Catches in the South-East are controlled by quotas which are based on assessments of fish stocks. For many years, industry, managers and researchers have recognised the problems with using catch and effort data from commercial logbooks as the main index of abundance for SESSF species. This has been particularly the case in the South-East where a range of management arrangements such as closed areas, bycatch TACs and stock rebuilding strategies result in avoidance fishing behaviours by fishermen and undermine commercial catch rates as indices of abundance. Market prices, quota availability, the emergence of other stocks also affect the way that fishers target catch. These behaviours mean that commercial catch rates are questionable, and in some cases meaningless as an index of abundance for affected species. This cycle was recently the subject of an FRDC article titled, The catch 22 of catch-less abundance calculations.
This is not an unusual fishery management issue internationally, and often fishery independent surveys (or FISs) are used as a solution. A FIS is a strictly controlled survey conducted in a consistent manner where the same shots, gear and methods are repeated at regular intervals over time. FIS abundance indices can be used in addition to, or instead of commercial catch rate data. SETFIA members have supported a FIS in the South-East for the last eight years.
Because they do not consist of commercial shots, the cost of conducting a FIS has been a major hurdle preventing their implementation in the past. Also, Australian research agencies no longer have research vessels that are suitable for undertaking trawl surveys. About 60 tonnes of fish caught during the FIS is known as “research allowance” and is deducted from the following year’s commercial quota. This survey fish is sold and the proceeds are used to offset the cost of the survey. Industry vessels are chartered under an arrangement where vessels are paid a daily or per-shot charter rate. To reduce costs and ensure that the vessel contracts are cost effective the Association is the principle investigator (project manager) of the FIS.
Each winter, in July and August, around 200 shots are completed at locations that were selected prior to the first survey. The survey provides robust indices for Silver Warehou, Blue Grenadier, Tiger Flathead, Jackass Morwong, Mirror Dory, Pink Ling, Common Sawshark, Southern Sawshark, Offshore Ocean Perch, Gummy Shark, John Dory, the Deepwater Shark basket; Western Gemfish, Redfish, Ocean Jacket, Latchet, King Dory, Stargazer, Frostfish and Red Gurnard. These stocks make up 88% by weight of the catch of quota species and 75% of their value and include the major target species.
In addition to collecting catch rate data the survey collects around 20,000 length measurements and more than 3,000 otiliths (ear bones which are used to age fish).
Surveys were run in 2008, 2010, 2012 and the 2014 survey has just finished. Now that there is a time series of FIS data over eight years, this information can begin to be used as an abundance index in stock assessments.