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Subject: Re: Is overfishing a scientific or legal term?
From: Mike Flaherty <[log in to unmask]>
Reply-To:Scientific forum on fish and fisheries <[log in to unmask]>
Date:Thu, 26 May 2005 11:33:33 -0400

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Donatella wrote:

Justin: overfishing is a common term of course derived from informal
language but the technical definition is easily found in every fishery
science book, you may also distinguish between growth overfishing
and recruitment overfishing (e.g.Sparre, 1987 and many others).

There is a text that I refer to often called...

Manual for understanding the Federal Fisheries
Management Process, Including
Analysis of the 1996 Sustainable Fisheries Act

It may be found for free at...

I have included some salient excerpts below on "recruitment overfishing" and
"growth overfishing".

Mike Flaherty
Wareham, MA

Assessment Based on a Little Biology (Age at First Spawning)

When little is known about the biology of a fish stock, one of the first
questions asked is, "At what age do the fish spawn?" The second question is,
"What proportion of the fish caught are one year, two-years, and three-years
old?" If some of the fish spawn when they are two-years old, and all spawn
at age three, and most of the fish caught are two-years old, then there is a
danger that too many fish may be caught before they can spawn and replace
themselves. This is called recruitment overfishing.


So far we have emphasized overfishing that leads to declining stocks. This
is often referred to as recruitment overfishing. The name indicates that the
mortality rate from fishing is severe enough to affect future recruitment to
the extent that catches are reduced and the stock is jeopardized. Another
type of overfishing is called growth overfishing. Growth overfishing occurs
when the bulk of the harvest is made up of small fish that could have been
significantly larger if they survived to an older age. The concern here is
that the fishery would produce more weight if the fish were harvested at a
larger size. The question biologists, economists, managers, and others must
answer is how much bigger or older should the fish get before they are

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