A Seasonal Survey of the Lipids in Calanus helgolandicus Claus from the English Channel

ABSTRACT Total lipid, lipid class composition, body nitrogen and dry weight of male, female and Stage V Calanus helgolandicus Claus from the English Channel were surveyed at approximately fortnightly intervals over 18 months. Similar analyses, including Chlorophyll a , were made of the particulate material from the same sea area. The total lipid levels of males and Stage V animals, which ranged from 20–40 μg/animal in winter to 100–130 μg/animal in summer, were very similar during spring and, at most times of the year, were higher than those of females which ranged from 10 μg/animal in winter to 55 μg/animal in summer. Dry weights varied from 105–244 μg (females), 117–273 μg (males) and 103–246 μg (Stage V), generally reflecting body lipid and nitrogen levels in males and Stage V and body nitrogen levels in females. Studies carried out during the two spring periods (1977 and 1978) indicated that a high level of lipid in the particulate material was accompanied by a high level of lipid in Stage V: however, at other times of the year there was little correlation between lipid levels in the phytoplankton and the copepods. Quantitative TLC analysis of lipid classes showed that wax esters remained the dominant class throughout the year in males and Stage V copepods. By contrast, females showed a much more variable lipid composition with wax esters dominant only during midsummer and late autumn, and polar lipids and free fatty acids the main components at all other times. The results are discussed with particular reference to the relationship between body lipids and development, feeding and reproduction by the animals.