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 ◽  
...  
Author(s):  
J.W. Horwood ◽  
R.S. Millner

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).


Author(s):  
A. Grioche ◽  
P. Koubbi ◽  
X. Harlay ◽  
B. Sautour

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.


2002 ◽  
Vol 59 (5) ◽  
pp. 829-843 ◽  
Author(s):  
Clara Ulrich ◽  
Sean Pascoe ◽  
Per J Sparre ◽  
Jan-Willem De Wilde ◽  
Paul Marchal

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.


2016 ◽  
Vol 73 (6) ◽  
pp. 1485-1493 ◽  
Author(s):  
Klaas Sys ◽  
Jan Jaap Poos ◽  
Jef Van Meensel ◽  
Hans Polet ◽  
Jeroen Buysse

Abstract We examine whether the landing rates of Belgian beam trawlers in the Southern Bight of the North Sea were affected through competitive interactions with the Dutch beam trawler fleet and whether the development of a pulse trawler fleet has altered competitive interactions between both fleets. Effects of competition were investigated through a natural experiment based on the different weekly exploitation patterns of both fleets. Logbook data were used to fit a generalized additive mixed model for the daily landing rates of the target species sole (Solea solea) and plaice (Pleuronectes platessa). Results showed that landing rates of sole by the Belgian beam trawlers (>221 kW) from 2006 to 2013 were lower during weekdays than during weekends when the Dutch trawler fleet is in harbour, while no such an effect was found for plaice. After the development of a pulse trawler fleet in 2011, the negative weekday effect in the sole landing rates was much more pronounced in 2012 and 2013. This increased loss of efficiency during weekdays, as a result of increased competition with the Dutch trawler fleet, coincided with a reallocation of fishing effort by the Belgian beam trawler fleet.


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