Ontogenetic changes in mouth structures, foraging behaviour and habitat use of Scomber japonicus and Illex coindetii |
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J.J. Castro and V. Hernández-García |
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The quick development of the skull structure is of vital importance to animals during the early stages of life given that here in are located the governing center and the mechanisms which make feeding possible. However, the rhythm of growth changes thoughout the life cycle, a process which is particularly manifest in the proportionate head/body growth. The mouth structures grow proportionately to head growth. These accentuated changes in the anatomy of the animal could be reflected in its behavioural pattern (migrations between two areas in the case of some species and significant changes in diet connecting to these migrations). Scomber japonicus (Pisces. Scombridae) and Illex coindetii(Cephalopoda, Ommastrephidae) both undergo significant changes in the rhythm of growth of their respective mouth structures when they reach around 13-15 and 14-20 cm of total body length (mantle length in cephalopods) respectively. In Illex coindetii there are also differences by sex, being the changes of growth at 15 cm in males and around 20 cm in females. In both of these species, this change in the rhythm of growth implies a significant variation in dietas the consequence of a shift of habitat. |
Keywords: Ontogeny, Scomber japonicus, Illex coindetii, mouthstructures, migration. |
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Sci. Mar. 59(3-4) : 347-355 |
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