Tuesdays with Turtles – Triumphant Return

Byoliveridley

So, blogging has been light this summer as Olive Ridley’s partner made her way to Canada and is settling in. Also, it is summer in BC and beautiful as hell, so the prospect of sitting down and typing on a computer with brains that are only half working, well, ain’t so hot! Also, Canada is just a much calmer place than the U.S. As I looked back at my many posts, most of them are bitter fulminations against American politics or the various shenanigans of the Emperor. Anyway, I am not under his rule any more, and while he’s gutting the Endangered Species Act as we speak, he will be history soon.

While Canadian policy debates are equally interesting, they are generally civil in comparison, except the occasional kerfluffle where old white men want their female opponents to go back to making tea, charming…

Anyway, I felt the blogging itch again and as always, it’s nice to get back with a story about turtles.

Researchers say they have figured out why sea turtles that normally feed and breed in shallow water or on land will, very rarely, go deep sea diving: the reptiles are on reconnaissance.

Sea Turtles Dive to Depths for Reconnaissance : Discovery News

Leatherbacks have amazing diving capabilities and can get up to a kilometre below the surface. Why? for food, of course! More precisely, the promise of future food. Turns out that jellyfish (or jellyfish like animals) hang out in the deep during day time and surface at night. Leatherbacks go looking for them during the daytime down in the deeps so they can get them on the surface for dinner. It’s akin to you taking a leisurely walk around downtown looking for the perfect dinner spot.

Interesting. As always, very fascinating and sexy creatures, and critically endangered.

Expect more regularly scheduled blogging just in time for the late summer sweeps!

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  • Obligatory Sea Turtle News o' the day

    Byoliveridley

    green turtle underwaterSince this is the Olive Ridley blog (hint, it is a sea turtle), I do write occasionally about sea turtles. this is a random bit of sea turtle news out of Texas, and it is a feel good story…

    Sea Turtles Rescued From Chilly Waters – New York Times

    At least three dozen juvenile sea turtles have been rescued from an arctic blast that caused the water temperature in an arm of the Gulf of Mexico to fall 18 degrees in 48 hours. The turtles, which are cold-blooded, were left comatose by the rapid temperature drop this week in the shallow bay where they feed. Animal rescuers feared that the cold would kill the turtles or make them so sluggish that they would be vulnerable to sharks.

    The nice thing about sea turtle conservation is that they are good looking beasts, harmless and very accessible. Anyone who summers on the coast of North Carolina, for instance, can see at least a cordoned off area marked as a sea turtle nests. And they’re encouraged to keep watch for hatching, keep any eye on the nest, watch out for nesting turtles, etc. U.S sea turtle conservation has a long, and fairly successful history.

    Here’s more on the green turtle.

    Photo’s courtesy of NOAA’s fisheries website.

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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?

  • Now we know where Juvenile sea turtles Hide

    Byoliveridley

    You see the hatchlings as they dig out of the nests all small and helpless and make a beeline towards the sea. You see the adult female as she comes back to lay her eggs. You see adult males when you go snorkeling , but the juveniles had kept a low profile, until now…

    Sea turtles’ mystery hideout revealed – LiveScience – MSNBC.com

    Once sea-turtle hatchlings hit the surf, they vanish for up to five years. Where the half-dollar-size tots spend these ‘lost years’ while ballooning to the size of dinner plates has been a mystery, until now.

    New research, published in the online edition of the journal Biology Letters, indicates the green sea turtles (Chelonia mydas) hide out in the open ocean, where they feast on jellyfish and other marine creatures.

    Turns out that they’ve been “hiding out” in the open ocean eating meat to augment their vegetarian adult diet. I have not seen the paper (reference below), but the study was based on an analysis of their shell content. Carbon and Nitrogen isotope analysis was used as a marker for diet and location.

    The ‘lost years’ of green turtles: using stable isotopes to study cryptic lifestages

    Kimberly J. Reich, Karen A. Bjorndal, Alan B. Bolten

    Archie Carr Center for Sea Turtle Research, Department of Zoology, PO Box 118525, University of Florida, Gainesville, FL 32611, USA

  • |

    Tuesdays with Turtles – Travel Edition

    Byoliveridley

    sm_mapping.jpgIt’s travel all the time for sea turtles. Of course, the great turtle race is finally on, and windy’s in the lead, my pick billie’s in second place, a mere 30 miles behind. There’s a new turtle in the race, Colbertia, named in honor of Stephen Colbert, in third place.

    Anything that gets turtles some attention is good.

    But this is only a 500 mile sprint. PBS’ nature series had a one hour documentary on an 8000 mile, one plus year journey of a loggerhead turtle from her juvenile feeding grounds in Mexico to her adult breeding ground in Japan. It’s great to spend an hour at that close proximity to a turtle. But to me, the other animals, the dolphin pods, the giant fish swarms, the hammerhead sharks, the other sharks, the jelly fish, those little fish that eat parasites off the turtles and sharks kinda stole the show. There is something about thousands of animals of the same species doing something in concert. 

    Anyway, nothing more to say, except that 8000 miles is a long way at a mile an hour. I don’t think any of us can appreciate the mindfulness and sense of purpose (do turtles have these qualities, or do they just keep on chuggin’?), not to mention the huge amount of luck it takes to get it done.

  • Tuesdays with Turtles – Hatcheries

    Byoliveridley

    A little old, but turns out that the WWF is establishing a hatchery for Olive Ridley sea turtles in Orissa.

    WWF-India comes with artificial hatchery for Olive Ridley eggs – Newindpress.com

    Large-scale destruction of Olive Ridley eggs at nesting sites in the State’s coast has prompted WWF-India to come with an artificial hatchery. It would also double up as a hatching protection centre. The artificial hatchery has been established near mouth of Rushikulya river where WWF-India staff have stored a large number of Olive Ridley eggs along with the arrangements for safe hatching. Last month alone, 116 nests were safeguarded and around 13,000 Olive Ridley eggs were stored in the artificial hatchery. Till end of the week, more than 2,000 eggs have hatched, chairman of WWF-India, Orissa State Committee Saroj Kumar Patnaik said.

    Hatcheries become necessary when the natural habitat can no longer be protected. The biggest advantage of a hatchery is the fact that once the eggs are relocated, they are now safe from poaching/predation. But, there are some disadvantages including the resources needed, the possible overcrowding effects if the hatcheries are not well designed, etc. Luckily, there are good resources available for building and managing a good hatchery. With the WWF’s funding and experience, I am sure it will be a very well managed hatchery.

One Comment

  1. Leatherbacks are amazing creatures. I’m sure you’ve read Carl Safina’s book on them. I recently finished it. Fantastic, but also sad.

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