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Cost of prey capture, growth rate and ration size in pike, Esox lucius L., as functions of prey weight
Author(s) -
Hart P. J. B.,
Connellan B.
Publication year - 1984
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1984.tb04876.x
Subject(s) - esox , pike , predation , biology , foraging , predator , zoology , growth rate , weight gain , functional response , body weight , ecology , fishery , fish <actinopterygii> , mathematics , endocrinology , geometry
Prey intake, amount of time feeding, pursuit and manipulation times and growth rate were studied in the pike, Esox lucius , in relation to prey weight. Predator and prey were observed in tanks at 15°C and with a 14:10 h LD photoperiod. A total of 444 captures were recorded from five 1 g prey weight groups varying from 0 to 4.9 g. Ten pike were used weighing between 50 and 149 g. As prey weight increased, the number and weight of prey consumed decreased as did the time spent feeding, which became concentrated into the first trial of the day. Pursuit time did not vary with prey weight, but manipulation time and the weight of prey gained per unit pursuit plus manipulation time increased with prey weight. The growth rate of pike was a positive function of ration size and a negative function of the amount of time spent capturing each gramme of prey (capture cost). Growth rate was also correlated with the mean length and weight of prey eaten. The most profitable prey, as estimated from optimal foraging theory, need only be available once every 84 min for pike to maximize their net energy gain. The data show that feeding behaviour can have a direct influence on the reproductive success of pike through its effect on growth rate.