Recreational fishers release fish for a variety of reasons, including adherence to legal size and bag limits, closed seasons, eating qualities and/or for ethical reasons (including catch and release fishing). Many factors can influence the subsequent survival of a released fish, including fisher influenced (level of exertion during capture, damage due to hooking, handling practices) and non-fisher influenced (fish condition, environmental conditions) factors.
Recognising the national significance of flathead to the recreational fishery, being the largest catch of any fish group taken by recreational fishers, and the level of released catch, in terms of numbers second only to bream, there is a clear need to evaluate factors that might influence post-release survival (PRS) and examine practical options, for example hook type and handling practices, that will maximize PRS. Several species of flathead are taken by recreational fishers with sand flathead dominating catches in Victoria and Tasmania and dusky flathead the main species in NSW and Queensland. The proposed study seeks to examine factors affecting PRS in these key flathead species.
The need for an assessment of PRS in flathead has been identified as a high priority in the FRDC National Strategy for the Survival of Released Line Caught Fish and the proposed study addresses The National R&D Plan for the Recreational Sector strategy relating to understanding the effects of fishing activities on fish and their ecosystems.
Flathead represent the largest catch of any fish group taken by recreational fishers in Australia and, after bream, account for the greatest numbers of fish released by recreational fishers (National Recreational Fishing Survey). Flathead are taken around Australia, with catches concentrated in the eastern states, including Tasmania. Sand flathead (Platycephalus bassensis) is the dominant species taken in estuarine and sheltered inshore waters of Tasmania and Victoria whereas dusky flathead (P. fuscus) is the main species taken from NSW and southern Queensland. Legal minimum size and bag limits apply for flathead, though there is little consistency between jurisdictions.
A review of post-release survival (PRS) in line caught fish (McLeay et al. 2002) identified flathead as a priority group, with research to focus on the effects of handling and hook damage on survival. The present study represents a component of the National Strategy for the Survival of Released Line Caught Fish.
The principal objectives of this study were to estimate the short-term post-release survival rates for sand and dusky flathead, and to determine whether there was any survival benefit in the use of circle hooks rather than conventional hook patterns. Recognising the increasing uptake of lures (especially soft plastics) for flathead, the potential impact of their use on post-release survival was also assessed. Using the results of this research we have been able to develop protocols that can be readily applied by recreational fishers to maximise the survival of flathead.
The study involved experiments in which flathead (sand flathead in Tasmania and dusky flathead in southern Queensland) were captured by angling and then held in aquaria for several days to assess short-term survival. In addition, catch rates and hooking locations for a range of hook types were compared. Volunteer anglers also provided hooking information for flathead captured using bait and lure fishing methods.
Keywords: Sand flathead, dusky flathead, post-release survival, hooking damage, circle hooks, recreational fishing practices.