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

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0228528 ◽  
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.

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

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.

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

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200464 ◽  
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

scholarly journals Different bottom trawl fisheries have a differential impact on the status of the North Sea seafloor habitats

2020 ◽  
Vol 77 (5) ◽  
pp. 1772-1786 ◽  
Author(s):  
A D Rijnsdorp ◽  
J G Hiddink ◽  
P D van Denderen ◽  
N T Hintzen ◽  
O R Eigaard ◽  
...  
Keyword(s):  
North Sea ◽  
Management Strategies ◽  
Demersal Fish ◽  
Time Interval ◽  
The North ◽  
The Status ◽  
Fisheries Conservation ◽  
The North Sea ◽  
The Impact ◽  
Trawl Fisheries

Abstract Fisheries using bottom trawls are the most widespread source of anthropogenic physical disturbance to seafloor habitats. To mitigate such disturbances, the development of fisheries-, conservation-, and ecosystem-based management strategies requires the assessment of the impact of bottom trawling on the state of benthic biota. We explore a quantitative and mechanistic framework to assess trawling impact. Pressure and impact indicators that provide a continuous pressure–response curve are estimated at a spatial resolution of 1 × 1 min latitude and longitude (∼2 km2) using three methods: L1 estimates the proportion of the community with a life span exceeding the time interval between trawling events; L2 estimates the decrease in median longevity in response to trawling; and population dynamic (PD) estimates the decrease in biomass in response to trawling and the recovery time. Although impact scores are correlated, PD has the best performance over a broad range of trawling intensities. Using the framework in a trawling impact assessment of ten métiers in the North Sea shows that muddy habitats are impacted the most and coarse habitats are impacted the least. Otter trawling for crustaceans has the highest impact, followed by otter trawling for demersal fish and beam trawling for flatfish and flyshooting. Beam trawling for brown shrimps, otter trawling for industrial fish, and dredging for molluscs have the lowest impact. Trawling is highly aggregated in core fishing grounds where the status of the seafloor is low but the catch per unit of effort (CPUE) per unit of impact is high, in contrast to peripheral grounds, where CPUE per unit of impact is low.

scholarly journals Modelling potential impacts of bottom trawl fisheries on soft sediment biogeochemistry in the North Sea†

2001 ◽  
Vol 2 (1) ◽  
Author(s):  
Daniel E Duplisea ◽  
Simon Jennings ◽  
Stephen J Malcolm ◽  
Ruth Parker ◽  
David B Sivyer
Keyword(s):  
North Sea ◽  
Bottom Trawl ◽  
Soft Sediment ◽  
The North ◽  
Sediment Biogeochemistry ◽  
The North Sea ◽  
Trawl Fisheries

scholarly journals Exit and entry of fishing vessels: an evaluation of factors affecting investment decisions in the North Sea English beam trawl fleet

2011 ◽  
Vol 68 (5) ◽  
pp. 961-971 ◽  
Author(s):  
Alex N. Tidd ◽  
Trevor Hutton ◽  
Laurence T. Kell ◽  
Gurpreet Padda
Keyword(s):  
North Sea ◽  
Choice Model ◽  
Investment Decisions ◽  
Strategic Decision ◽  
Beam Trawl ◽  
Factors Affecting ◽  
The North ◽  
Fishing Vessels ◽  
The North Sea ◽  
The Impact

Abstract Tidd, A. N., Hutton, T., Kell, L. T., and Padda, G. 2011. Exit and entry of fishing vessels: an evaluation of factors affecting investment decisions in the North Sea English beam trawl fleet. – ICES Journal of Marine Science, 68: 961–971. A profitable fishery attracts additional effort (vessels enter), eventually leading to overcapacity and less profit. Similarly, fishing vessels exit depending on their economic viability (or reduced expectations of future benefits) or encouraged by schemes such as decommissioning grants and/or when there is consolidation of fishing effort within a tradable rights-based quota system (e.g. individual transferable quotas). The strategic decision-making behaviour of fishers in entering or exiting the English North Sea beam trawl fishery is analysed using a discrete choice model by integrating data on vessel characteristics with available cost data, decommissioning grant information, and other factors that potentially influence anticipated benefits or future risks. It is then possible to predict whether operators choose to enter, stay, exit, or decommission. Important factors affecting investment include vessel age and size, future revenues, operating costs (e.g. fuel), stock status of the main target species, and the impact of management measures (e.g. total allowable catches) and total fleet size (a proxy for congestion). Based on the results, the predicted marginal effects of each factor are presented and the impact of each is discussed in the context of policies developed to align fleet capacity with fishing opportunities.

The importance of scale for fishing impact estimations

2009 ◽  
Vol 66 (5) ◽  
pp. 829-835 ◽  
Author(s):  
G. J. Piet ◽  
F. J. Quirijns
Keyword(s):  
Life History ◽  
Spatial Scale ◽  
Bottom Trawl ◽  
Spatial Processes ◽  
Temporal Scales ◽  
Fishing Impact ◽  
Trawl Fishery ◽  
Time Period ◽  
Spatio Temporal ◽  
The Impact

The impact of a bottom trawl fishery on fish or benthos is often determined by multiplying the frequency of the passing of the trawl by a factor for the effect (i.e., % mortality) of the singular passing of the gear. As fishing intensity in an area is not homogeneously distributed, it is necessary to determine the proportions of the area that are fished with different trawling frequencies, as these subareas together contribute to the overall species’ mortality. In this study, we show that the perceived proportion of the area fished with a specific trawling frequency depends upon the spatial and temporal scale used. A smaller spatial scale results in an increased perceived patchiness of the fishing intensity, while a longer time period does the opposite. The implication is that to determine the fishing-induced mortality of a particular species, the trawling frequency needs to be determined at those spatio-temporal scales that are appropriate considering the species’ spatial processes (e.g., dispersion) or temporal processes described by life history characteristics.

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

2008 ◽  
Vol 65 (6) ◽  
pp. 822-831 ◽  
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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