Comparison of relative fishing power between different sectors of the Queensland trawl fishery, Australia

Abstract

The effects of improvements in fishing gear and technology on prawn and scallop catches from the Queensland trawl fishery were investigated. The species, the spatial distribution of the stocks, and the management regulations were used to partition the fishery into five main sectors: Torres Strait tiger prawns, north Queensland tiger prawns, shallow-water (<50 fathoms) eastern king prawns, deep-water (>50 fathoms) eastern king prawns and saucer scallops. For each sector, annual changes in average relative fishing power were calculated as a function of the fishing gear and technology parameters estimated in a generalised linear model and the average and/or percentage use of different gears and technologies in the sector. Over the 11 years from 1989 to 1999, fishing power for an average vessel increased at a low of 4% in the saucer scallop sector to a high of 27% in the shallow-water eastern king prawn sector. Fishing power in the shallow-water eastern king and tiger prawn sectors had the highest rates of increase and was largely attributed to vessels upgrading to larger engines. Increases in the number of vessels using global positioning systems and computer mapping software also contributed to increased fishing power in the two tiger prawn sectors. In the deep-water eastern king prawn sector, increased fishing power was associated with net head rope length, however, current management controls over engine size and head rope length are likely to limit this source of increase in fishing power. Fishing power in the scallop sector was associated with a relatively low average trawl speed of about 2.2 kn, which differed from the prawn sectors where higher catches were generally taken at trawl speeds of at least 3 kn. The results should be used to standardise fishing effort and be incorporated into stock assessments for each sector.