Information on fishing effort by vessels fishing with traps in Scotland is limited. The recent availability of VMS data combined with landings information from vessel logbooks provides new opportunities to describe the spatial distribution of effort and catch for data-limited fisheries. This study evaluates the use of VMS data applied to trap fisheries and estimates an indicator of fishing effort for the offshore brown crab fishery in Scotland. VMS data seem to provide a valid basis for calculating effort (time fishing), assuming that fishing can be distinguished from other activities by selecting an appropriate speed range. Comparisons between high and low temporal resolution data show that the standard 2-hour transmission interval of VMS data introduces substantial uncertainty into effort estimates. Assumptions related to the relationship between fishing time and the number of creels fished, and on assigning catch data to VMS positions, were explored. The areas to the north of Scotland are the main target of the offshore brown crab fleet. Landings and effort by offshore crab vessels have generally increased up to 2016–2018 followed by a clear reduction in the last 3–5 years. The brown crab LPUE trend in this study was found to be similar with that obtained from indices based on survey data. Effort and LPUE estimates may be used to identify and inform managers of the main fishing areas for offshore vessels targeting brown crab and can also be applied to fisheries for other data-limited species, provided that VMS or other GPS logger systems are available. The methodology implemented in this study is sensitive to the temporal resolution of the data collection systems. Systems capable of providing higher temporal resolution data would be desirable, to obtain more accurate estimates of fishing effort.

中文翻译：

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使用 VMS 和观测数据估算苏格兰褐蟹（蟹蟹）诱捕渔业的捕捞努力量和 LPUE

有关苏格兰使用陷阱捕鱼的船只的捕捞努力的信息有限。最近提供的 VMS 数据与船舶日志中的上岸信息相结合，为描述数据有限的渔业的努力量和渔获量的空间分布提供了新的机会。本研究评估了 VMS 数据在诱捕渔业中的使用情况，并估算了苏格兰近海褐蟹渔业的捕捞努力量指标。 VMS 数据似乎为计算工作量（钓鱼时间）提供了有效的基础，假设可以通过选择适当的速度范围将钓鱼与其他活动区分开来。高、低时间分辨率数据之间的比较表明，VMS 数据的标准 2 小时传输间隔给工作量估计带来了很大的不确定性。探讨了与捕捞时间和捕捞鱼架数量之间的关系以及将捕捞数据分配给 VMS 位置相关的假设。苏格兰北部地区是近海褐蟹船队的主要目标。截至 2016 年至 2018 年，近海捕蟹船的上岸量和作业量普遍增加，但在过去 3-5 年明显减少。本研究中的褐蟹LPUE趋势与基于调查数据的指数得出的趋势相似。努力量和 LPUE 估计可用于识别和告知管理人员以褐蟹为目标的近海船只的主要捕捞区域，也可应用于其他数据有限物种的渔业，前提是有 VMS 或其他 GPS 记录系统可用。本研究中采用的方法对数据收集系统的时间分辨率很敏感。为了获得更准确的捕捞努力量估计，需要能够提供更高时间分辨率数据的系统。