Vallès Henri, Oxenford Hazel A
Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Cave Hill, Barbados.
Centre for Resource Management and Environmental Studies (CERMES), The University of the West Indies, Cave Hill Campus, Cave Hill, Barbados.
PLoS One. 2014 Jan 20;9(1):e86291. doi: 10.1371/journal.pone.0086291. eCollection 2014.
There is great need to identify simple yet reliable indicators of fishing effects within the multi-species, multi-gear, data-poor fisheries of the Caribbean. Here, we investigate links between fishing pressure and three simple fish metrics, i.e. average fish weight (an estimate of average individual fish size), fish density and fish biomass, derived from (1) the parrotfish family, a ubiquitous herbivore family across the Caribbean, and (2) three fish groups of "commercial" carnivores including snappers and groupers, which are widely-used as indicators of fishing effects. We hypothesize that, because most Caribbean reefs are being heavily fished, fish metrics derived from the less vulnerable parrotfish group would exhibit stronger relationships with fishing pressure on today's Caribbean reefs than those derived from the highly vulnerable commercial fish groups. We used data from 348 Atlantic and Gulf Rapid Reef Assessment (AGRRA) reef-surveys across the Caribbean to assess relationships between two independent indices of fishing pressure (one derived from human population density data, the other from open to fishing versus protected status) and the three fish metrics derived from the four aforementioned fish groups. We found that, although two fish metrics, average parrotfish weight and combined biomass of selected commercial species, were consistently negatively linked to the indices of fishing pressure across the Caribbean, the parrotfish metric consistently outranked the latter in the strength of the relationship, thus supporting our hypothesis. Overall, our study highlights that (assemblage-level) average parrotfish size might be a useful alternative indicator of fishing effects over the typical conditions of most Caribbean shallow reefs: moderate-to-heavy levels of fishing and low abundance of highly valued commercial species.
在加勒比地区多物种、多渔具且数据匮乏的渔业中，迫切需要确定简单而可靠的捕捞影响指标。在此，我们研究捕捞压力与三个简单的鱼类指标之间的联系，即平均鱼重（对个体鱼平均大小的估计）、鱼类密度和鱼类生物量，这些指标分别来自：（1）鹦嘴鱼科，这是一种在加勒比地区普遍存在的草食性鱼类；（2）包括笛鲷和石斑鱼在内的三类“商业性”肉食性鱼类，它们被广泛用作捕捞影响的指标。我们假设，由于大多数加勒比珊瑚礁遭受过度捕捞影响，相较于来自高度易受影响的商业鱼类群体的指标，来自较不易受影响的鹦嘴鱼群体的鱼类指标与当今加勒比珊瑚礁上的捕捞压力之间的关系会更强。我们利用来自加勒比地区348次大西洋和墨西哥湾快速珊瑚礁评估（AGRRA）礁体调查的数据，来评估两个独立的捕捞压力指标（一个来自人口密度数据，另一个来自开放捕捞与受保护状态）与上述四类鱼类的三个鱼类指标之间的关系。我们发现，尽管有两个鱼类指标，即鹦嘴鱼平均体重和选定商业物种的总生物量，在整个加勒比地区与捕捞压力指标始终呈负相关，但鹦嘴鱼指标在关系强度上始终高于后者，从而支持了我们的假设。总体而言，我们的研究强调，（群落水平的）鹦嘴鱼平均大小可能是在大多数加勒比浅礁典型条件下（即中度至重度捕捞水平和高价值商业物种丰度较低）捕捞影响的一个有用替代指标。
