NEWSLETTER 3/2009 14. December 2009
NEW PARTNER:
- Juan Carlos Pérez Jiménez, El Colegio de la Frontera Sur (ECOSUR), Campeche, México
- Hakan Kabasakal, Ichthyological Research Society, Istanbul, Turkey
- Dr. Dominique Delsate, Battincourt, Belgium
- Dr. José Rodrigo Rojas M., Naranjo, Alajuela, Costa Rica
- Prof. John Chamberlain, Department of Geology, Brooklyn College, New York, U.S.A.
- Lewis Barnett, Graduate Group in Ecology, 2148 Wickson Hall, University of California, Davis, U.S.A.
LAST UPDATES:
06.12.2009: 232 new data, 71 new analysed papers
22.11.2009: 173 new data, 134 new analysed papers
NEXT UPDATE:
Sunday, 20. December 2009 (22:00)
NEW FUNCTION OF THE WEBSITE:
Papers about fossil sharks/rays include the keywords "time" and "place". A list of the used keywords you will find here.
NEW PAPERS:
FOSSIL:
GARCÍA, E.X.M. & TELLES-ANTUNES, M. & CÁCERES-BALBINO, A. & RUIZ-MUÑOZ, F. &, CIVIS-LLOVERA, J. 2009
Los tiburones Lamniformes (Chondrichthyes, Galeomorphii) del Plioceno inferior de la Formación Arenas de Huelva, suroeste de la cuenca del Guadalquivir, España. Revista Mexicana de Ciencias Geológicas, 26 (3): 674-686 (Keywords: Neogene (Neogen), Pliocene (Pliozän), Europe (Europa), Spain (Spanien), Carcharias taurus, Alopias aff. vulpinus, Isurus desori, Isurus escheri, Isurus hastalis, Isurus sp., Carcharocles megalodon, Parotodus benedeni)
SHIMADA, K. 2009
The first associated teeth of the Late Cretaceous anacoracid shark, Pseudocorax laevis (Leriche), from the Mooreville Chalk of Alabama. Transactions of the Kansas Academy of Science, 112 (3/4): 164-168 (Keywords: Cretaceous (Kreide), Late Cretaceous (Oberkreide) North America (Nordamerika), Alabama Pseudocorax laevis)
EVERHART, M.J. 2009
First occurrence of marine vertebrates in the Early Cretaceous of Kansas: Champion Shell Bed, basal Kiowa Formation. Transactions of the Kansas Academy of Science, 112 (3/4): 201-210 (Keywords: Cretaceous (Kreide), Early Cretaceous (Unterkreide) North America (Nordamerika), Kansas, Nebraska, Illinois Polyacrodus sp., Carcharias amonensis, Pseudohypolophus mcnultyi, Rhinobatos sp.)
FARRÉS, F. & FIERSTINE, H.L. 2009
First record of the extinct sawfish Propristis schweinfurthi Dames, 1883 (Batoidea: Pristiformes: Pristidae) from the middle Eocene of Spain. Paläontologische Zeitschrift, 83 (4): 459-466 (Keywords: Paleogene (Paläogen), Eocene (Eozän) Europe (Europa), Spain (Spanien) Propristis schweinfurthi)
CIGALA-FULGOSI, F. & CASATI, S. & ORLANDINI, A. & PERSICO, D. 2009
A small fossil fish fauna, rich in Chlamydoselachus teeth, from the Late Pliocene of Tuscany (Siena, central Italy). Cainozoic Research, 6 (1-2): 3-23 (Keywords: Neogene (Neogen), Pliocene (Pliozän) Europe (Europa), Italy (Italien) Chlamydoselachus lawleyi, Chlamydoselachus anguineus, Hexanchus griseus, Echinorhinus richiardii, Centrophorus granulosus, Dalatias licha, Pristiophorus sp., Squatina sp., Carcharias taurus, Odontaspis ferox, Alopias superciliosus, Cetorhinus maximus, Isurus oxyrinchus, Carcharhinus cf. plumbeus, Carcharhinus cf. perezi, Prionace glauca)
GROGAN, E.D. & LUND, R. 2009
Two new iniopterygians (Chondrichthyes) from the Mississippian (Serpukhovian) Bear Gulch Limestone of Montana with evidence of a new form of chondrichthyan neurocranium. Acta Zoologica (Stockholm), 90 (1): 134-151 (Keywords: Carboniferous (Karbon), Early Carboniferous (Unterkarbon) North America (Nordamerika), Montana Rainerichthys zangerli, Papilionichthys stahlae, Rainerichthys, Papilionichthys Rainerichthys zangerli, Papilionichthys stahlae)
GINTER, M. 2009
The dentition of Goodrichthys, a Carboniferous ctenacanthiform shark from Scotland. Acta Zoologica (Stockholm), 90 (1): 152-158 (Keywords: Carboniferous (Karbon), Early Carboniferous (Unterkarbon) Europe (Europa), United Kingdom (England) Goodrichthys eskdalensis)
WANG, N.-Z. & ZHANG, X. & ZHU, M. & ZHAO, W.-J. 2009
A new articulated hybodontoid from Late Permian of northwestern China. Acta Zoologica (Stockholm), 90 (1): 159-170 (Keywords: Permian (Perm), Late Permian (Oberperm) Asia (Asien), China Gansuselache tungshengi Gansuselache Gansuselache tungseni)
LEBEDEV, O.A. 2009
A new specimen of Helicoprion Karpinsky, 1899 from Kazakhstanian Cisurals and a new reconstruction of its tooth whorl position and function. Acta Zoologica (Stockholm), 90 (1): 171-182 (Keywords: Permian (Perm), Early Permian (Unterperm) Asia (Asien), Kazakhstan (Kasachstan) Helicoprion bessonowi)
CIONE, A.L. & MEDINA, F.A. 2009
The oldest hexanchiform shark from Southern Hemisphere (Neoselachii; Early Cretaceous, Antarctica). Antarctic Science, 21 (5): 501-504 (Keywords: Cretaceous (Kreide), Early Cretaceous (Unterkreide) Antarctica (Antarktis) Hexanchiformes)
HAIRAPETIAN, V. & GINTER, M. 2009
Famennian chondrichthyan remains from the Chahriseh section, central Iran. Acta Geologica Polonica, 59 (2): 173-200 (Keywords: Devonian (Devon), Late Devonian (Oberdevon) Asia (Asien), Iran Siberiodus mirabilis, Phoebodus gothicus, Phoebodus gothicus cf. transitans, Phoebodus turnerae, Phoebodus aff. turnerae, Phoebodus typicus, Phoebodus cf. depressus, Thrinacodus tranquillus, Bransonella? sp., Cladodoides sp., Arduodens flammeus, Squatinactis glabrum, Dalmehodus turnerae, Dalmehodus turnerae, Protacrodus sp., Roongodus phijani, Lissodus sp., Cladodont indet., Elasmobranchii gen. et sp., Holocephali gen. et sp. indet. Arduodens, Roongodus Arduodens flammeus, Roongodus phijani)
BIEŃKOWSKA-WASILUK, M. & RADWAŃSKI, A. 2009
A new occurrence of sharks in the Menilite Formation (Lower Oligocene) from the Outer (Flysch) Carpathians of Poland . Acta Geologica Polonica, 59 (2): 235-243 (Keywords: Paleogene (Paläogen), Oligocene (Oligozän) Europe (Europa), Poland (Polen) Heptranchias howelli, Mitsukurina sp., Alopias sp., Cetorhinus sp.)
BOTELLA, H. & DONOGHUE, P.C.J. & MARTÍNEZ-PÉREZ, C. 2009
Enameloid microstructure in the oldest known chondrichthyan teeth. Acta Zoologica (Stockholm), 90 (1): 103-108 (Keywords: Devonian (Devon) Europe (Europa), Spain (Spanien) Leonodus carlsi, Celtiberina maderi)
FISCHER, J. & BUCHWITZ, M. & VOIGT, S. & SCHNEIDER, J.W. 2009
How certain is the assignment of fossil chondrichthyan egg capsule types to potential producer groups? In: Daniela SCHWARZ-WINGS, Oliver WINGS & Franziska SATTLER (Editors); 7th Annual Meeting of the European Association of Vertebrate Palaeontologists: 29 (Keywords: Carboniferous (Karbon) Palaeoxyris, Fayolia, Vetacapsula, Scapellites)
SHIMADA, K. & EVERHART, M.J. & DECKER, R. & DECKER, P.D. 2009
A new skeletal remain of the durophagous shark, Ptychodus mortoni, from the Upper Cretaceous of North America: an indication of gigantic body size. Cretaceous Research, in press: 1-6 (Keywords: Cretaceous (Kreide), Late Cretaceous (Oberkreide) North America (Nordamerika), Kansas Ptychodus mortoni)
SHIMADA, K. & RIGSBY, C.K. & KIM, S.H. 2009
Partial Skull of Late Cretaceous Durophagous Shark, Ptychodus occidentalis (Elasmobranchii: Ptychodontidae), from Nebraska, U.S.A. Journal of Vertebrate Paleontology, 29 (2): 336–349 (Keywords: Cretaceous (Kreide), Late Cretaceous (Oberkreide) North America (Nordamerika), Nebraska Ptychodus occidentalis)
RECENT:
SHIMADA, K. & RIGSBY, C.K. & KIM, S.H. 2009
Labial Cartilages in the Smalltooth Sandtiger Shark, Odontaspis ferox (Lamniformes: Odontaspididae) and Their Significance to the Phylogeny of Lamniform Sharks. The Anatomical Record, 292:813-817 (Keywords: recent (rezent) Odontaspis ferox)
ADRIM, F. & ADRIM, M. (2009)
The first record of a shark of the genus Glyphis in Indonesia. The Raffles Bulletin of Zoology, 57 (1): 113-118 (Keywords: Glyphis sp., Glyphis garricki, Glyphis glyphis)
DÍAZ-ANDRADE, M.C. & GALINDEZ, E.J. & ESTECONDO, S. 2009
The ovary of the bignose fanskate Sympterygia acuta Garman, 1877 (Chondrichthyes, Rajidae) in the Bahía Blanca estuary, Argentina: morphology and reproductive features. Brazilian Journal of Biology, 69 (2): 405-413 (Keywords: Sympterygia acuta)
GUTIÉRREZ-MEJÍA, E. & LARES, M.L. & SOSA-NISHIZAKI, O. 2009
Mercury and Arsenic in Muscle and Liver of the Golden Cownose Ray, Rhinoptera steindachneri, Evermann and Jenkins, 1891, from the Upper Gulf of California, México. Bulletin of Environmental Contamination and Toxicology, 83: 230-234 (Keywords: Rhinoptera steindachneri)
CHAPMAN, D.D. & PINHAL, D. & SHIVJI, M.S. 2009
Tracking the fin trade: genetic stock identification in western Atlantic scalloped hammerhead sharks Sphyrna lewini. Endangered Species Research, 2009: 1-8 (Keywords: Sphyrna lewini)
ORTEGA, L.A. & HEUPEL, M.R. & VAN BEYNEN, P. & MOTTA, P.J. 2009
Movement patterns and water quality preferences of juvenile bull sharks (Carcharhinus leucas) in a Florida estuary. Environmental Biology of Fishes, 84: 361-373 (Keywords: Carcharhinus leucas)
CHANG, J.H. & LIU, K.-M. 2009
Stock assessment of the shortfin mako shark (Isurus oxyrinchus) in the Northwest Pacific Ocean using per recruit and virtual population analyses. Fisheries Research, 98: 92-101 (Keywords: Isurus oxyrinchus)
LUIZ, O.J. & BALBONI, A.P. & KODJA, G. & ANDRADE, M. & MARUM, H. 2009
Seasonal occurrences of Manta birostris (Chondrichthyes: Mobulidae) in southeastern Brazi. Ichthyological Research, 56: 96-99 (Keywords: Manta birostris)
DEAN, M.N. & MULL, C.G. & GORB, S.N. & SUMMERS, A.P. 2009
Ontogeny of the tessellated skeleton: insight from the skeletal growth of the round stingray Urobatis halleri. Journal of Anatomy, 215 (3): 227-372 (Keywords: Urobatis halleri)
McCOMB, D.M. & TRICAS, T.C. & KAJIURA, M. 2009
Enhanced visual fields in hammerhead sharks. Journal of Experimental Biology, 212: 4010-4018 (Keywords: Sphyrna tiburo, Sphyrna lewini, Eusphyra blochii, Negaprion brevirostris, Carcharhinus acronotus)
BARNETT, L.A.K. & EBERT, D.A. & CAILLIET, G.M. 2009
Assessment of the dorsal fin spine for chimaeroid (Holocephali: Chimaeriformes) age estimation. Journal of Fish Biology, 75 (6): 1258-1270 (Keywords: Hydrolagus colliei)
ALMEIDA, M.P. & BARTHEM, R.B. & VIANA, A.S. & CHARVET-ALMEIDA, P. 2009
Factors affecting the distribution and abundance of freshwater stingrays (Chondrichthyes: Potamotrygonidae) at Marajó Island, mouth of the Amazon River. Pan-American Journal of Aquatic Sciences, 4 (1): 1-11 (Keywords: Plesiotrygon iwamae, Paratrygon aiereba, Potamotrygon motoro, Potamotrygon orbignyi, Potamotrygon scobina, Potamotrygon sp.)
MNASRI, N. & BOUMAÏZA, M. & CAPAPÉ, C. 2009
Morphological data, biological observations and occurrence of a rare skate, Leucoraja circularis (Chondrichthyes: Rajidae), off the northern coast of Tunisia (central Mediterranean). Pan-American Journal of Aquatic Sciences, 4 (1): 70-78 (Keywords: Leucoraja circularis)
SCHMIDT, J.V. & SCHMIDT, C.L. & OZER, F. & ERNST, R.E. & FELDHEIM, K.A. & ASHLEY, M.V. & LEVINE, M. 2009
Low Genetic Differentiation across Three Major Ocean Populations of the Whale Shark, Rhincodon typus. PLoS ONE 4(4): e4988. doi:10.1371/journal.pone.000498 (Keywords: Rhincodon typus)
JORGENSEN, S.J. & REEB, C.A. & CHAPPLE, T.K. & ANDERSON, S. & PERLE, C. & VAN SOMMERAN, S.R. & FRITZ-COPE, C. & BROWN, A.C. & KLIMLEY, A.P. & BLOCK, B.A. 2009
Philopatry and migration of Pacific white sharks. Proceedings of the Royal Society of London, Series B, doi: 10.1098/rspb.2009.1155: 1-10 (Keywords: Carcharodon carcharias)
MENDONÇA, F.F. & OLIVEIRA, C. & GADIG, O.B.F. & FORESTI, F. 2009
Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae) on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences. Neotropical Ichthyology, 7 (2): 213-216 (Keywords: Rhizoprionodon lalandii)
McGOWAN, D.W. & KAJIURA, S.M. 2009
Electroreception in the euryhaline stingray, Dasyatis sabina. Journal of Experimental Biology, 212: 1544-1552 (Keywords: recent (rezent), Dasyatis sabina)
NEW ONLINE MEDIA
24 Bulletin of the New Mexico Museum of Natural History are now online and free to download, e.g.:
Bulletin Nr. 27: Late Triassic microvertebrates from the lower Chinle Group
(Otischalkian-Adamanian: Carnian), southwestern U.S.A.
Bulletin Nr. 35: Late Cretaceous Vertebrates from the Western Interior
Bulletin Nr. 37: The Triassic-Jurassic Terrestrial Transition
Bulletin Nr. 41: The Global Triassic
MISCELLANEOUS
HAMMERHEADS' WIDE HEADS GIVE IMPRESSIVE STEREO VIEW
Kathryn Knight
Hammerhead sharks are some of the Ocean's most distinctive residents. ‘Everyone wants to understand why they have this strange head shape,’ says Michelle McComb from Florida Atlantic University. One possible reason is the shark's vision. ‘Perhaps their visual field has been enhanced by their weird head shape,’ says McComb, giving the sharks excellent stereovision and depth perception. However, according to McComb, there were two schools of thought on this theory. In 1942, G. Walls speculated that the sharks couldn't possibly have binocular vision because their eyes were stuck out on the sides of their heads. However, in 1984, Leonard Campagno suggested that the sharks would have excellent depth perception because their eyes are so widely separated. ‘In fact one of the things they say on TV shows is that hammerheads have better vision than other sharks,’ says McComb, ‘but no one had ever tested this’. Teaming up with Stephen Kajiura and Timothy Tricas, the trio decided to find out how wide a hammerhead's field of view is and whether they could have binocular vision (p. 4010).
Hammerheads come in all shapes and sizes so McComb and Kajiura, opted to work with species with heads ranging from the narrowest to the widest. Fishing for juvenile scalloped hammerheads off Hawaii and bonnethead sharks in the waters around Florida, the team successfully landed the fish and quickly transported them back to local labs to test the fish's eyesight.
The team tested the field of view in individual shark's eyes by sweeping a weak light in horizontal and vertical arcs around each eye and recorded the eye's electrical activity. Comparing the hammerheads with pointy nosed species, the team found that the scalloped hammerheads had the largest monocular visual field, at an amazing 182 deg., and the bonnethead had a 176 deg. visual field, which was bigger than that of the pointy nosed blacknose and lemon sharks, at 172 deg. and 159 deg., respectively.
Having collected the animals’ monocular visual fields, the team plotted the visual fields of both eyes on a chart of each fish's head to see whether they overlapped. Amazingly, they did. The scalloped hammerhead had a massive binocular overlap of 32 deg. in front of their heads (three times the overlap in the pointy nosed species) while the bonnet head had a respectable 13 deg. overlap. And when the team measured the binocular overlap of the shark with the widest hammerhead, the winghead shark, it was a colossal 48 deg. The hammerheads' wide heads certainly improved their binocular vision and depth perception.
Finally, the team factored in the sharks' eye and head movements and found that the forward binocular overlaps rocketed to an impressive 69 deg. for the scalloped hammerheads and 52 deg. for the bonnetheads. Even more surprisingly, the team realised that the bonnethead and scalloped hammerheads have an excellent stereo rear-view: they have a full 360 deg. view of the world.
‘When we first started the project we didn't think that the hammerhead would have binocular vision at all. We thought no way; we were out there to dispel the myth,’ says McComb. But despite their preconceptions, the team have shown that the sharks not only have outstanding forward stereovision and depth perception, but a respectable stereo rear view too, which is even better than the TV shows would have us believe.
References
McComb, D. M., Tricas, T. C. and Kajiura, S. M. (2009). Enhanced visual fields in hammerhead sharks. J. Exp. Biol. 212, 4010-4018.[Abstract/Free Full Text]
CSI Sharks: New Forensic Technique Gives Clues About Sharks from Bite Damage
ScienceDaily (Dec. 2, 2009) — Hit-and-run attacks by sharks can be solved with a new technique that identifies the culprits by the unique chomp they put on their victims, according to a University of Florida researcher and shark expert.
In a method analogous to analyzing human fingerprints, scientists can make identifications by precisely comparing shark bites to the jaws and teeth of the powerful predators, said George Burgess, director of the International Shark Attack File, which is housed at UF's Florida Museum of Natural History.
"Every time we investigate a shark attack one of the pieces of information that we want to have is what species was involved and what size it was," he said. "Because I've been looking at shark attack victims for 30 years I can estimate what did the damage, but I have never been able to actually prove it."
Now scientists can say with a degree of certainty whether the beast was a 14-foot tiger shark or a 9-foot bull shark, a distinction that has unforeseen emotional, ecological and even monetary benefits, said Burgess, who collaborated with researchers from the University of South Florida. Their findings are published in the November issue of Marine Biology.
"There's a psychological need for many shark attack victims to know what bit them," Burgess said. "One of the few things shark attack victims have going for them after a bite is bragging rights and the bragging rights include knowing what did the damage."
Because of the hype surrounding shark attacks, off-the-cuff estimates of shark size are often exaggerated, he said. "This will give an actual basis for determining what species was involved and the size, not that that's going to affect the size claimed by the victim in a bar," he said.
Using dried shark jaws from museums and private collections, the researchers were able to identify bite patterns of particular sizes and species of sharks by measuring jaw circumference and the distance between the six frontal teeth on the top and lower jaws, Burgess said. They experimented on 10 to 24 sets of shark jaws for each of the 14 species they analyzed. The technique works not only on human and animal tissue, but also on inanimate objects like surfboards and underground cable lines, he said.
The ability to make predictions from bite patterns is important to understanding the behavioral underpinnings of shark attacks and their prey habits, said lead researcher Dayv Lowry, a biologist with the Washington Department of Fish and Wildlife, who did the work as a graduate student at the University of South Florida.
"Often someone will send us a picture of a dolphin carcass or a sea turtle and want to know what kind of shark bit it," Lowry said. "Knowing that it's a large tiger shark, for example, would help us figure out what large tiger sharks like to eat and how they attack their prey. If an animal or person has been bitten on the rear end, then we know these sharks are likely to sneak up to get their prey instead of facing the victims."
Being able to determine what size shark attacked people in certain geographic areas such as South Africa where offshore nets are used to protect swimmers is valuable because it may influence the size mesh that is used, Lowry said. With larger sharks, beaches can get by with bigger mesh sizes, which are cheaper and less environmentally intrusive, he said.
The technique also has the potential to save thousands of dollars in damages caused by the sharks' penchant for attacking underwater electronic equipment, which includes intercontinental telephone wires, top-secret communication lines between government officials and sensors companies use to uncover oil fields, Burgess said.
Sharks are equipped with organs on the underside of their snouts -- gel filled pits called ampullae of Lorenzini -- that allow them to detect electromagnetic fields from their intended food, Burgess said. Unfortunately, sharks often do not distinguish between the signals sent by prey and equipment, which can be ruined by water seeping in through the bite marks, he said.
"That's one thing that makes them special -- they can sense electro-magnetic fields around their prey items," he said.
Laying cable lines at the bottom of the ocean is extremely expensive, and having to remove a piece, fix it and install it again adds to the cost, Burgess said. "Knowing that a certain species of shark did the damage is useful because in the future cable lines can be placed in a different location, outside the path of that particular shark's area of distribution," he said.
And the ability to determine what size shark was involved in an attack by the size and configuration of its bite marks could result in the installation of a heavier seal designed to withstand damage from that kind of shark, he said.
Story Source:
Adapted from materials provided by University of Florida.
Shark Fins Traced to Their Geographic Origin for First Time Using DNA Tools
ScienceDaily (Dec. 2, 2009) — Millions of shark fins are sold at market each year to satisfy the demand for shark fin soup, a Chinese delicacy, but it has been impossible to pinpoint which sharks from which regions are most threatened by this trade. Now, groundbreaking new DNA research has, for the first time, traced scalloped hammerhead shark fins from the burgeoning Hong Kong market all the way back to the sharks' geographic origin. In some cases the fins were found to come from endangered populations thousands of miles away.
Published online December 1 in the journal Endangered Species Research, the findings highlight the need to better protect these sharks from international trade, a move which will be considered by the Convention on International Trade in Endangered Species (CITES) at its March 2010 meeting in Qatar. The work was led by the Guy Harvey Research Institute and the Save Our Seas Shark Center at Nova Southeastern University and the Institute for Ocean Conservation Science at Stony Brook University.
The U.S. has proposed that CITES list the scalloped hammerhead and five other shark species under the organization's Appendix II, which would require permits for, and monitoring of, all trade in these species across international boundaries. Knowing the species and geographic origin of fins being traded would allow management and enforcement efforts to be allocated more effectively.
"Although we've known that a few million hammerhead shark fins are sold in global markets, we now have the DNA forensic tools to identify which specific hammerhead species the fins originate from, and in the case of scalloped hammerheads, also what parts of the world these fins are coming from," said Dr. Mahmood Shivji, senior author on the paper and Director of the Guy Harvey Research Institute (GHRI) and Save Our Seas Shark Center, both at Nova Southeastern University (NSU) in Florida. "This trade has operated for years and years under the cover of darkness," added lead author, Dr. Demian Chapman, now with the Institute for Ocean Conservation Science at Stony Brook University (SBU) in New York. "Our work shows that the scalloped hammerhead fin trade is sourced from all over the globe and so must be globally tracked and managed."
The new research paper is published in a special theme issue of Endangered Species Research entitled, "Forensic Methods in Conservation Research." Using CSI-like methods known as "genetic stock identification" or GSI, Drs. Chapman and Shivji along with Danillo Pinhal of the GHRI and Universidade Estadual Paulista, Brazil, analyzed fingernail-sized DNA samples from 62 scalloped hammerhead shark fins that had been obtained in the Hong Kong fin market. By examining each fin's mitochondrial DNA sequence -- a section of the genetic code passed down by the mother and traceable to a sharks' regional birthplace -- the researchers were able to exactly match 57 of the 62 fins to an Atlantic or Indo-Pacific ocean origin.
The team also analyzed mitochondrial sequences taken from 177 live scalloped hammerheads in the Western Atlantic and determined that the species is further divided into three distinct stocks in this region: northern (U.S. Atlantic and Gulf of Mexico), central (Belize and Panama), and southern (Brazil). The scientists traced 21 percent of the Hong Kong fins back to these Western Atlantic stocks. Scalloped hammerheads in the region have been categorized as endangered by the IUCN (International Union for the Conservation of Nature) since 2006. This coastal species appears to have collapsed in the western North Atlantic and Gulf of Mexico.
"The premium prices commanded by fins have fueled a global shark hunt of epic proportion," said Dr. Ellen Pikitch, Executive Director of the Institute for Ocean Conservation Science at SBU, which funded a portion of the research. "Earlier work found that up to 73 million sharks are killed annually to supply the fin markets, and approximately 1-3 million are hammerheads," said Dr. Pikitch, who is also a Professor of Marine Science at Stony Brook University. "Inadequate protection, combined with inexorable pursuit, has placed many shark species at grave risk." Just 1 kg (2.2 lbs) of scalloped hammerhead fin can sell for about $US120 at Hong Kong markets due to the large size and high "fin needle" content of this species' fins. Needles are the sought-after portion of the fins, used as thickener in the soup.
"The fact that scalloped hammerhead shark DNA shows strong population DNA signatures means that we can trace the geographic origin of most of their fins sold at markets," Dr. Shivji said. "From a broader perspective, this type of DNA forensic testing of fins will be an incredibly useful tool to prioritize areas for conservation and ensure sharks aren't wiped out in particular regions by excessive fishing."
This study builds upon a DNA test developed in 2005 at the Guy Harvey Research Institute by Dr. Shivji and Debra Abercrombie, a research scientist now with the Institute for Ocean Conservation Science at SBU. The test enabled scientists to rapidly and definitively distinguish between three similar hammerhead species: great, scalloped, and smooth, from fin or meat tissues alone. The new GSI technique takes that DNA test to the next level. GSI has been used to trace some fish, sea turtle and marine mammal catches back to their geographic origin. This study marks its first use with sharks. Dr. Chapman is now working on DNA tools to identify a shark's geographic origins even more precisely, while both he and Dr. Shivji are working on developing GSI for more shark species, including other large hammerheads.
"The international shark fin trade must not continue to operate in secrecy," Dr. Chapman said. "We must use all tools available -- from CITES permitting to DNA tests -- to shed light on this trade and make sure that it does not drive these sharks to extinction." Drs. Pikitch and Chapman plan to attend the CITES meeting in Qatar in March to urge that these sharks be listed under Appendix II to receive better protection from trade.
This research was funded by the Institute for Ocean Conservation Science at SBU, the Guy Harvey Research Institute at NSU and the Save Our Seas Foundation.
Story Source:
Adapted from materials provided by Stony Brook University, via EurekAlert!, a service of AAAS.
Journal Reference:
1. Chapman et al. Tracking the fin trade: genetic stock identification in western Atlantic scalloped hammerhead sharks Sphyrna lewini. Endangered Species Research, 2009 DOI: 10.3354/esr00241
