Ideal free distributions in fleet dynamics: a behavioral perspective on vessel movement in fisheries analysis

Gillis, Darren M.

doi:10.1139/z02-240

Cited by 91 publications

(78 citation statements)

References 59 publications

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“…This quota leasing would not occur in situations with low quota when all vessels are constrained by the quota, or in situations with high quota when no vessels are constrained. Third, the model does not incorporate any frequency or density dependent effects, such as exploitation and interference competition, which may negatively affect catch rates (Rijnsdorp et al 2000;Gillis 2003), or price formation (as in e.g. Dowling et al 2012).…”

Section: Discussionmentioning

confidence: 99%

High-grading and over-quota discarding in mixed fisheries

Batsleer

Hamon²,

Overzee³

et al. 2015

Rev Fish Biol Fisheries

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High-grading is the decision by fishers to discard fish of low value that allows them to land more valuable fish. A literature review showed high-grading is reported in commercial and non-commercial fisheries around the world, although the number of observations is small. High-grading occurs in fisheries that are restricted to land their total catch due to management, market or physical constraints. Using the mixed flatfish fishery as a model system, a dynamic state variable model simulation showed that high-grading of certain grades occurs throughout the year when their ex-vessel price is low. High-grading increases with the degree of quota restriction, while the level of over-quota discarding is unrelated to the quota level. The size composition of the high-graded catch differs from the landed catch. Due to the differences in the seasonal variation in size specific ex-vessel price, the effect of quota restrictions on the size composition of the discarded catch is nonlinear. High-grading is difficult to detect for the fishery inspection as it occurs on-board during the short period when the catch is processed. We conclude that highgrading is under-reported in fish stocks managed by restrictive quota, undermining the quality of stock assessments and sustainable management of exploited fish stocks.

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Section: Discussionmentioning

confidence: 99%

High-grading and over-quota discarding in mixed fisheries

Batsleer

Hamon²,

Overzee³

et al. 2015

Rev Fish Biol Fisheries

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“…The theory also has great promise to inform conservation and management (Rosenzweig 1987; reviews in Gillis [2003] and Morris [2003b]). Habitat-selection theory demands, therefore, rigorous and fool-proof tests, particularly in vertebrates where it is most often applied.…”

Section: Introductionmentioning

confidence: 99%

Active density‐dependent habitat selection in a controlled population of small mammals

Morris

MacEachern

2010

Ecology

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Abstract. Density-dependent habitat selection has numerous and far-reaching implications to population dynamics and evolutionary processes. Although several studies suggest that organisms choose and occupy high-quality habitats over poorer ones, definitive experiments demonstrating active selection, by the same individuals at the appropriate population scale, are lacking. We conducted a reciprocal food supplementation experiment to assess whether voles would first occupy a habitat receiving extra food, then change their preference to track food supplements moved to another habitat. Meadow voles, as predicted, were more abundant in food-supplemented habitat than in others. Density declined when food supplements ceased because the voles moved to the new habitat receiving extra food. Although males and females appeared to follow different strategies, meadow-vole densities reflected habitat quality because voles actively selected the best habitat available. It is thus clear that behavioral decisions on habitat use can motivate patterns of abundance, frequency, and gene flow that have widespread effects on subsequent evolution.

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“…Johnson & Carpenter 1994). Simply using mean fleet CPUE does not provide a good index of abundance, as CPUE may become equalised over fished areas as fishers move to maintain catches (Gillis et al 1993, Gillis 2003. Therefore, it is essential that CPUE is standardised to account for the spatial distribution of the fishing fleet (Sampson 1991).…”

Section: Discussionmentioning

confidence: 99%

Functional response of fishers in the Isle of Man scallop fishery

Murray

Hinz

Kaiser

2011

Mar. Ecol. Prog. Ser.

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To implement effective fisheries management, it is important to understand the variables influencing the distribution and intensity of fishing effort. The functional response of consumers to the availability of prey determines their impact on prey populations. The relationship between predator and prey observed in nature also applies to fishers and the populations they target. The present study focuses on the behaviour of a scallop dredging fleet fishing for Pecten maximus around the Isle of Man during a single fishing season. The functional response was investigated by examining the relationships between catches and fishing effort, scallop abundance and other variables. Scallop abundance was depleted rapidly during the first month of fishing. The increased patchiness of scallops towards the end of the season probably reduced their catchability, but fishers were able to maintain catch rates at intermediate abundance levels. The functional response did not conform to a particular type, but there was latent fishing capacity in the fishing fleet even at the highest levels of abundance. Therefore, reducing the number of vessels would not necessarily reduce fishing mortality unless combined with a reduction in the fishing power of individual vessels.

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Ideal free distributions in fleet dynamics: a behavioral perspective on vessel movement in fisheries analysis

Cited by 91 publications

References 59 publications

High-grading and over-quota discarding in mixed fisheries

High-grading and over-quota discarding in mixed fisheries

Active density‐dependent habitat selection in a controlled population of small mammals

Functional response of fishers in the Isle of Man scallop fishery

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