POD! Fish- DFG Fall Midwater trawl sampling Sept.-Dec.1967-2006

Midwater trawl sampling September-December 1967-2006 Purpose of DFG's Fall Midwater Trawl survey is to evaluate potential water project effects on survival of young striped bass. The objective of the fall midwater trawl survey is to produce an index of monthly abundance of young striped bass. The sum of the monthly indices is compared to the summer townet abundance index to evaluate survival. Midwater Trawl Field Activities: From 1967 to 1978 the survey length was variable, sometimes starting in July or August, with September the usual starting month. The survey was never run beyond March. In 1980 the survey was shortened to cover the period of September to December due to variability in abundance indices associated with winter storm events. Midwater trawl Sampling stations cover a broad range of habitats.

1967年至2006年9月至12月中层拖网（midwater trawl）采样。DFG发起的本秋季中层拖网调查，总体目的为评估水利工程对幼年条纹鲈（striped bass）存活率的潜在影响，具体目标为构建幼年条纹鲈的月度丰度指数。通过将月度丰度指数的总和与夏季小型拖网（townet）丰度指数进行对比，以此评估条纹鲈的存活率。中层拖网野外作业内容：1967年至1978年，调查周期不固定，有时始于7月或8月，通常以9月作为起始月份，且调查从未延续至3月之后。1980年，由于冬季风暴事件会导致丰度指数出现显著波动，调查周期被缩短至9月至12月。中层拖网采样站点覆盖了多种不同的水生生境类型。