E.H. & BUNKLEY-WILLIAMS, L. & EBERT, D.A. (2010); An accidental attachment of Elthusa raynaudii (Isopoda, Cymothoidae) in Etmopterus sp. (Squaliformes, Etmopteridae).; Acta Parasitologica, 55 (1): 99-101
HEOK HEE NG & HEOK HUI TAN & DARREN C. J. YEO & PETER K. L. NG (2010); Stingers in a strange land: South American freshwater stingrays (Potamotrygonidae) in Singapore.; Biological Invasions, (): in press
TORRES-ROJAS, Y.E. & HERNÁNDEZ-HERRERA, A. & GALVÁN-MAGAÑA, F. & ALATORRE-RAMÍREZ, V.G. (2010); Stomach content analysis of juvenile, scalloped hammerhead shark Sphyrna lewini captured off the coast of Mazatlán, Mexico.; Aquatic Ecology, 44 (1): 301-308
PETHYBRIDGE, H. & DALEY, R. & VIRTUE, P. & NICHOLS, P. (2010); Lipid composition and partitioning of deepwater chondrichthyans: inferences of feeding ecology and distribution .; Marine Biology, 157 (6): 1367-1384
MULLEY, J.F. & HOLLAND, W.H. (2010); Parallel retention of Pdx2 genes in cartilaginous fish and coelacanths.; Molecular Biology and Evolution, in press
LIM, D.D. & MOTTA, P. & MARA, K. & MARTIN, A.P. (2010); Phylogeny of hammerhead sharks (Family Sphyrnidae) inferred from mitochondrial and nuclear genes.; Molecular Phylogenetics and Evolution, 55 (2): 572-579
New Hammerhead Study Shows Cascade of Evolution Affected Size, Head Shape
May 18, 2010
The ancestor of all hammerhead sharks probably appeared abruptly in Earth's oceans about 20 million years ago and was as big as some contemporary hammerheads, according to a new study led by the University of Colorado at Boulder.
But once the hammerhead evolved, it underwent divergent evolution in different directions, with some species becoming larger, some smaller, and the distinctive hammer-like head of the fish changing in size and shape, said CU-Boulder Professor Andrew Martin of the ecology and evolutionary biology department.
Sporting wide, flattened heads known as cephalofoils with eyeballs bulging at each end, hammerhead sharks are among the most recognizable fish in the world. The bizarre creatures range in length from about 3 feet up to 18 feet and cruise warm waters around the world, Martin said.
In the new study, scientists focused on the DNA of eight species of hammerhead sharks to build family "gene trees" going back thousands to millions of generations. In addition to showing that small hammerheads evolved from a large ancestor, the team showed that the "signature" cephalofoils of hammerheads underwent divergent evolution in different lineages over time, likely due to selective environmental pressures, said Martin.
The team used both mitochondrial DNA passed from mother to offspring and nuclear DNA -- which is commonly used in forensic identification -- to track gene mutations. The researchers targeted four mitochondrial genes and three nuclear genes, which they amplified and sequenced for the study.
"These techniques allowed us to see the whole organism evolving through time," Martin said. "Our study indicates the big hammerheads probably evolved into smaller hammerheads, and that smaller hammerheads evolved independently twice."
A paper on the subject was published in this month's issue of Molecular Phylogenetics and Evolution. Led by former CU-Boulder ecology and evolutionary biology undergraduate student Douglas Lim, co-authors included Martin and University of South Florida researchers Philip Motta and Kyle Mara. Lim is currently a student at the University of Colorado School of Medicine. The National Science Foundation funded the study.
The researchers sampled hammerheads from across the globe -- including the waters of the southeast United States now under siege by the Gulf oil spill -- as well as Australia, Panama, Hawaii, Trinidad and South Africa. Most of the hammerhead DNA was obtained at local markets, where the peddling of sharks and other fish is common practice.
The team sequenced the DNA of the sharks, constructing a "phylogenetic" tree that shows how all of the species are related and when each species originated, said Martin. The hammerhead ancestor probably lived in the Miocene epoch about 20 million years ago.
The team found that two divergent lineages of small sharks about 3 to 4 feet long originated independently at separate times in the past. One of the species, the winghead shark, now lives in the warm waters north of Australia and the other, the bonnethead shark, inhabits the Caribbean and tropical eastern Pacific Ocean.
One reason for the "incredible shrinking shark" over the eons may be the process of neoteny -- the ability of some adult sharks to retain juvenile traits -- or their ability to achieve sexual maturity at earlier ages, Martin said. "As the sharks became smaller, they may have begun investing more energy into reproductive activities instead of growth."
While the cephalofoils appear to provide "lift" to large hammerheads as they cruise through the water -- much like the wing of an airplane -- smaller hammerheads don't appear to gain an advantage in lift, but may gain other attributes. "It looks like they sacrifice locomotion advantages for prey detection and visualization," he said.
Another advantage hammerheads may gain from larger cephalofoils is an increased number of electrical sensors in their flattened noses and heads that can detect extremely weak electrical emissions from molecules associated with potential prey. "Hammerheads appear to be able to triangulate on their prey, which is remarkable," said Martin.
Small sharks are highly variable in the size and shape of their cephalofoils, said Martin. The winghead shark, for example, has a laterally expanded head that is about half the size of its roughly 4-foot body length. At the other end of the spectrum is the bonnethead shark, about 3 feet long but which has the smallest cephalofoil of all hammerhead species -- a protrusion that resembles the head of a shovel, Martin said.
Martin said that hammerheads are an ideal biological study subject in part because of some important similarities to humans. Both have slow growth rates, mature late in life, give live birth and have relatively few offspring. While hammerheads may have a dozen or more pups, other oceanic fish regularly lay millions of eggs. Hammerheads generally live for about 30 years, he said.
While hammerhead sharks appear intimidating, attacks on humans are extremely rare, said Martin. Hammerheads have relatively small mouths facing downward that are used to grab food like fish, shellfish, shrimp, squid, octopuses and stingrays. "If you see a hammerhead, I'd say grab your camera and jump into the water," said Martin.
"Hammerheads are special fish, and there is nothing that remotely resembles them anywhere on the planet," said Martin. Unfortunately, hammerheads -- like most shark species -- are on the decline. In addition to being overfished, sharks often are the victims of a technique known as finning, in which fishermen catch them, cut off their fins for use in delicacy soups, and return them to the water to die, Martin said. Shark meat also is used for fertilizer and to make pet food.
There currently are 233 shark species on the International Union for the Conservation of Nature's "Red List of Threatened Species," and 12 shark species are classified as critically endangered. A study led by Virginia Tech showed the great hammerhead, scalloped hammerhead and smooth hammerhead species declined by an average of 90 percent from 1981 to 2005. "Their situation is generally pretty dire," Martin said.
A 2005 study by Martin and his colleagues on scalloped hammerheads indicated females tend to breed in the specific ocean regions where they were born, while males tended to move around more widely. A previous study by Martin's team also showed that male great white sharks roam Earth's oceans much more widely than females, a finding with implications for future conservation strategies for the storied and threatened fish.
Lake-Bed Trails Tell Ancient Fish Story
ScienceDaily (May 6, 2010) — Is it possible to track the movements of an extinct fish in a long-gone lake? It is if you are Emory paleontologist Anthony Martin. He's found that wavy lines and squiggles etched into a slab of limestone found near Fossil Butte National Monument are prehistoric fish trails, made by Notogoneus osculus as it fed along a lake bottom.
He led a detailed analysis, published in PLoS One, that gives new insights into the behavior of the extinct N. osculus, and into the ancient ecology of Wyoming's former Fossil Lake.
"We've got a snapshot of N. osculus interacting with the bottom of a lake that disappeared millions of years ago," Martin says. "It's a fleeting glimpse, but it's an important one."
Fossil Lake, part of a subtropical landscape in the early Eocene Epoch, is now a sagebrush desert in southwestern Wyoming, located in Fossil Butte National Monument and environs. The region is famous for an abundance of exquisitely preserved fossils, especially those of freshwater fish.
Trails left by these fish, however, are relatively rare. The National Park Service had identified about a dozen of them and asked Martin to investigate. Martin specializes in trace fossils, including tracks, trails, burrows and nests made by animals millions of years ago.
One of the fish trace fossils especially intrigued Martin. In addition to apparent fin impressions of two wavy lines, it had squiggles suggesting oval shapes. "The oval impressions stayed roughly in the center of the wavy lines and slightly overlapped one another. I realized that these marks were probably made by the mouth, as the fish fed along the bottom," Martin says.
He then deduced that the trace was likely made by N. osculus -- the only species found in the same rock layer whose fossils show a mouth pointing downward.
Martin brought his detailed notes, photos and sketches of the trace fossil back to Atlanta, where he enlisted the aid of disease ecologist Gonzalo Vazquez-Prokopec and geographer Michael Page, two of his colleagues in Emory's Department of Environmental Studies.
Vazquez-Prokopec, who does digital spatial analyses of geographic patterns of diseases and pathogens, applied similar techniques to the trace fossil data. The results showed a mathematical correlation between the trace impressions and the mouth, tail, pelvic and anal fins of an 18-inch N. osculus.
"This provides the first direct evidence of N. osculus bottom feeding," Martin says. "Not only that, the fish was bottom feeding in the deepest part of the lake. Previous research had suggested that the bottom of the lake had such low levels of oxygen that it was hostile to life. Our analysis indicates that, at least seasonally, some fish were living on the lake bottom."
The scientists were also able to calculate how the fish was moving, and the pitch and yaw of its swimming motion. "The trace fossil lines look simple, but they're not so simple," Martin says, explaining that even the gaps in the lines carry information. "As the British say, 'Mind the gap.'"
"All three of us believe in making scientific data as open and assessable as possible," Martin says, adding that he thinks it may be the first collaboration between a paleontologist, a disease ecologist and a geographer. "This opens up a new technique for studying trace fossils that we hope other people will try and test."
Adapted from materials provided by Emory University.
- Anthony J. Martin, Gonzalo M. Vazquez-Prokopec, Michael Page, Andrew Allen Farke. First Known Feeding Trace of the Eocene Bottom-Dwelling Fish Notogoneus osculus and Its Paleontological Significance. PLoS ONE, 2010; 5 (5): e10420 DOI: 10.1371/journal.pone.0010420
Megalodon Shark Nursery Found
A 10-million-year-old nursery for the extinct megalodon shark has just been found in Panama, according to University of Florida researchers who report their findings in the latest issue of the journal PLoS ONE.
Megalodon, aka "Big Tooth," is thought to have been the world's largest fish and shark. It grew to around 67 feet in length and looked like a heftier great white shark.
(Credit: Niels Stensen)
“The study provides evidence of megalodon behavior in the fossil record,” said lead author Catalina Pimiento, who just completed a master’s degree in zoology from UF and worked in the Florida Museum of Natural History’s vertebrate paleontology division. “Behavior doesn’t fossilize, but we were able to interpret ancient protection strategies used by extinct sharks based on the fossil record.”
Prior suggested fossil shark paleo-nursery areas, the Paleocene Williamsburg Formation and late Oligocene Chandler Bridge Formation of South Carolina, were based only on the anecdotal presence of juvenile teeth accompanied by marine mammals.
“Neither of the collections from previously suggested nursery grounds has been as rigorously analyzed as the specimens in this study, which better supports the presence of this paleo-nursery area,” Pimiento said. She discussed her preliminary findings with Discovery News back in September.
For this latest study, she and her team collected 400 fossil shark teeth between 2007 and 2009 from the shallow marine Gatun Formation, which connected the Pacific Ocean and the Caribbean Sea during the late Miocene Epoch in Panama. Most of the 28 Carcharocles megalodon specimens were surprisingly small, Pimiento said. Further analysis determined the size did not relate to tooth position in the jaw or the size of the species during the late Miocene.
(University of Florida vertebrate paleontology graduate student Dana Ehret measures a juvenile megalodon tooth from the Gatun Formation, Panama, at the Florida Museum of Natural History on the UF campus May 6. Ehret is a co-author of the study that describes the first Neotropical megalodon shark nursery. The four teeth pictured on the right are from the Gatun Formation. The tooth on the far left is an adult megalodon tooth from Florida.
Florida Museum of Natural History photos by Jeff Gage)
( The lateral cuspids shown in this close-up of a juvenile megalodon shark tooth from the Gatun Formation, Panama, are characteristic of older adult Carcharocles species, but are only found occasionally in juveniles.)
( Here Ehret compares the size of a juvenile megalodon tooth from the Gatun Formation, Panama, left, with an adult megalodon tooth from Florida.)
“Our study suggests the specimens represent mostly juveniles with lengths between 2 and 10.5 meters (6.5 to 34.5 feet),” Pimiento said.
Michael Gottfried, associate professor and curator of vertebrate paleontology at Michigan State University Museum, helped review the PLoS ONE article.
"Shark nursery areas are very poorly known, both for living and fossil species," Gottfried said. "If the teeth from Panama described by Catalina and her collaborators do indeed come from a nursery area for the giant megalodon shark, they have the potential to provide a lot of interesting information on the paleobiology of this enormous, but still very enigmatic, fossil
The mystery of why thresher sharks have such huge tails has been solved.
For years, biologists have been unsure why thresher sharks uniquely sport tails that can grow as long as the shark's body.
Now video footage has confirmed their true function: thresher sharks use their huge tails to swat and stun much smaller prey fish.
The discovery explains why thresher sharks are often caught by their tails by baited long-line fishing gear.
Three species of thresher shark swim the oceans: the common thresher (Alopias vulpinus), bigeye thresher (A. superciliosus) and pelagic thresher (A. pelagicus).
Each species has a similar general appearance, including an elongated tail which can extend up to half the total shark's length.
Biologists have guessed that the sharks might use their tails to stun prey.
Thresher sharks are frequently caught by the tail by long-line fishing hooks baited with small fish, or by fishing boats dragging slow-moving lure fish.
There is also a report dating back to 1923 of a thresher shark being observed to use its tail while feeding.
But until now, there has been no documentary evidence proving what the sharks use their tails for.
That was until marine biologist Dr Chugey Sepulveda and colleagues at The Pfleger Institute of Environmental Research in Oceanside, California, US and the University of Massachusetts in Dartmouth, US decided to film thresher sharks feeding in the wild.
To flick or strike?
To do so, the researchers towed a submersible video camera behind a research boat cruising the waters of southern California.
In front of the camera, they towed two baited lines, hoping to lure in common thresher sharks, which commonly feed on dense schools of anchovy and sardine.
Over 27 separate days, the team recorded 650 minutes of footage.
During this time, they filmed 33 common thresher sharks swimming near or approaching the bait.
Remarkably, 14 of the 33 sharks attempted to strike the bait fish with their tails, hitting the fish with a success rate of 65%.The sharks struck with their tails in two distinct ways: either they waggled their body and surged forward, creating a wave down their body that ended in a tail flick, or they positioned their body alongside the bait fish, before making a sideways strike with their tail.
These observations confirm that common thresher sharks use their long caudal fins to pursue and stun their prey, which are then easy to catch, the scientists report in the Journal of Fish Biology.
"The common thresher is for now, the only species that this feeding behaviour has been documented for. But we hypothesise that all three actively pursue prey with their elongate caudal fins," Dr Sepulveda told the BBC.
It also explains why so many thresher sharks are caught by their tail by long-line fisheries, which dangle fish on hooks attached to long drifting fishing lines.
Surviving the hook
The study by Dr Chugey Sepulveda and colleagues was supported by the National Science Foundation, the George T. Pfleger Foundation, the William H. and Mattie Wattis Harris Foundation and the National Oceanic and Atmospheric Administration Bycatch Reduction and Engineering Program.
They are now researching how many thresher sharks caught by recreational fisheries survive.
Fishermen often return sharks after the struggle of the catch, but because threshers tend to be caught by their tails, they have difficult breathing underwater when hooked.
Most sharks breathe by swimming forward, ensuring their gills are ventilated by the water moving over them.
Thresher sharks caught by their tail face the wrong way and are unable to do this, and Dr Sepulveda's initial results suggest more die after release than other shark species.The researchers now hope to encourage fishermen to use more traditional methods that capture thresher sharks by the mouth, which would at least allow the sharks to continue breathing until they are released.