Premium
A mathematical consideration on the adaptation strategy of marine fishes
Author(s) -
Tanaka Syoiti
Publication year - 1983
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02539632
Subject(s) - sardine , anchovy , fishing , biology , tuna , fishery , population , fish <actinopterygii> , demography , sociology
Summary Selections of life history is examined quantitatively for marine fishes based on mechanical models on survival, growth and maturation. For survival model, usual exponential model is applied and for growth model von Bertalanffy growth curve is used. Total assimilation, total egg production, mean duration of generation and equilibrium catch of one year class throughout its life are calculated. Effects on these quantities of manipulating parameters are examined particularly for K of Bertalanffy's growth curve, life span T and natural mortality coefficient M . Three kinds of strategies are taken into consideration. They are to maximize (1) growth rate of population, (2) energy efficiency for egg production and (3) total egg production throughout the life. Adaptation strategies are considered under the condition of no fishing. Strategists of first kind include anchovy and saury and have large K and M values and small T values. Strategiests of second kind include sardine and herring and have large values of all K, M and T . Strategists of third kind include tuna and flatfishes and have small K and M and large T values. Referring to tuna, sardine and anchovy, three sets of parameter values are posturated and the effects of fishing are examined. Tuna type fish are most severely affected by fishing but sardine and anchovy type fish are affected moderately or slightly by fishing provided that only adult fish are exploited. Particularly anchovy type fish are considered to be quite tough against fishing. Discussions are presented on such subjects as relation between environment and selection of life history, types of population fluctuation, and fisheries management problems.