Biomass estimates and harvest strategies for the Western Australian Octopus aff. tetricus fishery

Abstract

Abstract Octopus aff. tetricus is the target of Australia’s most significant octopus fishery. We utilized both fishery-independent surveys and fishery data from spatially detailed catch and effort logbooks to examine distribution and abundance across the spatial and depth ranges of the population. From this, a harvest strategy was developed to form the basis for monitoring, assessment, and management. Octopus aff. tetricus is abundant and widely distributed in Western Australia, with a biomass density range of 150–1000 kg km−2. This is comparable to Octopus vulgaris fisheries in the Mediterranean and sub-Saharan Africa. From an estimated habitat area of 20 073 km2, total biomass on the West Coast was estimated to be a minimum of 3600 tonnes whole weight with 90% certainty. At the current annual catch of 300 tonnes, overall population exploitation rate is low, given the high natural productivity of the species, which has a maximum age of 1.5 years and two recruitment pulses per year. A formal species name for O. aff. tetricus is required so its contribution to the Australian cephalopod fisheries harvest can be officially recognized.