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J. A. GULLAND AND J. E. CARROZ
B. The need f o r further research
From the experience of the commissions which have already taken
action to restrict the amount of fishing, and of the other commissions
which are actively considering such action, some of the requirements for
achieving full management can be deduced. First, the essential basis
of any management is the proper biological understanding of the state
of the stocks concerned. Unless the administrators know what the
probable effects of regulation on the stock and future catches may be,
they have no means of assessing the desirability of taking action. The
fishery scientist should be able to provide estimates of the effects of
any regulatory measure proposed, not only on the stock directly
concerned, but on related stocks. For instance, a complete study of thc
fishing on the Peruvian anclioveta (Fig. 12), and the need for regulation
of the fishery on it, should include an assessment of the effect of
different amounts of fishing on the food available to the guano birds,
and hence the likely effects on the guano industry. Theoretically the
chain of related stocks, the first preying on the second, which competes
FIG. 12. A catch of anchoveta off Peru, which supports the biggest fishery in the ~ o r l d .
An estimated 583 660 000 individual fish were taken from a single year-class
(Boerema et ul., 1965). (Photo: F.A.O.)