Measurement and Mitigation of Operational Interactions between the South Australian Sardine Fishery and Common Dolphins

1. This study was initiated in response to recommendations arising from an ecological assessment of the South Australian Sardine Fishery (SASF), undertaken pursuant to the Commonwealth Environment Protection Biodiversity Conservation Act 1999.
2. The ecological assessment report provided the SASF with a 5-year exemption from further assessment and recommended that: • mechanisms be established to allow fishers to record interactions with Threatened,
Endangered and Protected Species (TEPS) at a species level and at an appropriate level of accuracy; and
• if information became available to indicate that the SASF was having significant interactions with any TEPS, that measures to mitigate those interactions should be
implemented within 12 months.
3. Logbook data collected between 1999 and 2004 suggested that the rates of dolphin interactions within the SASF were low and did not identify the species involved.
4. An observer program conducted between November 2004 and June 2005 revealed high rates
of encirclement (1.78 per net-set) and mortality (0.39 dolphins per net-set) of common dolphins (Delphinus delphis).
5. The SASF was subsequently closed during August and September 2005 to prevent further interactions with common dolphins.
6. A TEPS Working Group, that had been established prior to the closure, finalised a Code of Practice (CoP) to mitigate operational interactions with TEPS, especially dolphins.
7. The key guidelines of the CoP were: • that fishing operations would be delayed or relocated if when dolphins were observed near the vessel; • that crews would take swift action to release encircled dolphins; and
• that a net-set would be aborted if other methods for releasing dolphins were not successful.
8. The observer program conducted after the implementation of the CoP showed that rates of
dolphin encirclement and mortality were reduced to 0.22 and 0.01 dolphins per net-set respectively, suggesting that the CoP had reduced encirclement rates by 87.34% and
mortality rates by 97.11%.
9. The success of the CoP in reducing the operational interactions between the SASF and common dolphins is attributable to both the practicality and effectiveness of the guidelines and the industry’s strong commitment to resolving the problem.