Wormuth j h (1 risultati)

Three large data sets on cephalopods are critically examined with respect to several sources of error: day-night avoidance, net size, mode of fishing, and patchiness. Catches are low and variable and results only suggest problems with present sampling techniques. Specific field sampling is suggested to quantify several of these sources of error. Volume filtered and time fished are compared as measure of effort . Variability of volume filtered and net speed within a single tow are examined. 21 pp., 4 figs, gr. 8.…