Growth and development rates of the copepod Calanus finmarchicus reared in the laboratory

Abstract

Development rates, nitrogen-and carbon-specific growth rates, size, and condition were determined for the copepod Calanus finmarchicus reared at 3 temperatures (4, 8, and 12°C) at non-limiting food concentrations and 2 limiting food concentrations at 8°C in the laboratory. Development rates were equiproportional, but not isochronal. Naupliar stage durations were similar, except for non-feeding stages, which were of short duration, and the first feeding stage, which was prolonged, while copepodite stage durations increased with increasing stage of development. Under limiting food concentrations at 8°C, development rates were prolonged but similar relative patterns in stage durations were observed. Body size (length and weight) was inversely related to temperature and positively related to food concentration. Condition measurements were not affected by temperature, but were positively related to food concentration. Growth rates increased with increasing temperature and increased asymptotically with increasing food concentration. At high food concentrations, growth rates of naupliar stages were high (except for individuals molting from the final naupliar stage to the first copepodite stage, in which growth rates were depressed), while growth of copepodites decreased with increasing stage of development. Neither nitrogen nor carbon growth rates, the former a proxy for structural growth, were exponential over the entire life cycle, but rather sigmoidal. Carbon-specific growth rates were greater than nitrogen-specific growth rates, and this difference increased with increasing stage of development, reflecting an augmentation in lipid deposition in the older stages. However, nitrogen and carbon growth rates were more similar under foodlimited conditions. Based on this study, we recommend that secondary production rates of Calanus finmarchicus and possibly other lipid-storing copepods not be estimated from egg production measurements alone, as has been suggested for other species of copepods, because growth, including structural growth, is not equivalent for all stages.

Medium-term exposure of the North Atlantic copepod <i>Calanus finmarchicus</i> (Gunnerus, 1770) to CO<sub>2</sub>-acidified seawater: effects on survival and development

“…The fact that no males developed in any of the groups was probably related to the modest volume (2 L) of the bottles used for the exposure of the animals. Limited container size and/or density have previously been reported to negatively affect the proportion of developing males in C. finmarchicus (Campbell et al, 2001). Future experiments incorporating multiple generations in a similar system should therefore use larger experimental units to secure development of males, and successful fertilization.…”

Disentangling the mechanisms behind climate effects on zooplankton

“…The warmer, southwestern areas within our study region are near the core areas for C. finmarchicus in the Norwegian Sea, and higher C. finmarchicus biomass in summer downstream of these core areas (i.e., where influx from these areas is highest) leads to a positive association between spring temperature and spatially resolved C. finmarchicus biomass in summer. Nonetheless, it is well established that temperature might directly (41,42) or through temperature effects on food availability (43) influence C. finmarchicus growth rate and egg production. The observed relationship mostly reflects temperature−abundance associations for stages CIV-CV, which dominate biomass in summer.…”

Nucleic acids and growth of Calanus finmarchicus in the laboratory under different food and temperature conditions

“…The experiment took place from July to October 1996. A brief summary of the culture techniques is given here; further details can be found in Campbell et al (2001). Calanus finmarchicus were reared in the laboratory in 100 l plastic tanks, with 2 replicate tanks maintained in each of 5 experimental treatments.…”

“…Although the food in the experimental tanks was adjusted twice daily to the nominal phytoplankton concentrations, the average food concentrations dur-ing the entire experiment differed from the nominal values, especially in the high and medium food treatments. Mean food concentrations were calculated for each 12 h interval between feedings (Campbell et al 2001), and averaged 333 to 390 µg C l -1 in the high food tanks, 39 to 40 µg C l -1 in the medium food tanks and 24 to 28 µg C l -1 in the low food tanks over the duration of the experiment. As a rule, the mean food concentration was lower than the nominal concentration.…”