Recreational Scalefish Research

Post-release Survival of Mako Shark

Title: Post-release Survival of Captured Mako Sharks: Contributing to developing best-practice for catch and release game fishing, November 2015.
Lead Agency:
Institute for Marine and Antarctic Studies.
Funding:  Fishwise – Your licence fees at work.

Summary

This study assessed the post-release survival of recreationally caught shortfin mako sharks using Survivorship Pop-up Archival Transmitting (sPAT) tags and examined physiological indicators of capture stress from blood samples as well as any injuries that may be caused by hook choice.

Overall, post release survival rate is 90% when shortfin mako sharks are caught on rod and reel, subjected to relatively high fight times up to 500 minutes and handled for up to 12 minutes. Circle hooks significantly reduced foul hooking when compared with J hooks.

  • Post-release survival in this species is most likely to be impacted by hooking injuries which can be reduced through the adoption of circle hooks. If sharks are deep hooked, leaving hooks in may be beneficial, rather than risk further internal injury trying to remove them.
  • The unique physiology of the species probably enabled it to cope with long fight times and the associated physiological responses to capture.
  • Sharks that appeared moribund (at death’s door) when boat-side made a complete recovery after release which is an important factor to take into consideration when conducting survivorship studies and when making a decision about whether or not to release an individual.
  • As a consequence, as long as the shark has not sustained injuries, recreational capture and release of mako sharks results in high survivorship and as such is likely to have minimal impact on this species populations. The high survival rate supports the effectiveness of catch and release as a conservation method for shortfin mako as a strategy promoting responsible fishing for this species.
Download the full report.

Southern Bluefin Tuna Code of Practice

Title: Capture-induced physiological stress and post-release survival of recreationally caught Southern Bluefin Tuna
Lead Agency: Institute for Marine and Antarctic Studies

Summary

The primary objective of the study was to assess the post-release survival rate of SBT caught by the recreational fishery in Australia.

  • The results showed that recreationally caught SBT have a low incidence of mortality (3%) occurring during the capture event related directly to the hooking and retrieval of the fish. An exception to the low pre-landing mortality was attributed to seal predation of SBT caught in Tasmanian waters. Seal predation accounted for mortality of 31% of fish hooked in Tasmanian waters.   The majority of recreational fishing targeting SBT occurs in close proximity to the coastline and islands.  These areas have haul outs used by the seals and concentrations of food sources like small pelagics fish which increases the possibility of an interaction with seals. 
  • Predation on hooked SBT by seals whilst fishing adjacent to Tasmania does contribute a substantial degree of unaccounted mortality and further research to investigate measures to reduce interactions are warranted.
  • Most methods currently used by recreational fishers to capture SBT are effective at minimizing damage to the fish. Fish caught using treble hooks tend to display more severe physical damage than fish caught using single J hooks. 
Copies of the code of practice which collates the recommendations for ‘best practice ’for the catching, handling, release and tagging of SBT can be obtained from game fishing clubs, tackle shops, TARFish and Fishcare Volunteers.

Adoption of practices outlined in the code will possibly improve post-release survival, animal welfare, the level of community approval for recreational fisheries, improve data quality collected from recreational fish tagging programs and reduce fish wastage.

Catchability of Flathead

Title: Relating Catchability of Flathead to their seasonal activity and movement.
Lead Agency: Institute for Marine and Antarctic Studies

Summary

The research was commissioned by DPIPWE because flathead is Tasmania’s most important recreational fish at around 70% of all fish caught.  Recreational fishers retain over 1 million flathead (over 230 tonnes) annually, about 6 times the commercial catch.

This study combines experimental catch data and telemetry data from Pittwater and Frederick Henry Bay (FHB) on the southeast coast of Tasmania as well as metabolic rate data collected in the laboratory to determine the nature and drivers of seasonal patterns in catch per unit effort (CPUE) of the sand flathead.

Analysis of CPUE from both rod and line and longline data revealed that the seasonal variability in catches differed in magnitude by area, with a strong seasonal pattern in the shallow coastal estuary of Pittwater and a limited seasonal pattern in FHB, the deeper bay at the mouth of the estuary.

Low catch rates in Pittwater in winter were most likely caused by seasonal movement of flathead out of Pittwater into FHB at the start of winter, followed by a return to Pittwater at the start of the following spring. In FHB on the other hand, the fact that CPUE was slightly decreased in winter even though the movement data indicated this to be the species’ winter habitat suggests that catches in this area are likely to be influenced by seasonal changes in the receptiveness of flathead to bait.

Download the report.

Abundance and Population of Sand Flathead

Title: Developing a Low-Cost Monitoring Regime to Assess Relative Abundance and Population Characteristics of Sand Flathead 2014
Lead Agency: Institute for Marine and Antarctic Studies

The research was commissioned by DPIPWE because flathead is Tasmania’s most important recreational fish at around 70% of all fish caught.  Recreational fishers retain over 1 million flathead (over 230 tonnes) annually, about 6 times the commercial catch. Key findings of the report include:

  • Catch rates declined in the D’Entrecasteaux Channel, Frederick Henry/Norfolk Bays and Great Oyster Bay, suggesting a possible decline in the abundance of flathead;
  • Females grow more quickly and to greater sizes than males, thereby reaching the 30cm size limit at younger ages making them more vulnerable to fishing;
  • Reducing fishing pressure should be considered.
Download the report.

Offshore Recreational Fishing in Tasmania

Fish illustration by Peter Gouldthorpe Title: Offshore Recreational Fishing in Tasmania 2011/12
Lead Agency: Institute for Marine and Antarctic Studies

The report provides a detailed assessment and characterisation of the recreational gamefish and offshore fisheries in terms of fishing effort (boat days), catch rates, and harvest for key species. Species include southern bluefin tuna, yellowfin tuna, albacore, mako sharks, striped trumpeter and blue eye trevalla. A summary report is available.

Recreational Gillnetting in Tasmania

Title: Recreational Gillnetting in Tasmania - An evaluation of fishing practices and catch and effort.
Lead Agency: Institute for Marine and Antarctic Studies

The project comprised two components: a description of how recreational net fishing practices have changed in relation to management changes and target species availability; the second component focused on participation, intensity of fishing, catch rates, and catch by netting for the 2009/10 licensing year.

The findings of this research project formed part of a larger IMAS project assessing the impacts of recreational commercial gillnetting in Tasmania, Assessing the impacts of gillnetting in Tasmania: implications for by-catch and biodiversity.


Recreational Set-line Usage in Tasmania

Title: Recreational Set-line Usage in Tasmania
Lead Agency: Institute for Marine and Antarctic Studies

A recreational set-line licence was introduced in Tasmania for the first time for the 2009-10 licensing year, with over 3500 licences issued. Up to 30 hooks can be fished using setlines and the lines are generally configured as longlines to target shark or as droplines to target species such as blue-eye trevalla and striped trumpeter. Relatively little information is available about set-line usage in Tasmania, such as fishing practices, target species, catch rates, by-catch, seasonality and spatial patterns of the fishery.

Spawning Dynamics of Striped Trumpeter

Title: Spawning dynamics and age structure of wild caught Tasmanian striped trumpeter during the 2010 spawning season
Lead Agency: Institute for Marine and Antarctic Studies

Fishwise Community Grants Research Report CoverThe objective of the research was to describe spatial variations in the spawning dynamics of striped trumpeter, including:
    • the onset and duration of the spawning season across the latitudinal distribution along the east coast of Tasmania;
    • spatial variance in the age at maturity;
    • size specific fecundity.
The research also developed yield and spawner per recruit models to assess maximum and minimum size limit scenarios - to optimise size limit management regulations.


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