Sea Turtle News of the day, genocide edition

Byoliveridley

Depressing as always, but this is a yearly headline around turtle nesting season.

1,000 Giant Turtles Wash Ashore in India, Bangladesh

It’s nesting season for the sea turtles of Bangladesh and India, but this year the beaches where the animals lay their eggs are eerily still.

Nearly a thousand dead turtles have washed ashore along the coasts of both countries in the past few weeks, conservation workers report.

About 200 dead reptiles have appeared in the past week alone along a single stretch of beach, pictured here, in the Bangladeshi tourist town of Cox’s Bazar (see Bangladesh map).

A team of scientists visiting the beach on Monday to investigate the mysterious mass deaths concluded that fishing nets were to blame.

Sea turtles swarming the shores to nest are getting entangled in poorly laid nets and drowning, the experts told Bangladesh’s Financial Express.

The survival rate of turtle hatchlings is estimated at anywhere between 0.1 and 1%. Assuming 0.5%, this represents 20000 hatchlings. Assuming a hatching success (not all eggs hatch successfully) of about 2/3rds, that is 30,000 eggs, or between 200-250 nests. In my two years of turtle conservation work on an approximately 3 mile stretch of beach, we relocated about a 100 nests. These aren’t the same turtles (they tend to come back to nest very close to where they hatched), but there’s my two seasons of work down the drain and then some!

Turtle safe fishing is a well researched technology and is not expensive. As I have mentioned before in a similar context, the gaps between the availability of a certain technology and its actual adoption and use are depressingly huge.

When it comes to serious problems like global warming, all the talk is going to be about the cool science and innovative solutions, but how the technology transfers to India and China, how it is implemented, and the nature of the interactions between the traditional powers and the emerging ones is going to be more critical than the science. Something to remember as a scientist!

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  • Casuarina plantations and the Olive Ridley

    Byoliveridley

    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

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    Killer nets reinstated

    Byoliveridley

    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?

  • |

    Sea Turtle News o' the day – Global warming edition

    Byoliveridley

    ScienceDaily: Scientists Warn Of Climate Change Risk To Marine Turtles

    North American marine turtles are at risk if global warming occurs at predicted levels, according to scientists from the University of Exeter. An increase in temperatures of just one degree Celsius could completely eliminate the birth of male turtles from some beaches. A rise of three degrees Celsius would lead to extreme levels of infant mortality and declines in nesting beaches across the USA.

    Here’s the paper.

    Like a lot of other reptiles, the sex of the hatchling is dependent on nest temperature. Warmer temperatures make female turtles (my mnemonic was hot females!), and even warmer temperatures just kill the eggs. But, I wonder if the turtles would adapt by nesting a little earlier. I don’t think it is yet clear when turtles decide to nest. If it is based on sea temperature, then they would eventually figure it out. This paper from 2004 appears to conclude that loggerheads in Florida do nest earlier than before, so there is hope.

    John F. Weishampel, Dean A. Bagley, Llewellyn M. Ehrhart (2004) Earlier nesting by loggerhead sea turtles following sea surface warming Global Change Biology 10 (8), 1424–1427

    The onset of spring, noted by the timing of wildlife migratory and breeding behaviors, has been occurring earlier over the past few decades. Here, we examine 15 years of loggerhead sea turtle, Caretta caretta, nesting patterns along a 40.5 km beach on Florida’s Atlantic coast. This small section of beach is considered to be the most important nesting area for this threatened species in the western hemisphere. From 1989 to 2003, the annual number of nests fluctuated between 13 000 and 25 000 without a conspicuous trend; however, based on a regression analysis, the median nesting date became earlier by roughly 10 days. The Julian day of median nesting was significantly correlated with near-shore, May sea surface temperatures that warmed an average of 0.8°C over this period. This marine example from warm temperate/subtropical waters represents another response of nature to recent climate trends.

    So the truth lies somewhere between easy adaptation and giant swarms of frustrated female turtles!

  • Tuesdays with Turtles – Lighsticks Kill

    Byoliveridley

    Following up on the fishing issues from last week, here’s word that lights used to lure tuna towards longline fisheries attract juvenile sea turtles as well.

    Article – Science & Technology – Lightsticks may hold deadly attraction for sea turtles

    RALEIGH, N.C. Longline fishermen use lightsticks similar to the glowing tubes that delight trick-or-treaters to lure tuna and swordfish to baited hooks. New research by University of North Carolina-Chapel Hill scientists suggests that for endangered sea turtles the lights may hold a fatal attraction.

    Lab experiments by Ken Lohmann, a University of North Carolina biology professor and John Wang, a graduate who is now a research associate at the University of Hawaii and National Marine Fisheries, found that young loggerhead turtles in a tank tended to swim toward lights.

    It’s well known that hatchling turtles on a beach will crawl toward lights as they try to find the surf. But researchers did not know whether juvenile loggerheads in the water shared that attraction. Young loggerhead and leatherback sea turtles, which are protected because of declining numbers, are inadvertently hooked during longline fishing.

    Well, not so surprising, is it? Bioluminescence is a common enough phenomenon that especially at night, animals will be attracted to light as it can signal food. It’s tricky, but when you try to catch fish, tyou will catch other animals as well. So, when you change something about the way you catch fish, you need to study how it affects other endangered species…

    Off topic, but it is ironic that I read this in the ocregister, which is a newspaper from Orange County, California. It reported on work done by UNC Chapel Hill, which is in Orange County, North Carolina.

3 Comments

  1. Hi! I was hoping to find some more information on olive ridley turtles…my friend and I will be travelling through India from March 4-20 this year and would love to see the turtles hatching if possible. Even better would be to volunteer to help out, so I am wondering which organizations to contact about doing this. Or whether I can just show up. Do you know when approximately the turtles will be hatching and who I can contact about helping? Any info you could provide would be very much appreciated, thank you 🙂

  2. Shaylin:

    Cool! Hope you enjoy your trip, if it is your first time, prepare to be utterly overwhelmed!

    Early March would be the beginning of the hatching season as the Olive Ridley starts nesting end of December and the first nests hatch end of February-Beginning of March. Where are you going to be? The East coast is where most of the turtles nest. The Bhitarkanika national park in Orissa is the site of an Arribada (or mass nesting). I can get you the contact info for people in Chennai who would be able to take you out on a turtle walk (if they’re still doing that, I would need to check).

  3. Hello turtle lovers!
    I am also in India right now (March 10th) and I am working on a children’s book about sea turtles. I would love to come to the east asap to help out as well. Can you let me know who I can contact?
    Thanks,
    Kathy

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