Small-scale variability in growth and condition of dab Limanda limanda (L.) larvae in relation to an Irish Sea tidal-mixing front off the west coast of the Isle of Man

2007 ◽  
Vol 71 (4) ◽  
pp. 1056-1068 ◽  
Author(s):  
O. Lee ◽  
B. S. Danilowicz ◽  
R. D. M. Nash
Keyword(s):  
West Coast ◽  
Tidal Mixing ◽  
Irish Sea ◽  
Small Scale ◽  
The West ◽  
Isle Of Man ◽  
Tidal Mixing Front

scholarly journals Small-scale spatio-temporal variability in ichthyoplankton and zooplankton distribution in relation to a tidal-mixing front in the Irish Sea

2005 ◽  
Vol 62 (6) ◽  
pp. 1021-1036 ◽  
Author(s):  
O. Lee ◽  
R.D.M. Nash ◽  
B.S. Danilowicz
Keyword(s):  
Temporal Dynamics ◽  
Fish Larvae ◽  
Sampling Period ◽  
Tidal Mixing ◽  
Irish Sea ◽  
Small Scale ◽  
Surface Salinity ◽  
Average Value ◽  
Tidal Mixing Front ◽  
Spatio Temporal

Abstract This study examines the spatio-temporal dynamics of fish larvae and their prey at a tidal-mixing front in the central Irish Sea. The distribution of ichthyoplankton and zooplankton was analysed in relation to environmental variables (depth, surface temperature, surface salinity, and water column stratification) using Redundancy Analysis (RDA). Significant interannual variability in the formation and position of the tidal-mixing front coincided with large differences in the species abundances of both ichthyoplankton and zooplankton. During the summer, ichthyoplankton and zooplankton communities were structured by a combination of depth and hydrography, and the variability in species composition was directly related to the average value of the stratification parameter. Several ichthyoplankton species were consistently associated with frontal waters, while fewer species were concentrated in mixed water masses throughout the sampling period. The distribution of individual zooplankton species was also examined, and water mass affinities were shown to vary with developmental stage.

Biological studies in the vicinity of a shallow-sea tidal mixing front. I. Physical and chemical background

1985 ◽  
Vol 310 (1146) ◽  
pp. 407-433 ◽  
Keyword(s):  
Ammonium Nitrogen ◽  
Tidal Mixing ◽  
Irish Sea ◽  
Total Biomass ◽  
Shallow Sea ◽  
High Biological Activity ◽  
Biological Studies ◽  
Chemical Background ◽  
Tidal Mixing Front ◽  
Physical And Chemical

A study has been made of the distribution and activities of bacteria and zooplankton as they varied seasonally in 1980 and 1981 in the vicinity of a shallow-sea tidal mixing front in the western Irish Sea (approximate position 53° 20' N, 5° 45' W to 53° 50' N, 5° 0' W ). This paper presents the physical and chemical background to these studies as shown by the variations in temperature and salinity and concentrations of chlorophyll a , phaeopigments, cellular adenosine triphosphate (ATP), nitrate, nitrite and ammonium nitrogen, in sections normal to the front. Observations at drogue stations were made to establish the extent of diurnal variations in these properties but these appeared to be small relative to other variations. As the front developed, higher chlorophyll a concentrations appeared in the surface stratified water, in contrast to the bottom stratified water and mixed water, with highest concentrations at the surface at the stratified side of the front and in subsurface patches in the vicinity of the pycnocline. As the phytoplankton populations increased nitrate became depleted in the surface stratified water but nitrite and ammonium nitrogen concentrations remained at about the same levels. Cellular ATP concentration did not appear to be a useful measure of total biomass but indicated high biological activity in the surface stratified water.

Population dispersal in the brittle-star Ophiocomina nigra (Abildgaard) (Echinodermata: Ophiuroidea)

1977 ◽  
Vol 57 (2) ◽  
pp. 405-439 ◽  
Author(s):  
J. B. Wilson ◽  
N. A. Holme ◽  
R. L. Barrett
Keyword(s):  
West Coast ◽  
Personal Communication ◽  
Irish Sea ◽  
English Channel ◽  
The West ◽  
The North ◽  
Sea Bed ◽  
Cook Strait ◽  
The North Sea ◽  
The Irish Sea

A number of species of ophiuroid are known to occur in dense clusters on the sea-bed. Aggregations of Ophiothrix fragilis (Abildgaard) have been recorded from the English Channel by Allen (1899), Vevers (1951, 1952), Barnes (1955), Ancellin (1957), Cabioch (1961, 1967, 1968), Holme (1966), Warner (1969, 1971), and by Allain (1974). Beds of the same species have been found in the Irish Sea by Jones (1951) and by Brun (1969), on the west coast of Ireland by Könnecker & Keegan (1973) and Keegan (1974), and on the west coast of Scotland, where it is widespread in sea lochs and elsewhere around the coast (McIntyre, 1956, and personal communication, 1975). Records of Ophiothrix fragilis from the North Sea have been summarized by Ursin (1960). In the Mediterranean, aggregations of Ophiothrix quinquemaculata (D.Ch.) have been described by Guille (1964, 1965) from off the south coast of France, and by Czihak (1959) from the Adriatic. Hurley (1959) gives underwater photographs of Ophiocomina bollonsi Farquhar from the Cook Strait, New Zealand. Further examples of aggregation in ophiuroids and other echinoderms are cited by Reese (1966), Mileykovskiy (1967) and by Warner (1978).

scholarly journals Temporal patterns of spatial genetic structure and effective population size in European plaice (Pleuronectes platessa) along the west coast of Scotland and in the Irish Sea

2009 ◽  
Vol 67 (4) ◽  
pp. 607-616 ◽  
Author(s):  
Phillip C. Watts ◽  
Suzanne M. Kay ◽  
Drew Wolfenden ◽  
Clive J. Fox ◽  
Audrey J. Geffen ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Population Size ◽  
Effective Population Size ◽  
West Coast ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Irish Sea ◽  
Effective Population ◽  
The West ◽  
Pleuronectes Platessa

Abstract Watts, P. C., Kay, S. M., Wolfenden, D., Fox, C. J., Geffen, A. J., Kemp, S. J., and Nash, R. D. M. 2010. Temporal patterns of spatial genetic structure and effective population size in European plaice (Pleuronectes platessa) along the west coast of Scotland and in the Irish Sea. – ICES Journal of Marine Science, 67: 607–616. The European plaice (Pleuronectes platessa) is a relatively mobile flatfish species, and previous studies have reported broad-scale genetic homogeneity among samples distributed throughout much of its northern European range, with no evidence for isolation-by-distance (IBD) population structure. Using microsatellite loci, the pattern of spatial genetic structure and effective population size is characterized for >800 plaice collected from locations off the west coast of Great Britain over a 3-year period (2001–2003). The plaice populations are characterized by weak spatial genetic structure, consistent with tagging data, and relatively low effective population sizes. In contrast to previous work, a pattern of isolation by distance is present among pairs of plaice from within each sampling period. However, IBD spatial structure was not observed for comparisons of plaice from different sampling years or using the entire dataset, indicating a patchy temporal genetic structure. Therefore, pooling the data from several years can mask subtle patterns of population structure and potentially confound estimation of other important demographic parameters, such as effective population size.

The catch characteristics and population structure of the brown crab (Cancer pagurus) fishery in the Isle of Man, Irish Sea

2017 ◽  
Vol 99 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Fikret Öndes ◽  
Jack A. Emmerson ◽  
Michel J. Kaiser ◽  
Lee G. Murray ◽  
Kevin Kennington
Keyword(s):  
Sex Ratio ◽  
Temporal Variations ◽  
Irish Sea ◽  
Strong Increase ◽  
Small Scale ◽  
Catch Per Unit Effort ◽  
Isle Of Man ◽  
Spatial Coverage ◽  
Sampling Regime ◽  
Survey Designs

Brown crab contributes to small-scale fisheries in the Isle of Man and landings (495 t) were worth in excess of £0.5 million in 2012. The present study sought to fill evidence gaps needed to improve the scientific understanding of this fishery. Observer data were collected to examine the spatial and temporal variations in the size distribution and sex ratio of crabs around the Isle of Man. This study also aimed to evaluate the catch characteristics of brown crab using logbook data (2007–2012), observer data (2012–2013) and questionnaire survey data (2013). The sex ratio is highly variable in different areas across seasons and was perhaps indicative of migration patterns in relation to mating. This change was most notable with a strong increase in the proportion of females to the south and west of the Isle of Man in the autumn months. The depth and pot volume were important factors that influenced the catch per unit effort (CPUE). Future survey designs would need to ensure adequate spatial coverage of the east and west coast of the Isle of Man together with a seasonal sampling regime that captures the spatial change in the distribution and abundance of male and female crabs.

Biological studies in the vicinity of a shallow-sea tidal mixing front VII. The frontal ecosystems

1985 ◽  
Vol 310 (1146) ◽  
pp. 555-571 ◽  
Keyword(s):  
Nitrogen Cycling ◽  
Dynamic Equilibrium ◽  
Standing Stock ◽  
Tidal Mixing ◽  
Irish Sea ◽  
Heterotrophic Activity ◽  
Plume Front ◽  
Biological Studies ◽  
Tidal Mixing Front ◽  
Standing Stocks

Three, possibly four, ecosystems forming seasonally are associated with the tidal mixing front in the western Irish Sea. They are distinguished not only by the presence or absence of particular species but by their relative intensities of heterotrophic activity and degree of organization as shown in the number of statistically significant correlations between the variables pertaining to them. The mam body of surface stratified water, at first dominated by an expanding population of phototrophs, attains during the summer a state of dynamic equilibrium in which the standing stock of phytoplankton remains at about the same level, its primary productivity being balanced by high levels of heterotrophic activity and cycling of nitrogen. The bottom stratified water, besides having minimal photosynthetic activity, shows low zooplankton stocks, low heterotrophic activity and the lowest level of organization. Mixed water has lower standing stocks, less heterotrophic activity, lower rates of nitrogen cycling, and is a less highly organized system than the surface stratified water. The stratified water in a band about 10 km wide adjacent to the front does not show conspicuously higher total standing stocks of phytoplank ton, bacteria and zooplankton in the water column down to the pycnocline, than the rest of the stratified water. Animals migrating into it do not provide an appreciable extra source of nutrients for the phytoplankton. It does, however, show much higher heterotrophic activity and rates of nitrogen cycling than the rest of the stratified water. This is tentatively attributed to increased photosynthesis, consequent on the redistribution of phytoplankton by frontal eddies, being taken up in increased heterotrophic activity rather than in growth of the phytoplankton itself. A similar situation appears to exist at the plume front in Liverpool Bay but here there is the additional factor of collection at the front of particulate organic matter derived from river inflow.

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