Obligatory Sea Turtle News o' the day

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

I mentioned recently that elevated temperatures from climate could skew sea turtle sex ratios towards females. The featured news article highlights research which speculates that storm surges caused by increased hurricane (they call them cyclones in Austraila and India) intensity from climate change might lead to the flooding of green turtle nests in Florida, hastening their extinction. Why only the greens? Because they nest later than the other turtles and tend to be around during the height of the Atlantic hurricane season.

We know from previous research that loggerhead turtles have been nesting earlier because of elevated temperatures. Will the greens catch up. More pertinently, will there be enough survival of the early nesters of this generation to keep a viable population going while the whole population adapts? As with all climate change suspense thrillers, only time will tell… Depressing, at any rate.

News in Science – Cyclones may blast turtles to extinction – 15/05/2007

More severe tropical cyclones expected as a result of climate change may lead to the extinction of the green sea turtle in some areas within 100 years, researchers say.

The cyclones are expected to threaten how well the turtles nest and hatch eggs, placing pressure on already endangered populations, some of which are also threatened by fish trawling.

Researchers including PhD candidate David Pike, from the School of Biological Sciences at the University of Sydney, report their findings online in the journal Oecologia.

The researchers studied more than 40,000 sea turtles nests on an uninhabited, 38 kilometre stretch of beach along the Atlantic coast of Florida from 1995 to the end of 2005.

Each night during this period researchers surveyed the beach for turtles emerging to lay eggs, or for tracks of turtles that had already deposited eggs.

The stretch of beach is home to the loggerhead, green, and leatherback sea turtles, which start nesting at the beginning in April and end in late September.

This nesting season largely coincides with region’s tropical storm season, which runs from June to November.

Leatherback turtles (Dermochelys coriacea) and, to a lesser degree, loggerhead turtles (Caretta caretta) get around this by nesting and hatching earlier.

Only nests laid late in the season are inundated with seawater during storm surges.

But green turtles (Chelonia mydas) nest last.

Their entire nesting season occurs during Florida’s tropical cyclone season, which means their nests and developing eggs are extremely vulnerable to being washed away and killed.

Researchers are concerned that increases in the severity of tropical cyclones in the future may cause green turtle nesting success to worsen.

Man, I have a serious case of the summer blahs and am in desperate need of a vacation. Anyways, can’t think very hard. Here’s a nice picture though, courtesy renoir7777’s photostream on flickr.

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.

My favorite turtle organization, the Chennai students’ sea turtle conservation network is in the process of getting a website together. It will be at http://www.sstcn.org, which is not much to look at right now!