Essential relationships incorporating the influence of age, size and condition on variables required for estimation of reproductive potential in Atlantic cod Gadus morhua

Abstract

Evidence accumulated over the last decade indicates that reproductive potential of marine fish stocks is not correctly represented by spawning stock biomass. Fundamental variables that affect reproductive potential of fish stocks (i.e. proportion mature at age, fecundity, and offspring size and viability) have found to vary with age, size, and condition of spawning fish, and/or spawning experience. Modeling initiatives that attempt to describe reproductive potential by incorporating all available information on reproductive variables require extensive, high quality data of a temporal and spatial origin. In this study, we explored the influence of female age, size, and condition on several reproductive variables for the cod Gadus morhua, including maturity, fecundity, egg density and size, and larval size and growth. In addition, we described the potential for annual variation in these relationships to increase our knowledge of temporal stability for fundamental variables that influence reproductive potential.

Changes in size at maturity of European hake Atlantic populations in relation with stock structure and environmental regimes

“…Engelhard and Heino (2004a) observed in Norwegian herring that during a collapse of the population, age at maturity diminished, whereas size at maturity increased slightly, probably as a compensatory response. Marteinsdottir and Begg (2002) described for Atlantic cod a decrease in size and age at maturity, not only between years due to overexploitation, but also between Northern and Southern stocks, probably as a consequence of changes in temperature.…”

“…Maternal physiological status, spawning experience (recruit or repeat spawners) or food rations during gametogenesis are all known to alter fecundity, egg and larval quality, as well as duration of the spawning season (Hislop et al, 1978;Kjesbu et al, 1991;Trippel, 1999;Marteinsdottir and Begg, 2002). Fecundity and relative fecundity generally increase with body size (Wootton, 1979;Kjesbu et al, 1998).…”

“…Regardless the causes of maturation variation, this population characteristic can have large effects on the reproductive output of a stock. For example, shifts to maturation at smaller sizes and younger a ges affect fecundity (Rijnsdorp 1991, Kraus et al 2002, Marteinsdottir and Begg 2002, egg and larval size and viability (Trippel et al, 1997).…”

Paternal identity impacts embryonic development for two species of freshwater fish

“…Paternal contributions were believed to have only a limited influence on embryonic development and larval fitness traits in fishes as compared to maternal contributions (Keckeis et al, 2000;Marteinsdottir and Begg, 2002). Paternal contributions to progeny are solely the product of nuclear-genetic material from the spermatozoon (Rideout et al, 2004).…”

Variability in Fish Tissue Proximate Composition is Consistent with Indirect Effects of Hypoxia in Chesapeake Bay Tributaries

“…For instance, environmental conditions that are encountered prior to spawning can affect the reproductive performance of European Anchovy Engraulis encrasicolus (Pecquerie et al 2009). Comprehensive models that include variability in reproduction (e.g., weight-and agespecific fecundity; Marteinsdottir and Begg 2002;Spencer and Dorn 2013) are currently under development, and additional refinements should be considered. The clear effects of hypoxia on Atlantic Croaker reproduction should be quantified in assessment models, as bias in the number (or weight) of spawning females may lead to overestimation of the spawning stock's reproductive potential.…”