Influence of trends in fishing power on bioeconomics in the North Sea flatfish fishery regulated by catches or by effort quotas

2002 ◽  
Vol 59 (5) ◽  
pp. 829-843 ◽  
Author(s):  
Clara Ulrich ◽  
Sean Pascoe ◽  
Per J Sparre ◽  
Jan-Willem De Wilde ◽  
Paul Marchal
Keyword(s):  
North Sea ◽  
Fishery Management ◽  
Single Species ◽  
Simulation Modelling ◽  
Economic Benefits ◽  
Total Allowable Catch ◽  
The North ◽  
Control Rules ◽  
Solea Solea ◽  
The North Sea

Total allowable effort quotas (TAEs) are often considered as promising alternatives to single-species total allowable catch quotas (TACs) in fisheries management. However, implementing TAEs would primarily require converting nominal effort into fishing mortality rate, i.e., developing a relevant model of the dynamics of catchability. Assuming that trends in the catchability may occur through fishing-power creeping linked to increased capital invested and technology, we compare, by stochastic and dynamic simulation modelling, the relative biological and economic benefits and drawbacks of TAEs and TACs in the North Sea sole (Solea solea L.) and plaice (Pleuronectes platessa L.) fishery. Management targets are based on the Precautionary Approach and Harvest Control Rules developed by the International Council for the Exploration of the Sea (ICES). Fishermen are assumed to set their effort at the most (TAE) or least (TAC) conservative level. Overall, the outcomes are more sensitive to the catchability model when implementing TAEs, especially in the medium and long term, but the variability in catchability has a much greater impact on stock levels than on the fisheries profit.

From single-species advice to mixed-species management: taking the next step

2004 ◽  
Vol 61 (8) ◽  
pp. 1398-1409 ◽  
Author(s):  
Morten Vinther ◽  
Stuart A. Reeves ◽  
Kenneth R. Patterson
Keyword(s):  
North Sea ◽  
Fishery Management ◽  
Single Species ◽  
Mixed Species ◽  
The North ◽  
Recent Approach ◽  
Starting Point ◽  
The North Sea ◽  
Management Advice ◽  
Management Priorities

Abstract Fishery management advice has traditionally been given on a stock-by-stock basis. Recent problems in implementing this advice, particularly for the demersal fisheries of the North Sea, have highlighted the limitations of the approach. In the long term, it would be desirable to give advice that accounts for mixed-fishery effects, but in the short term there is a need for approaches to resolve the conflicting management advice for different species within the same fishery, and to generate catch or effort advice that accounts for the mixed-species nature of the fishery. This paper documents a recent approach used to address these problems. The approach takes the single-species advice for each species in the fishery as a starting point, then attempts to resolve it into consistent catch or effort advice using fleet-disaggregated catch forecasts in combination with explicitly stated management priorities for each stock. Results are presented for the groundfish fisheries of the North Sea, and these show that the development of such approaches will also require development of the ways in which catch data are collected and compiled.

Cold Induced Abnormal Catches of Sole

1998 ◽  
Vol 78 (1) ◽  
pp. 345-347 ◽  
Author(s):  
J.W. Horwood ◽  
R.S. Millner
Keyword(s):  
North Sea ◽  
Cold Water ◽  
The South ◽  
Total Allowable Catch ◽  
The North ◽  
Solea Solea ◽  
The North Sea ◽  
The Uk ◽  
The Eu ◽  
Made In

Large catches of sole (Solea solea) were made in early 1996 from the south-western North Sea. Sole suffer physiological damage in waters below 3–4 C. In February 1996 cold water of 3–4 C unusually extended from the Continental coast onto the Dogger Bank. It is likely that the increased catches were due to the consequential distribution and behaviour of the sole, making them more susceptible to capture.Exceptionally large catches of mature sole (Solea solea (L.)) were made in February 1996 by Lowestoft fishermen from the south-western North Sea. Surprisingly this was not welcome. The UK allocation of the North Sea sole is -4 % of the EU Total Allowable Catch (TAC), and fishermen are restricted nationally, and by the fishing companies, to a tightly managed ration. The Lowestoft Journal (8 March 1996) reported the suspension of a local fishing skipper for not throwing back 5000 kg of sole caught in the Silver Pits. We will show that the abnormal catches were due to exceptionally cold waters.Sole in the North Sea are at the northern extremity of their range, with sole seldom living in waters below 5°C (Horwood, 1993). In fact, North Sea sole were successfully introduced into Lake Quarun, Egypt, where they lived in temperatures in excess of 30°C (El-Zarka, 1965). Young sole migrate from their shallow inshore nursery grounds, such as the Waddensea, as winter approaches (Creutzberg & Fonds, 1971).

scholarly journals Reconciling single-species TACs in the North Sea demersal fisheries using the Fcube mixed-fisheries advice framework

2011 ◽  
Vol 68 (7) ◽  
pp. 1535-1547 ◽  
Author(s):  
Clara Ulrich ◽  
Stuart A. Reeves ◽  
Youen Vermard ◽  
Steven J. Holmes ◽  
Willy Vanhee
Keyword(s):  
North Sea ◽  
Single Species ◽  
Simple Approach ◽  
Total Allowable Catch ◽  
Traditional Management ◽  
The North ◽  
Management Objectives ◽  
Species Management ◽  
The North Sea ◽  
Management Advice

Abstract Ulrich, C., Reeves, S. A., Vermard, Y., Holmes, S. J., and Vanhee, W. 2011. Reconciling single-species TACs in the North Sea demersal fisheries using the Fcube mixed-fisheries advice framework. – ICES Journal of Marine Science, 68: 1535–1547. Single-species management is a cause of discarding in mixed fisheries, because individual management objectives may not be consistent with each other and the species are caught simultaneously in relatively unselective fishing operations. As such, the total allowable catch (TAC) of one species may be exhausted before the TAC of another, leading to catches of valuable fish that cannot be landed legally. This important issue is, however, usually not quantified and not accounted for in traditional management advice. A simple approach using traditional catch and effort information was developed, estimating catch potentials for distinct fleets (groups of vessels) and métiers (type of activity), and hence quantifying the risks of over- and underquota utilization for the various stocks. This method, named Fcube (Fleet and Fisheries Forecast), was applied successfully to international demersal fisheries in the North Sea and shaped into the advice framework. The substantial overquota catches of North Sea cod likely under the current fisheries regimes are quantified, and it is estimated that the single-species management targets for North Sea cod cannot be achieved unless substantial reductions in TACs of all other stocks and corresponding effort reductions are applied.

scholarly journals Achieving maximum sustainable yield in mixed fisheries: a management approach for the North Sea demersal fisheries

2016 ◽  
Vol 74 (2) ◽  
pp. 566-575 ◽  
Author(s):  
Clara Ulrich ◽  
Youen Vermard ◽  
Paul J. Dolder ◽  
Thomas Brunel ◽  
Ernesto Jardim ◽  
...  
Keyword(s):  
North Sea ◽  
Regional Scale ◽  
Single Species ◽  
Maximum Sustainable Yield ◽  
Management Approach ◽  
Sustainable Yield ◽  
Total Allowable Catch ◽  
The North ◽  
Trade Offs ◽  
The North Sea

Achieving single species maximum sustainable yield (MSY) in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. The North Sea mixed fisheries are a representative example of an issue that is generic across most demersal fisheries worldwide, with the diversity of species and fisheries inducing numerous biological and technical interactions. Building on a rich knowledge base for the understanding and quantification of these interactions, new approaches have emerged. Recent paths towards operationalizing MSY at the regional scale have suggested the expansion of the concept into a desirable area of “pretty good yield”, implemented through a range around FMSY that would allow for more flexibility in management targets. This article investigates the potential of FMSY ranges to combine long-term single-stock targets with flexible, short-term, mixed-fisheries management requirements applied to the main North Sea demersal stocks. It is shown that sustained fishing at the upper bound of the range may lead to unacceptable risks when technical interactions occur. An objective method is suggested that provides an optimal set of fishing mortality within the range, minimizing the risk of total allowable catch mismatches among stocks captured within mixed fisheries, and addressing explicitly the trade-offs between the most and least productive stocks.

scholarly journals Predicting the effects of area closures and fishing effort restrictions on the production, biomass, and species richness of benthic invertebrate communities

2006 ◽  
Vol 63 (5) ◽  
pp. 822-830 ◽  
Author(s):  
J.G. Hiddink ◽  
T. Hutton ◽  
S. Jennings ◽  
M.J. Kaiser
Keyword(s):  
Species Richness ◽  
North Sea ◽  
Fishery Management ◽  
Benthic Communities ◽  
Fishing Effort ◽  
Management Actions ◽  
The North ◽  
The North Sea ◽  
Effort Reduction ◽  
Positive Effect

AbstractTo effectively implement an Ecosystem Approach to Fisheries (EAF), managers need to consider the effects of management actions on the fishery and the ecosystem. Methods for assessing the effects on target stocks are generally well developed, but methods for assessing the effects on other components and attributes of the ecosystem are not. Area closures and effort controls are widely used fishery management tools that affect the distribution of fishing effort and may therefore have consequences for a range of species and habitats. An approach is developed to predict the effects of area closures and effort control on the biomass, production, and species richness of benthic communities in the North Sea. The redistribution of beam trawling effort as a result of management action was modelled with a random utility model, assuming that fishers selected fishing grounds on the basis of their knowledge of past catch rates. The effects of trawling on benthic invertebrates were predicted using a size-based model that accounted for differences in habitat among fishing grounds. Our simulations demonstrated that closures of different sizes and in different locations could have positive or negative effects on benthic communities. These predicted effects resulted from the trade-off between recovery in the closed areas and additional trawling effects in the open areas that arose from displaced fishing activity. In the absence of effort controls, closure of lightly fished areas had the strongest positive effect on benthic communities. Effort reduction also had a positive effect. Therefore, area closures in lightly fished areas, coupled with effort reduction, are expected to minimize the effects of fishing on benthic communities. As it was not possible to access full international data for the North Sea beam trawl fleet, the results of the analyses are illustrative rather than complete. Nevertheless, what is demonstrated is an effective approach for assessing the environmental consequences of fishery management action that can be used to inform management decision-making as part of an EAF.

Sole larval distribution (Solea solea) in the eastern English Channel and Southern Bight of the North Sea

2001 ◽  
Vol 81 (4) ◽  
pp. 673-678 ◽  
Author(s):  
A. Grioche ◽  
P. Koubbi ◽  
X. Harlay ◽  
B. Sautour
Keyword(s):  
North Sea ◽  
Environmental Parameters ◽  
English Channel ◽  
Southern Bight ◽  
Intermediate Variable ◽  
Larval Stages ◽  
The North ◽  
Larval Distribution ◽  
Solea Solea ◽  
The North Sea

The distribution of sole (Solea solea) eggs and larvae were described from two cruises conducted in April and May 1995 along the French coast of the eastern English Channel and the Belgian coast of the Southern Bight of the North Sea. Sole migration was investigated using larval stages and univariate spatial analysis as geostatistics (variograms). Important environmental parameters were selected by comparison with larval distribution. Path analysis was used to remove spatial correlation and to define links between abundance and environmental variables.  Sole larvae were found to be coastal throughout their development. Strong links between larval distribution and environmental parameters were identified, particularly for the younger stages which were found in higher abundance in areas of high chlorophyll-a concentration. The association was not direct, suggesting that the larval spatial distribution was influenced by an undetermined, intermediate variable, such as larval prey. Sole larvae are retained in the coastal area throughout ontogeny despite the strong hydrodynamics which characterize the region. Larval distribution resulted from behavioural mechanisms as well as environmental influences.

Mesh-size matters in epibenthic surveys

2002 ◽  
Vol 82 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ruth Callaway ◽  
Simon Jennings ◽  
John Lancaster ◽  
John Cotter
Keyword(s):  
Community Structure ◽  
North Sea ◽  
Processing Time ◽  
Mesh Size ◽  
Community Analysis ◽  
Single Species ◽  
Spatial Gradients ◽  
The North ◽  
Significant Difference ◽  
The North Sea

This study aimed to identify the effects of different sieve mesh-sizes on processing time, the number of species retained, diversity measures and multivariate community analysis in the North Sea. Samples were collected at 63 sites throughout the North Sea and washed through two successive sieves, 10-mm and 5-mm mesh respectively.  Processing time for whole samples (5- and 10-mm fraction) averaged 91± 25 min compared with 55±16 min for the 10-mm mesh fraction. Altogether 40% of free-living species and 9% of attached species were recorded exclusively in the 5-mm fraction. The majority of these species were rare. Spatial gradients of species diversity and community structure were identical, independent of the mesh-size used. Multivariate community analysis showed no significant difference between descriptions of community structure based on fauna from 10-mm or 5-mm mesh.  The use of coarser sieving mesh would save time and money, if the aims of an epibenthic survey were to describe broad patterns of community structure and relative diversity. It would be possible to process approximately 50% more samples, if the time saved with 10-mm mesh were allocated to additional sampling. However, if information on single species is required, then sorting with the finer sieve mesh will yield crucial information. It was decided to employ a 5-mm mesh for epibenthic monitoring of the North Sea.

scholarly journals Microchemical variation in juvenile Solea solea otoliths as a powerful tool for studying connectivity in the North Sea

2010 ◽  
Vol 401 ◽  
pp. 211-220 ◽  
Author(s):  
EL Cuveliers ◽  
AJ Geffen ◽  
J Guelinckx ◽  
JAM Raeymaekers ◽  
J Skadal ◽  
...  
Keyword(s):  
North Sea ◽  
The North ◽  
Solea Solea ◽  
The North Sea

Recent Changes in the Central and Southern North Sea Herring Stocks

1985 ◽  
Vol 42 (S1) ◽  
pp. s192-s206 ◽  
Author(s):  
A. C. Burd
Keyword(s):  
North Sea ◽  
Maximum Yield ◽  
Total Allowable Catch ◽  
Underlying Assumption ◽  
Southern North Sea ◽  
The North ◽  
Management Procedure ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The North Sea

Since 1980 there has been a sudden recovery of recruitment to the central and southern North Sea herring stocks (Bank and Downs, respectively). In contrast, recruitment to the northern North Sea has continued at a low level and spawning stock biomass has even declined since 1979. These events underline the independence of the substocks in the North Sea, each of which has reacted differently to the cessation of the directed herring fishery in the North Sea since 1977. A precondition to the reopening of a herring fishery in the North Sea was that the severely depleted spawning stock biomass should have recovered to 800 000 t, the underlying assumption being that all components would respond in a similar manner and that a reopening of the whole North Sea would be possible. This has not happened and it may well be that management of the North Sea as a single unit is not a viable management procedure. The paper examines the historic changes in sizes of the Bank and Downs stocks, with particular emphasis on the most recent period. Evidence of density-dependent growth change is considered together with the recent data on fecundity and larval herring production. It is concluded that if the separate stocks are to be managed individually for maximum yield, then global North Sea regulations such as a total allowable catch and size regulation are inappropriate. Regulations must also take into consideration the seasonal distributions of the stocks. Indeed, this would lead, in particular, to more restrictive and specific regulation of the industrial fisheries.

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