Assessment of larval growth patterns: A comparison across five fish species in the Bay of Biscay

Abstract

Hake, mackerel, horse mackerel, anchovy and sardine larvae were identified from samples of ichthyoplankton collected during eight surveys in the Bay of Biscay between 2000 and 2005. Comparative analyses were carried out to explore the early growth patterns of these species based on differences in body proportion and the interpretation of the otolith microstructure to estimate their age. Statistical differences in development rates were observed for different body proportions. On the one hand, the larvae of hake, mackerel and horse mackerel prioritise the growth of those parts of the body related to feeding (body weight, head and jaw), while those of anchovy and sardine prioritise those related to swimming (body length). We propose that these different strategies are adaptations to reduce larval mortality, each of them focusing on the main factor that controls it during the early stages: starvation and predation. These growth strategies are interpreted from an environmental perspective mainly related to the characteristics of the food and the abundance of predators in the environment in which the larvae develop during this vulnerable life stage.