Preliminary estimation of ray by-catch in the longline fishery in Subarea 48.3

The total capture of rays in the Subarea 48.3 longline fishery is composed both of rays brought on board and a number that are knocked off the line or fall off before they reach the deck. We estimated total capture (ray numbers) for some of vessels fishing in Subarea 48.3 in 2001 by utilising new information collected by observers on the rays appearing during their tally period. This estimate is entirely independent of vessel records of landed and discarded rays. For the one vessel that we have good species composition and mean weight data we have extended the number estimate to give capture weight by species.