Early development and growth of the laboratory reared north‐east Atlantic mackerel Scomber scombrus L.

Abstract

The early development, growth and morphological changes of mackerel Scomber scombrus were investigated at different incubation temperatures (8, 10, 13, 15 and 18° C). Details on the early life history are illustrated with special reference to morphological transformations. Culture techniques to rear larval mackerel stages are described using laboratory cultured foods. Artificially fertilized eggs were hatched after 80·6 h at 18·4° C and 256·8 h at 8·7° C. The standard length (LS) of the individuals at first feeding was 4·71 ± 0·18 mm. Four mortality critical periods and cannibalistic behaviour were identified. A maximum average larval size of 37·5 ± 4·41 mm LS was attained 30 days post‐hatch (dph) at 18·4° C. Development and growth were affected significantly by temperature during both endogenous and exogenous feeding periods. Larvae grew more rapidly at high, than at low temperatures. Daily specific growth rate (in mass) ranged from 2·4% at 10·6° C to 16·9% at 18·4° C. Likewise, average growth rate (in length) ranged from 0·05 mm day−1 at 8·4° C to 0·37 mm day−1 at 18·4° C. The allometric relationship of LS, with several body measurements was not affected by temperature. Comparison with larvae collected in the Bay of Biscay did not show any significant difference in the dry mass and LS relationship; conversely, the growth rate in length differed significantly between both laboratory and field conditions. The trends observed in the laboratory are described in relation to some aspects of the year‐class strength regulation.