Testing Rectangular Mesh Gillnet to Reduce Bycatch in an Estuarine Fishery Directed for Flatfishes

Monofilament gillnets fished in North Carolina (USA) estuaries have high levels of bycatch relative to target catch of southern flounder Paralichthys lethostigma.  Modifications to gillnet characteristics and fishing styles intended to reduce bycatch rates of important species such as red drum Sciaenops ocellatus but maintain southern flounder catch rates have not proven particularly effective.  We conducted a study to determine whether a novel rectangular shape would maintain catch rates of southern flounder and reduce rates of bycatch.  Nets of each of the two mesh shapes and three stretched mesh sizes (5.5, 5.75, and 6 inches) (30 m panels) were fished in paired net trials between mesh shapes.  Square mesh nets caught greater average numbers of legal and sub-legal southern flounder, red drum, and individuals across all bycatch species.  The average catch ratio of red drum:southern flounder was greater in square mesh nets but the ratio of all bycatch:southern flounder was not different between mesh types.  The median total length of southern flounder from rectangular mesh nets was greater than square mesh nets in paired comparisons.  Rectangular mesh netting appears to be a means by which bycatch rates are reduced along with catch rates of target flatfishes.