NEWSLETTER 6/2010 15. June 2010


NEW PARTNERS:

  • · Catalina Pimiento, Department of Biology, University of Florida, Gainesville, Florida, U.S.A.
  • · Javier Rey, Instituto Espanol de Oceanografía (IEO), Málaga, Spain
  • · Anatoly Velikanov, Head of department of marine biological resources, Sakhalin Research Institute of Fisheries & Oceanography, Yuzhno-Sakhalinsk, Russia

Partner in Google-Maps

 

LAST UPDATES:

29.05.2010: 612 new data, 83 new analysed papers

12.06.2010: 173 new data, 237 new analysed papers


NEXT UPDATE:

Sunday, 27.06.2010

 

STATISTIC:

Currently this database contains 8.916 papers (6.408 about recent sharks, rays and chimaeras, 2.508 about fossil sharks,  rays and chimaeras). Out of this 8.916 papers, 4.382 papers had been evaluated, and there is the possibility of free downloading 1.299 papers.

 

MEETINGS:

ICES Annual Science Conference 2010
20-24 September
Nantes, France
Session E:
Elasmobranch Fisheries: Developments in stock assessment, technical mitigation and management measures
http://www.ices.dk/iceswork/asc/2010/ThemeSessions/Session%20E%20synopsis%20final.pdf
http://www.ices.dk/iceswork/asc/2010/themesessions.asp

All abstracts must be received on or before Thursday 15 April 2010

Early registration opens March 2010

Early registration deadline Tuesday 31 August 2010

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The II Colombian Meeting on Chondrichthyans

16-20 August 2010

Cali (Colombia)


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

EEA conference 2010, Galway, Ireland - 2nd call for abstracts.

The abstract submission deadline has been extended to June 16th.

Click here for the abstract submission page.

NEW PAPERS:

FOSSIL:

PIMIENTO, C. & EHRET, D.J. & MacFADDEN, B.J. & HUBBELL, G. (2010); Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama.; PLoS ONE 5(5): e10552, doi: 10.1371/journal.pone.0010552

FISCHER, J. & VOIGT, S. & SCHNEIDER, J.W. & FRANZ, M. & JOACHIMSKI, M.M. & TICHOMIROWA, M. (2010); Oxygen isotopes from hybodont shark tooth enameloid – Palaeoenvironmental implications for the late Triassic Central European Basin. Abstract; Geophysical Research Abstracts, 12, EGU2010-11782

PIMIENTO, C. (2010); Systematics, paleobiology, and paleoecology of late Miocene sharks (Elasmobranchii, Selachii) from Panama: integration of research and education.; Master Thesis: Gainesville: University of Florida. 131 p.

TOMITA, T. & OJI, T. (2010); Habitat Reconstruction of Oligocene Elasmobranchs from Yamaga Formation, Ashiya Group, Western Japan.; Paleontological Research, 14 (1): 69-80, doi: 10.2517/1342-8144-14.1.069

BildGINTER, M. & HAMPE, O. & DUFFIN, C.J. (2010); Handbook of Paleoichthyology, Vol. 3D: Chondrichthyes Paleozoic Elasmobranchii: Teeth; Verlag Dr. Friedrich Pfeil, pp. 168, 154 fig., 4 Tab.

sample page 10

sample page 17

 

RECENT:

COELHO, R. & REY, J. & GIL-DE-SOLA, L. & FERNANDEZ-DE-CARVALHO, J. & ERZINI, K.  (2010); Comparing Atlantic and Mediterranean populations of the velvet belly lanternshark, Etmopterus spinax, with comments on the efficiency of density-dependent compensatory mechanisms.; Marine Biology Research, in press, doi: 10.1080/17451000903300885

COELHO, R. & ERZINI, K. (2010); Depth distribution of the velvet belly, Etmopterus spinax, in relation to growth and reproductive cycle: The case study of a deep-water lantern shark with a wide-ranging critical habitat.; Marine Biology Research, in press, doi: 10.1080/17451000802644706

REY, J. & COELHO, R. & LLORIS, D. & SEACUTERET, B. & GIL-DE-SOLA, L. (2010); Distribution pattern of Galeus atlanticus in the Alboraacuten Sea (south western Mediterranean) and some sexual character comparison with Galeus melastomus.; Marine Biology Research, in press, doi: 10.1080/17451000903042487

SÉRET, B. & FENCHEL, T. & UIBLEIN, F. (2010); European Research Focus on Sharks and Rays.; Marine Biology Research, in press, doi: 10.1080/17451001003657729

SÉRET, B. (2010); Guide des requins, des raies et des chimères des pêches françaises.; Direction de la Pêche Maritime et de L’aquaculture, 154 pp

CANNAS, R. & FOLLESA, M.C. & CABIDDU, S. & PORCU, C. & SALVADORI, S. & IGLEACUTESIAS, S.P. & DEIANA, A.M. & CAU, A. (2010); Molecular and morphological evidence of the occurrence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) in the Mediterranean Sea.; Marine Biology Research, in press, doi: 10.1080/17451000903428496

KOUSTENI, V. & KONTOPOULOU, M. & MEGALOFONOU, P. (2010); Sexual maturity and fecundity of Scyliorhinus canicula (Linnaeus, 1758) in the Aegean Sea.; Marine Biology Research, in press, doi: 10.1080/17451000903233771

SPERONE, E. & MICARELLI, P. & ANDREOTTI, S. & SPINETTI, S. & ANDREANI, A. & SERENA, F. & BRUNELLI, E. & TRIPEPI, S. (2010); Social interactions among bait-attracted white sharks at Dyer Island (South Africa).; Marine Biology Research, in press, doi: 10.1080/17451000903078648

KITCHEN-WHEELER, A.-M. (2010); Visual identification of individual manta ray (Manta alfredi) in the Maldives Islands, Western Indian Ocean; Marine Biology Research, in press, doi: 10.1080/17451000903233763

VELIKANOV, A.Y. (2010); The record of the white shark Carcharodon carcharias (Lamnidae) from Aniva Bay, Sakhalin.; Journal of Ichthyology, 50 (4): 347-350, doi: 10.1134/S0032945210040089

BROWN, A.C. & LEE, D.E. & BRADLEY, R.W. & ANDERSON, S. (2010); Dynamics of White Shark Predation on Pinnipeds in California: Effects of Prey Abundance; Copeia, 2010 (2): 232-238, doi: 10.1643/CE-08-012

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, doi: 10.1007/s10452-009-9245-8

CARTAMIL, D.P. & WEGNER, N.C. & AALBERS, S. & SEPULVEDA, C.A. & BAQUERO, A. & GRAHAM, J.B. (2010); Diel movement patterns and habitat preferences of the common thresher shark (Alopias vulpinus) in the Southern California Bight.; Marine and Freshwater Research, 61 (5): 596-604, doi: 10.1071/MF09153

PAPASTAMATIOU, Y.P. &WETHERBEE, B.M. & O’SULLIVAN, J. & GOODMANLOWE, G.D. & LOWE, C.G. (2010); Foraging ecology of Cookiecutter Sharks (Isistius brasiliensis) on pelagic fishes in Hawaii, inferred from prey bite wounds.; Environmental Biology of Fishes, in press, doi: 10.1007/s10641-010-9649-

LAST, P.R. & WHITE, W.T. & POGONOSKI, J.J. (2010); A new wobbegong shark, Orectolobus leptolineatus sp. nov. (Orectolobiformes: Orectolobidae), from the Western Central Pacific.; CSIRO Marine and Atmospheric Research Paper, 32: 1-16

WHITE, W.T. & LAST, P.R. & LIM, A.P.K. (2010); Rediscovery of the rare and endangered Borneo Shark Carcharhinus borneensis (Bleeker, 1858) (Carcharhiniformes: Carcharhinidae).; CSIRO Marine and Atmospheric Research Paper, 32: 17-28

COMPAGNO, L.J.V. & WHITE, W.T. & CAVANAGH, R.D. (2010); Glyphis fowlerae sp. nov., a new species of river shark (Carcharhiniformes; Carcharhinidae) from northeastern Borneo.; CSIRO Marine and Atmospheric Research Paper, 32: 29-44

WHITE, W.T. & LAST, P.R. & NAYLOR, G.J.P. & HARRIS, M. (2010); Resurrection and redescription of the Borneo Broadfin Shark Lamiopsis tephrodes (Fowler, 1905) (Carcharhiniformes: Carcharhinidae).; CSIRO Marine and Atmospheric Research Paper, 32: 45-60

WHITE, W.T. & LAST, P.R. & NAYLOR, G.J.P. (2010); Scoliodon macrorhynchos (Bleeker, 1852), a second species of spadenose shark from the Western Pacific (Carcharhiniformes: Carcharhinidae).; CSIRO Marine and Atmospheric Research Paper, 32: 61-76

COMPAGNO, L.J.V. & LAST P.R. (2010); A new species of wedgefish, Rhynchobatus springeri (Rhynchobatoidei, Rhynchobatidae), from the Western Pacific.; CSIRO Marine and Atmospheric Research Paper, 32: 77-88

LAST P.R. & FAHMI & ISHIHARA, H. (2010); Okamejei cairae sp. nov. (Rajoidei: Rajidae), a new skate from the South China Sea.; CSIRO Marine and Atmospheric Research Paper, 32: 89-100

LAST, P.R. & LIM, A.P.K. (2010); A new species of skate Okamejei jensenae sp. nov. (Rajoidei: Rajidae) from the seas off Borneo, with a redescription of the Kwangtung Skate, Dipturus kwangtungensis.; CSIRO Marine and Atmospheric Research Paper, 32: 101-114

LAST, P.R. & MANJAJI-MATSUMOTO, B.M. (2010); Description of a new stingray, Pastinachus gracilicaudus sp. nov. (Elasmobranchii: Myliobatiformes), based on material from the Indo-Malay Archipelago.; CSIRO Marine and Atmospheric Research Paper, 32: 115-128

LAST, P.R., FAHMI & NAYLOR, G.J.P (2010); Pastinachus stellurostris sp. nov., a new stingray (Elasmobranchii: Myliobatiformes) from Indonesian Borneo.; CSIRO Marine and Atmospheric Research Paper, 32: 129-140

WHITE, W.T. & LAST, P.R. & NAYLOR, G.J.P. & JENSEN, K. & CAIRA, J.N. (2010); Clarification of Aetobatus ocellatus (Kuhl, 1823) as a valid species, and a comparison with Aetobatus narinari (Euphrasen, 1790) (Rajiformes: Myliobatidae).; CSIRO Marine and Atmospheric Research Paper, 32: 141-164

 


INFORMATION FROM PARTNER

Dr Dimitrios Damalas
Mathematician - PhD Biological Oceanography

Address 1
Ichthyology Lab, Section of Zoology-Marine Biology
Department of Biology, Univ. of Athens
Panepistimiopolis, 15784, Ilissia
Athens GREECE
e-mail : ddamalas@biol.uoa.gr
Tel. : +30-210-7274621
Fax. : +30-210-7274602

Address 2
Hellenic Center for Marine Research
Institute of Marine Biological Resources
Ag. Kosmas, Ellinikon, 16777
Athens GREECE
e-mail: shark@ath.hcmr.gr
Tel. :+30-210-9856717
Fax. :+30-210-9811713
Mobile :+30-6972691375


These are amateur videos taken last week in Korinthiakos Gulf 80 km SW of Athens, GREECE.

http://www.youtube.com/watch?v=XoZrMxy40no

http://www.youtube.com/watch?v=Q12z3OFnNnU

http://www.youtube.com/watch?v=lJ98aceiHzc&NR=1

It is most likely a blue shark (Prionace glauca). Locals claim that they come in large numbers lately and they have already caught a few of them. This is extremely unusual for the area.

I have a Msc & PhD on blue sharks and I can assure you that they are relatively rare in the Greek waters (compared to the numbers reported in W. Mediterranean, Atlantic & Pacific), especially in a closed isolated Gulf like this one.

This seems as a very strange behavior since they are of pelagic nature and they do not tend to move close to the coast. In fact there are studies from S. Africa and Australia on beach protecting nets, citing that although thousands of sharks have been entangled on these protecting nets the past 40 years, never have they seen a blue shark on them.

If you find this behavior unusual please circulate this mail among colleagues that may have a hint.

The subject is about to make headlines on TV news and it is most likely that things may go the wrong way afterward...


MISCELLANEOUS

ScienceDaily (May 26, 2010) — The six-foot-long babies of the world's biggest shark species, Carcharocles megalodon, frolicked in the warm shallow waters of an ancient shark nursery in what is now Panama, report paleontologists working at the Smithsonian Tropical Research Institute and the University of Florida.

"Adult giant sharks, at 60-70 feet in length, faced few predators, but young sharks faced predation from larger sharks," said Catalina Pimiento, visiting scientist at STRI and graduate student at the University of Florida. "As in several modern shark species, juvenile giant sharks probably spent this vulnerable stage of their lives in shallow water where food was plentiful and large predators had difficulty maneuvering."

Paleontologists from the Smithsonian and the University of Florida collected more than 400 fossil shark teeth from Panama´s 10-million-year-old Gatun Formation as part of ongoing work to reveal the origins of this narrow land-bridge that rose to connect North and South America about 3 million years ago. "The 28 teeth that we identified as C. megalodon were mostly from neonates and juveniles," said Pimiento. Researchers used reference collections at the Smithsonian's National Museum of Natural History and the Florida Museum of Natural History to characterize the teeth.

"Very little is known about the life cycle of this giant shark that ruled the oceans not so long ago. Now we think that the young spent their first years close to the coast among mangroves," said STRI staff scientist Carlos Jaramillo, who heads the Canal excavation project.

The team discarded several other explanations for the concentration of small teeth at the site. Before their discovery in Panama, two other fossil beds have been proposed as paleo-shark nurseries: the Williamsburg Formation from the Paleocene and the Oligocene Chandler Bridge Formation, both in the U.S. state of South Carolina.

The sandy soils of the Gatun Formation have been used for years to make cement. Soon these outcrops will be exhausted. Scientists continue to race against the clock to find out more about the ancient inhabitants of the region.

These results, generated with funds from the U.S. National Science Foundation, are published


Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Smithsonian Tropical Research Institute, via EurekAlert!, a service of AAAS.


Journal Reference:

  1. Catalina Pimiento, Dana J. Ehret, Bruce J. MacFadden, Gordon Hubbell, Anna Stepanova. Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama. PLoS ONE, 2010; 5 (5): e10552 DOI: 10.1371/journal.pone.0010552

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Sharks use math to hunt
Marine predators cruise the seas using fractal principles
Web edition : Wednesday, June 9th, 2010
font_down font_up Text Size
access
Walk this way An animal moving according to random, or Brownian, motion (top left and bottom) often returns to the same place it started. One conducting a Lévy walk (top right) makes rare long trips. The lengths of both journeys are identical. Courtesy G. Viswanathan

The great white shark in Jaws knew exactly where it was going — to the closest pair of plump legs around. But where might it head if it didn’t have a tasty human snack in its sights?

A new study suggests that some sharks and other marine predators can follow strict mathematical strategies when foraging for dinner. The work, reported online June 9 in Nature, is the latest aiming to show whether animals sometimes move in a pattern called a Lévy walk.

Unlike random motion — in which animals take similar-sized steps in any direction, like a drunk stumbling around — Lévy walks are punctuated by rare, long forays in any direction. Draw a Lévy walk on a graph, and its squiggly pattern echoes a fractal, the mathematical phenomenon whose shape remains similar no matter the viewing scale.

“Living organisms, when allowed to make freely willed decisions, seem to end up obeying some kind of mathematical law,” says Gandhimohan Viswanathan, a theoretical physicist at the Federal University of Alagoas in Maceió, Brazil, who was not involved in the study.

Biologists had long thought that animal foraging was dominated by random walks. But in 1996 a team led by Viswanathan reported that wandering albatrosses, fitted with radio-tracking devices, made the occasional long flight that is the hallmark of a Lévy pattern.

Soon, biologists were reporting Lévy behavior in everything from deer to bumblebees and speculating how it might drive human migrations or the spread of genetically engineered crops. But many of those studies were flawed, says David Sims, a researcher at the Marine Biological Association of the United Kingdom in Plymouth. “Patchy data could mean you think you have a Lévy flight when you haven’t,” he says. And in 2007, researchers debunked the original 1996 albatross paper by noting that many of the reported “Lévy walks” — in which the birds’ transmitters remained dry, supposedly during extended flight — actually were birds resting on their nests.

Now, however, Sims and his colleagues say they have firm evidence for Lévy behavior in 14 species of open-ocean marine predators, including tuna, swordfish, marlin and sharks (although not great whites). The key is the sheer amount of data, on depth and location, gathered by electronic tags, says Sims. His group collected more than 12 million data points describing how the animals swam in the ocean over 5,700 days.

Many of the animals displayed Lévy behavior at least some of the time, Sims and his colleagues report — “the strongest evidence yet that these Lévy patterns are exhibited by wild animals,” he says. Lévy behavior showed up more often in waters where plankton, fish and other food was scarce. In regions with plentiful food, random motion dominated. This observation, says Viswanathan, fits with earlier suggestions that “animals may use a Lévy flight motion to improve their chances of finding prey.”

Not all experts are on board with the new study. Simon Benhamou, an ecologist at the National Center for Scientific Research, or CNRS, in Montpellier, France, hasn’t analyzed the new marine data but says that statistical errors can often suggest Lévy behavior where it doesn’t exist. Benhamou also argues that Lévy pattern studies wrongly assume that predators are “fully stupid, unable to process information and act accordingly” as their environment changes.

Others say Lévy patterns are a logical strategy for animals to take when hunting for food. “From the biological point of view, it makes sense that this way of searching should evolve,” says H. Eugene Stanley, a physicist at Boston University.

Sims and his team are now looking to identify Levy behavior in lower marine animals such as octopuses. The researchers also want to probe the evolutionary history of Lévy behavior — for instance by monitoring the movements of the "living fossil" known as the nautilus, which has not evolved much for hundreds of millions of years, as well as by analyzing fossil traces of other marine animals.

http://www.sciencenews.org/view/generic/id/60106/title/Sharks_use_math_to_hunt

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Cookiecutter sharks prefer Swordfish

Cookiecutter sharks prefer Swordfish

Copyright © NOAA, Creative Commons

Parasitic Cookiecutter sharks seem to prefer biting chunks from Swordfish as opposed to other species.

According to the results of a study by US biologists, parasitic Cookiecutter sharks, Isistius brasiliensis, preferentially attack Swordfish, Xiphias gladius, over other pelagic fish.

Experts from the University of Hawaii, the University of Rhode Island, the Monterey Bay Aquarium and California State University studied bite scars left by Cookiecutter sharks on fish landed at the Honolulu Fish Auction.

The results showed that 25% of Swordfish examined had scars from previous Cookiecutter shark bites, compared to 8.3% of Opah, Lampris guttatus, and much lower numbers for other pelagic fishes.

More bites than other fish

The findings, which have just been published in the journal Environmental Biology of Fishes, also state that most fish have just one Cookiecutter shark bite per individual.

However, Swordfish, often had more than five bites each, as well as a higher proportion of healed scars from previous shark attacks.

The study's authors, Yannis Papastamatiou, Brad Wetherbee, John O'Sullivan, Gwen Goodmanlowe and Christopher Lowe wrote: "Seasonal changes in the probability of hooked fish being bitten by sharks were apparent for Swordfish, Bigeye Tuna and Opah.

"Based on bite scar diameter, larger Cookiecutter Sharks may preferentially attack Swordfish rather than the other species of pelagic fish."

Bites left by a Cookie cutter shark

Daily migrations
Prior to the study, little was known about its feeding behaviour, but it's been reported to have taken chunks out of a range of things, including fishes, marine mammals, squid, human corpses and even inanimate objects such as submarines and undersea cables.

The Cookiecutter shark, Isistius brasiliensis, is a small dogfish-sized shark and is found in warm oceans across the globe.

The species often lives in deep waters and has been recorded as deep as 3.7km/2.3 miles down.

Every day, the Cookiecutter shark migrates vertically through the water column to feed on large pelagic fishes at night. As the sun rises in the morning, it descends into the depths.

The authors claim that their study also adds weight to the vertical migration hypothesis.

"When taken in conjunction with diving behavior of pelagic fish, and fishing depths, the results add further support to the hypothesis that Cookiecutter Sharks perform diel vertical migrations," they added.

Cookiecutter shark factoids
1. Cookiecutter sharks get their name from their characteristic circular bite marks, which resemble the cuts left by a cookie cutter.

2. Cookiecutters have a dark collar-like marking around the head, which is believed to mimic the silhouette of a fish, allowing them to creep up on potential victims.

3. Shipwreck survivors have reported small, deep, clean bites after being attacked in the water at night. Several post-mortems of human corpses have also revealed bites by Cookiecutter sharks.

4. Cookiecutter sharks are luminescent and glow green for several hours after being removed from the water. Their glowing body is believed to attract victims.

5. They reach sexually maturity at just 36-39cm/14-15" long and give birth to 6-12 live pups.

6. Cookiecutter sharks have caused problems for the US Navy several times. In the 1970s, it is claimed that the US Navy believed that enemies had a new weapon that they were using against its submarines. They later learned that the neoprene covered sonar domes had been attacked by Cookiecutter sharks.

For more information see the paper:  Papastamatiou YP, Wetherbee BM, O'Sullivan J, Goodmanlowe GD and CG Lowe (2010) - Foraging ecology of Cookiecutter Sharks (Isistius brasiliensis) on pelagic fishes in Hawaii, inferred from prey bite wounds. Environmental Biology of Fishes, 10.1007/s10641-010-9649-2.

http://www.practicalfishkeeping.co.uk/content.php?sid=2868

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Rare sawfish could be spill casualty

'Smalltooth' species could get hit if oil hits southwest Florida habitat

Image: Smalltooth sawfish
Florida Program for Shark Research, University of Florida
Smalltooth sawfish used to have a wide habitat but are now concentrated off Flolrida's southwest coast.
updated 7:47 p.m. ET June 1, 2010

The massive oil slick that is spreading throughout the waters of the Gulf of Mexico threatens the existence of a critically endangered sawfish, as well as other already threatened species that dwell there, scientists say.

Louisiana's state bird is among the species that could take a hit from the oil.

"You don't have to be a marine biologist to know that the Gulf oil spill is an environmental disaster of the first order," said Gerald Weissmann, editor-in-chief of the FASEB Journal, published by the Federation of the American Societies for Experimental Biology.

The largetooth sawfish, a popular curio item known for its sawlike snout, was proposed as a federally endangered species on May 7, less than three weeks after massive amounts of oil started gushing into Gulf waters, said George Burgess, an ichthyologist and sawfish expert at the University of Florida in Gainesville.

The fish's already endangered relative, the smalltooth sawfish, is also likely to be impacted by the oil leak, which has been growing for more than a month.

"The oil spill will not only have very dire effects on such highly visible creatures as seabirds and dolphins, but also threatens a multitude of bottom-dwelling organisms including the smalltooth sawfish, which already is in considerable trouble as its range diminished and its numbers dwindled," Burgess said.

While the smalltooth sawfish used to range from New York to Texas, what's left of its population is now confined to the lower peninsula of Florida, Burgess said, with its most important habitat extending from Charlotte Harbor, on the southwestern Gulf coast of Florida, through the Ten Thousand Islands area of the Everglades into Florida Bay and the Keys.

These areas may be exposed to the oil by the effects of the Loop Current , a strong flow of warm water in the Gulf that could funnel some of the oil into the Florida Straits, threatening many species there, including sensitive coral reefs.

"As oil gets caught up in the Loop Current, it will be pulled down into the Gulf Stream, which goes right by Key West on its way up the U.S. East Coast," Burgess said. "The opportunities for serious ecological problems are mind-boggling, with dire implications for what's left of [the sawfish species] in the northwest Atlantic Ocean if the oil reaches critical mangrove habitat."

Corals, pelicans and whales
Many coral reefs in the Gulf and Caribbean are already under stress from warming oceans and diseases. The entrance of oil into their habitat could exacerbate their already tough situation.

"Stuff leaching from the ocean floor is the worst environmental challenge a coral reef can face," Weissmann said.

Oil can particularly affect coral reefs as they are spawning, because the egg and sperm are released by the corals at very precise times, and stay at shallow water depths until settling down to mature — oil can compromise the reproductive success of the corals if it interferes with this cycle, according to the National Oceanic and Atmospheric Administration. Coral reefs in the Gulf of Mexico spawn in late summer or fall.

Scientists and conservationists are also worried about the potential impact of the oil slick on the brown pelican , Louisiana's state bird, which was listed as an endangered species after it was largely wiped out from the use of the pesticide DDT in the 1960s.

The deaths of three sperm whales have also been attributed to the oil spill, threatening the small population of the species that is native to the Gulf, said Celine Godard-Codding, an assistant professor at The Institute of Environmental and Human Health at Texas Tech University in Lubbock. Godard-Codding also warned that already threatened Kemp’s ridley and loggerhead sea turtles could face major population decimation as they breathe in toxic fumes and ingest crude oil.

Will historic sawfish return?
The largetooth sawfish, which was most common in the northwestern Gulf of Mexico, has not been encountered in decades. The smalltooth sawfish was listed as an endangered species in 2003.

Conservationists had hoped conditions would become favorable for both sawfish species eventually to stage a comeback in Gulf waters, Burgess said. Far more common to South and Central America, the largetooth sawfish migrated up the Central American coast during the summer into the Gulf, the edge of its natural geographic range, he said.

The oil leak could thwart the fish's return.

 


"If important underwater habitat is destroyed, neither species will have a place to return to," he said. "They can't come back to an underwater desert."

A creature of historic and cultural interest, the sawfish was sometimes depicted as a so-called monster on postcards from the turn of the century, with stories of sawfish catches routinely published in newspapers outside Florida, Burgess said. Today it is not unusual to find the fish's "saw" hanging from the walls of South Florida bars, he said.

The sawfish's fearsome, long, toothy snout is utilized to stun fishes and unearth crustaceans, shellfish and other food buried in the bottom.

It takes longer for sawfish to rebound than other species because of its relatively slow growth rate and its late onset of sexual maturity, Burgess said. He and his colleagues have used their research on the species to develop a recovery plan to help speed its return.

"Our recovery plan covers 100 years, which should give a pretty good indication of how much trouble the animal is in," Burgess said.

© 2010 LiveScience.com. All rights reserved.

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