Shelf edge, from the north coast of Spain, Biscay, Celtic Sea to west of Ireland

Zooplankton and zoobenthos morphological parameters; Chlorophyll pigment concentrations in water bodies; Dissolved oxygen parameters in the water column; Salinity of the water column; Temperature of the water column; Zooplankton taxonomy-related abundance per unit volume of the water column; Concentration of suspended particulate material in the water column; Zooplankton and zoobenthos development stage parameters; Alkalinity, acidity and pH of the water column; Zooplankton egg hatch proportion

Fluorometers; plankton nets; salinity sensor; dissolved gas sensors; pH sensors

An international series of cruises undertaken to estimate the spawning stock biomass of the western mackerel and horse mackerel stocks by plankton survey. Only the surveys carried out by England are listed below: 1977: Five surveys of 70-85 samples each were undertaken, carried out between March and July. Mackerel and Horse Mackerel eggs were counted and staged. Mackerel, Horse Mackerel, Hake and Blue Whiting larvae were counted and measured. A spawning stock biomass estimate for mackerel was produced. Environmental parameters were measured as follows: continuous measurements of temperature, turbidity, oxygen, pH and in-vivo chlorophyll-a concentrations; 'V' shape profiles of temperature on each sampling position; surface salinity measurements from bottle samples from each sampling position. 1980: Three surveys of 90-140 samples each were undertaken, carried out between March and July. Analysis was as for 1977. Environmental parameters were measured as follows: continuous measurement of temperature; 'V' shape profiles of temperature on each sampling position; surface salinity measurements from bottle samples from each sampling position. 1983: Two surveys of 110-150 samples each were undertaken, carried out between March and June. Mackerel, Horse Mackerel, Hake and Blue Whiting eggs were staged and larvae measured. A spawning stock biomass estimate for mackerel was produced. Environmental parameters were measured as in 1980 plus a 'V' shape profile of salinity on each sampling position. 1986: One survey of 158 samples was carried out between May and June. All fish eggs and larvae were identified. Mackerel and Horse Mackerel eggs were staged. Mackerel larvae were measured. Environmental parameters were measured as follows: continuous measurement of temperature and salinity; 'V' shaped profiles of temperature and salinity on each sampling position; continuous in- vivo chlorophyll-a measurements. 1989: One survey of 148 samples was carried out between May and June. Mackerel and Horse Mackerel eggs were staged. Environmental parameters were measured as follows: continuous measurements of temperature and salinity; 'V' shape profiles of temperature and salinity on each sampling position. 1992: One survey of 132 samples was carried out between May and June. All fish eggs were identified. Mackerel and Horse Mackerel eggs were staged. Environmental parameters were measured as follows: continuous measurements of temperature and salinity; 'V' shape profiles of temperature and salinity on each sampling position. 1995: One survey of 83 samples was carried out during April/May. All fish eggs were sorted from the samples. Only Mackerel and Horse Mackerel eggs were identified and staged. Environmental parameters were measured as follows: continuous measurements of temperature and salinity; 'V' shape profiles of temperature and salinity on each sampling position.

Lockwood, S.J., Nichols, J.H. and Dawson, W.A. (1981) The estimation of a mackerel (Scomber scombrus L.) spawning stock size by plankton survey., Journal of Plankton Research, 3 (2): 217-233.; Thompson, B.M., et al. (1984) The Western mackerel spawning stock estimate for 1983., ICES C.M. 1984/H:15, 12pp.; Lockwood, S.J. (1985) Marine environment data inventory for the Bay of Biscay, Celtic Sea and West of Ireland, March-July 1977., Data Report, MAFF Direct Fish Research, No. 6: 44 pages.; Milligan, S.P. (1989) Marine environment data inventory for the Bay of Biscay, Celtic Sea and west of Ireland, March-July 1980, 1983, 1986. ICES Working Group on mackerel and horse mackerel egg surveys., Data Rep., MAFF Direct Fish Res. No. 17.

Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory
Pakefield Road
Lowestoft
Suffolk
NR33 OHT
United Kingdom