Introduction and Project Design & Methods

Statewide Angler Diary Program 1997 - 2003

Introduction

The development of rational and acceptable fishery management arrangements requires regular assessments of the status of fish stocks. The analysis of fishery catch information is an essential component of most fish stock assessment processes. Collection of a time series of catch information provides important indicators of fishery trends and fluctuations in the status of fish stocks, and may allow assessments of the relative influence of fishing pressure versus environmental factors on stock abundance.

Recreational fishers, unlike commercial fishers, are not required to provide fishing catch and effort returns, and there is consequently less data on which assessments can be based. The associated costs have generally precluded the conduct of regular surveys of anglers to obtain catch and effort data in Victoria. Recreational fisheries management has therefore usually been undertaken without the benefits provided by the availability of a time series of catch information. An alternative survey approach is to use anglers to record and report their own catch data. This approach may provide a cost effective means to improve the management of recreational fisheries (Conron 2003). Catch rates reported by highly skilled anglers can provide an index of abundance of the fish stock both above and below the Legal Minium Length (LML). The size composition of fish in angler catches can provide an indication of the impact of fishing, and can also be used to forecast the timing and amount of future recruitment.

An angler fishing diary program was established in Victoria in 1997 to provide a time series of catch rate and size composition information to assist in assessing the status of fisheries and fish stocks. The purpose of this report is to review the information collected since 1997 and to assess the Programs usefulness in assisting with the management of Victorian fisheries.

Project Design and Methods

Catch details recorded

The initial fishing diary format was specifically designed to monitor the catch rate of various size/year-classes of black bream populations in Victorian estuaries. Participating anglers altered their fishing techniques in order to catch the complete size range of black bream. The detailed catch diary recorded the time spent fishing, fish lengths, and bait and hook sizes used (Appendix 1.1).

In 1998, the fishing diary format was altered to collect catch and effort information from a broad range of marine and freshwater angling methods. It was recognised as important to minimise the inconvenience to some of the anglers involved. The new diary format allowed anglers to choose the level of detail they wished to record. At the basic level, anglers recorded date of trip, target species, fishing location, fishing effort, number of rods, bait, hook type, number and species of fish kept, and number and species of fish released. At the next level of detail, anglers provided length measurements on the fish retained. The final level of detail involved recording the lengths all the fish caught, included fish released as well as those kept. Lengths were recorded as fork length (FL) (length along the midline of the body from the most anterior part of the head to the end of the medial rays of the caudal fin), or total length (TL) for species that had no fork in the tail. Gummy and school shark lengths were recorded from the most posterior gill to the base of the tail. Anglers were instructed to record lengths to the nearest whole centimetre below the observed length. A space was provided for comments to be made in regard to each fishing trip (Appendix 1.2). Anglers were initially provided with an explanatory letter, ruler and fishing diary. To minimise the non-reporting of poor catches, anglers were asked to record every trip for their nominated target species and fishing region. Replacement diaries were supplied, with anglers also receiving a hat and T-shirt promoting the program. More regular contact (phone and letters) with the participating anglers was undertaken in 2002/03. At the completion of the 2002/03 season, a fishing satisfaction survey was undertaken with participating anglers. The survey questions were similar to those asked as part of the Attitudinal Questionnaire from the National Recreational and Indigenous Fishing Survey (Henry and Lyle 2003). Anglers were asked to identify their preferred target species and fishing water body, primary motivation for fishing in that particular fishery, and their level of satisfaction with their fishing experience in the 2002/2003 season (Appendix 1.3).

Selection of anglers

The anglers recruited to the program were volunteers and generally had a high degree of fishing expertise and an excellent knowledge of their preferred fishery. The existence of the Angler Fishing Diary Program was promoted through newsletters to fishing clubs, articles in newspapers and general word of mouth by department staff and the anglers involved.

Data Analysis

Catch data from returned angler fishing diaries were entered into an Access database. A time series of catch rates and size composition information was generated for four key target species in four fishing regions of interest to Fisheries Victoria: snapper in Port Phillip Bay and Western Port, King George whiting in Port Phillip Bay and Western Port, black bream in the Gippsland Lakes, and trout (rainbow and brown) in the Goulburn river. Average catch rates for key species were calculated from angler fishing trips where the species of interest was nominated as a target species. Three components from catches recorded by anglers were used to estimates catch rates; total catch rates (all captured fish reported), retained catch rate (fish reported as kept or above the LML) and released catch rates (fish reported as released or below the LML). Average catch rates were calculated using the ratio-of-means estimator (Jones et al. 1995). The bootstrap method was used to estimate confidence limits (CL) for the catch rate estimates, using a resample size of n/2 (Efron and Tibshirani 1993). Separate size distributions were generated for the retained and released components of the catch. All results were grouped by financial year which is considered to be the best representation of a single fishing season.

The results of the fishing satisfaction survey were analysed by all anglers surveyed, anglers who targeted the key species State-wide and those targeting the key species in the four fishing regions of interest.

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