Marine ecologist Larry Crowder from Duke University in the US is reported at BBC News Online claiming that leatherback turtles face extinction within 30 years if there are not dramatic changes to fishing practices.
According to the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species there has been a 70 percent decline in the global population of female Leatherbacks in one generation.
The IUCN attributes the dramatic decline to poaching of the turtle’s eggs as well as entanglement in fishing lines.
According to Professor Crowder:
“Globally, each day, there are around four million hooks in the world’s oceans fishing for tuna and swordfish.
Turtles will eat the bait and get caught on the hooks, or simply get entangled in the lines.
Because the range of leatherbacks is so great, national legislation on long lines will not be sufficient to save the animals.
“If you tag one with a satellite tag in Monterey bay, it will shoot straight across to Indonesia,” Professor Crowder explained.
“They are the most widely distributed sea turtle. They swim from 50 degrees south to 50 degrees north. Trying to regulate their interactions with fisheries out in international waters is really difficult.”
Professor Crowder told delegates [at a conference in Denver] that there was much that could be done to minimise the impact of long line fishing, such as changing the shape of hooks.”
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I have previously written that plastic bags can kill marine turtles particularly Leatherbacks, click here.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
My understanding of Turtle life cycle is that the greatest mortality takes place during the trek down the beach to the water, with the first few months in the water as a distant second place. This suggests that the survival of the species can be influenced most by reducing predation at these points to produce an expanded population all along the line.
But Crowder seems more intent on shafting the tuna industry than he is on preventing egg poaching. The latter course would be much more contributive and cheaper while the former shifts the cost to the private sector with minimal impact on the outcome.
Is Crowder ‘shafting’ the tuna industry, or simply suggesting a change in hook design? Long line fisheries have high incidental takes of other species apart from turtles, such as sea birds.
As noted, plastic bags are a problem for marine animals, as well as debris entanglement, vessel strikes, human consumption in some countries and unusual weather events. Right across their range and life cycle they face large pressures. Crowder is coming up with a practical solution, whereas patrolling remote beaches in some countries to ensure there is no egg poaching is often not feasible.
If a change in hook design, that will still satisfy the needs of the industry is all he is calling for then that is fine. But it is clear where the real long term solution lies. Egg protection and hatchling protection is the really contributive option.
And it is probably best served by privatising the process so that turtles can be tagged by the communities that protect the hatchlings in a scheme where the person who catches the adult can cash in the tag (at appropriate age) for half its value with the other half being sent back to the community that tagged it. Much like a musical royalty payment.
But that would involve recognition of ownership or an attached right to wildlife and a recognition of the role of the profit motive. And urban greens just couldn’t get their heads around the idea. Could they?
Ian,
Why do you feel the need to make the comment “urban greenies just couldn’t get their head around the idea?” It is in the same vein as the global warming hippies needing to get their hair cut. What starts as a totally reasonable comment seems to degrade into a sort of paranoid and prejudiced venom-spit that serves no purpose whatsoever.
Dr Crowder is probably best suited to answer queries regarding this article and the associated comments, and he hopefully knows why his ears are burning.
If communities were paid per tag of given age, then just keep the tag in your drawer at home or safeguard the turtle in a private rockpool. Ok so you’d have regulations and inspections to prevent that and other forms of cheating, no doubt. Given that the turtles themselves, and the impacts on breeding age turtles don’t observe local boundaries, you’d need an internationally agreed regulatory framework .. not unlike the one for whales (IWC) against which you rally.
This tagging proposal could encourage lotto tag seekers to rush known marine and land areas where turtles appear (including nesting sites) and try to catch them to recover their tags – a potential minefield of problems. When a tag is handed in, how to ascertain the turtle hasn’t been injured, perhaps eaten, or eggs crushed in the process?
The complicated tagging system’s desired effect – protecting eggs and hatchlings – can happen more simply via tourism. There are places where the same locals who used to hunt the turtles and eggs are now the defenders of the turtles and earn more money from tourism. Moral suasion also helped: once these locals were educated about the plight of the turtles and given an alternative livelihood, they became dedicated protectors.
In addition to human activities, note that climate change has its impacts too: rising water levels and storms remove nesting sites and changing temperatures affect the gender balance.
Re: your anti-green rant that they won’t admit rights attached to wildlife, you are encouraged to make a bet on the survival of albatross.
You seem to be reading a lot more into it than I put there. There wasn’t the faintest touch of venom in that statement. It was a simple statement as to the primary blockage to good ecology. I am sorry if you find that too close or uncomfortable but I have seen far too many good ideas bite the ideological dust to think otherwise. And there is not an ounce of paranoia nor bile for that would only be unhealthy. But there is also only one way to get a message across and that is to tell it like it is. Without it the people causing the problems would just cruise along in the delusion that they are saving the planet.
Actually, the issue of what’s the best stage in turtles’ life history to focus conservation efforts was addressed – mathematically – a long time ago. See the Crouse, Crowder & Caswell paper of 1987 (Ecology 68:1412-1423). It’s for loggerheads, but the basics of leatherbacks’ life history aren’t all that different. Bottom line of that work was that, although it appears that the best place to put conservation effort is with eggs and hatchlings, there are other life history stages that actually provide better conservation bang for buck.
It’s counterintuitive, but then the best science can be. There’s been plenty of papers since then on matrix elasticities (from both Crowder’s and Caswell’s labs) that expand on these ideas. Crowder’s not an idiot & has been at this for quite a while now.
If people want to get their heads around this population modelling stuff, Caswell’s 2001 book “Matrix Population Models” is a good place to start. As long as people understand matrix algebra and aren’t afraid of writing a little code, they can even use freely available software (e.g. R: http://www.r-project.org/) to run their own models, & see how their ideas play out. Or if they have Excel, download PopTools from CSIRO http://www.cse.csiro.au/poptools/ & run models with it. Have fun. Learn.
There you go Ian – time to ditch the envelope and upgrade to proper population matrices. Please report back ASAP.
Ian Mott says: “But that would involve recognition of ownership or an attached right to wildlife and a recognition of the role of the profit motive. And urban greens just couldn’t get their heads around the idea. Could they?”
How can one man be wrong so often?
I have had a long term interest and involvement with FAME here in Melbourne, which runs for- profit native wildlife sanctuaries including Mt Rothwell (formerly Little River) near Geelong.
On behalf of the Victorian Greens and FAME I organised a Greens tour of Mt Rothwell. I and everyone else was most impressed. Not one person raised any objection to the private for-profit nature of the venture.
On greenie profit innovations, here’s last year’s link on betting on albatross:
http://www.ladbrokes.com/bigbirdrace/
The world’s biggest bookmaker has teamed up with the Conservation Foundation and the Tasmanian State Government to launch an environmental project with all the excitement of the Grand National.
Didn’t many of the albatross in last year’s race not reach their destination? This brings us back to Dr Crowder’s long line hooks. By changing long line hooks or practices, not only can the incidental take of turtles be reduced (hopefully) but also albatross and other sea birds. It is a measure that will get results for a number of threatened species, but still allow the fishery to operate, which is surely a win-win situation (unless you are a tuna fish).
Programs to protect hatchlings and involve local communities can be just as valuable, and also tied in to support other conservation efforts.
But why have 99% of species died?
Or is our understanding of the topic incomplete?
Very interesting, Steve Munn. So do you eat your surplus wildlife? You do produce a surplus, don’t you? Or is this a Gucci Green ‘Dude Ranch’?