Length–weight relationships of commercial species in the eastern Australian sea cucumber fishery

Biological data, such as length–weight relationships, are essential for the management and stewardship of harvested individuals. Sea cucumbers are a lucrative industry globally but many of the associated fisheries lack species-level biological data, which reduces the effectiveness of any management strategy. The Queensland Sea Cucumber Fishery (QSCF) on the Great Barrier Reef is managed through various controls: primarily catch limits, effort limits, zoning, and size restrictions. Over 20 species may be harvested but there is a lack of comprehensive biological data for many of these species, particularly important life history characteristics. This study addresses this knowledge gap by assessing 2621 individual length–weight relationships of key-target sea cucumber species associated with the fishery across the range of the distribution of the species and covering a variety of habitats, depths, sampling times, and management zones. Linear models with log transformations were used to analyse the relationships between length and weight. Results revealed significant positive relationships for all assessed species, with Holothuria atra having the clearest relationship between length and weight (R² = 0.45). Only negative allometric relationships were observed, as is the case for many species of holothurians. Despite challenges associated with measuring and weighing these soft and elastic animals, results will be useful for understanding length–weight dynamics across species. This research underscores the importance of robust biological data for the effective management of sea cucumber fisheries and ultimately reef health.