Ecological Relations Between the Herring and the Plankton off The North-East Coast of England

I. 430 plankton samples, which were taken by several herring drifters using the Continuous Plankton Recorder in the Shields fishing area during the summer seasons of 1931 to 1933, are analysed to show the main changes in the plankton during those seasons. 2. A comparison is made between the proportions of the different zooplankton organisms found in the plankton and the proportions of these recorded by Savage (1937) in the stomachs of herring obtained from drifters working in the same area and during the same time. The comparisons are made for 29 ten-day periods in the seasons 1931 to 1933, and in addition, for 6 ten-day periods relating to a single drifter which obtained both plankton and stomach samples at the same time in 1932. 3. The comparisons in 2 provide evidence that the herring feeds by selecting certain organisms by individual acts of capture and not by swimming open-mouthed to strain out the plankton indiscriminately: (a) Calanus and Temora in the stomachs either correspond fairly closely to the proportions in the plankton or they may be in very much higher proportions. The latter is always true regarding Anomalocera. (b) Acartia, Oithona, Cladocera and Lamellibranch larvae are always in larger proportions in the plankton than in the stomachs; this applies also to Centropages with two insignificant exceptions. (c) There is a close correspondence between the numbers of Limacina and Sagitta in the plankton and stomachs in the latter half of the 1931 season, but not during 1932 and 1933, when the numbers in the stomachs were insignificant ; during the former period there was a great scarcity of Calanus in the plankton.

Recovery of a biodiversity action plans species in northwest England: possible role of climate change, artificial habitat and water quality amelioration. Occasional Publication of the Marine Biological Association 16

The honeycomb reef worm Sabellaria alveolata is recognised as being an important component of intertidal communities. It is a priority habitat within the UK Biodiversity Action Plan and as a biogenic reef forming species is covered by Annex 1 of the EC habitats directive. S. alveolata has a lusitanean (southern) distribution, being largely restricted to the south and west coasts of England. A broad-scale survey of S. alveolata distribution along the north-west coasts was undertaken in 2003/2004. These records were then compared with previous distribution records, mainly those collected by Cunningham in 1984. More detailed mapping was carried out at Hilbre Island at the mouth of the River Dee, due to recent reports that S. alveolata had become re-established there after a long absence.

North Atlantic and North Sea climate change: curl up, shut down, NAO and ocean colour

The strength of the North Atlantic Current (NAC) (based on sea-surface elevation sloped derived from altimeter data) is correlated with westerly winds (based on North Atlantic Oscillation [NAO] Index data over a nine year period [1992-2002] with 108 monthly values). The data time window includes the major change in climate forcing over the last 100 years (1995 to 1996). It is shown that the NAO Index can be used for early earning of system failure for the NAC. The correlation response or early warning time scale for western Europe and south England is six months. The decay scale for the NAC and Subtropical Gyre circulation is estimated as three years. Longer period altimeter elevation/circulation changes are discussed. The sea-surface temperature (SST) response of the North Sea to negative and positive NAO conditions is examined. The overall temperature response for the central North Sea to NAO index forcing, reflecting wind induced inflow, shelf circulation and local climate forcing, is similar to 5 months. In years with strong North Atlantic winter wind induced inflow, under marked NAO positive conditions, mean temperatures ( similar to 10.5 degree C) are about 1 degree C warmer than under negative conditions. In 1996 under extreme negative winter NAO conditions, the North Sea circulation stopped, conditions near the Dogger Bank became more continentally influenced and the winter (March) temperature fell to 3.1 degree C whereas in 1995 under NAO positive winter conditions the minimum temperature was 6.4 degree C (February). Seasonal advance of North Atlantic and North Sea temperature is derived in relation to temperature change. Temperature change and monthly NAO Index are discussed with respect to phytoplankton blooms, chlorophyll-a measurements, ocean colour data and the anomalous north-eastern Atlantic 2002 spring/summer bloom SeaWiFS chlorophyll concentrations.

A change in the zooplankton of the central North Sea (55 degree to 58 degree N): A possible consequence of changes in the benthos

The mesozooplankton taken in continuous plankton recorder samples from the Central North Sea has changed from being numerically dominated by holoplanktonic calanoid copepod species from 1958 to the late 1970s to a situation where pluteus larvae of echinoid and ophiuroid echinoderms have been more abundant than any single holoplanktonic species in the 1980s and early 1990s. The abundance of the echinoderm larvae as a proportion of the zooplankton taken in the samples has followed a continuous increasing trend over the Dogger Bank, but off the eastern coast of northern England and southern Scotland the increase did not become obvious until the 1980s. This trend is consistent with reported increases in abundance of the macrobenthos. It is proposed that changes in the benthos have influenced the composition of the plankton.

Responses Of Mytilus-Edulis On Exposure To The Water-Accommodated Fraction Of North-Sea-Oil

Individuals of Mytilus edulis L., collected from the Erme estuary (S.W. England) in 1978, were exposed to low concentrations (7 to 68 μg l-1) of the water-accommodated fraction (WAF) of North Sea crude oil. The pattern of accumulation of petroleum hydrocarbons in the body tissues was affected by the presence of algal food cells, the period of exposure, the hydrocarbon concentration in seawater, the type of body tissue and the nature of the hydrocarbon. Many physiological responses (e.g. rates of oxygen consumption, feeding, excretion, and scope for growth), cellular responses (e.g. lysosomal latency and digestive cell size) and biochemical responses (e.g. specific activities of several enzymes) were significantly altered by short-term (4 wk) and/or long-term (5 mo) exposure to WAF. Stress indices such as scope for growth and lysosomal latency were negatively correlated with tissue aromatic hydrocarbons.

Polychlorinated Biphenyl DDT And Dieldrin Residues In Grey Seal (Halichoerus-Grypus) Males Females And Mother-Foetus Pairs Sampled At The Farne Islands England During The Breeding-Season

PCB, DDT, DDE, dieldrin and total non-polar organohalogen residues have been determined in the blubber-lipid of grey seals (Halichoerus grypus) sampled during the 1972 breeding season (November) at the Farne Islands off the north eastern coast of England. PCBs were analysed by gas-liquid chromatography linked to a chlorine- and carbon-selective microwave plasma detector and total organohalogen residues were determined by microcoulometry. Total organohalogen residues were negatively correlated with blubber thickness and positively correlated with age in males (aged 1 to 24 y) and females (aged 5 to 38 y). However, the correlation of blubber-lipid residue with age in males depended upon the inclusion of immature (aged < 6 y) animals, and in females reflected only a small residue increment. The mean blubber organohalogen concentration of the males was significantly greater than that of the females. PCB and DDT group residue concentrations were significantly correlated. PCB, DDT, DDE and dieldrin were detected in the liver of mother/foetus pairs demonstrating transplacental movement of these residues. The possibility of the condition of the seals at breeding time influencing residue levels and of these residues influencing the health of the population is discussed.

Ecological Investigations with the Continuous Plankton Recorder: The Zooplankton (other than Copepoda and Young Fish) in the Southern North Sea, 1932-37.

I. The report describes the main monthly changes in the distribution and abundance of the zooplankton, other than Copepoda and young fish (dealt with in separate reports), over the southern part of the North Sea from 1932 to 1937. The work is part of the survey carried out by Continuous Plankton Recorders towed at a depth of 10 metres on regular steamship lines between England and the Continent. 2. The limitations to the sampling method are discussed, and it is shown to be unsuitable for recording Mysidacea and Euphausiacea on account of their marked diurnal variation due presumably to vertical migration; they are omitted from the report. 3. The changing distribution of Sagitta, Limacina, Clione, Lamellibranch larvae, Cladocera, Caprellid Amphipoda, Decapod larvae, Echinoderm larvae and Oikopleura are shown in a series of monthly charts while their seasonal fluctuations are compared in time-chart histograms. 4. The Alima larvae of Squilla are recorded on a few occasions in the regions where the Channel opens into the North Sea. 5. The distributional characteristics of the different forms, i.e. their tendencies to even or " patchy " production, are compared.