Growth of the spiny lobster Jasus verreauxi (Decapoda: Palinuridae) off the east coast of Australia

Abstract

The eastern rock (spiny) lobster, Jasus verreauxi occurs along the east coast of Australia and North Island of New Zealand. The resource off New South Wales (NSW), Australia, is managed through a suite of input controls and individual catch quotas. The stock assessment process has identified that the length‐based model used in annual stock assessments would be improved with more precise information about the species’ growth patterns. This study provides the first published information on a growth model for this species by describing the results of tagging experiments from 1995 to 2001 (inclusive). Lobsters were tagged with anchor tags across six locations spanning the main distribution of the species off NSW. The maximum time that a tagged lobster was at liberty was 2573 days. Recapture data were fitted to the von Bertalanffy growth function (VBGF) using Fabens method, including parameters for seasonal growth and individual variability in growth, and extraneous information about the average length and age of puerulus larvae so that the parameter t0 could be calculated. Males had a longer predicted mean growth increment at 98 mm antennal carapace length (CL) and 202 mm (CL) (gα and gβ, the two input sizes used in the model) than females. Transformed values (with CI) for the VBGF parameter K were 0.13 (0.12–0.16) and 0.14 (0.12–0.15) for females and males, respectively. Respective values for the VBGF L 8 were 239.77 (224.37–243.51 mm CL) and 246.10 (244.69–280.70). The eastern rock lobster is amongst the largest of the palinurid family. The species is exploited for approximately 4 years before reaching sexual maturity (approximately 8 years of age) and for approximately 3 years after that time until the legal maximum length is attained. These exploitation circumstances expose this long‐lived species (approximately 30 years) to the risk of recruitment overfishing and consequently this risk is assessed annually through a stock assessment process.