Analysis of fluctuations observed in the trawl fleet landings of the Balearic Islands
Pere Oliver

A fluctuation with a pronounced periodicity has been observed in a historical series of landings of hake and red mullet by the trawling fleet of the Balearic Islands. Virtual Population Analysis was applied, based on monthly samples from 1980 to 1991, to clarify this phenomenon, as well as to assess these exploited stocks. The analysis shows a situation of over exploitation, due to an unreasonably high level of fishing effort and an inappropriate fishing pattern based on catches of the youngest age-classes. The need to observe the marine system as a unit is discussed, and expected increases in terms of biomass derived from the monospecific evaluations must be analysed taking into account the estimates of the "carrying capacity" of the system. It is concluded that moderate increments in fishery production can be hoped for, if technical measures to modify the actual exploitation pattern are introduced.

Keywords: Mediterranean, hake, red mullet, fisheries, stock assessment.
Contents of this volume Sci. Mar. 57(2-3) : 219-227 Back PDF
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