Abstract

Fishery discard survival depends on multiple conditions; caution is essential when survival study outputs are employed to support management decisions. The study presents a stepwise procedure, devised to estimate discard survival, that accounts for the variability characterizing commercial fishing practices. The procedure was applied to the first survival study performed onboard rapido trawlers targeting Solea solea in the Mediterranean Sea. Undersized specimens collected during sorting were assessed for vitality; some were retained for captive observation. The main drivers affecting discard survival at the time of catch sorting (immediate survival) were identified and used to outline four different operational conditions set (scenarios). Immediate survival in each scenario was subsequently modified by applying a hazard coefficient of survival after 5 days of captive observation in relation to each vitality class, thus obtaining relative survival estimates following discarding. Temperature and air exposure duration were found to exert a major effect on survival, with catch weight and seabed type being additional important factors. The relative survival rate showed an aggregate value of 22.9% (10.5–33.4%). Scenario approach can enhance our understanding of the stressors influencing discard survival. The outcomes are discussed to explore the potential applications of the procedure to the identification of mitigation strategies.

中文翻译：

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相对生存方案：在地中海拖网捕捞中对尺寸较小的普通（Solea solea L.）的应用

摘要

渔业丢弃物的生存取决于多种条件；当将生存研究结果用于支持管理决策时，谨慎是必不可少的。这项研究提出了一种分阶段的程序，旨在估算丢弃物的存活率，从而说明了商业捕鱼行为的多样性。该程序已应用于针对Solea solea的机载Rapido拖网船进行的首次生存研究在地中海。评估在分选过程中收集的尺寸过小的标本的活力；一些被保留供俘虏观察。确定了影响渔获物分拣时丢弃物生存（直接生存）的主要驱动因素，并用于概述四种不同的操作条件集（场景）。随后通过对每项生命力类别进行5天的观察观察后，通过应用生存危险系数修改每种情况下的立即生存，从而获得丢弃后的相对生存估计。发现温度和空气暴露持续时间对生存有重要影响，渔获量和海床类型是其他重要因素。相对存活率显示总值为22.9％（10.5-33.4％）。方案方法可以增进我们对影响丢弃物生存的压力源的理解。讨论了结果，以探索该程序在确定缓解策略中的潜在应用。