Investigating the historical abundance of estuary perch in Lake Tyers

November 2014
Recreational Fishing Grants Program Research Report

Executive Summary

Lake Tyers is an intermittently open estuary located in south-eastern Victoria, approximately 15 km east of Lakes Entrance. Estuary perch Percalates colonorum, is a popular species for recreational anglers due to their sporting and eating qualities and is known to be present in Lake Tyers. Recreational fishers expressed concern that the population of estuary perch in Lake Tyers has suffered recruitment failure and not successfully bred since the cessation of commercial fishing in 2003. Subsequently, the Lake Tyers Beach Angling Club successfully applied for a Recreational Fishing Licence Small Grant in 2013 and commissioned Fisheries Victoria to investigate the historical abundance of estuary perch in Lake Tyers. This study aimed to:

1. Examine past commercial fishing records to establish catch levels prior to the cessation of commercial fishing in 2003
2. Identify and examine available angling club and other relevant records to establish historical level of recreational targeting/catch of estuary perch in Lake Tyers.
3. Conduct semi-structured interviews with local recreational and commercial fishermen as to their recollections of estuary perch in Lake Tyers

Although Lake Tyers supports a healthy and well known, fishery for other species, this study found estuary perch has historically never been a significant component of either the recreational or commercial fishery. 

• Over a period of 40 years (1964 and 2003), estuary perch were rarely taken by commercial fishermen with peak catches occurring between 1989 and 1991, while in most years none were caught.
• In angler creel surveys undertaken between 1979 and 1985, estuary perch were not a considerable target or catch for recreational anglers.
• Local knowledge surveys of nine long-term experienced recreational fishers of Lake Tyers suggested catches of estuary perch in Lake Tyers occurred between the mid 1930's until present, but statements regarding the frequency and size of catches varied among interviewees. Six of the nine interviewed recreational angler recollections of estuary perch being caught or seen in larger numbers around 20-30 years ago than present, were relatively consistent with catches observed in commercial catch data
• Several recreational fishers anecdotally reported catches of estuary perch in recent times and six records of estuary perch catches were reported in the Voluntary Angler Diary Program by one angler in 2002.
• While data analysed in this study suggested that the abundance of estuary perch may have fluctuated over time, the current status of the estuary perch population in Lake Tyers is unknown, and there is insufficient information to determine if the abundance of estuary perch has changed appreciably over time and whether or not recruitment failure has occurred. Both commercial and recreational fishing in Lake Tyers may select for species other than estuary perch, which does not allow for a true assessment of population abundance. Commercial catch data suggests estuary perch may be episodic recruiters to the lake.
• A fishery independent survey would be required to obtain a more accurate and current index of abundance and an indication of whether recruitment failure has occurred for estuary perch in Lake Tyers.

This information can be used by fisheries managers to make informed decisions regarding the management recreational fisheries in Lake Tyers. If estuary perch abundance and recruitment were determined to be depressed and enhancement of the population and fishery at Lake Tyers was desired, stock enhancement with hatchery-bred fingerlings is one option that may increase abundance of the species.