Project number: 2013-011
Project Status:
Completed
Budget expenditure: $380,000.00
Principal Investigator: Simon D. Goldsworthy
Organisation: SARDI Food Safety and Innovation
Project start/end date: 30 Jun 2013 - 31 May 2016
Contact:
FRDC

Need

The last 25 years have seen a 3.5 fold increase in the population size of New Zealand fur seals (NZFS) in SA, which now number over 85,000 individuals. This recovery may continue for a further 15-30 years, and the level at which populations may stabilise is unknown. New haul-out sites and breeding colonies are establishing across the State, some in close proximity to finfish aquaculture, and major commercial and recreational fishing areas. In addition, an Australian fur seal population has recently established in SA and has more than doubled in the last five years. There is also growing concern from the seafood and ecotourism (little penguins, giant cuttlefish) industries and the community that fur seals are overabundant and that their populations and impacts need to be managed. As a consequence of this broad industry and public concern, this project was listed as one of the priority areas for investment by the SAFRAB.

Most of the seals that interact with fisheries, aquaculture and ecotourism are juvenile and sub-adult males that restrict their feeding the shelf waters; however the diet and foraging behaviour of this part of the population is poorly understood. Little is also understood about the potential competitive interactions between the three species of seals that may be limiting the recovery of the threatened Australian sea lion. The project aims to investigate the diets and foraging distributions of seals in SA’s gulf and shelf waters to assess the importance of commercial fish and finfish aquaculture species in their diet. Trophic modelling will be used to assess the impact of consumption on current and future seafood production, and industry questionnaires and consultation will be used to assess the economic impact and the degree and nature of interactions between seals and finfish aquaculture, fisheries and marine ecotourism industries.

Objectives

1. Determine the importance of commercial and recreational fish and fin-fish aquaculture species in diets of seals
2. Determine the spatial distribution of foraging and consumption effort of fur seals relative to important fin-fish aquaculture and commercial and recreational fishing areas
3. Estimate the impacts of consumption by seals, and the implications of increasing populations on the future biomass of commercially and recreationally important marine taxa on seafood and marine ecotourism industries
4. Estimate the costs to the fin-fish aquaculture industry from stock losses, deterrent methods and maintenance requirements associated with seal interactions
5. Assess perceptions of the economic impacts of operational and trophic interactions with seals on seafood and on other species such as little penguin, giant cuttlefish and the potential ecological displacement of Australian sea lions from increasing fur seal populations

Final report

ISBN: 978-1-876007-16-4
Author: Simon Goldsworthy
Final Report • 2019-06-20 • 11.75 MB
2013-011-DLD.pdf

Summary

This report provides the most comprehensive assessment of the impact of seals on the seafood industry in South Australia, where management of both the real and perceived impacts of seals has become a very complex socio-ecological economic issue. 
The objectives of the project where to:
1. Determine the importance of commercial and recreational fish and fin-fish aquaculture species in diets of seals
2. Determine the spatial distribution of foraging and consumption effort of fur seals relative to important fin-fish aquaculture and commercial and recreational fishing areas
3. Estimate the impacts of consumption by seals, and the implications of increasing populations on the future biomass of commercially and recreationally important marine taxa on seafood and marine ecotourism industries
4. Estimate the costs to the fin-fish aquaculture industry from stock losses, deterrent methods and maintenance requirements associated with seal interactions
5. Assess perceptions of the economic impacts of operational and trophic interactions with seals on seafood and on other species such as little penguin, giant cuttlefish and the potential ecological displacement of Australian sea lions from increasing fur seal populations
The social perception surveys confirmed that concerns about the impacts of recovering populations of seals on seafood industries, marine communities and coastal ecosystems of South Australia have clearly intensified in recent years - thus becoming a very complex socio-ecological economic issues.

Related research

Industry
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Environment