Accounting for the fish condition in assessing the reproductivity of a marine eel to achieve fishery sustainability

• Main Authors: Ji, Y. (Author), Mu, X. (Author), Ren, Y. (Author), Xu, B. (Author), Xue, Y. (Author), Zhang, C. (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2021
• Subjects: biomass; body condition; Body condition; Cong myriaster; Conger myriaster; decision making; Decision making; Decision support systems; fecundity; Fecundity; Fish; Fisheries; Harvest restriction; Hepatosomatic indices; recruitment (population dynamics); Reference points; reproduction; Reproductivity; spawning; Spawning potential ratio; Spawnings; SPR; sustainability
• Online Access: View Fulltext in Publisher

 Spawning potential ratio (SPR) is a commonly used biological reference point to inform management decisions; however, the fish reproductivity may vary substantially with different body conditions, and the variability has not been well understood. Here, we examined the maturity, fecundity, and SPR of a marine eel Conger myriaster. The results showed that total fecundity increased with length and hepatosomatic indices (HSI), whereas relative fecundity (total fecundity/body weight) decreased with body weight, suggesting length- and condition-driven reproductive strategies. A length-structured per-recruit model was used to estimate SPR and examine the influence of HSI in resultant management decisions. Our results suggested that this stock was subject to a high risk of recruitment overfishing. Fish condition greatly influences the estimates of SPR-related reference points. For example, when HSI increased from 0.6% to 1.8%, F40% increased by 91%. In addition, using spawning stock biomass to calculate F40% could produce a bias of 23%. We highlight the need for monitoring the changes in fish fecundity and conditions in fisheries assessment, which may contribute to the robust management of data-poor fisheries. © 2021 The Author(s)