Since Johan Hjort published his treatise on the great fisheries of Northern Europe one hundred years ago, there has been widespread agreement that the early life history of fish represents a crucial stage in the life cycle that can determine variations in population abundance. The larval stage bottleneck can occur over a short 'critical period' (sensu Hjort 1914) due to starvation following yolk absorption, or over a more protracted period from hatch to metamorphosis. In both instances, understanding the key factors influencing these processes comes down to investigating patterns of growth and their potential relationships with the larvae's feeding environment.
In this study, Pepin et al. have investigated individual variability in the relationship between stomach content (a common index of short-term feeding success), and otolith growth (an index of longer-term feeding success) across 11 species in which stomach content and otolith growth had previously been measured in the same individual fish larvae.
Instantaneous measures of feeding success were highly variable but positively (albeit weakly) correlated with growth rates across all taxa. The strength of the feeding-growth relationship among taxa was reflected in the autocorrelation of individual growth rates, suggesting that fast and stable growth is achieved through consistent feeding success. Within taxa, however, random events play an important role in determining relative success among individuals, with larger size being achieved in fish with the most variable daily growth.
While the positive link found in all taxa between feeding success and growth supports the current larval growth-survival paradigm, the much stronger association between these vital rates combined to the higher growth serial correlation in fast-growing species indicate that the potential for a 'critical period' during the first-feeding stage could be maximum in fast-growing fish because of the greater consequences of departures from that relationship.
During the early larval stage of Atlantic mackerel, the relationship between otolith growth increments and copepod nauplius prey capture success strengthens through development and has implications for survival; © Claude Nozères and Gérald Darnis.
Article title: Once upon a larva: Revisiting the relationship between feeding success and growth in fish larvae
Authors: Pierre Pepin, Dominique Robert, Caroline Bouchard, John F. Dower, Marianne Falardeau, Louis Fortier, Gregory P. Jenkins, Véronique Leclerc, Keith Levesque, Joel K. Llopiz, Mark G. Meekan, Hannah M. Murphy, Marc Ringuette, Pascal Sirois, and Su Sponaugle