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.

Annual publications involving the application of coupled physical-biological models for understanding fish recruitment processes have increased over the last decade. Sixty-nine papers were reviewed to assess the contribution these models have made to recruitment prediction and understanding. The majority of models reviewed were 2-and 3-dimensional numerical simulation models, although a limited number of 1-dimensional analytical models were included. Most models used a Lagrangian tracking algorithm to advect and diffuse particles within the model domain. The vertical and horizontal resolutions and temporal durations of the models varied widely. This review identified 3 categories of papers: explanatory, inferential and hypothesis generating. Reviewed papers were dominated by explanatory approaches. Assessment of the sensitivity of model predictions to the model parameters were rare, but not entirely absent in this group of papers. Inferential approaches were the next most common, and sought to infer the presence or role of a particular mechanism. Hypothesis-generating publications were the rarest, but perhaps have the most to contribute to a greater understanding of recruitment processes. An increase in the frequency of hypothesis-generating applications of coupled physical-biological models may be expected over time as the field matures and refinements to both the physical and biological processes included in the models are made.

Accumulating evidence indicates that as global temperatures rise, reproductive behaviors, including migrations, are occurring earlier across a range of taxa. Alone, these changes are ecologically important; however, for some fish populations, management practices may unknowingly interact with climate‐induced changes in reproductive phenology, leading to unanticipated changes in fishing mortality. The potential for such an interaction exists for the Chesapeake Bay Striped Bass Morone saxatilis fishery, which opens on the same week each year during the spawning season. Earlier migrants spawn before the fishery opens; however, later migrants are vulnerable to fishing before they reach the spawning grounds. Consequently, if there are climate‐induced changes in Striped Bass spawning phenology, unexpected levels of fishing mortality may occur for egg‐bearing, prespawn females. To evaluate the potential consequences of this temporally fixed fishing season, we analyzed a time series of gill‐net catch data using an inference‐based modeling approach to identify the environmental cues driving variation in the migratory timing of Striped Bass onto their two primary spawning grounds. We hypothesized that factors driving migratory timing would also influence the proportion of egg‐bearing, prespawn females caught in the fishery each year. Results indicated that spring water temperature was the primary factor influencing the timing of movement onto spawning grounds, with higher temperatures resulting in early migrations. Importantly, our results indicated that in cool years, when females moved onto the spawning grounds later, more egg‐bearing females were caught in the fishery before they could spawn. This situation provides impetus for establishing management approaches that reduce potential climate‐induced variability in fishing mortality in the Chesapeake Bay and fisheries around the globe. Received December 20, 2012; accepted September 5, 2013 Published online February 10, 2014

Vertebral samples of little skate (Leucoraja erinacea) and winter skate (Leucoraja ocellata) were collected from Cape Hatteras, USA, to Canadian waters to estimate age, growth, and length at weight relationships for both species throughout this range. Maximum observed age was 12.5 and 20.5 years for little skate and winter skate, respectively. Significant length at weight relationships were found for both species. von Bertalanffy growth curves for the northwestern Atlantic were estimated for little skate (k = 0.19, L ∞ = 56.1 cm, t 0 = -1.17, p < 0.0001, n = 236) and winter skate (k = 0.07, L ∞ = 122.1 cm, t 0 = -2.07, p < 0.0001, n = 229). Additionally, latitudinal patterns in size and growth were observed in little skate, with individuals in northern regions growing slower and reaching a larger asymptotic size: von Bertalanffy growth estimates (mid-Atlantic, k = 0.22, L ∞ = 53.26 cm, t 0 = -1.04, p < 0.0001; southern New England -Georges Bank, k = 0.20, L ∞ = 54.34 cm, t 0 = -1.22, p < 0.0001; Gulf of Maine, k = 0.18, L ∞ = 59.31 cm, t 0 = -1.15, p < 0.0001). Although differences were observed for sex-specific growth curves for both species, only winter skate curves were significantly different.Résumé : Nous avons prélevé des échantillons de vertèbres chez la raie hérisson (Leucoraja erinacea) et la raie tachetée (Leucoraja ocellata) depuis le cap Hatteras, É.-U., jusque dans les eaux canadiennes afin d'estimer l'âge, la croissance et les relations de la longueur en fonction de la masse chez les deux espèces dans cette aire de répartition. L'âge maximal observé est de 12,5 ans chez la raie hérisson et de 20,5 ans chez la raie tachetée. Il existe des relations significatives de la longueur en fonction de la masse chez les deux espèces. Nous avons estimé les courbes de croissance de von Bertalanffy pour la raie hérisson (k = 0,19, L ∞ = 56,1 cm, t 0 = -1,17, p < 0,0001, n = 236) et pour la raie tachetée (k = 0,07, L ∞ = 122,1 cm, t 0 = -2,07, p < 0,0001, n = 229) dans le nord-ouest de l'Atlantique. De plus, nous avons observé des patrons latitudinaux de taille et de croissance chez la raie hérisson; en effet, les individus des régions nordiques croissent plus lentement et atteignent une taille plus grande à l'asymptote (Atlantique moyen, k = 0,22, L ∞ = 53,26 cm, t 0 = -1,04, p < 0,0001; sud de la Nouvelle Angleterre et banc Georges, k = 0,20, L ∞ = 54,34 cm, t 0 = -1,22, p < 0,0001; golfe du Maine, k = 0,18, L ∞ = 59,31 cm, t 0 = -1,15, p < 0,0001). Bien que des différences aient été observées entre les courbes de croissance spécifiques à chaque sexe chez les deux espèces, seules les différen-ces entre les courbes de la raie tachetée sont significatives.[Traduit par la Rédaction] Frisk and Miller 1091

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