Growth and recruitment overfishing can co‐occur when a fishery is subjecting small and immature fish in conjunction with adult fish to excessive exploitation rates such that it reduces the spawning biomass to the point where recruitment is significantly impaired. Such conditions are generally evident in open‐access fisheries and are especially detrimental to long‐lived species as they reach maturity at older ages. Here, we investigate the conditions of a long‐lived lutjanid, Malabar Blood Snapper Lutjanus malabaricus, in Kuwait waters, for which catches declined by about 95% between 1995 and 2009 with negligible recovery afterward, yet exploitation rates are likely high and remain hardly regulated. Using an age‐structured model and length and age distributions for over 47,000 Malabar Blood Snapper, we (1) underscore the impacts of recruitment and growth overfishing on fish biomass and catch and (2) demonstrate the efficacy of improving the size limit policy to address both issues. The proportion of small fish (length‐classes <50 cm; age‐classes = 1–4 years) in the catch rose from 40–50% in 1981 to over 70% between 1992 and 1998, indicating growth overfishing. Due to the selection of immature fish at high exploitation rates, the age‐structured model showed that recruitment dropped virtually linearly with decreasing biomass by the mid‐1990s, implying recruitment overfishing. Future scenarios show that by increasing the current mean age at vulnerability (1 year or 34 cm) to the age at first maturity (5 years or 61 cm), biomass and catch would increase by at least 300% and 130%, respectively, relative to status quo. Biomass would rebuild to higher levels if exploitation rates are regulated at sustainable levels. Our study highlights the importance of simple management changes in alleviating both types of overfishing, particularly when open‐access conditions cannot be rapidly remedied due to weak management institutions.

中文翻译：

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通过简单的管理变更来缓解生长和招聘过度捕捞：对过度开采的长寿鱼类的见解

当渔业对小型和不成熟的鱼类与成年鱼类一起过度开采时，可能会发生生长过度捕捞和过度捕捞的情况，从而使产卵生物量减少到捕捞能力严重受损的地步。这种情况通常在开放式渔业中很明显，并且随着年龄的增长，对长寿物种尤其有害。在这里，我们研究了一种长寿的lutjanid马拉巴尔Blood夺者Lutjanus malabaricus的状况在科威特水域，其捕捞量在1995年至2009年之间下降了约95％，随后的恢复程度可忽略不计，但开采率可能很高，而且几乎没有受到监管。我们使用年龄结构模型和47,000多种马拉巴尔鲷鱼的长度和年龄分布，我们（1）强调了过度捕捞和捕捞对鱼类生物量和渔获量的影响，以及（2）证明了改进规模限制政策以解决问题的有效性这两个问题。捕捞中小鱼（长类<50 cm；年龄类= 1-4年）的比例从1981年的40％至50％上升到1992年至1998年之间的70％以上，表明过度捕捞的增长。由于选择了高开发率的未成熟鱼类，因此年龄结构模型显示，到1990年代中期，招聘数量随生物量的减少而线性下降，意味着招募过度捕捞。未来的情况表明，通过将当前的易受害平均年龄（1年或34厘米）提高到首次成熟的年龄（5年或61厘米），生物量和捕获量将相对增加至少300％和130％维持现状。如果将开发速度控制在可持续水平，生物质将重建到更高的水平。我们的研究强调了简单的管理变革对缓解两种过度捕捞的重要性，特别是在由于管理机构薄弱而无法迅速纠正开放获取条件的情况下。如果将开发速度控制在可持续水平，生物质将重建到更高的水平。我们的研究强调了简单的管理变革对缓解两种过度捕捞的重要性，特别是在由于管理机构薄弱而无法迅速纠正开放获取条件的情况下。如果将开发速度控制在可持续水平，生物质将重建到更高的水平。我们的研究强调了简单的管理变革对缓解两种过度捕捞的重要性，特别是在由于管理机构薄弱而无法迅速纠正开放获取条件的情况下。