Fishers’ knowledge as an indicator of spatial and temporal trends in abundance of commercial fish species: Megrim (Lepidorhombus whiffiagonis) in the northern North Sea

Marine Policy ◽  
2014 ◽  
Vol 45 ◽  
pp. 228-239 ◽  
Author(s):  
P. Macdonald ◽  
C.H. Angus ◽  
I.R. Cleasby ◽  
C.T. Marshall
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Temporal Trends ◽  
Commercial Fish ◽  
Northern North Sea ◽  
Spatial And Temporal Trends

scholarly journals Spatial and temporal trends in order richness of marine phytoplankton as a tracer for the exchange zone between coastal and open waters

2016 ◽  
Vol 97 (3) ◽  
pp. 477-489 ◽  
Author(s):  
A.S. Jung ◽  
R. Bijkerk ◽  
H.W. Van Der Veer ◽  
C.J.M. Philippart
Keyword(s):  
Particulate Matter ◽  
North Sea ◽  
Coastal Waters ◽  
Wadden Sea ◽  
Temporal Trends ◽  
Marine Phytoplankton ◽  
Environmental Drivers ◽  
Suspended Particulate ◽  
Phytoplankton Communities ◽  
Spatial And Temporal Trends

Quantifying exchange of particulate matter between coastal and open waters is an important and often unresolved issue. Here, we apply phytoplankton order richness as an innovative marine tracer to identify the geographic position of a coastal exchange zone in the SE North Sea, including its variability in time and space. Previous observations on dynamics of suspended particulate matter accumulation resulted in a hypothesized boundary between coastal waters (including the Wadden Sea) and open North Sea waters, the so-called ‘line-of-no-return’. Our study along two transects (Terschelling, Noordwijk) in the Dutch coastal zone showed seasonality patterns in phytoplankton order richness, both for diatoms and flagellates. The coastal Wadden Sea was found to be clearly different from the open North Sea, implying that seasonality in Wadden Sea phytoplankton is at least partly driven by local environmental conditions. Seasonality in flagellates was found to be more uniform than seasonality in diatoms. Stations in the coastal North Sea to a distance of 10 km (Terschelling) to 20 km (Noordwijk) from the shore appeared to be at the inside of the ‘line-of-no-return’. Our findings indicate that this approach is a useful aid in exploring mixing of particulate matter between coastal and open waters and to study the responses of phytoplankton communities to environmental drivers.

Effects of North Sea oil and gas developments on fisheries

1987 ◽  
Vol 316 (1181) ◽  
pp. 511-511
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Oil And Gas ◽  
Marine Ecosystem ◽  
Fishing Industry ◽  
Commercial Fish

North Sea oil and gas developments have introduced pressures on the fishing industry, on fishing operations, and on the marine ecosystem including commercial fish species. Operational incompatibilities and competition for personnel, facilities on land and space at sea may arise.

scholarly journals Indicator-based status assessment of commercial fish species in the North Sea according to the EU Marine Strategy Framework Directive (MSFD)

2013 ◽  
Vol 70 (3) ◽  
pp. 694-706 ◽  
Author(s):  
Wolfgang Nikolaus Probst ◽  
Matthias Kloppmann ◽  
Gerd Kraus
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Marine Strategy Framework Directive ◽  
Commercial Fish ◽  
Fish Stocks ◽  
The North ◽  
The Status ◽  
Status Assessment ◽  
The North Sea ◽  
The Eu

Abstract Probst, W. N., Kloppmann, M., and Kraus, G. Indicator-based status assessment of commercial fish species in the North Sea according to the EU Marine Strategy Framework Directive (MSFD). – ICES Journal of Marine Science, 70: 694–706. The EU Marine Strategy Framework Directive (MSFD) is structured into eleven descriptors of good environmental status (GES). For each descriptor the current status of the marine environment should be assessed against its GES using ecosystem criteria and indicators. Within Descriptor 3 (D3) the MSFD addresses the status of exploited fish stocks according to three criteria (exploitation rate, stock size and size structure). This study performed an MSFD-compliant assessment of exploited fish stocks in the North Sea by aggregating data from analytical stock assessments and scientific research surveys to calculate indicator metrics for each criterion within each stock time-series. A stock achieved GES, when each indicator for each criterion had a good status. Of 43 assessed fish stock suggested by the EU Data Collection Framework, 63% (27) achieved GES. Though the MSFD explicitly demands that all exploited fish stocks achieve GES, this demand may be challenged by reality, because the status of exploited stocks depends not only on fishing impacts, but also on environmental conditions and ecological interactions. Therefore an alternative approach based on binomial distributions is presented to define limits for GES at the descriptor level. The implications and pitfalls of the applied assessment methods are discussed.

scholarly journals Seasonal cycling of phosphorus in the Southern Bight of the North Sea

2005 ◽  
Vol 2 (1) ◽  
pp. 27-42 ◽  
Author(s):  
C. van der Zee ◽  
L. Chou
Keyword(s):  
North Sea ◽  
Organic Phosphorus ◽  
Salinity Gradient ◽  
Temporal Trends ◽  
Elemental Ratios ◽  
Southern Bight ◽  
The North ◽  
Limiting Nutrient ◽  
Spatial And Temporal Trends ◽  
Inorganic And Organic

Abstract. We have investigated the seasonal cycle of nutrients, chlorophyll a, dissolved organic nitrogen (DON), and dissolved and particulate organic carbon (DOC and POC) for 10 stations in the Belgian coastal zone. Special attention was given to phosphorus speciation, i.e. dissolved inorganic and organic phosphorus (DIP and DOP) and particulate inorganic and organic phosphorus (PIP and POP). Spatial and temporal trends of the inorganic nutrients and the organic species are discussed. The Belgian part of the southern North Sea is strongly influenced by the river plumes of the Rhine, Meuse and Scheldt resulting in northeast-southwest salinity gradient. Extrapolation of winter nutrient and DOC concentrations versus salinity plots yielded zero-salinity values typical of the river Scheldt. The polyphosphate concentration did not show any temporal trend, whereas both the phosphate and the DOP concentrations exhibited distinct seasonal variations. Silica or phosphorus was the potential limiting nutrient for phytoplankton growth based on elemental ratios.

Spatial and temporal trends in the distribution of harbour porpoises, white-beaked dolphins and minke whales off Aberdeenshire (UK), north-western North Sea

2007 ◽  
Vol 87 (1) ◽  
pp. 327-338 ◽  
Author(s):  
Caroline R. Weir ◽  
Karen A. Stockin ◽  
Graham J. Pierce
Keyword(s):  
North Sea ◽  
Survey Methods ◽  
Temporal Trends ◽  
Harbour Porpoise ◽  
Breeding Habitat ◽  
Balaenoptera Acutorostrata ◽  
Cetacean Species ◽  
Minke Whales ◽  
Spatial And Temporal Trends ◽  
Strong Seasonality

Most North Sea cetacean species are wide-ranging and consequently poorly studied. Spatial and temporal trends in the distribution of the harbour porpoise Phocoena phocoena, white-beaked dolphin Lagenorhynchus albirostris, and minke whale Balaenoptera acutorostrata were assessed at a coastal North Sea study area in Aberdeenshire, Scotland. Between March 1999 and October 2001, cetacean data were collected using both land- and vessel-based survey methods. A total of 174 sightings of these three cetacean species was recorded during approximately 330 h of combined survey effort (228 h land-based and 102 h vessel-based). Harbour porpoises were present throughout the year with peak occurrence during August and September. The presence of white-beaked dolphins and minke whales was strictly seasonal, with a peak in occurrence during August. The fine-scale distribution of all three species varied within the study area, with an apparent preference for sections of coast adjacent to deeper water. Most porpoise calves and juveniles were recorded between June and September, when 35% of harbour porpoise groups contained immature animals. The proportion of calves amongst porpoise sightings was higher during June than any other month. White-beaked dolphin calves were present in 32% of groups, and occurred in all three months that the species was recorded. Group size was higher in white-beaked dolphin pods containing immature animals. The strong seasonality in occurrence of all three species may relate to requirements for breeding habitat, movements of shared prey species and/or inter-specific competition with other species.

Spatial and temporal trends in nutrient concentrations in the Belgian Continental area of the North Sea during the period 1993–2000

2004 ◽  
Vol 61 (3) ◽  
pp. 517-528 ◽  
Author(s):  
Sandra De Galan ◽  
Marc Elskens ◽  
Leo Goeyens ◽  
André Pollentier ◽  
Natacha Brion ◽  
...  
Keyword(s):  
North Sea ◽  
Temporal Trends ◽  
Nutrient Concentrations ◽  
The North ◽  
The North Sea ◽  
Continental Area ◽  
Spatial And Temporal Trends

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

2017 ◽  
pp. 65-73
Author(s):  
Edward Vladimirovich Nikitin
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Commercial Fish ◽  
Autumn Period ◽  
Fish Juveniles ◽  
Qualitative Characteristics ◽  
Shallow Coastal Waters

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.

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