in many fisheries is zero. If a fishery were to be maintained by regulation near MSY,
then too many boats would appear to take that catch, again distributing the profit so
thinly that the mean would be near zero. Limiting fishing days or gear type often does
this. Thus, fishers (and expensive gear) must sit idle much of the time or use the least-
efficient equipment. Fishing industries regulated in these ways are typically low on
productivity per unit capital, and labor productivity is abominable. The best solutions
are franchise fisheries (where the fisher folk own the fish stock) and limited-entry
fisheries. The politics of those are fearsome, but such schemes are being established
in some places, notably coastal Japan, British Columbia, Alaska, and even for US
West Coast trawl fisheries.
Regime Changes
(^) Since the late 1980s, fisheries scientists have been fascinated by what they have come
to call “regime changes” (e.g. Hollowed et al. 1987); in fisheries these are the
responses of stocks to the decadal climate oscillations introduced in the last chapter.
An example was given above, the shift in CPUE of yellowfin tuna around 1985. Such
substantial differences in stock levels and production between multi-year and multi-
decade intervals occur everywhere in the oceans, to all sorts of fish. The best-studied
examples are found among the forage fishes (mostly Clupeidae: sardines, anchovies,
herrings, capelin, and others), which are subject to industrial fisheries. Bakun (Bakun
1996; Bakun et al. 2009) points out that these fish are the “waist” in what he calls
“wasp-waisted” pelagic ecosystems. Phytoplankton and zooplankton are usually
moderately diverse, with many species, while the schooling forage fish feeding upon
them belong to one or two species, one generally being strongly dominant at any
given time. Those forage fish are fed upon in turn by a diverse range of fish, squid,
birds, and mammals: mackerel, salmon, cod, ommastrephid squid, seals, terns, and
whales. Thus, intermediate trophic transfers pass through a low-diversity link, the
wasp waist, between more complex levels below and above.
(^) In temperate and eastern tropical neritic seas (out to 100+ nautical miles), the
dominant forage species is often a sardine or an anchovy. For example, the dominant
schooling fish in the California Current are usually Sardinops sagax cerulea (sardine)
or Engraulis mordax (anchovy). Fishing off the California coast began at the end of
the 19th century and became a substantial industry in the 1920s (Fig. 17.18a),
generating good data on take. The sardine fishery, particularly off central California,
built up to takes over 0.6 Mt in the 1930s, when biomass is believed to have been 3.6
Mt, and sustained that level to the late 1940s. Then it crashed, failing to support any
fishery after 1951 with biomass reaching 0.01 Mt in the 1960s. It isn’t clear exactly
when anchovy stocks appeared to replace these sardines, because no significant
fishery for them developed until the 1970s. Development of fisheries requires not