Long-term changes in the pelagos, benthos and fisheries of the North Sea

Pronounced changes have occurred in the fisheries, plankton and benthos of the North Sea over the last five decades. Attribution of the relative contribution of anthropogenic versus natural hydrometeorological modulation to these changes is still unclear. As a background a summary history of our understanding of the state of health of the North Sea is outlined. We then focus on two contrasting periods in the North Sea, one between 1978-82 (cold) and the other post 1987 (warm) when pronounced alterations in many ecosystem characteristics occurred. The scale of the changes in the second of these periods is sufficiently large and wide ranging for it to have been termed a regime shift. A combination of local, regional and far field hydrometeorological forcing, and in particular variability in oceanic inflow, is believed to be responsible for the observed changes. Finally attention is drawn to the poor status of North Sea fish stocks where 7 stocks are documented as being fished outside safe biological limits. This situation is primarily believed to be a consequence of overfishing, but may have been exacerbated by environmental change.

Temporal differences across a bio-geographical boundary reveal slow response of sub-littoral benthos to climate change

The English Channel is located at the biogeographical boundary between the northern Boreal and southern Lusitanian biozones and therefore represents an important area to study the effects of global warming on marine organisms. While the consequences of climatic change in the western English Channel have been relatively well documented for fish, plankton and inter-tidal benthic communities, data highlighting the same effects on the distribution of sub-littoral benthic organisms does, to date, not exist. The present study resurveyed a subset of sites originally surveyed from 1958 to 1959 along the UK coast of the English Channel. The main aims of this resurvey were to describe the present status of benthic communities and to investigate potential temporal changes, in particular distributional changes in western stenothermal ‘cold’ water and southern Lusitanian ‘warm’ water species. The increase in water temperature observed since the historic survey was predicted to have caused a contraction in the distribution of cold water species and an extension in the distribution of warm water species. The temporal comparison did not show any clear broad-scale distributional changes in benthic communities consistent with these predictions. Nevertheless, 2 warm water species, the sting winkle Ocenebra erinacea and the introduced American slipper limpet Crepidula fornicata, did show range extensions and increased occurrence, possibly related to climatic warming. Similarly, warm water species previously not recorded by the historic survey were found. The absence of broad-scale temporal differences in sub-tidal communities in response to climatic warming has been reported for other areas and may indicate that these communities respond far more slowly to environmental changes compared to plankton, fish and inter-tidal organisms.

Temporal differences across a bio-geographical boundary reveal slow response of sub-littoral benthos to climate change

The English Channel is located at the biogeographical boundary between the northern Boreal and southern Lusitanian biozones and therefore represents an important area to study the effects of global warming on marine organisms. While the consequences of climatic change in the western English Channel have been relatively well documented for fish, plankton and inter-tidal benthic communities, data highlighting the same effects on the distribution of sub-littoral benthic organisms does, to date, not exist. The present study resurveyed a subset of sites originally surveyed from 1958 to 1959 along the UK coast of the English Channel. The main aims of this resurvey were to describe the present status of benthic communities and to investigate potential temporal changes, in particular distributional changes in western stenothermal ‘cold’ water and southern Lusitanian ‘warm’ water species. The increase in water temperature observed since the historic survey was predicted to have caused a contraction in the distribution of cold water species and an extension in the distribution of warm water species. The temporal comparison did not show any clear broad-scale distributional changes in benthic communities consistent with these predictions. Nevertheless, 2 warm water species, the sting winkle Ocenebra erinacea and the introduced American slipper limpet Crepidula fornicata, did show range extensions and increased occurrence, possibly related to climatic warming. Similarly, warm water species previously not recorded by the historic survey were found. The absence of broad-scale temporal differences in sub-tidal communities in response to climatic warming has been reported for other areas and may indicate that these communities respond far more slowly to environmental changes compared to plankton, fish and inter-tidal organisms.

Report on trawling and other investigations carried out in the Bays on the South-East Coast of Devon during 1901 and 1902

Section 1. The Brixham fishing-grounds and fishery statistics. Section 2. Distribution and migrations of food-fishes. Section 3. The reproduction of the flat-fishes. Appendix 1. Preliminary Report on the Trawling Experiments in the Bays on the South Coast of Devon.