Identifying historical baseline at the onset of exploitation to improve understanding of fishing impacts

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

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Natura 2000 sites and fisheries in German offshore waters

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn193 ◽

2008 ◽

Vol 66 (1) ◽

pp. 155-169 ◽

Cited By ~ 44

Author(s):

Søren Anker Pedersen ◽

Heino Fock ◽

Jochen Krause ◽

Christian Pusch ◽

Anne L. Sell ◽

...

Keyword(s):

Marine Mammals ◽

Fishery Management ◽

Conservation Status ◽

Natura 2000 ◽

Management Measures ◽

Favourable Conservation Status ◽

Management Plans ◽

Natura 2000 Site ◽

Environmentally Sound ◽

Fishing Impacts

Abstract Pedersen, S. A., Fock, H., Krause, J., Pusch, C., Sell, A. L., Böttcher, U., Rogers, S. I., Sköld, M., Skov, H., Podolska, M., Piet, G. J., and Rice, J. C. 2009. Natura 2000 sites and fisheries in German offshore waters.–ICES Journal of Marine Science, 66: 155–169. The principal objective of sites selected as part of Natura 2000 is to achieve or maintain a favourable conservation status of habitats and species named in the EU Birds and Habitats directives. In the German exclusive economic zone, the habitat types protected by this legislation are sandbanks and reefs; protected species include marine mammals, seabirds, and specific migratory fish species. The ICES project Environmentally Sound Fishery Management in Protected Areas (EMPAS) aims to answer two questions: (i) To what extent do specific fishing activities significantly threaten attainment of the conservation objectives of the Natura 2000 sites? (ii) What management measures would reduce these conflicts and how effective would they be at helping to ensure the favourable condition of these sites? Assessments of fishing impacts on Natura 2000 sites require basic data on the conservation status of individual habitats and species, as well as data for fine-scale distributions of ongoing fishing activities. This paper describes and discusses the process used by the EMPAS project in developing fishery-management plans for each Natura 2000 site in German offshore waters.

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Investigation of seabed fishing impacts on benthic structure using multi-beam sonar, sidescan sonar, and video

ICES Journal of Marine Science ◽

10.1093/icesjms/fsm056 ◽

2007 ◽

Vol 64 (5) ◽

pp. 1053-1065 ◽

Cited By ~ 14

Author(s):

Mashkoor A. Malik ◽

Larry A. Mayer

Keyword(s):

Gulf Of Maine ◽

Fishing Ground ◽

Sidescan Sonar ◽

Data Sets ◽

Frequency Filtering ◽

Data Set ◽

Detection And Identification ◽

Spatial Frequency Filtering ◽

Disparate Data ◽

Fishing Impacts

Abstract Malik, M. A., and Mayer, L. A. 2007. Investigation of seabed fishing impacts on benthic structure using multi-beam sonar, sidescan sonar, and video. – ICES Journal of Marine Science, 64: 1053–1065. Long, linear furrows of lengths up to several kilometres were observed during a recent high-resolution, multi-beam bathymetry survey of Jeffreys Ledge, a prominent fishing ground in the Gulf of Maine located about 50 km from Portsmouth, NH, USA. These features, which have a relief of only a few centimetres, are presumed to be caused either directly by dredging gear used in the area for scallop and clam fisheries, or indirectly through the dragging of boulders by bottom gear. Extraction of these features with very small vertical expression from a noisy data set, including several instrumental artefacts, presented a number of challenges. To enhance the detection and identification of the features, data artefacts were identified and removed selectively using spatial frequency filtering. Verification of the presence of the features was carried out with repeated multi-beam bathymetry surveys and sidescan sonar surveys. Seabed marks that were clearly detected on multi-beam and sidescan sonar records were not discernible on a subsequent video survey. The inability to see the seabed marks with video may be related to their age. The fact that with time, the textural contrasts discernible by video imagery are lost has important ramifications for the appropriateness of methodologies for quantifying gear impact. The results imply that detailed investigations of seabed impact are best done with a suite of survey tools (multi-beam bathymetry, sidescan sonar, and video) and software to integrate the disparate data sets geographically.

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Physical and electrical disturbance experiments uncover potential bottom fishing impacts on benthic ecosystem functioning

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2021.151628 ◽

2021 ◽

Vol 545 ◽

pp. 151628 ◽

Cited By ~ 1

Author(s):

Justin C. Tiano ◽

Emil De Borger ◽

Sarah O'Flynn ◽

Chiu H. Cheng ◽

Dick van Oevelen ◽

...

Keyword(s):

Ecosystem Functioning ◽

Fishing Impacts

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Shift of Small Scale Fishing Impacts on Fish Trophic Levels in Lake Iro Revealed by Species-Based Indicators

Fisheries and Aquaculture Journal ◽

10.4172/2150-3508.1000167 ◽

2016 ◽

Vol 07 (02) ◽

Author(s):

Modou Thiaw ◽

Mbaye Tine

Keyword(s):

Trophic Levels ◽

Small Scale ◽

Fishing Impacts

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Recent advances in understanding the environmental footprint of trawling on the seabed

Canadian Journal of Zoology ◽

10.1139/cjz-2018-0248 ◽

2019 ◽

Vol 97 (9) ◽

pp. 755-762 ◽

Cited By ~ 4

Author(s):

Michel J. Kaiser

Keyword(s):

Habitat Structure ◽

Meta Analysis ◽

Environmental Footprint ◽

Physical Disturbance ◽

Carbon Footprints ◽

Modelling Framework ◽

Management Measures ◽

Highly Sensitive ◽

Different Types ◽

Fishing Impacts

Bottom trawling accounts for nearly a quarter of wild-capture seafood production, but it is associated with physical disturbance of the seabed leading to changes in benthic abundance, habitat structure, and biogeochemical processes. Understanding the processes of benthic depletion and recovery in relation to different types of fishing gears, and in different seabed types, is an important pre-requisite to inform appropriate management measures to limit or reduce the effects of trawling on the seabed. The combined approaches of meta-analysis and modelling that link fishing-gear penetration of the seabed to benthic depletion, and recovery to taxon longevity, have enabled the development of a modelling framework to estimate relative benthic status in areas subject to trawling. Such estimations are highly sensitive to the spatial resolution at which fishing footprint (trawl track) data are aggregated, and this leads to overinflated estimates of fishing impacts on benthos when coarse-level aggregation is applied. These approaches present a framework into which other “sustainability” criteria can be added, e.g., the consideration of carbon footprints of fishing activities.

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Investigating Fishing Impacts in Nigerian Coastal Waters Using Marine Trophic Index Analyses

Marine and Coastal Fisheries ◽

10.1002/mcf2.10077 ◽

2019 ◽

Vol 11 (4) ◽

pp. 287-294

Author(s):

Tunde Adebola ◽

Kim Mutsert

Keyword(s):

Coastal Waters ◽

Trophic Index ◽

Fishing Impacts

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Kelp forest ecosystems: biodiversity, stability, resilience and future

Environmental Conservation ◽

10.1017/s0376892902000322 ◽

2002 ◽

Vol 29 (4) ◽

pp. 436-459 ◽

Cited By ~ 991

Author(s):

Robert S. Steneck ◽

Michael H. Graham ◽

Bruce J. Bourque ◽

Debbie Corbett ◽

Jon M. Erlandson ◽

...

Keyword(s):

Case Studies ◽

Sea Urchin ◽

North Atlantic ◽

Forest Ecosystems ◽

Kelp Forest ◽

Kelp Forests ◽

Apex Predators ◽

The Past ◽

The North ◽

Fishing Impacts

Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.

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