Intermittent recruitment and exploitation pulse underlying temporal variability in a demersal deep-water fish population

Recent temporal variability in abundance, size and age structure, distribution, and recruitment of the Skagerrak population of the commercially exploited long-lived deep-water demersal macrourid roundnose grenadier (Coryphaenoides rupestris) appeared strongly influenced by a combined effect of a single pronounced recruitment incident in the early 1990s and a subsequent pulse in targeted exploitation a decade later. Fishery-independent annual survey data showed that probably only one strong year class occurred across an almost three-decade period, 1985–present. Recruitment studies in deep-water fish remain few, yet rarity of successful recruitment events may have to be added to life-history characteristics already recognized as limiting the potential for sustainable harvesting of deep-water demersal fish, i.e. extended lifespan, slow growth, high age at first maturity, and low fecundity.