A. Stephen Weithman

We examined the accuracy and application of sequential sampling to determine structure of fish stocks, using electrofishing data for largemouth bass (Micropterus salmoides) as an example. Structure of the stock was categorized with the index of Proportional Stock Density (PSD), which is the percentage of quality-size fish in the stock. Minimum stock and quality sizes for largemouth bass were defined as 20 and 30 cm, respectively. Sequential sampling is based on data evaluation during collection. An average reduction in sample size of 42% is realized when populations are sampled...

Five yearling northern pike (Esox lucius). muskellunge (Esox masquinongy), or their F, hybrid ("tiger muskie") were stocked in duplicate 0.2-ha ponds in April, 1974. Two additional ponds were stocked with a combination of five fish of each of the three forms. In 58 hours of angling from April to September, northern pike were 3.1 and 4.2 times more vulnerable than tiger muskies and muskellunge, respectively. No fish were caught in 18 hours of fishing from 15 June to 13 August. Repeat catches accounted for 35. 6% of the total catch; hooking mortality was negligible (1.7%).