Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

In too deep: Challenges of managing a basket of data poor deepwater species (#36)

Sushmita Mukherji 1 , Colin Simpfendorfer 1 , Nils Krueck 1 , Natalie Dowling 2
  1. Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
  2. Commonwealth Scientific and Industrial Research Organisation , (CSIRO), Hobart, Tasmania, Australia

Sixteen deepwater sharks caught in southeastern Australia are managed as a basket of species group within the Australian Southern and Eastern Scalefish and Shark Fishery (SESSF). Deepwater sharks are known to be highly vulnerable to exploitation with many populations rapidly depleted following intensive fishing and have slow recovery rates that requires ongoing assessment of population status to enable management. Additionally, management for these species is difficult due to the challenge of identifying many deepwater sharks to species level, and a general lack of reliable records of catch due to the high prevalence of unreported discards. Given the low gross value of production of the deepwater shark basket within the fishery, it is unlikely that the quality of available data will improve. As such, robust analytical assessments to provide estimates for total allowable catch are unable to be conducted. This study aims to confront these limitations by assessing these data poor, highly vulnerable, basket of species. We will compare the pitfalls of applying analytical methods in a data-limited context with empirical methods that would produce indicators which are proxies of abundance. This information will be assessed in the context of providing advice based on the Australian Fisheries Management Authority harvest strategy framework. Specifically, we will investigate the use of limited data in analytical methods that inherently violate the assumptions of these assessments and the cost of collecting improved data to inform them. This will be compared to empirical approaches that require far less data but produce indicators that result in a high level of uncertainty for management under the harvest strategy framework. Finally, we propose potential options to overcome these challenges when assessing data-poor, low gross-value basket species like deepwater sharks.