Macroalgae-dominated reefs are a prominent habitat in tropical seascapes that support a diversity of fishes, including fishery target species. To what extent, then, do macroalgal habitats contribute to small-scale tropical reef fisheries? To address this question we: (1) Quantified the macroalgae-associated fish component in catches from 133 small-scale fisheries, (2) Compared life-history traits relevant to fishing (e.g. growth, longevity) in macroalgal and coral-associated fishes, (3) Examined how macroalgae-associated species can influence catch diversity, trophic level and vulnerability and (4) Explored how tropical fisheries change with the expansion of macroalgal habitats using a case study of fishery-independent data for Seychelles. Fish that utilised macroalgal habitats comprise 24% of the catch, but very few fished species relied entirely on macroalgal or coral habitats post-settlement. Macroalgal and coral-associated fishes had similar life-history traits, although vulnerability to fishing declined with increasing contribution of macroalgae association to the catch, whilst mean trophic level and diversity peaked when macroalgal-associated fish accounted for 20%–30% of catches. The Seychelles case study revealed similar total fish biomass on macroalgal and coral reefs, although the biomass of primary target species increased as macroalgae cover expanded. Our findings reinforce that multiple habitat types are needed to support tropical fishery stability and sustainability. Whilst coral habitats have been the focus of tropical fisheries management, we show the potential for macroalgae-associated fish to support catch size and diversity in ways that reduce vulnerability to overfishing. This is pertinent to seascapes where repeated disturbances are facilitating the replacement of coral reef with macroalgal habitats.

中文翻译：

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大型藻类相关鱼类对小型热带珊瑚礁渔业的贡献

以大型藻类为主的珊瑚礁是热带海景中的重要栖息地，支持多种鱼类，包括渔业目标物种。那么，大型藻类栖息地在多大程度上有助于小型热带珊瑚礁渔业？为了解决这个问题，我们：(1) 量化了 133 个小型渔业渔获物中与大型藻类相关的鱼类成分，(2) 比较了大型藻类和珊瑚相关鱼类与捕鱼相关的生活史特征（例如生长、寿命）， (3) 检查与大型藻类相关的物种如何影响渔获物多样性、营养水平和脆弱性，以及 (4) 使用塞舌尔独立于渔业的数据的案例研究，探索热带渔业如何随着大型藻类栖息地的扩大而变化。利用大型藻类栖息地的鱼类占渔获量的 24%，但很少有捕捞物种在定居后完全依赖大型藻类或珊瑚栖息地。大型藻类和与珊瑚相关的鱼类具有相似的生活史特征，尽管随着大型藻类对捕捞量的贡献增加，捕鱼的脆弱性下降，而当大型藻类相关鱼类占捕捞量的 20%–30% 时，平均营养水平和多样性达到顶峰。塞舌尔的案例研究表明，大型藻类和珊瑚礁上的鱼类总生物量相似，尽管主要目标物种的生物量随着大型藻类覆盖范围的扩大而增加。我们的研究结果强调，需要多种栖息地类型来支持热带渔业的稳定性和可持续性。虽然珊瑚栖息地一直是热带渔业管理的重点，我们展示了大型藻类相关鱼类以降低过度捕捞脆弱性的方式支持渔获量和多样性的潜力。这与海景有关，在这些海景中，反复的干扰正在促进珊瑚礁被大型藻类栖息地所取代。