scholarly journals Changes in abundance of demersal fish species in the North Sea between 1906–1909 and 1990–1995

1996 ◽  
Vol 53 (6) ◽  
pp. 1054-1062 ◽  
Author(s):  
A Rijnsdorp
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Demersal Fish ◽  
The North ◽  
The North Sea

scholarly journals Impact of additional small-scale survey data on the geostatistical analyses of demersal fish species in the North Sea

2005 ◽  
Vol 69 (4) ◽  
pp. 587-602 ◽  
Author(s):  
Gerd Peter Zauke ◽  
Vanessa Stelzenmüller ◽  
Siegfried Ehrich
Keyword(s):  
Survey Data ◽  
North Sea ◽  
Fish Species ◽  
Demersal Fish ◽  
Small Scale ◽  
The North ◽  
The North Sea

scholarly journals Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls

2008 ◽  
Vol 65 (4) ◽  
pp. 531-538 ◽  
Author(s):  
Helen M. Fraser ◽  
Simon P. R. Greenstreet ◽  
Rob J. Fryer ◽  
Gerjan J. Piet
Keyword(s):  
Species Diversity ◽  
Spatial Variation ◽  
North Sea ◽  
Fish Species ◽  
Environmental Parameters ◽  
Demersal Fish ◽  
Marine Biodiversity ◽  
The North ◽  
The North Sea ◽  
Fish Species Diversity

Abstract Fraser, H. M., Greenstreet, S. P. R., Fryer, R. J., and Piet, G. J. 2008. Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls. – ICES Journal of Marine Science, 65: 531–538. The paper maps spatial patterns of groundfish species diversity. It considers how the catchability of different fish species in two different types of bottom trawls, the IBTS GOV and the 8-m beam trawl, influences the estimates of species diversity. Maps of groundfish species diversity derived from these two survey trawls are compared to determine the extent to which the maps of spatial variation in groundfish species diversity are influenced by gear type. Catchability-at-length coefficients were applied to the IBTS data to raise the observed catches to estimates of “actual” numbers of fish present in the path of the trawl, which are then used to produce maps of “actual” species diversity across the North Sea. Finally, these raised maps of “actual” groundfish species diversity are shown to be more explainable based on physical environmental parameters such as depth. We suggest that species diversity maps that take account of catchability provide more reliable information on which to base management decisions than “gear-biased” views. The implications for management are discussed, with particular emphasis on using closed areas to conserve marine biodiversity.

scholarly journals Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community

2012 ◽  
Vol 69 (1) ◽  
pp. 8-22 ◽  
Author(s):  
Simon P. R. Greenstreet ◽  
Helen M. Fraser ◽  
Stuart I. Rogers ◽  
Verena M. Trenkel ◽  
Stephen D. Simpson ◽  
...  
Keyword(s):  
North Sea ◽  
Fish Community ◽  
Size Structure ◽  
Demersal Fish ◽  
Community Size ◽  
The North ◽  
Management Objectives ◽  
The North Sea ◽  
Composition Structure ◽  
And Function

Abstract Greenstreet, S. P. R., Fraser, H. M., Rogers, S. I., Trenkel, V. M., Simpson, S. D., and Pinnegar, J. K. 2012. Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community. – ICES Journal of Marine Science, 69: 8–22. Broader ecosystem management objectives for North Sea demersal fish currently focus on restoring community size structure. However, most policy drivers explicitly concentrate on restoring and conserving biodiversity, and it has not yet been established that simply restoring demersal fish size composition will be sufficient to reverse declines in biodiversity and ensure a generally healthy community. If different aspects of community composition, structure, and function vary independently, then to monitor all aspects of community general health will require application of a suite of metrics. This assumes low redundancy among the metrics used in any such suite and implies that addressing biodiversity issues specifically will require explicit management objectives for particular biodiversity metrics. This issue of metric redundancy is addressed, and 15 metrics covering five main attributes of community composition, structure, and function are applied to groundfish survey data. Factor analysis suggested a new interpretation of the metric information and indicated that a minimum suite of seven metrics was necessary to ensure that all changes in the general health of the North Sea demersal fish community were monitored properly. Covariance among size-based and species-diversity metrics was low, implying that restoration of community size structure would not necessarily reverse declines in species diversity.

How benthic habitats and bottom trawling affect trait composition in the diet of seven demersal and benthivorous fish species in the North Sea

2018 ◽  
Vol 142 ◽  
pp. 132-146 ◽  
Author(s):  
Jacqueline D. Eggleton ◽  
Jochen Depestele ◽  
Andrew J. Kenny ◽  
Stefan G. Bolam ◽  
Clement Garcia
Keyword(s):  
North Sea ◽  
Fish Species ◽  
Benthic Habitats ◽  
Benthivorous Fish ◽  
Bottom Trawling ◽  
The North ◽  
The North Sea

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.

Plastic ingestion by pelagic and demersal fish from the North Sea and Baltic Sea

2016 ◽  
Vol 102 (1) ◽  
pp. 134-141 ◽  
Author(s):  
Christoph D. Rummel ◽  
Martin G.J. Löder ◽  
Nicolai F. Fricke ◽  
Thomas Lang ◽  
Eva-Maria Griebeler ◽  
...  
Keyword(s):  
Baltic Sea ◽  
North Sea ◽  
Demersal Fish ◽  
The North ◽  
The North Sea

scholarly journals Changes in the structure and function of the North Sea fish foodweb, 1973–2000, and the impacts of fishing and climate

2005 ◽  
Vol 62 (5) ◽  
pp. 847-868 ◽  
Author(s):  
Michael R. Heath
Keyword(s):  
North Sea ◽  
Secondary Production ◽  
Demersal Fish ◽  
Biological Data ◽  
Similar Species ◽  
The North ◽  
Production And Consumption ◽  
The North Sea ◽  
Vacant Niches ◽  
And Function

Abstract North Sea environmental and biological data were analysed to examine 30-year changes in production and consumption in the fish foodweb. The analysis revealed that the demand for secondary production placed on the ecosystem by fish declined from approximately 20 g C m−2 y−1 in the 1970s to 16 g C m−2 y−1 in the 1990s. Over the same period, the proportion of demand provided by zooplankton production increased from around 70% to 75%. The overall decrease was mainly due to a reduction in piscivorous demersal fish. Average secondary production by omnivorous zooplankton was estimated to be 35 g C m−2 y−1, and annual fluctuations were positively correlated with the gross production of planktivorous fish. The results suggest a “bottom-up” control of the pelagic foodweb. Individual planktivore species have been impacted by fishing, but the populations of other functionally similar species have expanded to fill the vacant niches, thus maintaining the planktivore role in the system. In contrast, the results indicate that benthos production was more “top-down” controlled. Overall, demersal fish species have been depleted by fishing, with no obvious species expansions to fill the vacant niche, releasing the benthos from predation pressure, and leading to an increase in benthic production and fisheries for invertebrates.

Coincident changes in four components of the North Sea ecosystem

1999 ◽  
Vol 79 (1) ◽  
pp. 183-185 ◽  
Author(s):  
K.F. Pearce ◽  
C.L.J. Frid
Keyword(s):  
Time Series ◽  
Species Composition ◽  
North Sea ◽  
Food Chain ◽  
Demersal Fish ◽  
North West ◽  
The North ◽  
The North Sea ◽  
Chain Links ◽  
Single Set

An analysis of species composition of the zooplankton, macrobenthos (two stations) and demersal fish from Northumberland (north-west North Sea) are reported. The four time-series show synchronous changes in species composition. While some of these changes coincide with changes in climateological variables, others do not. The degree of synchrony implies that either all the time-series are responding to a single set of extraneous forcing factors, or that food chain links, rapidly translate the signal through all ecosystem components.

Sign in / Sign up

Export Citation Format

Share Document