Distribution and abundance of recruits of the eastern rock lobster (Jasus verreauxi) along the coast of New South Wales, Australia

Abstract

In the mid 1990s, the New South Wales government introduced management measures to increase the size of the population of the eastern rock (spiny) lobster, Jasus verreauxi. A fully orthogonal sampling design was begun in July 1995 to test, amongst others, the hypothesis that the relative abundance of recruits (stages of peuruli to early juveniles combined) to the eastern rock lobster population will change over space and time. In the design for the full sampling strategy were the factors of Year (eight levels) and Location (four levels). Three replicate collectors at each of three sites at each location were sampled during the first quarter of each lunar month between August and January between 1995–96 and 2002–03 (inclusive). Recruits occurred on collectors between September and January each year. Results of the two‐factor ANOVA showed a significant interaction between Year and Location, meaning that differences in mean relative abundance of recruits between years will depend upon the location. Comparison of means (SNK test) show that in each year the relative abundance of recruits was greatest at the southern locations, but no pattern in mean relative abundance between years for each location was apparent. Management measures introduced in the mid 1990s to increase population size have not to date resulted in increasing levels of recruitment. Considering this, levels of recruitment to the population appear to be influenced most by variation in environmental factors rather than levels of egg production from the stock.