Tuesdays with Turtles – Hiatus Edition
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.
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Tuesdays with Turtles – Poaching in Mexico
This article brings up some interesting information about sea turtle poaching in Mexico, including the fact that sea turtle eggs are considered aphrodisiacal in certain cultures…
But there have been recent gains. WiLDCOAST, a small conservation organization also co-founded by Nichols, has implemented a media campaign. It started in 2005, when Argentine singer and Playboy model Dorismar attracted controversial attention by appearing in television and poster PSAs, hitting Mexican men—who eat turtle eggs mistakenly believing they are aphrodisiacs—below the belt. The message above a salacious Dorismar reads: “My man doesn’t need to eat turtle eggs; because he knows they don’t make him more potent.” The bold campaign reached a global audience of 300 million and resulted in a decrease in consumption of sea turtle eggs.
Well, the unfortunate thing about aphrodisiacs is that if you believe, it works! So, I guess a Playboy model telling you that sea turtles eggs are baloney may work. They author does say there was a decrease in consumption, but presumably, it is not quite that easy to ascribe causation relationships to particular parts of a campaign!
Other highlights…
Turtle smuggling is thought to be a proving ground, a gateway into drug trafficking. Mexico is the principal transit country for 70 to 90 percent of cocaine entering the U.S., and the largest outside source of
marijuana and methamphetamine.This, I did not know.
Grupo Tortuguero continues its David-vs.-Goliath efforts to co-opt fishermen and volunteers from Baja’s fishing communities to monitor, tag and protect sea turtles. The group has dozens of sites along the peninsula and all have drug issues, ranging from trafficking to addiction. “I’ve interacted with fishers who were not ‘poachers,’ but were poaching for money to feed their habit,” says Nichols
The article is interesting because it points out the similarities between sea turtle smuggling and drug smuggling, the use of young women, the co-opting of users to become dealers, the bribery of local officials, the organization to avoid capture, etc. Hmm…
Tuesdays with Turtles – Green Turtles Deluged?
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.
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.
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.
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?
Sea Turtle News o' the day – Global warming edition
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.
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!
Fishing Major threat to Turtles
Well, not the least bit surprising, sea turtles have always been very difficult to track, and we’re finally getting verification that, gasp, turtles’ lives cannot be described in simple juvenile = open sea, adult = coast behavior.
BBC NEWS | Science/Nature | Fishing ‘major threat’ to turtles
Until now scientists have believed that young turtles live in the open ocean, but change to a coastal habitat when they reach a certain size.
But researchers working in Cape Verde found that most adults nesting there retain their open water behaviour, with the attendant risk posed by longline boats.
“The bottom line is that we thought juveniles experienced this risk out in the open ocean with longline fisheries,” said Brendan Godley from the University of Exeter.
“We thought that if you got them past that, then unless they’re being taken by inshore fisheries, you’re OK,” he told the BBC News website.
“But now you’ve got adults exposed to longline fisheries, which is very worrying.”