Biology and Fishery of Estuary Perch (Macquaria colonorum) in coastal catchments of NSW

Estuary perch are a relatively common fish that inhabit coastal rivers and lakes of NSW and Victoria. Although once virtually unknown, advancements in lure technology and fishing techniques have seen an increasing number of anglers targeting the species. In particular, there is a growing fishery for estuary perch based on artificial lures and flies, with many fish being released following capture. Estuary perch are commonly caught up to 3kg and 50cm in length and appear to spawn in the lower reaches of rivers in winter and spring. At other times they move upstream and downstream in estuaries, but generally their ecological requirements and life history characteristics are unknown or not documented. There is almost no information on the recreational fishery and its interaction with commercial fishing activities.

AIM
The aim of this three year study funded by the NSW Recreational Fishing Trusts is to obtain biological and fisheries-related information on estuary perch to provide advice on the future management of the species.

OBJECTIVES

• Populations of estuary perch will be sampled on a monthly basis to obtain important biological information on the maturation of gonads to identify the time and location of spawning as well as size and age at maturity. Examination of the microstructure of otoliths will investigate patterns of age and growth of estuary perch.

• A tag-release program will study the movement and growth of fish throughout estuaries, with experienced researchers and recreational fishers doing the tagging work. Estuary perch implanted with acoustic transmitters will be tracked in real time to monitor short term movement and habitat relationships. Fixed listening stations deployed within the estuary will monitor the long term seasonal migrations of estuary perch.

• A profile of the recreational fishery for estuary perch will be established using logbook information provided by recreational fishers. Data collected will include quantities and sizes of fish caught along with other important catch variables. A series of hook mortality experiments will test the effects of a variety of fishing methods on the post release survival of these fish.