The estimation and robustness of F sub(MSY) and alternative fishing mortality reference points associated with high long-term yield

• Published in: Canadian journal of fisheries and aquatic sciences 2012-09, Vol.69 (9), p.1468-1480
• Main Authors: Horbowy, J, Luzenczyk, A
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/F2012-070

Equations for equilibrium yield and biomass are presented and used to derive F sub(MSY) and alternative reference points (ARPs). ARPs are analogues of the traditional points based on yield-per-recruit (YPR) or spawning stock-per-recruit (SPR) (F sub(0.1), F sub(40%), F sub(50%)), but refer to the equilibrium total yield or biomass. The method combines YPR and SPR analysis with stock-recruitment relationships. The sensitivity of F sub(MSY) and ARPs to the range of available stock-recruitment data, recruitment variance, various steepness levels in the stock-recruitment models, assessment variance, and bias are tested. The analysis showed that in most cases, F sub(40%B) and F sub(50%B), defined by the equilibrium biomass (B), were the most robust relative to the different sources of uncertainty. However, in the case of the misspecification of the stock-recruitment relationship, F sub(MSY) showed superior performance. F sub(40%B) for the Beverton and Holt stock-recruitment model and F sub(50%B) for the Ricker recruitment model can be recommended as conservative fishing mortalities associated with high long-term yield. For the considered steepness, they produced yield up to 5%-10% lower than yield at F sub(MSY).Original Abstract: Des equations pour le calcul du rendement et de la biomasse equilibres sont presentees et utilisees pour calculer le taux de mortalite correspondant au rendement maximum durable (FMSY) et des points de reference alternatifs (ARP). Les ARP sont des analogues de points traditionnels bases sur le rendement par recrue (YPR) ou sur le stock reproducteur par recrue (SPR) (F0,1, F40 %, F50 %), qui sont toutefois calcules par rapport a la biomasse ou au rendement equilibre total. La methode jumelle l'analyse du YPR et du SPR aux relations stock-recrutement. Une evaluation est presentee de la sensibilite de FMSY et des ARP a la fourchette de donnees disponibles pour etablir les relations stock-recrutement, a la variance du recrutement, aux divers niveaux de declivite (< steepness >) dans les modeles de stock-recrutement, a la variance de l'evaluation et aux biais. L'analyse demontre que, dans la plupart des cas, F40 %B et F50 %B definis par la biomasse equilibree (B) sont les taux les plus robustes aux vues des differentes sources d'incertitude. Par contre, dans les cas d'erreur de specification de la relation stock-recrutement, FMSY donne de meilleurs resultats. A la lumiere des resultats obtenus, F40 %B pour le modele stock-recrutement de Bev