Publication Date

1976

Series Number

Fisheries Report 25

Publisher

Department of Fisheries and Wildlife Western Australia

City

Perth

Abstract

Historically, the Western Australian production of Australian herring (Arrtpts georgtanus) has fluctuated from year to year in response to changing market demand. Prior to 1968, the annual catch taken by professional fishermen was relatively stable, ranging from 200 000 kg (approx. 500 000 pounds) to 450 000 kg (approx. 1 000 000 pounds). From 1968, commercial production has risen to a peak of 1 187 440 kg (2 617 857 pounds) recorded in 1972/73 (Table I). An increase in demand for herring as bait for the rock lobster fishery is considered to be the major factor involved in this observed rise in Australian herring production.

In addition to the expanding professional fishery, the amateur fishery has expanded as a result of population growth in Western Australia and the increase in privately owned pleasure boats. Conflict between professional net fishermen and amateur line fishermen has grown with the expanding fisheries. This has been found to be particularly severe in May, which is the month in which Australian herring appear to be most abundant and is also the school holiday period, when amateur and professional fishing pressure is expected to be at a maximum.

The possible effect on the Australian herring fishery of the expanding professional and amateur sectors has caused concern both to management and to the fishing fraternity.

An initial step towards assessing the effects of the increasing fishing pressure on the Australian herring stocks of Western Australia, and in attempting to resolve the conflict between professional and amateur fishermen, is the estimation of the total catch. The professional catch can be relatively easily obtained from .fishermen's monthly statistical returns or from research logbooks. No catch data is available for the amateur fishery, however, and if this should happen to comprise a relatively large portion of the total catch, then considerable bias would be introduced by interpreting only the professional catch and effort data.

The problem of assessing the amateur catch has arisen in many sport fisheries throughout the world. Three methods commonly used to provide harvest data are tagging, postal questionnaires and creel census. The tagging method basic­ally consists of using the ratio of amateur returns to pro­fessional returns in conjunction with the professional catch to obtain an estimate of the amateur catch. The major pro­blems associated with this technique are the release of sufficient tagged fish, the possible non-random distribution of the tagged fish, and non-reporting of recaptured fish. Carline (1972) reported the resvlts of an experiment which compared the postal questionnaire and creel census techniques, in which he concluded that estimates of fishing success were seriously overestimated by the postcard method. Although other studies discussed by Carline have found the postal questionnaire technique to be relatively free from bias, it would appear that the creel census method is more likely to produce an accurate estimate of the total harvest than the postcard method.

On consideration of the three techniques, tagging and postal questionnaire methods appeared to be most likely to be biassed. Accordingly, a creel census of amateur Aust­ralian herring fishermen was carried out in April, May and June of 1973, the results of which are reported in this paper.

Number of Pages

61

Keywords

Australian herring (Arripis georgianus), Western Australia, Fishery

Disciplines

Aquaculture and Fisheries | Data Science | Design of Experiments and Sample Surveys | Marine Biology | Natural Resources and Conservation | Natural Resources Management and Policy

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