587 American Fisheries Society Symposium , 2006 © 2006 by the American Fisheries Society * Corresponding author: mbroadhurst@nmsc.edu.au Working Laterally Towards Perfect Selectivity in Fishing Gears MATT BROADHURST New South Wales Department of Primary Industries, Fisheries Conservation Technology Unit Post Office Box J321, Coffs Harbour, New South Wales 2450 Australia STEVEN J. KENNELLY AND CHARLES GRAY New South Wales Department of Primary Industries, Cronulla Fisheries Centre Post Office Box 21, Cronulla, New South Wales 2230 Australia Abstract.—Few fishing methods and gears are entirely selective for the targeted species and their sizes, with many retaining at least some incidental catches (collectively termed “bycatch”). Of primary concern is the contribution that the mortalities of such bycatches may have on subsequent stocks. While extensive work to develop modifications to fishing gears has facilitated considerable reductions in bycatches over the past 20 years, very few (if any) of the changes made are 100% effective. There remains, therefore, a substantial mortality of discards in many fisheries, particularly those using trawls. To work more comprehensively towards the ultimate goal of achieving perfect selectivity, we propose that, in addition to conventional bycatch reduction strategies, a lateral approach should also be adopted involving completely alternative gears that, because of their design, operation, or both, have selective mechanisms that could be used to address problematic gears. Introduction The majority of the world’s fishing methods and gears are considerably less than 100% selective for the targeted species and their sizes and so retain incidental catches (termed “bycatch”, sensu Saila 1983). This bycatch can vary from isolated occurrences in some hook- and-line fisheries, to large and disproportional numbers of juveniles of key species in trawl fisheries. The mortality of large quantities of bycatch has attracted substantial attention over the past 20 years and culminated in extensive efforts to address this issue, primarily via modi- fications to problematic fishing gears (espe- cially trawls) and practices. In most cases, the successful development and adoption of solutions to reduce the fishing mortality of bycatch can be summarized in a simple framework (see also Kennelly and Broadhurst 1996, 2000; Kennelly 1997) which involves fishers and scientists each ap- plying their respective areas of expertise to the particular problem. This framework comprises five key steps: 1) quantifying bycatches, 2) identifying the main bycatch species and their sizes of concern, 3) developing alterations to existing fishing gears and practices that mini- mize the mortality of these species, 4) testing