Patterns of Variation in The Prosome Length of Overwintering Stage V Copepodites of Calanus Finmarchicus in The Firth of Clyde

• Published in: Journal of the Marine Biological Association of the United Kingdom
• Main Authors: Grigg, H., Bardwell, S. J., Tyzack, S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1981
• Subjects: Aquatic Science; Calanus finmarchicus; Copepods
• Online Access: http://dx.doi.org/10.1017/s0025315400023031; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315400023031

In attributing variations in growth and metabolism within a population to environmental fluctuations, and in interpreting the biological response to environmental fluctuations, it is important to recognize the variations that are intrinsic to the population or species. Consequently, it is common practice in studies on the growth and metabolism of calanoid copepods to separate instars and, in the case of adults, males and females when analysing measurements. Although studies on calanoids, in particular species of Calanus and Euchaeta , have demonstrated the existence of pronounced sexual differences in parameters such as dry weight, biochemical composition and respiration rate (e.g. Comita, Marshall & Orr, 1966; Marshall, 1973; Bamstedt, 1975, 1979; Gatten et al. 1979, 1980), the possibility that similar differences might occur in pre-adult instars has not been examined, this despite the fact that in many species in this group it is possible to distinguish the sex of copepodites IV and V, the two instars preceding the adult.