Paleonet: Nautilus capture-release results and deep sea inverts for interested parties
argo at u.washington.edu
argo at u.washington.edu
Thu Aug 11 04:54:51 GMT 2011
I am amidst a US-Philippines project to determine the population numbers of Nautilus pompilius in the Philippine Islands. We are using traditional fisheries techniques and local fishermen in the traditional fisheries locales. All specimens being caught are measured and immediately returned to the sea. Already we know that our current catch using multiple boats and 40 traps per day is between one and two orders of magnitude less than a decade ago.
The traps are resting at 250-400m and we are bringing up associated fauna. I am keeping one example of each crustacean encountered. However, this morning we found a one meter long stalked crinoid of great beauty entangled in our trap, with holdfast gone. We have preserved this believing that return to the sea would be useless for it. Does anyone out there want this, crustaceans, glass sponges, microgastropods, very peculiar tiny echinoids with enormous spines, and three species of sea star that I have never seen before? All will be preserved at University of San Carlos, Cebu City, and can be sent to interested taxonomists. Tentacle snips from 5 nautilus also available to interested DNA workers. This number can be increased if necessary , as it is non-lethal.
As far as Nautilus goes, please see the abstract below, to be delivered to the American Fisheries Society annual meeting, to be held next month in Seattle. The number of shells coming into the US alone may be only half the annual take: please look at these incredible numbers obtained over a year by scientists at US Fish and Wildlife and US National Marine Fisheries.
Nautilus takes 15 years to reach sexual maturity, then lays 10-15 eggs, and like other cephalopods may then die after breeding (or may not) - but in any event, very low fecundity and virtually no dispersal ability across deep water, so habitats rendered extinct cannot be repopulated in anything other than geological time. There also appear to be at least 10 and probably 10 different species of what we no call Nautilus pompilius, and I believe one of these is already extinct in the Philippines or is in extinction debt countdown.
“The species in these genera are slow-growing and late-maturing, with a low reproduction rate and low recovery potential, making them susceptible to overharvest. These species are native to western Pacific and Indo-Pacific coastal reefs, including the U.S. territory, American Samoa. Population declines have been reported in areas where intensive fisheries exist or have existed. The species appear to be unable to re-colonize localities from which they have been extirpated and captive breeding has not produced viable offspring beyond the hatchling stage. The primary threats to the Nautilidae (Nautilus and Allonautilus, now accepted based on multiple DNA studies this decade) are commercial harvest and habitat loss or degradation throughout its range. The species are internationally traded as shell products, jewelry, unworked shell, trim, and live specimens, for the curio and tourist markets,
and possibly for the aquarium and pet trade. More than 579,000 specimens were imported into the United States between 2005 and 2008, reported mainly from the Philippines, Indonesia, and China. Approximately 99 percent of these specimens are reported as wild-harvested.”
Professor Peter D Ward
Dept of Biology
The University of Washington
206-543-2962 ( Office )
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