Sediment mobilization by bottom trawls: a model approach applied to the Dutch North Sea beam trawl fishery

Abstract Bottom trawls impact the seafloor and benthic ecosystem. One of the direct physical impacts is the mobilization of sediment in the wake of trawl gear components that are in contact with or are close to the seabed. The quantity of sediment mobilized is related to the hydrodynamic drag of the gear components and the type of sediment over which they are trawled. Here we present a methodology to estimate the sediment mobilization from hydrodynamic drag. The hydrodynamic drag of individual gear components is estimated using empirical measurements of similarly shaped objects, including cylinders, cubes, and nets. The method is applied to beam trawls used in the Dutch North Sea flatfish fishery and validated using measurements of beam trawl drag from the literature. Netting contributes most to the hydrodynamic drag of pulse trawls, while the tickler chains and chain mat comprise most of the hydrodynamic drag of conventional beam trawls. Taking account of the silt content of the areas trawled and the number of different beam trawl types used by the fleet, sediment mobilization is estimated as 9.2 and 5.3 kg m−2 for conventional 12 m beam and pulse trawls, respectively, and 4.2 and 4.3 kg m−2 for conventional 4.5 m beam and pulse trawls.

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Predictive framework for codend size selection of brown shrimp (Crangon crangon) in the North Sea beam-trawl fishery

PLoS ONE ◽

10.1371/journal.pone.0200464 ◽

2018 ◽

Vol 13 (7) ◽

pp. e0200464 ◽

Cited By ~ 3

Author(s):

Juan Santos ◽

Bent Herrmann ◽

Daniel Stepputtis ◽

Claudia Günther ◽

Bente Limmer ◽

...

Keyword(s):

North Sea ◽

Brown Shrimp ◽

Beam Trawl ◽

Crangon Crangon ◽

Size Selection ◽

Trawl Fishery ◽

The North ◽

Sea Beam ◽

The North Sea ◽

Selection Of

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Modelling combined harvest and effort regulations: the case of the Dutch beam trawl fishery for plaice and sole in the North Sea

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn057 ◽

2008 ◽

Vol 65 (6) ◽

pp. 822-831 ◽

Cited By ~ 13

Author(s):

A. Hoff ◽

H. Frost

Keyword(s):

North Sea ◽

Stock Assessment ◽

Beam Trawl ◽

Trawl Fishery ◽

The North ◽

Feedback Model ◽

Economic Operation ◽

The North Sea ◽

Fishing Fleets ◽

Fleet Dynamics

Abstract Hoff, A. and Frost, H. 2008. Modelling combined harvest and effort regulations: the case of the Dutch beam trawl fishery for plaice and sole in the North Sea. – ICES Journal of Marine Science, 65: 822–831. Currently, several European fishing fleets are regulated through a combination of harvest and effort control. The two regulation schemes are interrelated, i.e. a given quota limit will necessarily determine the effort used, and vice versa. It is important to acknowledge this causality when assessing combined effort and harvest regulation systems. A bioeconomic feedback model is presented that takes into account the causality between effort and harvest control by switching back and forth between the two, depending on which is the binding rule. The model consists of a biological and an economic operation module, the former simulating stock assessment and quota establishment, and the latter simulating the economic fleet dynamics. When harvest control is binding, catch is evaluated using the biological projection formula, whereas the economics-based Cobb–Douglas production function is used when effort is binding. The method is applied to the Dutch beam trawl fishery for plaice and sole in the North Sea.

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Short-term survival of discarded target fish and non-target invertebrate species in the “eurocutter” beam trawl fishery of the southern North Sea

Fisheries Research ◽

10.1016/j.fishres.2014.01.018 ◽

2014 ◽

Vol 154 ◽

pp. 82-92 ◽

Cited By ~ 45

Author(s):

Jochen Depestele ◽

Marieke Desender ◽

Hugues P. Benoît ◽

Hans Polet ◽

Magda Vincx

Keyword(s):

North Sea ◽

Beam Trawl ◽

Short Term ◽

Term Survival ◽

Trawl Fishery ◽

Invertebrate Species ◽

Southern North Sea ◽

Target Fish ◽

Short Term Survival

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Mitigating ecosystem impacts of bottom trawl fisheries for North Sea sole Solea solea by replacing mechanical by electrical stimulation

10.1101/2020.01.21.913731 ◽

2020 ◽

Author(s):

A.D. Rijnsdorp ◽

J. Depestele ◽

O.R. Eigaard ◽

N.T. Hintzen ◽

A. Ivanovic ◽

...

Keyword(s):

Electrical Stimulation ◽

North Sea ◽

Bottom Trawl ◽

Beam Trawl ◽

Electrode Arrays ◽

Impact Indicator ◽

Total Allowable Catch ◽

Trawl Fishery ◽

The Impact ◽

Trawl Fisheries

AbstractEcosystem effects of bottom trawl fisheries are a major concern. We analysed whether the replacement of mechanical stimulation by electrical stimulation may reduce the adverse impacts on the benthic ecosystem in the beam trawl fishery for sole. Although the use of electricity is not allowed to catch fish in European Union waters, a number of beam trawlers got derogation and switched to pulse trawling to explore the potential to reduce impacts. We extended a recently developed assessment framework and showed that the switch to pulse trawling substantially reduced benthic impacts when exploiting the Total Allowable Catch of sole in the North Sea. We applied the framework to Dutch beam trawl logbook data from 2009 to 2017 and estimated that the trawling footprint decreased by 23%; the precautionary impact indicator of the benthic community decreased by 39%; the impact on median longevity decreased by 20%; the impact on benthic biomass decreased by 61%; the amount of sediment mobilised decreased by 39%. The decrease is due to the replacement of tickler chains by electrode arrays, a lower towing speed and higher catch efficiency for sole. The effort and benthic impact of the beam trawl fishery targeting plaice Pleuronectes platessa in the central North Sea increased with the recovery of the plaice stock. This study illustrates the usefulness of a standardized methodological framework to assess the differences in time trends and trawling impact between gears.

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Mitigating seafloor disturbance of bottom trawl fisheries for North Sea sole Solea solea by replacing mechanical with electrical stimulation

PLoS ONE ◽

10.1371/journal.pone.0228528 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0228528 ◽

Cited By ~ 1

Author(s):

A. D. Rijnsdorp ◽

J. Depestele ◽

O. R. Eigaard ◽

N. T. Hintzen ◽

A. Ivanovic ◽

...

Keyword(s):

North Sea ◽

Benthic Community ◽

Bottom Trawl ◽

Beam Trawl ◽

Electrode Arrays ◽

Physical Disturbance ◽

Trawl Fishery ◽

Solea Solea ◽

The Impact ◽

Trawl Fisheries

Ecosystem effects of bottom trawl fisheries are of major concern. Although it is prohibited to catch fish using electricity in European Union waters, a number of beam trawlers obtained a derogation and switched to pulse trawling to explore the potential to reduce impacts. Here we analyse whether using electrical rather than mechanical stimulation results in an overall reduction in physical disturbance of the seafloor in the beam-trawl fishery for sole Solea solea. We extend and apply a recently developed assessment framework to the Dutch beam-trawl fleet and show that the switch to pulse trawling substantially reduced benthic impacts when exploiting the total allowable catch of sole in the North Sea. Using Vessel Monitoring by Satellite and logbook data from 2009 to 2017, we estimate that the trawling footprint decreased by 23%, the precautionary impact indicator of the benthic community decreased by 39%, the impact on median longevity of the benthic community decreased by 20%, the impact on benthic biomass decreased by 61%, and the amount of sediment mobilised decreased by 39%. The decrease in impact is due to the replacement of tickler chains by electrode arrays, a lower towing speed and higher catch efficiency for sole. The effort and benthic physical disturbance of the beam-trawl fishery targeting plaice Pleuronectes platessa in the central North Sea increased with the recovery of the plaice stock. Our study illustrates the utility of a standardized methodological framework to assess the differences in time trends and physical disturbance between gears.

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