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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Tuesdays with Turtles – Why Adult Turtles Die so You Can Eat Fish

Byoliveridley

An interesting paper featuring a North Carolinian turtle researcher Larry Crowder from Duke University:

Blackwell Synergy – Conservation Biology, Volume 21 Issue 1 Page 79 – February 2007 (Full Text)

Abstract: Although some sea turtle populations are showing encouraging signs of recovery, others continue to decline. Reversing population declines requires an understanding of the primary factor(s) that underlie this persistent demographic trend. The list of putative factors includes direct turtle and egg harvest, egg predation, loss or degradation of nesting beach habitat, fisheries bycatch, pollution, and large-scale changes in oceanographic conditions and nutrient availability. Recently, fisheries bycatch, in particular bycatch from longline fisheries, has received increased attention and has been proposed as a primary source of turtle mortality. We reviewed the existing data on the relative impact of longline bycatch on sea turtle populations. Although bycatch rates from individual longline vessels are extremely low, the amount of gear deployed by longline vessels suggests that cumulative bycatch of turtles from older age classes is substantial. Current estimates suggest that even if pelagic longlines are not the largest single source of fisheries-related mortality, longline bycatch is high enough to warrant management actions in all fleets that encounter sea turtles. Nevertheless, preliminary data also suggest that bycatch from gillnets and trawl fisheries is equally high or higher than longline bycatch with far higher mortality rates. Until gillnet and trawl fisheries are subject to the same level of scrutiny given to pelagic longlines, our understanding of the overall impact of fisheries bycatch on vulnerable sea turtle populations will be incomplete

Adult sea turtle killing by humans occurs due to

  1. Harvest, killing them deliberately for food

  2. Incidental bycatch in fishing nets

  3. Habitat loss

The paper focuses on long line fishing and its effects on turtle mortality. So, if like me, you’re not a fisherperson, what is long line fishing and what are some other kinds of fishing techniques that have effects of sea turtles? Well, the Duke Project GloBal research team on studying bycatch has a nice primer. Some highlights:

  1. Longlines: As the word suggests, longlines are very long (>10 km) lines of 2000+ individually baited hooks that drift close to the surface and are used to catch tuna, swordfish, halibut, etc. Crowder’s paper suggests that while each individual longline hook has low probability of catching a turtle, because of their number and ubiquitousness, they catch many many turtles.

  2. Gillnets: These are giant rectangular mesh nets, either stationary or drifting, that catch marine life indiscriminately. There’s not much that can be done by way of reducingsea turtle catch in gillnets, except monitoring, observation and just using less of them

  3. Trawls: Big funnel shaped bags that catch fish. Bottom trawling fishing boats used to, and still catch turtles at an alarming rate. Trawls are now (at least in the U.S and other “developed” countries) required to be outfitted with Turtle Excluder Devices (TEDS) to let turtles swim to safety.

  4. Purse Seines: These are weighted on the bottom and float at the corners. They are indiscriminate, and especially hard on dolphins. It appears that mitigation efforts aimed at reducing dolphin mortality have the unintended effect of increasing sea turtle catch. Battle of the cute species!!

Take home message? Catching fish causes a lot of turtles to die. While trawl fishing is the worst culprit, it is also the most studied and the technique for which a viable mitigation strategy exists. THe other kinds of fishing are less studied, and there is precious little that can be done to avoid sea turtle bycatch.

Happy fishing!

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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?

Tuesdays with Turtles – Archie Carr Edition

Byoliveridley

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.

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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 – Wednesday Edition

Byoliveridley

Where I’m a day late and a dollar short. It turns out that the Mediterranean sea is awash with plastic and most of the loggerheads there have swallowed plastic bags. So, the next time you’re out looking for loggerhead nests and find one in which all the eggs have been double bagged, do not be surprised! Now. if they start swallowing egg cartons…

Mediterranean drowning in a hidden sea of plastic rubbish – Independent Online Edition > Europe

A recent study of the endangered loggerhead turtle off Spain’s Mediterranean coast found that 75 per cent of them had swallowed plastic bags. Mr Rodriguez said: “We have to understand the sea is not a tip; it will constantly return to us what we throw in.”

Seriously, plastic bags need to go away.

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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