Predicting the recreational western rock lobster (Panulirus cygnus) catch in Western Australia

Abstract

The number of fishers purchasing recreational rock-lobster licences in Western Australia increased from ~15 000 during 1986–87 to 33 000 during 1998–99. The quantity landed was estimated from mail surveys conducted during this period. The recreational catch of western rock lobster increased from approximately 220 to 630 tonnes, or from 1.8% to 4.8% of the commercial catch. This study has shown that total recreational catches of western rock lobster in Western Australia are correlated with licence usage rates (r² = 0.81) and puerulus settlement indices at Alkimos, in the southern region of the fishery, 3 to 4 years earlier (r² = 0.59). A multipleregression analysis using both of these variables (r² = 0.91) was used to predict future recreational lobster catches. If future usage were to remain at 1998–99 levels, it is predicted that the recreational catch would be 700 t in 1999–2000, 650 t in 2000–01, and 550 t in 2001–02. We attempted to improve predictions by analysing the data according to puerulus settlement and licence usage in the two coastal management regions. The correlation for the southern region (where most of the recreational fishing is concentrated) was marginally better than that for the total fishery (r² = 0.93), but the correlation was poor for the northern coastal zone (r² = 0.55), where licence usage has been relatively steady and where the recreational catch has consistently remained at around 98 t per annum over the last decade.