[Coral-List] The battle for biodiversity
sfrias_torres at hotmail.com
Tue Nov 30 09:46:01 EST 2010
Both John and Martin are correct. The last piece of evidence in the Florida spiny lobster population jigsaw is that when we put together the catch taken in the 2-day mini season and the commercial and recreational catch, very few lobsters are left to rebuild the stock. So even if there is self-recruitment (some lobster scientists were estimating about 30 % of Florida lobsters are self-recruitment), it seems there is not enough native stock left at the end of the season. Which suggests that the Florida spiny lobster population indeed depends largely on larval influx from Caribbean sources.
Another interesting twist in the lobster story: many fishers in Florida blame the goliath grouper (Epinephelus itajara) as responsible for declines in the spiny lobster, snapper and grouper populations. They see the recovering population of the previously nearly extinct goliaths as a threat, because fishers consider goliath groupers are super-predators of lobster, snappers and groupers. All scientific evidence shows goliaths are mostly invertebrate predators, and although they predate on lobsters, the do so as part of a diverse diet which includes snails, worms, crabs and poisonous fish (stingrays, catfish, Diodontidae).
It is quite an interesting human trait: rather than analyzing our own actions (in this case, overfishing the spiny lobster, the groupers and the snapper stocks), we prefer to find someone else to blame for our mistakes (here, the culprit is the goliath grouper).
Are we ever going to learn from our mistakes?
Sarah Frias-Torres, Ph.D. Postdoctoral Scholar &Schmidt Research Vessel Institute Postdoctoral Fellowhttp://independent.academia.edu/SarahFriasTorresOcean Research & Conservation Association 1420 Seaway Drive, 2nd Floor Fort Pierce, Florida 34949 USA http://www.teamorca.org
> From: jbruno at unc.edu
> To: coral-list at coral.aoml.noaa.gov
> Date: Tue, 30 Nov 2010 02:22:50 +0000
> Subject: [Coral-List] The battle for biodiversity
> A case in point is the spiny lobster fishery of Florida. It has been shown
> through analysis of mitochondrial DNA (Silberman, et. al., 1994) that, as
> expected, genetic analysis shows no evidence of genetic structure in the spiny
> lobster (P. argus) population, which is consistent with a high gene flow
> throughout the population. This also indicates that the population of spiny
> lobsters in Florida is dependent on larval influx from Caribbean sources.
> Martin, thank you for that really interesting post, especially your insights on the response of lobster fishers to NOAAs catch shares plan. Not to suggest that I know anything about lobster population genetics, but the lack of genetic structure within a population (or among populations) doesn't necessarily mean strong demographic connectivity and that result certainly doesn't indicate that "the population of spiny lobsters in Florida is dependent on larval influx from Caribbean sources". For one, a relatively small degree of migration between subpopulations can be enough to genetically homogenize them without creating much if any demographic connectivity. Even if there were effective demographic connectivity between Florida and Caribbean populations, that would not necessarily mean the Florida populations were a sink and wholly dependent on larval subsidies.
> John Bruno
> Associate Professor
> UNC Chapel Hill
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