BDBSA Project Metadata Detail

Survey/Project Number: 1111          Total No. of Sites: 9
Survey/Project Name: Strategies for managing seal-fisher interactions in SA Lakes & Coorong Fishery
Abstract: This project aims to determine strategies for managing seal/fisher interactions in the South Australian Lakes and Coorong Fishery (LCF). The LCF is a small-scale, multi-species, multi-method, community-based fishery that operates within a dynamic environment, recognised internationally for its unique ecological character. The LCF includes the waters of three separate, but closely linked, ecosystem components: 1. Freshwater Lower Lakes (Lakes Alexandrina and Albert); 2. Coorong estuary; 3. Adjacent coastal marine waters along the Sir Richard and Younghusband Peninsulas. BACKGROUND: The fishery uses mainly gill nets to harvest a variety of finfish species, including Yelloweye Mullet, Mulloway, Golden Perch and European Carp. In most years, catches taken using gill nets account for >98% of the fishery's total annual harvest of finfish. With the recent recovery and growth of Long-nosed Fur Seal [New Zealand Fur Seal] (Arctocephalus forsteri) populations in South Australia, Fur Seal interactions with fisheries and aquaculture industries have increased. Long-nosed Fur Seal are native to Australia and New Zealand, and are protected under both South Australian and Australian government legislation. Scientific surveys estimate there has been an annual increase in Fur Seal numbers in South Australia of 5.5% over the past 25 years. Approximately seven years ago, significant numbers of Long-nosed Fur Seal began to interact with the LCF, after they entered the Coorong estuary and Lower Lakes. Unlike many other marine mammal/fishery interactions, interactions between Fur Seal and the LCF do not typically involve the fishery impacting adversely on the seals, but rather the opposite where the seals affect the harvest from the fishery through depredation. This occurs as seals eat fish that are caught in gill nets. This issue has grown in recent years to the point where the fishing industry estimate that a significant (and growing) portion of the catch is being taken by Fur Seals, threatening the ongoing viability of the fishery. This estimated impact is currently approximately $2m/year out of a total catch value of approximately $8m. A variety of meetings between the Government of SA and stakeholders of the LCF have been held to discuss solutions to this issue. The Government of SA has made it clear that management efforts should be focussed on non-lethal ways to keep seals away from catches (using the existing fishing gear) and/or developing alternative fishing gears that may allow the fishery to catch sustainable quantities of fish without seal depredation. A workshop was convened by PIRSA Fisheries and Aquaculture at Glenelg, South Australia on 31 July 2015, to identify and confirm alternative fishing methods/gears and/or seal deterrent methods that could be trialled to minimise the impacts of Long-nosed Fur Seal on the LCF. Attendees included representatives from the fishing industry, conservation sector, seal experts, independent scientists, Fisheries Research and Development Corporation, Department of Environment, Water and Natural Resources, PIRSA Fisheries and Aquaculture and SARDI. Since that meeting, the Government of SA has invested $100,000 for research into alternative fishing gears/methods and seal deterrent devices, with the Australian Government, through the Fisheries Research and Development Corporation, contributing a further $158,000 to the project.
 
Start Date: 01/03/2016      End Date: 31/07/2016
Survey Type: Fauna only
   
Study Area Description: Coorong National Park
Objectives
         Vegetation: *** No vegetation survey objectives recorded
         Fauna: The specific objectives of the research project are: 1) To undertake a review of global seal and fisher interactions and to review best practice mitigation and management options relevant to the LCF; 2) To assess operational changes to current practices, including the use of deterrent methods to reduce the rates of seal depredation on caught fish and damage to fishing gear; and 3) Develop and trial alternative fishing gears/methods based on best practice that are less vulnerable to seal depredation of catches and gear damage, and provide economically viable alternatives to current practices. This component of the project aims to assess the effectiveness of non-lethal underwater firecrackers (seal crackers) for temporarily deterring long-nosed fur seals from commercial gill netting operations in the Coorong estuary. Seal crackers (also known as seal bombs, seal control units, seal bangers) are used extensively by fishing and aquaculture industries around the world (e.g. South Africa, United States, West Africa, Australia), to deter marine mammals, including seals (Shaunghnessy et al. 1981; Pemberton and Shaughnessy 1993; Jefferson and Curry 1996; Scordino 2010). In Tasmania, crackers have been used to deter fur seals from aquaculture leases (salmon pens) and commercial fishing activities since the 1980s (Pemberton and Shaughnessy 1993). In 2015, approximately 26,000 underwater crackers were deployed by the aquaculture industry in Tasmania (Mike Greenwood, DPIPWE, pers.comm.).
Methodology
         Vegetation: *** No vegetation methodology recorded
         Fauna: The research will involve paired trials of modified gill netting operations, including the option to use seal crackers to deter fur seals, alongside conventional gill netting operations (without access to seal crackers) to compare fur seal depredation rates, gear damage, and catches of targeted and non-targeted finfish species in the Coorong estuary. Paired trials will be undertaken by LCF fishers, under the management and close supervision of the project principle investigator (J. Earl), and involve on-board fishery-independent observers (SARDI and DEWNR staff) to collect a range of data, including the numbers of fish (by species) damaged by fur seals, presence/absence of seal-related damage to fishing gear and changes to seal behaviour. Analysis of the information collected during the trials will be considered to determine whether seal crackers may assist LCF fishers with minimising the impacts of long-nosed fur seals. All project investigators and industry representatives involved with the trials have attended theoretical, practical, legal and ethical training in the safe handling, storage and use of seal crackers to deter marine animals. This training was delivered by experts from the Tasmanian Department of Primary Industries, Parks, Water and Environment (DPIPWE) Wildlife Management Branch, whom have extensive (>20 years) experience using seal crackers, and representatives from DEWNR, SARDI and Safework SA. The training also included a included a comprehensive overview of the Animal Welfare Act 1985 (Section 13 offences) presented by Deb Kelly, Manager of Animal Welfare, DEWNR.

Data Distribution Rules: Public Dataset
Project Basis: Fauna : Pest/Diseases/Threats - control project
Information Authority: Department of Primary Industries and Resources SA