Energetic cost of gonad development in Calanus finmarchicus and C-helgolandicus

International audienc

Growth and development of Calanus helgolandicus reared in the laboratory

International audienc

Egg production rates of Calanus helgolandicus females reared in the laboratory: variability due to present and past feeding conditions

International audienc

Is weight an important parameter when measuring copepod growth?

International audienc

Secondary production of Calanus helgolandicus in the Western English Channel.

International audienc

Comparison of five methods for estimating growth of Calanus helgolandicus later developmental stages (CV�CVI)

The activity of the enzymes aminoacyl-tRNA synthetases (AARS) in adult females and males and copepodites stage V of Calanus helgolandicus was studied at the L4 time-series station in the English Channel from June 2002 to December 2003. AARS activity was explored as an index of somatic growth in the laboratory as well as in the field by comparison with other methods of measuring growth: (1) the direct method (Heinle in Chesapeake Sci 7:59�74, 1966), (2) the weight increment (WI) method, (3) the Hirst and Bunker (HB) equation (Limnol Oceanogr 48(5):1988�2010, 2003) and (4) the egg production (EPR) method. AARS activity showed a significant correlation with the direct measurement of growth in the laboratory (R 2=0.55). However, the correlation was lower for growth assessed either with the WI or the HB approaches in the field (R 2=0.05�0.17). Female AARS activity showed a positive correlation with specific EPR during the reproductive season (R 2=0.40) but no relationship was found during the non-reproductive period