to the group. Apologies for idiot reply to the list. (again)
Donatella Del Piero
Dip. Biologia
via Weiss 2
I-34141 Trieste
++39 040 676 2016
Murphy law: few months in laboratory may save three hours in the library
----- Original Message -----
From: Donatella Del Piero <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, July 11, 2002 12:55 PM
Subject: R: Re: Fishing of large vs. small fish
> I'ill happy to have it. thanks
> Donatella Del Piero
> Dip. Biologia
> via Weiss 2
> I-34141 Trieste
>
> ++39 040 676 2016
> Murphy law: few months in laboratory may save three hours in the library
> ----- Original Message -----
> From: Mark Tupper <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, July 11, 2002 5:35 AM
> Subject: Re: Fishing of large vs. small fish
>
>
> > Dear Fish-Sci,
> >
> > Regarding the Conover and Munch study, there were some excellent
> discussions
> > posted on FishFolk over the last couple of days. If anyone not
subscribing
> > to FishFolk would like to read this material, I will happily compile it
> and
> > send it to you.
> >
> > Cheers,
> > Mark Tupper
> >
> >
> >
> > Dr. Mark H. Tupper, Assistant Professor
> > University of Guam Marine Laboratory
> > UOG Station, Mangilao, GU 96915, USA
> > tel 671-735-2185; fax 671-734-6767
> > www.uog.edu/marinelab/tupper/index.html
> >
> > Coordinator, Marine Protected Areas Research Group
> > www.uog.edu/marinelab/mpa/index.html
> >
> >
> > ----- Original Message -----
> > From: "William Silvert" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Wednesday, July 10, 2002 4:14 AM
> > Subject: Fishing of large vs. small fish
> >
> >
> > > The AFS mailing list recently reported the following item. I don't
find
> it
> > > surprising, a number of my colleagues are concerned about
> > over-exploitation
> > > of large mature fish, but I thought that the item was worth reposting.
> > >
> > > Some of you may have seen a posting on the sci.bio.ecology newsgroup
> about
> > > the FISH-ECOLOGY mailing list being located at SEARN. I don't know how
> the
> > > item got posted, but it is several years out of date. FISH-ECOLOGY is
> > > located in the Canary Islands, and FISH-SCI continues to be the list
> > located
> > > at SEARN.
> > >
> > > William Silvert, co-owner, FISH-SCI list
> > >
> > > July 09, 2002
> > > Study Questions Wisdom of Harvesting Only the Largest Fish
> > >
> > > SCIENCE
> > >
> > > Fisheries managers frequently set minimum size limits for captured
> > animals,
> > > mandating that the smallest--and thus youngest--be freed to allow for
> full
> > > maturation. But findings detailed in the current issue of the journal
> > > Science suggest that these regulations may actually be shrinking the
> > average
> > > size of wild fish over time. Plucking the largest fish from the gene
> pool,
> > > the authors report, leaves only hereditary information from the
smallest
> > > fish for the next generation.
> > >
> > > To examine the potential evolutionary effects of selective extraction
,
> > > David Conover and Stephan Munch of the State University of New York at
> > Stony
> > > Brook studied a common marine fish called Menidia menidia. Allowing
> groups
> > > of the fish to grow in separate tanks, the scientists removed and
> weighed
> > > the largest 90 percent of individuals from some tanks, the smallest 90
> > > percent from others, and a random 90 percent assortment from the rest.
> > After
> > > the remaining fish matured and spawned, the team repeated the process.
> > > Initially, the large fish-harvested tanks produced the highest yields.
> > After
> > > four generations of such "fishing," however, the total weight of all
the
> > > fish extracted from the small fish-harvested tanks, as well as the
> average
> > > weight of each creature, amounted to twice that of the large
> > fish-harvested
> > > tanks. Additionally, since the reproductive capability of large fish
is
> > much
> > > greater than that of small ones, small fish-harvesting resulted in
more
> > > fertile animals. Juvenile survival rates were about the same for all
> > groups,
> > > indicating that evolved changes in growth, not viability, caused these
> > > results. The findings suggest that in the real world, taking only the
> > > largest fish may in the long run result in a calamitous decrease in
> yield,
> > > and thus income, for the entire industry.
> > >
> > > Fishing is big business for many coastal communities. "In New York
State
> > > alone, the commercial fishing, recreational fishing, and the seafood
> > > industries make a $11.5 billion contribution to the state's economy
and
> > > employ over 100,000 people," remarks Jack Mattice of New York Sea
Grant,
> > one
> > > of the funders of this project. A successful industry is based on a
> > healthy
> > > fishery, however. "Our study illustrates how well-intentioned
management
> > > plans that appear to maximize yield on ecological time scales may have
> the
> > > opposite effect after accounting for evolutionary dynamics," Conover
> > notes.
> > > The researchers thus propose both creating no-fish areas to prevent an
> > > irreversible loss of important genetic diversity, and setting a
maximum
> > size
> > > limit in addition to the minimum. --Rachael Moeller
> > >
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