Spawning in the nick of time? Effect of adult demographics on spawning behaviour and recruitment in Chesapeake Bay striped bass

Abstract

Striped bass (Morone saxatilis) is an iteroparous anadromous species that spawns dispersive offspring into freshwater habitats and exhibits a high fecundity and high embryo and larval mortality rates. Field studies indicate that temperature differentially affects spawning behaviour and larval survival, and periods of high egg production are often mis-timed for optimal larval survival. I hypothesize that age structure of females may be an important determinant in reducing variability in recruitment through its influence on spawning behaviour. Age diversity of Chesapeake Bay female striped bass is indexed according to expectations of age-specific reproductive values in an unexploited population. The age diversity index was positively correlated to spawning dispersion (egg presence ratio) and 0+ juvenile abundance during the recent period of population recovery (1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995). Diversity in age structure and spawning behaviour may contribute to a storage effect, because in most years minority behaviours would result in sustained recruitment. A diverse age structure may thus contribute to an accumulation of spawning stock biomass and increase the future likelihood of dominant year classes. International Council for the Exploration of the Sea

Dynamics of white perch Morone americana population contingents in the Patuxent River estuary, Maryland, USA

“…they are iteroparous with moderate longevity). Overlapping generations of spawners provide a 'storage effect' (Chesson 1984, Secor 2000 for reproductive potential, and when the infrequent (but eventual) conditions arise for successful reproduction, multiple generations can benefit (again the dominant year-class effect of Hjort 1914).…”

Fisheries-induced evolution: present status and future directions

“…This makes fisheries increasingly dependent on young, inexperienced spawners that are less fecund and produce eggs and larvae of lower quality (Trippel 1995, Berkeley et al 2004, Birkeland & Dayton 2006. This is deleterious for stock renewal; for instance, a low age diversity, corresponding to a large proportion of young individuals, is correlated with poor recruitment in Icelandic cod (Marteinsdottir & Thorarinsson 1998; see also Secor 2000). More generally, the truncation of the age structure caused by fishing removes a buffer against years of poor recruitment and exacerbates fluctuations in year-class strength.…”

Maternal Age as a Determinant of Larval Growth and Survival in a Marine Fish, Sebastes Melanops

“…While the advantage of longevity for persistence of a population in a variable environment is intuitive, a growing body of evidence suggests that a broad age distribution can also reduce recruitment variability (Lambert 1990, Marteinsdottir and Thorarinsson 1998, Secor 2000b. There are at least two mechanisms by which this buffering could occur: (1) there may be age- related differences in the time and location of spawning (Lambert 1987, Hutchings andMyers 1993), effectively spreading larval production over temporally and spatially variable environmental conditions, and (2) older fish may produce more fit eggs and larvae (Hislop 1988, Marteinsdottir andSteinarsson 1998), which can survive under conditions inadequate for survival of progeny from younger fish.…”