Pelagic Fish Biomass Survey on the Africana Voyage 097, November 1991

The Pelagic Fish Biomass Survey was conducted on the Africana Voyage 097 from 07 November to 03 December 1991. The objectives of the cruise were to estimate the biomass and population length structure of anchovy, pilchard, and round herring off South Africa by means of echo-integration and midwater trawling; to estimate anchovy biomass by means of the egg production method, and trial estimate pilchard biomass by means of the egg production method; to describe the distribution and behaviour patterns of commercially harvested epi-pelagic and meso-pelagic fish, and the influence of oceanographic variables on these; to collect biological data on reproduction, condition and diet of pelagic fish species; to determine phytoplankton biomass in the nanophytoplankton (<10 µm) and netphytoplankton (>10 µm) size-classes in surface waters; to obtain information on the distribution and abundance of meso-zooplankton; to estimate secondary production rates of adult copepods using the egg production method; to investigate relationships between water temperature, phytoplankton size, phytoplankton biomass, copepod biomass and production, and the distribution of pelagic fish; the examination of feeding ecology and food production selection of pilchard; the retrieval of a current meter mooring off Cape Columbine; and profiling of currents by means of the acoustic doppler current profiler.

1991年11月7日至12月3日，科研团队在Africana Voyage 097航次中开展了远洋鱼类生物量调查（Pelagic Fish Biomass Survey）。本次航次的调查目标包括：采用回声积分法（echo-integration）与中层拖网采样法，估算南非外海鳀鱼（anchovy）、沙丁鱼（pilchard）及圆鲱鱼（round herring）的生物量与种群体长结构；采用产卵量法估算鳀鱼的生物量，并尝试采用该方法估算沙丁鱼的生物量；描述商业捕捞的近表层远洋鱼类与中层远洋鱼类的分布及行为模式，以及海洋环境变量对其产生的影响；收集远洋鱼类物种的繁殖、健康状况与食性相关的生物学数据；测定表层水体中超微型浮游植物（nanophytoplankton，<10 µm）与网采浮游植物（netphytoplankton，>10 µm）不同粒径分级的浮游植物生物量；获取中型浮游动物（meso-zooplankton）的分布与丰度信息；采用产卵量法估算成年桡足类（copepods）的次级生产力速率；探究水温、浮游植物粒径、浮游植物生物量、桡足类生物量与生产力，以及远洋鱼类分布之间的内在关联；研究沙丁鱼的摄食生态与食物选择偏好；回收哥伦比亚角（Cape Columbine）外海布设的海流计锚系；采用声学多普勒海流剖面仪（acoustic doppler current profiler）开展海流剖面测量。