C. Halsband-lenk et al., Seasonal cycles of egg production of two planktonic copepods, Centropages typicus and Temora stylifera, in the north-western Mediterranean Sea, J PLANK RES, 23(6), 2001, pp. 597-609
Reproduction of the dominant copepods Centropages typicus and Temora stylif
era was studied at a permanent station in the Ligurian Sea (north-western.
Mediterranean). Seasonal patterns of egg production, clutch size, egg size
and female prosome length were followed from January 1998 to December 1999.
Female carbon content and weight-specific egg production were compared in
autumn 1998 and spring 1999. Reproductive patterns of C. typicus and T. sty
lifera were very similar, indicating that reproduction was affected by the
same environmental factors. Reproductive activity, was highest in autumn in
both species and years. A second peak of egg production was observed in ea
rly summer, which was less intense in 1999 after a bloom of sales. Egg prod
uction rates reached maximal values of 33.5 and 33.3 eggs female(-1) day(-1
) and annual means of 10.8 and 11.7 eggs female(-1) day(-1) in Centropages
and Temora, respectively. Maximal weight-specific egg production was 0.21 d
ay(-1) in both species in November 1998, when female carbon contents were 6
.7 (C. typicus) and 12.0 mug (T. stylifera). No statistical relationship be
tween egg production and food availability or temperature was detected. Rep
roductive activity, did not reflect the seasonal abundance patterns, with C
. typicus dominating in spring and T. stylifera in autumn.