Limits...
Interactions between a Trawl fishery and spatial closures for biodiversity conservation in the Great Barrier Reef World Heritage Area, Australia.

Grech A, Coles R - PLoS ONE (2011)

Bottom Line: The past decade has seen the implementation of conservation and fisheries management strategies to reduce the impact of the ECOTF on the seabed and improve biodiversity conservation.The decline in effort as a result of fishing industry structural adjustment, increasing variable costs and business decisions of fishers is likely to continue a trend to fish only in the most productive areas.This will provide protection for most benthic habitats without any further legislative or management intervention.

View Article: PubMed Central - PubMed

Affiliation: Fisheries Queensland, Department of Employment, Economic Development and Innovation, Cairns, Queensland, Australia. alana.grech@jcu.edu.au

ABSTRACT

Background: The Queensland East Coast Otter Trawl Fishery (ECOTF) for penaeid shrimp fishes within Australia's Great Barrier Reef World Heritage Area (GBRWHA). The past decade has seen the implementation of conservation and fisheries management strategies to reduce the impact of the ECOTF on the seabed and improve biodiversity conservation. New information from electronic vessel location monitoring systems (VMS) provides an opportunity to review the interactions between the ECOTF and spatial closures for biodiversity conservation.

Methodology and results: We used fishing metrics and spatial information on the distribution of closures and modelled VMS data in a geographical information system (GIS) to assess change in effort of the trawl fishery from 2001-2009 and to quantify the exposure of 70 reef, non-reef and deep water bioregions to trawl fishing. The number of trawlers and the number of days fished almost halved between 2001 and 2009 and new spatial closures introduced in 2004 reduced the area zoned available for trawl fishing by 33%. However, we found that there was only a relatively minor change in the spatial footprint of the fishery as a result of new spatial closures. Non-reef bioregions benefited the most from new spatial closures followed by deep and reef bioregions.

Conclusions/significance: Although the catch of non target species remains an issue of concern for fisheries management, the small spatial footprint of the ECOTF relative to the size of the GBRWHA means that the impact on benthic habitats is likely to be negligible. The decline in effort as a result of fishing industry structural adjustment, increasing variable costs and business decisions of fishers is likely to continue a trend to fish only in the most productive areas. This will provide protection for most benthic habitats without any further legislative or management intervention.

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Number of days fished per year by the East Coast Otter Trawl Fishery (ECOTF) and annual trawl catch.The graph shows that the number of days fished in the ECOTF has been in decline since 1997. Despite this reduction in the number of days fished, catch has remained relatively constant with a downward trend beginning in 2004 showing recovery in recent years.
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pone-0021094-g001: Number of days fished per year by the East Coast Otter Trawl Fishery (ECOTF) and annual trawl catch.The graph shows that the number of days fished in the ECOTF has been in decline since 1997. Despite this reduction in the number of days fished, catch has remained relatively constant with a downward trend beginning in 2004 showing recovery in recent years.

Mentions: The East Coast Otter Trawl Fishery (ECOTF) of Queensland, Australia fishes for penaeid shrimps (e.g. eastern king prawn and brown tiger prawn) and scallops [9], and is the only demersal fishery in these waters. Depletion trends led to the implementation of multiple management tools in the early 1990's which ensure sustainability, reduce impact on bottom habitats and limit by-catch in the fishery [9], [10]. These management tools include: mandatory turtle excluder devices; restrictions on the number of vessels and their length; limited entry to the fishery; effort reduction strategies; and, spatial and temporal closures that control the spatial footprint of the fishery. Spatial closures are summarised in the Queensland Fisheries (East Coast Trawl) Management Plan 1999 and include a mixture of large areas that influence the location and time of fishing effort, and small and complex closures that are specifically targeted (e.g. scallop replenishment sites and ports). Temporal closures are employed widely in the ECOTF to synchronise the fishery with times when the target species are of an optimal size to capture highest market value. In addition, the northern two thirds of the fishery underwent a dramatic change in 2004 with the introduction of an ecosystem-scale network of ‘no take’ marine reserves (Figure 1) covering ∼33% of the Great Barrier Reef World Heritage Area (GBRWHA) [11], [12]. The goal of this network is to improve biodiversity conservation through a comprehensive and representative multiple-use zoning regime [13]. The biophysical operational principles designed to achieve the ecological objectives of the new zoning included specific recommendations to protect at least 20% of the area of 70 reef, non-reef and deep bioregions in ‘no take’ zones [11].


Interactions between a Trawl fishery and spatial closures for biodiversity conservation in the Great Barrier Reef World Heritage Area, Australia.

Grech A, Coles R - PLoS ONE (2011)

Number of days fished per year by the East Coast Otter Trawl Fishery (ECOTF) and annual trawl catch.The graph shows that the number of days fished in the ECOTF has been in decline since 1997. Despite this reduction in the number of days fished, catch has remained relatively constant with a downward trend beginning in 2004 showing recovery in recent years.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113906&req=5

pone-0021094-g001: Number of days fished per year by the East Coast Otter Trawl Fishery (ECOTF) and annual trawl catch.The graph shows that the number of days fished in the ECOTF has been in decline since 1997. Despite this reduction in the number of days fished, catch has remained relatively constant with a downward trend beginning in 2004 showing recovery in recent years.
Mentions: The East Coast Otter Trawl Fishery (ECOTF) of Queensland, Australia fishes for penaeid shrimps (e.g. eastern king prawn and brown tiger prawn) and scallops [9], and is the only demersal fishery in these waters. Depletion trends led to the implementation of multiple management tools in the early 1990's which ensure sustainability, reduce impact on bottom habitats and limit by-catch in the fishery [9], [10]. These management tools include: mandatory turtle excluder devices; restrictions on the number of vessels and their length; limited entry to the fishery; effort reduction strategies; and, spatial and temporal closures that control the spatial footprint of the fishery. Spatial closures are summarised in the Queensland Fisheries (East Coast Trawl) Management Plan 1999 and include a mixture of large areas that influence the location and time of fishing effort, and small and complex closures that are specifically targeted (e.g. scallop replenishment sites and ports). Temporal closures are employed widely in the ECOTF to synchronise the fishery with times when the target species are of an optimal size to capture highest market value. In addition, the northern two thirds of the fishery underwent a dramatic change in 2004 with the introduction of an ecosystem-scale network of ‘no take’ marine reserves (Figure 1) covering ∼33% of the Great Barrier Reef World Heritage Area (GBRWHA) [11], [12]. The goal of this network is to improve biodiversity conservation through a comprehensive and representative multiple-use zoning regime [13]. The biophysical operational principles designed to achieve the ecological objectives of the new zoning included specific recommendations to protect at least 20% of the area of 70 reef, non-reef and deep bioregions in ‘no take’ zones [11].

Bottom Line: The past decade has seen the implementation of conservation and fisheries management strategies to reduce the impact of the ECOTF on the seabed and improve biodiversity conservation.The decline in effort as a result of fishing industry structural adjustment, increasing variable costs and business decisions of fishers is likely to continue a trend to fish only in the most productive areas.This will provide protection for most benthic habitats without any further legislative or management intervention.

View Article: PubMed Central - PubMed

Affiliation: Fisheries Queensland, Department of Employment, Economic Development and Innovation, Cairns, Queensland, Australia. alana.grech@jcu.edu.au

ABSTRACT

Background: The Queensland East Coast Otter Trawl Fishery (ECOTF) for penaeid shrimp fishes within Australia's Great Barrier Reef World Heritage Area (GBRWHA). The past decade has seen the implementation of conservation and fisheries management strategies to reduce the impact of the ECOTF on the seabed and improve biodiversity conservation. New information from electronic vessel location monitoring systems (VMS) provides an opportunity to review the interactions between the ECOTF and spatial closures for biodiversity conservation.

Methodology and results: We used fishing metrics and spatial information on the distribution of closures and modelled VMS data in a geographical information system (GIS) to assess change in effort of the trawl fishery from 2001-2009 and to quantify the exposure of 70 reef, non-reef and deep water bioregions to trawl fishing. The number of trawlers and the number of days fished almost halved between 2001 and 2009 and new spatial closures introduced in 2004 reduced the area zoned available for trawl fishing by 33%. However, we found that there was only a relatively minor change in the spatial footprint of the fishery as a result of new spatial closures. Non-reef bioregions benefited the most from new spatial closures followed by deep and reef bioregions.

Conclusions/significance: Although the catch of non target species remains an issue of concern for fisheries management, the small spatial footprint of the ECOTF relative to the size of the GBRWHA means that the impact on benthic habitats is likely to be negligible. The decline in effort as a result of fishing industry structural adjustment, increasing variable costs and business decisions of fishers is likely to continue a trend to fish only in the most productive areas. This will provide protection for most benthic habitats without any further legislative or management intervention.

Show MeSH
Related in: MedlinePlus