Processed outputs and R codes from a dispersal model to investigate the influence of offshore eddies on larval transport loss and cool-water mortality of two commercial shrimp species on the Sofala Bank, Mozambique Channel

we simulated larval dispersal of the two most important commercial shrimp species (penaeus indicus and metapenaeus monoceros) on the sofala bank, mozambique using a lagrangian biophysical modelling tool ichthyop (lett et al. 2008), coupled to a regional ocean modeling system (roms) configuration developed for the bank (malauene et al. 2018). in total, 30 000 simulated larvae for the two species combined were released every 3 days for 5 model years from nine areas (including their true spawning areas (malauene et al. 2021)), here referred to as five release areas comprising both inshore and offshore locations (fig.1). for each simulation, individual larval trajectories were tracked for 15 days, the pelagic larval duration for these species. at the end of the simulation, shrimp larvae found outside the release areas (which are also the recruitment areas) were considered lost from the sofala bank population. to investigate the potential effect of cool water temperatures on larval mortality, we tested lethal temperature threshold values from 20 to 25oc for model year 5, i.e. one year for each of the six temperature simulations. in the simulations, larvae died when they encountered water cooler than the temperature thresholds. the present data are the processed simulation outputs of mean (with corresponding standard errors) percentages of larvae lost from all nine areas combined, the five release areas combined, and from each of the nine release areas, as well as larval mortality for each temperature simulation. the data include the total distances travelled along each trajectory and the linear distance from the origin to the final location for all larvae.

本研究采用拉格朗日生物物理模型工具Ichthyop（Lett et al., 2008）对莫桑比克索法拉岸上两种最重要的商业对虾种类（斑节虾（Penaeus indicus）和单角虾（Metapenaeus monoceros））的幼虫扩散进行模拟。该工具与专为该岸域开发的区域海洋模型系统（ROMS）配置相结合（Malauene et al., 2018）。总计释放了30,000条模拟幼虫，两种物种合并，每3天释放一次，持续5个模型年，从九个区域释放（包括其真实产卵区（Malauene et al., 2021）），此处称为五个释放区，包括近岸和远岸位置（图1）。对于每个模拟，追踪单个幼虫轨迹15天，即这些物种的浮游幼虫持续时间。在模拟结束时，发现于释放区（也是补充区）外的虾幼虫被视为从索法拉岸种群中消失。为了研究水温对幼虫死亡率潜在影响，我们针对第5个模型年（即六种温度模拟中的每一种温度模拟的一年）测试了从20至25℃的致死温度阈值。在模拟中，幼虫遇到低于温度阈值的冷水时死亡。当前数据包括所有九个区域合并的幼虫丢失率的均值（及相应的标准误），五个释放区合并的幼虫丢失率，以及每个九个释放区的幼虫丢失率，以及每个温度模拟的幼虫死亡率。数据还包括每个轨迹的总行程距离以及所有幼虫从起点到最终位置的线性距离。