Horse Mackerel Hydroacoustic Survey on the Africana Voyage 107, October 1992

The Horse Mackerel Hydroacoustic Survey was conducted on the Africana Voyage 107 from 07-23 October 1992. The objectives of the survey were to obtain a hydroacoustic estimate of horse mackerel abundance in the area between East London and Mossel Bay; to obtain acoustic estimates of anchovy and pilchard abundance east of Mossel Bay to assist in the design of the pelagic spawner biomass survey in November; to obtain a target strength/length relationship for horse mackerel and target strength data for anchovy and pilchard; to collect biological data pertaining to horse mackerel; to investigate the foraging behaviour of horse mackerel and food preference of pilchard; to test for relationships between horse mackerel movement and near-surface and mid-water currents, and to add to the ADCP data base for the southeast coast; to measure thermal salinity structure of the water column and to measure basic biotic parameters (oxygen, nutrient and chlorophyll); to collect data from the satellite imager on the large-scale influence of the Agulhas current; to sample mesopelagic fauna off the shelf with a number of ad hoc deep trawls; and to characterise zooplankton patches acoustically on a number of cross-shelf transects.

1992年10月7日至23日，科考团队依托阿非利卡号107航次开展了竹荚鱼（Horse Mackerel）水声学调查。本次调查的目标包括：获取东伦敦至莫塞尔湾区间内竹荚鱼种群丰度的水声学估算值；获取莫塞尔湾以东海域鳀鱼与沙丁鱼种群丰度的声学估算值，为11月开展的上层产卵亲体生物量调查提供设计依据；建立竹荚鱼的目标强度（target strength）-体长关系模型，并获取鳀鱼与沙丁鱼的目标强度实测数据；采集竹荚鱼相关生物学数据；研究竹荚鱼的觅食行为与沙丁鱼的食物偏好；探究竹荚鱼移动与近表层、中层海流之间的关联，并补充东南沿海的声学多普勒流速剖面仪（ADCP）数据库；测定水柱的热盐结构，并采集基础生物参数（溶解氧、营养盐与叶绿素）数据；通过卫星成像仪获取阿古拉斯海流（Agulhas Current）的大尺度影响相关数据；利用多组专项深海拖网对陆架外侧的中层带生物进行采样；在多条跨陆架断面上通过声学手段表征浮游动物斑块特征。