Life history traits' scoring to calculate a trawl disturbance indicator on mega- epibenthic fauna

Particularly suited to the purpose of measuring the sensitivity of benthic communities to trawling, a trawl disturbance indicator (de Juan and Demestre, 2012, de Juan et al. 2009) was proposed based on benthic species life history traits to evaluate the sensibility of mega- and epifaunal community to fishing pressure known to have a physical impact on the seafloor (such as dredging and bottom trawling). The selected biological traits were chosen as they determine vulnerability to trawling: mobility, fragility, position on substrata, average size and feeding mode that can easily be related to the fragility, recoverability and vulnerability ecological concepts. Life history traits of species have been defined from the BIOTIC database (MARLIN, 2014) and from information given by Le Pape et al. (2007), Brindamour et al. (2009) and Garcia (2010). For missing life history traits, additional information from literature has been considered. The five categories retained are life history functional traits that were selected based on the knowledge of the response of benthic taxa to trawling disturbance (de Juan and Demestre, 2012). They reflect respectively the possibility to avoid direct gear impact, to benefit from trawling for feeding, to escape gear, to get caught by the net and to resist trawling/dredging action, each of these characteristics being either advantageous or sensitive to trawling. Then, to allow quantitative analysis, a score was assigned to each category: from low vulnerability (0) to high vulnerability (3). The five categories scores were then summed for each taxon (the highly vulnerable taxon could reach the maximum score is 15) and this value may be considered as a species index of sensitivity to trawling disturbance. The scores of 773 taxa commonly found in bottom trawl by-catch in the southern North Sea, English Channel and north-western Mediterranean were described.

本数据集专为测量底栖生物群落（benthic community）对拖网捕捞的敏感性而设计。研究基于底栖物种生活史特征，提出了拖网扰动指数（trawl disturbance indicator，de Juan与Demestre, 2012；de Juan等, 2009），用于评估大型和表栖生物群落（mega- and epifaunal community）对已知会对海底造成物理干扰的捕捞压力（如疏浚作业与底拖网捕捞）的敏感性。
所选生物学性状均为决定物种对拖网捕捞脆弱性的核心特征，涵盖活动性、脆弱性、栖息基底位置、平均体型及摄食模式，上述性状可直接关联至脆弱性、恢复力与生态敏感性等生态学核心概念。
物种的生活史特征来源于BIOTIC数据库（MARLIN, 2014），以及Le Pape等（2007）、Brindamour等（2009）与Garcia（2010）的研究成果。对于缺失的生活史特征，本研究补充了已发表文献中的相关数据。
最终保留的5类生活史功能性状，是基于底栖分类群（taxon，复数形式为taxa）对拖网扰动的响应研究（de Juan与Demestre, 2012）筛选所得。这5类性状分别对应：规避渔具直接冲击的能力、从拖网作业中获取摄食机会的能力、逃离渔具的能力、被网具捕获的可能性以及抵抗拖网/疏浚作业的能力，每一类特征均对拖网作业表现出敏感性或优势性。
为开展定量分析，为每类性状赋值：脆弱性等级从低（0分）至高（3分）。随后将每个分类群的5类性状得分求和（高度脆弱的分类群最高可获得15分），该求和值即可作为物种对拖网扰动敏感性的量化指数。
本研究记录了北海南部、英吉利海峡以及地中海西北部海域底拖网兼捕渔获（by-catch）中常见的773个分类群的得分情况。