|

Tuesdays with Turtles – Right Flipperedness Edition

Across a population studied by scientists, more turtles preferred to use their right rear flipper rather than their left when laying eggs.The result, published in the journal Behavioural Brain Research, is the first time a species of turtle has found to prefer one limb over another.The discovery adds to growing evidence that even lower vertebrates prefer to use one side of the body more often.Such preference is known by scientists as a “lateralised functional behaviour”, and it usually indicates that an animal's brain function is also lateralised, with one side of the brain dominating control of certain tasks.

via BBC – Earth News – Turtles are ‘right-flippered’.

Ha, just when you thought Tuesdays with Turtles was gone, it is Tuesday (here in Canada) and a sea turtle post. Turns out, leatherbacks, the biggest of ths sea turtles and critically endangered tend to be right flippered while on land and laying eggs. A slight predilection to right sidedness runs all the way down to reptiles. It is 54%-46%, which does not seem like much, but the report indicates that among humans, it is the same once you control for a cultural right hand bias!

Anyway, got to love those sexy beasts, even if they’re right flippered, right Ned?

Similar Posts

  • Small-Scale Fisheries Bycatch Jeopardizes Loggerheads

    35AA810F-45DF-436A-B609-5EF72D09CC9B.jpg

    This is almost a 1000 juveniles killed in a year in Baja California alone. The authors mention that over 99% of all fisherpeople are employed in small scale fisheries, which surprised me.

    PLoS ONE: Small-Scale Fisheries Bycatch Jeopardizes Endangered Pacific Loggerhead Turtles:

    Although bycatch of industrial-scale fisheries can cause declines in migratory megafauna including seabirds, marine mammals, and sea turtles, the impacts of small-scale fisheries have been largely overlooked. Small-scale fisheries occur in coastal waters worldwide, employing over 99% of the world’s 51 million fishers. New telemetry data reveal that migratory megafauna frequent coastal habitats well within the range of small-scale fisheries, potentially producing high bycatch. These fisheries occur primarily in developing nations, and their documentation and management are limited or non-existent, precluding evaluation of their impacts on non-target megafauna.

    This is a surprising and unexpected finding because you would expect smaller fishing boats to have smaller impacts. I guess smaller scale fishing fleets in Mexico (and other developing nations) have not been targeted for education, awareness and enforcement of turtle safe fishing practices.

    The good news from the study is that a major source of mortality has been identified and the authors point to recent efforts to increase awareness in the community about turtle safe fishing. But it will be a long and hard fight to be tackled all over the world.

  • |

    Tuesdays with Turtles – Climate change and nesting patterns

    Turns out that in Guyana, nesting patterns are changing. Different types of sea turtles are showing up, and earlier than they used to. The earlier part can be explained by climate change, but the species distribution? I am sure there are other factors involved including habitat loss, poaching, etc. Anyway, interesting story.

    Stabroek News

    The changing nesting patterns of endangered sea turtles in Guyana, is alerting environmentalists to the impact of climate change on these marine animals.

    The shell beaches in Region One have hosted thousands of nesting turtles over the years, and conservationists have been endeavouring to protect the turtles from heavy domestic use and from being traded.

    Project Coordinator of the Guyana Marine Turtle Conservation Society (GMTCS) Michelle Kalamandeen told Stabroek News recently that climate change is affecting the sea turtle population.

    According to Kalamandeen, in the 1960s the Hawksbill (critically endangered) and the Olive-Ridley (endangered) were our main nesting turtles, now the green turtles (endangered) and the leatherbacks (critically endangered) are mostly coming to nest on Guyana’s shores. The Pacific Leatherback is said to be now extinct and the Atlantic Leatherback is facing extinction.

    The change in the time period for nesting in Guyana, she said, may also be a significant sign.

    Usually sea turtles nest in Guyana from March to August every year. However, for the last three to four years, says Kalamandeen, the nesting pattern has shifted from mid-January to mid-July. This may have a significant impact on the hatchlings as food availability may be an issue for them.

  • Casuarina plantations and the Olive Ridley

    The Students’ Sea Turtle Conservation Network was featured in the Hindu today.

    Sea turtle lovers are concerned at the disturbance caused to turtle nesting habitats along the Tamil Nadu coastline, where casuarinas have been raised by the State Forest Department.The sea turtle’s egg-laying season began a month ago. Volunteers of the Chennai-based Students’ Sea Turtle Conservation Network (SSTCN) had written to the World Bank stating that the Forest Department should reverse the damage done.The SSTCN also wanted the Bank to provide funds for taking up transplantation work.Akila Balu, co-ordinator, SSTCN, said after the tsunami, the World Bank funded an Emergency Tsunami Reconstruction Project (ETRP) in Tamil Nadu.Under this programme, the State Forest Department had taken up the work of raising casuarina plantations to act as a bio-shield on the coastline. The casuarina saplings were planted right up to the high-tide line. In the process, it eliminated large stretches of sea turtle nesting habitat.Department’s defenceA senior Forest Department official said casuarinas had not been raised all along the State coastline.Adequate space had been provided between each sapling through which the turtles could enter the sand and lay eggs.The ETRP is a conservation-oriented programme, and so far the department has not received any complaints that the casuarina plantation had affected egg-laying of the Olive Ridleys, the official said.“In most of the areas, the saplings are not touching the high-tide line. If we plant closer to the line, the saplings will not survive. On the whole, the plantation will surely not affect the egg-laying turtles,” the official added.

    The Hindu : Tamil Nadu / Chennai News : “Casuarina plantations affecting turtle nesting habitats”

    To find out more, visit the SSTCN website.

    cross-posted at the Students’ Sea Turtle Conservation Network

    Blogged with Flock

    Tags: , , ,

  • Tuesdays with Turtles – Archie Carr Edition

    Archie Carr is considered the father of modern sea turtle research. And now, there’s a book about him about to come out. It’s called “The Man who Saved Sea Turtles”.

    Well, I guess saved is going a little too far. I would have said “postponed the extinction of”, given the imminent extinction of the Pacific leatherback. But hey, forget about the title, I am sure it’s going to be a good book to read.

    Oxford University Press: The Man Who Saved Sea Turtles: Frederick R. Davis

    Archie Carr, one of the greatest biologists of the twentieth century, played a leading part in finding a new and critical role for natural history and systematics in a post-1950s world dominated by the glamorous science of molecular biology. With the rise of molecular biology came a growing popular awareness of species extinction. Carr championed endangered sea turtles, and his work reflects major shifts in the study of ecology and evolution. A gifted nature writer, his books on the natural history of sea turtles and their habitats in Florida, the Caribbean, and Africa entertained and educated a wide audience. Carr’s conservation ethic grew from his field work as well as his friendships with the fishermen who supplied him with many of the stories he retold so engagingly. With Archie Carr as the focus, The Man Who Saved Sea Turtles explores the evolution of the naturalist tradition, biology, and conservation during the twentieth century.

  • |

    Killer nets reinstated

    Council Decisions: March 2006

    Drift Gillnet Management

    The Council adopted a recommendation to NMFS to authorize an exempted fishing permit (EFP) that would allow drift gillnet fishing in the current August 15-November 15 closed area. The EFP fishery would be governed by several requirements for all vessels, including, to carry an observer; to limit total fishing effort in the EFP fishery to 300 sets; to immediately cease the EFP fishery if, and when, two leatherback sea turtles were encountered by the fishing gear; and to immediately cease the EFP fishery if one mortality or serious injury occurred to any of the following marine mammals: short-finned pilot whale, sperm whale, fin whale, gray whale, humpback whale, or minke whale.

    And, with that, starts the rather egregious practice of drift gillnet fishing. The restrictions seem fairly tight, an observer on every boat, and end to the fishery after two incidences of capture. There is definitely more than meets the eye here, I don’t know what. Drift gillnet fishing is well documented to cause turtle catch, this from the 1998 Fishery Bulletin for 1990-1995

    In the drift gillnet fishery, seven out of 387 mammals observed entangled were released alive. In the set gillnet fishery, five out of 1,263 mammals observed entangled were released alive. Estimates of incidental kill are presented along with estimates of entanglement for species that were observed to be released alive. For the period under consideration, the estimated mortality for the drift gillnet fishery was over 450 marine mammals each year. A total of 20 turtles and 3 seabirds were observed entangled during the entire period. The most frequently entangled species in this fishery were common dolphins, Delphinus spp., and northern elephant seals, Mirounga angustirostris. Estimated cetacean mortality in the driftnet fishery decreased from 650 in 1991 to 417 in 1995; pinniped mortality decreased from 173 in 1991 to 116 in 1995. Estimated cetacean mortality in the set gillnet fishery ranged from a high of 38 in 1991 to a low 14 in 1993; pinniped mortality rose to a high of 4,777 in 1992 and then decreased to 1,016 in 1995. We postulate that there has been a decline in the number of pinnipeds and cetaceans in the setnet fishery owing to area closure. No similar proposal can be made for the driftnet fishery. The most frequently entangled mammals in the setnet fishery were California sea lions, Zalophus californianus, and harbor seals, Phoca vitulina. Six turtles and 1,018 seabirds were estimated entangled in this fishery during the NMFS Observer Program from July 1990 to December 1995.

    So what’s the deal, this thing caught 20 turtles in 5 years, so it is going to catch turtles, no doubt about it. Anyone who does not get what the death of one adult sea turtle means read this. Sea turtles are wonderfully fragile animals given their size, they take long to mature sexually, they do not breed all that much and less than 1% of turtle hatchlings survive to adulthood. Leatherbacks are highly endangered.

    I have a feeling that this is the first part of a one-two punch intended to reinstate the famed turtle killer long line swordfish nets on the pacific coast. The “proof” that these nets do not catch turtles will be used to lobby for longline swordfishing in, oh say three months?