The Salmon Purse Seine - Competition and Information Among British Columbia Salmon Purse Seiners
In partial summary, the question in British Columbia is one of fishing power--the ability of gear, boats, or fleets, in the B.C. and P.E.I. cases and others, to exploit or overexploit fish stocks. Without a historical perspective based on quantitative (and innovative) field research, we are doomed to repeat our work loads: In the absence of extensive (and often necessarily alternative) time series of fishing effort and effectivity (fishing power), stock assessment and fisheries management become absurd. Like they said on P.E.I., a fleet (or transient cluster) of purse seiners can wipe out a stock (anywhere in the world).
(PRWEB) November 15, 2004 -- In British Columbia, Canada, salmon purse
seiners line up at fishing access points, forming well defined queues. These
queues were measured over time, using a one-dimensional recording scale.
Sixty-one overflights of Johnstone Strait and Queen Charlotte Strait were
attempted; 51 flights were completed.
Two models were presented for
exploitation rates in relation to queuing patterns. The overflight model was fit
to the line-up distributions. One underlying assumption was that the skippers
possessed fairly accurate information regarding the distribution of catches
(analysis of variance methods utilizing skippers' logbook data showed that
line-up lengths reflected catch rates). The model fit well and the parameter
estimates reflected anecdotal and statistical information about fish behavior.
The exploitation rates saturated at an effort level of 100 vessels (whereas the
maximum effort observed was 363 boats) and indicated that (at saturation) the
fleet caught 80% to 90% of the vulnerable migrating salmon present in Johnstone
and Queen Charlotte Straits during what were commonly 48- or 72-hour fishing
openings. (Note: Salmon successfully migrating through the strait on days that
were closed to seiners and salmon that were not vulnerable to the gear--e.g.,
below the depth of the nets--escaped the purse-seine fleet.)
In general,
traditional assumptions were rejected. Vessels did not operate independently.
Boats were not distributed in a random fashion. The overflight model provided
predicted exploitation rates. The exploitation response to effort was
qualitatively distinct from the forms incorporated in traditional
models.
In partial summary, the question is one of fishing power--the
ability of gear, boats, or fleets, in the B.C. and P.E.I. cases and others, to
exploit or overexploit fish stocks. Without a historical perspective based on
quantitative (and innovative) field research, we are doomed to repeat our work
loads: In the absence of extensive (and often necessarily alternative) time
series of fishing effort and effectivity (fishing power), stock assessment and
fisheries management become absurd. Like they said on P.E.I., a fleet (or
transient cluster) of purse seiners can wipe out a stock (anywhere in the
world).
http://www33.brinkster.com/ledbetter/
http://thefishfinder.com/members/saltwater/ledbetter/
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Source : http://www.prweb.com/releases/2004/11/prweb178134.htm