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Two types of fish attractors, brush attractors made of cedar trees and Berkley and Company's Fish-Hab modules, were placed in a final cut coal mine lake and evaluated for fish concentrating effectiveness. Dives were conducted biweekly and numbers and species of fish at attractors were recorded. Data were then evaluated using Analysis of Variance tests.A total of 623 fish were recorded on attractors during the eight dives made from July 21 to October 24, 1986. Brush attractors held 485 fish or 78% of the total. Module attractors concentrated 105 fish (17%) and 33 fish (5%) were observed in the control areas. Brush attractors concentrated nearly five times as many fish as the modules and 15 times as many fish as the control area. The modules concentrated over three times as many fish as the control area. Results indicated there was no significant difference (0.05) in numbers of fish attracted by brush and modules with an Analysis of Variance With Repeated Measures test but density of individual species was not considered. Furthur analysis of attractors by date and specie over the study period using a One-Way Analysis of Variance revealed that brush attractors concentrated significantly (0.05) more fish than modules in mid to late summer, but not in the early fall. Modules were much less effective at concentrating fish and were never significantly different than the control areas.Scuba diving worked well as a method of evaluation for the attractors. Water clarity was adequate for visual observations and fish did not display a fright response or leave when the diver approached. At no time was there difficulty in identifying or counting fish greater than 10 cm.Ball State UniversityMuncie, IN 47306

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The bycatch of cetaceans in fishing gear is considered to be one of the biggest conservation threats to these species. Gear modifications have the potential to reduce these bycatches in global fisheries but there is little available information on how such modifications may change the fishing performance of gear, or indeed the behavior of cetaceans interacting with fishing gear. Generalized linear models (GLMs) were used to identify factors related to cetacean bycatches in UK bottom set gillnets. Rigged net height had a significant positive relationship with harbour porpoise (Phocoena phocoena) bycatch in ICES Area VII suggesting that lowering the profile of gillnets may have the potential to reduce bycatch rates. Modifications to gillnets, such as changing the amount of floatation or increasing the density of the meshes, were found to have significant effects on the active fishing heights of these nets. However, results from a bycatch mitigation trial in Argentina showed that the reduced fishing profile of one experimental net did not result in a concurrent reduction in the bycatch rate of Franciscana dolphins (Pontoporia blainvillei). While there was no significant difference in the rate, length or intensity of harbour porpoise encounters in the presence or absence of gillnets, the proportion of fast echolocation click trains were significantly higher when a net was present, indicating that porpoises either increased acoustic inspection of the net or foraging in the vicinity of the net. An analysis of underwater video footage collected inside trawl nets in an Australia fishery showed that bottlenose dolphins (Tursiops sp.) were present inside nets more frequently than they were caught and were actively foraging inside these nets. The orientation of dolphins inside these nets indicates that the current design of excluder devices used in this fishery could be improved to further reduce bycatch rates.

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