Publisher :
Place of publication :
Publication year : 2008
Thematic : Fisheries
Language : English
Note
What to do about fisheries collapse and the
decline of large fishes in marine ecosystems is a critical
debate on a global scale. To address one aspect of this
debate, a major fisheries management action, the removal
of gill nets in 1994 from the nearshore arena in the
Southern California Bight (34°2630N, 120°2709W to
33°3203N, 117°0728W) was analyzed. First, the impetus
for the gill net ban was the crash of the commercial fishery
for white seabass (Atractoscion nobilis; Sciaenidae) in
the early 1980s. From 1982 to 1997 catch remained at a historically
low level (47.8 § 3.0 mt) when compared to landings
from 1936–1981, but increased significantly from
1995–2004 (r = 0.89, P < 0.01) to within the 95% confidence
limit of the historic California landings. After the
white seabass fishery crashed in the early 1980s, landings
of soupfin (Galeorhinus galeus; Triakidae) and leopard
shark (Triakis semifasciata; Triakidae) also significantly
declined (r = 0.95, P < 0.01 and r = 0.91, P < 0.01, respectively)
until the gill net closure. After the closure both
soupfin and leopard shark significantly increased in CPUE
(r = 0.72, P = 0.02 and r = 0.87, P < 0.01, respectively).
Finally, giant sea bass (Stereolepis gigas; Polyprionidae)
the apex predatory fish in this ecosystem, which was protected
from commercial and recreational fishing in 1981,
were not observed in a quarterly scientific SCUBA monitoring
program from 1974 to 2001 but reappeared in 2002–
2004. In addition, CPUE of giant seabass increased significantly
from 1995 to 2004 (r = 0.82, P < 0.01) in the gill net
monitoring program. The trends in abundance of these
fishes return were not correlated with sea surface temperature
(SST), the Pacific Decadal Oscillation (PDO) or the
El Niño/Southern Oscillation (ENSO). All four species
increased significantly in either commercial catch, CPUE,
or in the SCUBA monitoring program after the 1994
gill net closure, whereas they had declined significantly,
crashed, or were absent prior to this action. This suggests
that removing gill nets from coastal ecosystems has a positive
impact on large marine fishes.
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Keywords :
Encoded by : Pauline Carmel Joy Eje
