北部湾二长棘鲷资源开发保护策略研究

运用单位补充量模型评价了北部湾二长棘鲷资源，显示雌雄个体问生长和死亡率并没有显著差异。推测在当前捕捞死亡系数下，单位补充量产卵群体生物剩量为16．76％，表明该渔业已处于过度捕捞，存在未来幼鱼补充失败的可能。比较了几种管理策略，最小开捕体长、禁渔期和禁渔区的组合，确定何种开发模式既能提高单位补充量产卵群体生物量又不造成过度降低单位补充量渔获量而引发渔民的经济利益冲突。研究表明，实施禁渔期、禁渔区管理在当前捕捞死亡系数下都可一定程度地提高单位补充量产卵群体生物量。建议在保持当前禁渔期管理的同时，再配合最小开捕体长104mm措施，可使单位补充量产卵群体生物剩量恢复到28．39％，单位补充量渔获量提高31．95％，保证该渔业不致崩溃。但要实现该渔业的可持续发展，相关捕捞努力量还需减少32．50％。图7，表4，参24。

Management Recommendation for Paragyrops edita in Beibu Gulf based on Per-recruilment Analysis

The status of the crimson tai resource in Beibu Gulf is assessed using a per-recruit model noting that there are no significant differences in growth and mortality between sexes. It is estimated that at the current fishing mortality rate the spawning biomass per recruit is 16.76% indicating that the fishery is overfished with a recruitment failure at present. A number of management scenarios, based on minimum size limits, including closed season and closed areas were evaluated for this fishery in order to determine which of the scenario would increase spawning biomass per recruit without comprising yield harvest rates to levels which may lead to socio-economic hardship among fishers. The resuits show that the closed season and closed areas can improve spawner biomass per recruit to some extent under current fishing moaality. It is proposed that the current management measures with minimum catchable length of 104mm can restore spawning biomass per recruit to 28.39 % of the unfished level and prevent this fishery from collapsing and increase yield per recruit in mass up 31.95 %. However, relevant fishing effort should reduce 32.50% in order to realizing the fishery sustainable exploitation.