Pilchard (Sardina pilchardus, Walbaum) egg distribution in the English Channel from plankton surveys in 1978, 1981, 1988 and 1991

The distribution, abundance and production of pilchard (Sardina pilchardus, Walbaum) eggs are described from a series of plankton surveys in the English Channel. These are discussed in relation to surface temperature and compared with the results from previously published surveys. The surveys confirm that spawning begins in the western English Channel during the second half of March, progresses eastwards and is 2–3 weeks later in the eastern English Channel. Some spawning still occurs in the southern North Sea and at a similar level to that found on surveys in 1950 and 1967. Pilchard eggs were found developing in surface temperatures down to 8.5°C. Concentrations as high as 1500 m−2 were found in the Bay of the Seine at 10–10.5°C. These surveys suggest that increasing egg production is linked to increasing sea temperature and that the major production occurs in the western English Channel at surface temperatures >14.5°C.