The impact of global positioning systems and plotters on fishing power in the northern prawn fishery, Australia

Abstract

The impact of global positioning systems (GPS) and plotter systems on the relative fishing power of the northern prawn fishery fleet on tiger prawns (Penaeus esculentus Haswell, 1879, and P. semisulcatus de Haan, 1850) was investigated from commercial catch data. A generalized linear model was used to account for differences in fishing power between boats and changes in prawn abundance. It was found that boats that used a GPS alone had 4% greater fishing power than boats without a GPS. The addition of a plotter raised the power by 7% over boats without the equipment. For each year between the first to third that a fisher has been working with plotters, there is an additional 2 or 3% increase. It appears that when all boats have a GPS and plotter for at least 3 years, the fishing power of the fleet will increase by 12%. Management controls have reduced the efficiency of each boat and lowered the number of days available to fish, but this may not have been sufficient to counteract the increases. Further limits will be needed to maintain the desired levels of mortality.

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

“…Generalised linear regression approaches have been used to standardise average catches in the Gulf of Mexico prawn trawl fishery (Brunenmeister, 1984;Griffin et al, 1997), the Australian royal red prawn trawl fishery (Baelde, 1991) and to quantify the effects of global positioning systems (GPS) on average catches of tiger prawns in Australia's northern prawn fishery (Robins et al, 1998). Bishop et al (2000) further developed the analysis of Robins et al (1998) by using the generalised estimating equations (GEE) regression approach to account for spatial and temporal correlations in the data. In contrast to the regression approach, Salthaug and Godø (2001) used a model for standardisation based on the relative fishing power between pairs of vessels fishing at the same time and place to estimate fishing power relative to a 'standard' vessel; see also Hall and Penn (1979).…”

An overview of historical changes in the fishing gear and practices of pelagic longliners, with particular reference to Japan’s Pacific fleet

“…At a broader level, it is possible to gain insights into variations in fishing power by comparing the performance of two or more vessels using different gear or practices. Robins et al (1998), for example, examined the impact of GPS and plotters on fishing power in an Australian prawn fishery. They found that vessels using GPS had 4% greater power than vessels without GPS.…”

“…The addition of a plotter increased power by 7% over vessels without this equipment. Power increased by 12% when both pieces of equipment were used for at least three years (Robins et al 1998). In one of the few studies of longliner fishing power, Lin et al (1997) compared the performance of longliners using contemporary and traditional longline systems.…”

Standardizing fishery-dependent catch and effort data in complex fisheries with technology change

“…Historical information may be acquired from administration registers, interview of skippers, owners, ship builders, net makers, ship chandlers, and so on (for example, Robins et al 1998), and on-going fleet surveys are inexpensive relative to ongoing surveys of the resource.…”

“…Otherwise, changes in catch per unit effort that are due to variable catchability may be incorrectly concluded to be due to changes in abundance. Variable catchability can arise from patterns of availability and vulnerability, non-uniform recruitment and migration, and schooling behavior (Ricker 1975;Swain and Sinclair 1994;Arreguin-Sanchez 1996;Vignaux 1996a); technological changes in fishing gear and gear deployment (Dickson 1993;Rahikainen and Kuikka 2002) and changes in fishing strategies, target species and fleet dynamics (Vignaux 1996b;Gillis and Peterman 1998;Robins et al 1998;Walters 2003;Campbell 2004). This school of thought is in favor of focusing on reality and minimizing bias, above other considerations when modeling.…”