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Is batch variability in hatching time related to size heterogeneity and cannibalism in pikeperch ( Sander lucioperca )?
Author(s) -
Steenfeldt Svend,
Lund Ivar,
Höglund Erik
Publication year - 2011
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2010.02681.x
Subject(s) - hatching , biology , larva , cannibalism , human fertilization , yolk , incubation , zoology , incubation period , ecology , yolk sac , embryo , egg incubation , fishery , anatomy , biochemistry
Larval size heterogeneity is known to induce cannibalism, and procedures to avoid larval size differences are consequently implemented already during egg incubation and hatching. We investigated the relation between larval development variability, size heterogeneity and cannibalism in pikeperch. Larvae were sorted into five groups according to the time of hatching during a 65‐h period. The larvae with different times of hatch were then reared separately or together during an 18‐day period. Late hatched larvae were longer ( P =0.003) and had less yolk remaining ( P <0.001) than early hatched individuals at the time of hatching. However, on 11 days post fertilization, the late‐hatching larvae tended to have larger yolk reserves than earlier hatched individuals ( P =0.07). Furthermore, the next day, a lower proportion in the late fraction had switched to exogenous feeding ( P =0.024). That larvae with a late hatching time developed slower suggests a positive relationship between the hatching time and the embryonic developmental rate. However, differences in the length and available yolk reserves at hatching between larval fractions with different hatching times suggest that hatching is not strictly associated with a specific developmental stage, and that factors other than the development rate of the embryo are involved in the timing of hatching.