Larval Size and Recruitment Mechanisms in Fishes: Toward a Conceptual Framework

TLDR

Recruitment in fishes remains poorly understood, with most studies species‑specific and lacking a conceptual framework that links larval size to survival and recruitment. The authors propose an integrating framework that connects larval body size to recruitment success. They examined evidence for size effects on feeding, starvation, activity, searching ability, and predation risk across species. Regression analyses of 72 species show that body size unifies many observations, indicating that a size‑based framework can integrate larval growth and survival data and guide future recruitment studies.

Abstract

Understanding the mechanisms controlling recruitment in fishes is a major problem in fisheries science. Although the literature on recruitment mechanisms is large and growing rapidly, it is primarily species specific. There is no conceptual framework to integrate the existing information on larval fish ecology and its relationship to survival and recruitment. In this paper, we propose an integrating framework based on body size. Although all larval fish are small relative to adult fish, total length at hatching differs among species by an order of magnitude. As many of the factors critical to larval survival and growth are size dependent, substantially different expectations arise about which mechanisms might be most important to recruitment success. We examined the evidence for the importance of size to feeding and starvation, to activity and searching ability, and to risk of predation. Regressions based on data from 72 species of marine and freshwater species suggest that body size is an important factor that unifies many of the published observations. A conceptual framework based on body size has the potential to provide a useful integration of the available data on larval growth and survival and a focus for future studies of recruitment dynamics.