Biological Oceanography

(ff) #1

coastal regions, are often drowned while entangled in gill nets that are not lost. Recent
international conventions have somewhat reduced the net loss problem by requiring
shorter, better-marked runs of net, and have reduced bycatch (and possibly catch) by
closing some areas. These problems cannot be totally eliminated if we are going to
fish. However, the tuna fisheries in the eastern tropical Pacific have achieved great
reductions in porpoise mortality, despite continuing to set seines around porpoise
schools. Similar reductions in sea-turtle mortality have been achieved in shrimp
fisheries by installing turtle-excluding devices in trawl mouths. These and other
success stories show that careful design of operations can minimize bycatch and
habitat destruction.


(^) A movement now afoot among environmentalists, fishery managers, and even the
fishing industry seeks to protect commercial fishery stocks, other populations, and
some parts of the marine habitat, by establishing reserves closed to fishing. It is
reasonable to expect that refuges could allow some individual organisms to reach
large size and high reproductive rates (to become BOFFF); that the young will prosper
in undisturbed habitats; and that burgeoning populations will spread from reserves
into surrounding fishing zones. Many aspects of reserve design are under study,
including physical dimensions, types of bottom to include, and siting that takes
advantage of flow patterns. Both spawning sites, where abundant species congregate
intermittently, and nursery areas are obvious candidate locations. Evaluation of sites
and quantification of reserve effects have become research topics in their own right.
Results already available show dramatic success at improving habitat quality and
fishing in neighboring zones (Lubchenco et al. 2007), sometimes primarily just
outside the reserve perimeter.


Last Words


(^) If you reached this point by reading the whole book, congratulations and thanks. We,
too, are glad to have reached it. Take the day off and go fishing. There are still some
fish, if only some.

Free download pdf