In Nigerian coastal waters (NCW), fishing has increased steadily over the last seven decades. Artisanal fisheries cover the entire 850‐km length of the coast, where over 1 million fishermen exploit estuarine and oceanic resources up to 40 m deep, and approximately 250 industrial trawlers target fish resources in deeper waters beyond the first 9.26 km (5 nautical miles) from shore. We investigated the hypothesis that growth in fishing effort will increase impacts on coastal fish stocks, as reflected by significant reductions in the mean trophic level (MTL) and maximum mean length of the catch and an increase in the fishing‐in‐balance index. Our analyses are based on a 60‐year time series from 1950 to 2010 (obtained from the Sea Around Us Project; www.seaaroundus.org). Results showed that the impacts of fishing in NCW are high. The sustained increases in landings from the 1970s to the 2000s have resulted in less productive coastal fisheries, a reduction in the MTL of the catch (which might mean reduced biodiversity), a reduction of average size in the fisheries, and the need to expand further into deeper waters to maintain catch levels. This research contributes to fisheries ecology by furthering our understanding of coastal fisheries and their impacts on marine biodiversity.

中文翻译：

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使用海洋营养指数分析调查尼日利亚沿海水域的捕鱼影响

在尼日利亚的沿海水域（NCW）中，过去七十年来捕鱼一直稳定增长。手工渔业覆盖了整个海岸的850公里，超过一百万的渔民利用河口和海洋资源开发了40 m深的水域，大约有250艘工业拖网将目标资源定在了最初9.26公里（5海里）后的更深水域从岸边。我们调查了以下假设：捕捞努力的增加将增加对沿海鱼类种群的影响，这反映在平均营养水平（MTL）和最大平均捕捞长度的减少以及捕捞平衡指数的增加上。我们的分析基于1950年至2010年的60年时间序列（从“我们周围的海洋”项目获得； www.seaaroundus.org）。结果表明，捕捞对NCW的影响很大。从1970年代到2000年代，登陆量的持续增加导致沿海渔业的生产力下降，渔获量的最大数量减少（这可能意味着生物多样性减少），渔业的平均规模减少以及需要进一步扩大进入更深的水域以保持捕捞水平。这项研究通过加深我们对沿海渔业及其对海洋生物多样性的影响的了解，为渔业生态学做出了贡献。