Indirect estimate of gill net mesh size selectivity for landlocked alewives

During summer 1999, 5,004 landlocked ale wives (Alosa pseudoharengus) were captured from 12 Connecticut lakes using horizontal gill nets with mesh siz es of 9.5, 12.7, 15.9, 19.1, 25.4, and 31.8 mm (bar measure). The most effe ctive mesh size was 12.7-mm, capturing 3,035 alewives. The modal length of alewives caught in each mesh size increased as the mesh size increased from 9.5 to 25.4 mm. No alewives less than 70 mm total length or greater than 2 45 mm were captured. Modal lengths of selectivity curves estimated indirect ly using the Holt model were 85, 114, 143, 172, and 228 mm for the 9.5-, 12 .7-, 15.9-, 19.1-, and 25.4-mm mesh sizes, respectively. Adding a 22.3-mm m esh and removing the 31.8-mm mesh is suggested to sample landlocked alewive s between 100 and 245 mm in Connecticut lakes.