Costos metabólicos de Engraulis ringens y Sardinops sagax en relación al peso, temperatura y el nivel de actividad

Abstract

The stan,dard metabolism (calculated f or 14 ºC-20º.C) is higher f or an­chovy than for sardine; for the larvae by an average factor of 2.3 and by a factor of 2.1 for juveniles and adults. The contrary occurs with the active metabolism: for a swimming speed of 1 body length per second (=routine .metabolism) an adult anchovy (bigger than 20 g at 20ºC and bigger than 50 g at 14°C) requires less energy than a sardine of the same. size. Increasing the swimming speed to 3 body lengths per second, at 17°C, all sardines bigger than 1.5 g require more energy than anchovy (a sardine of 5 g by a factor of .1.5 and one of 25 g. by a factor of 3.8) A temperature changé of 6.ºC (from •l4ºC to. 20ºC) affects both species in a differént way; assuming a swimming speed of 1 body length per second an anchovy larva (0.1 g) has to increase its metabolic expenditure twice as much as a sárdine larva but and adult ancbovy (40 g) needs just 60% of that of a sardine of the same size.