ARE IN-SITU WEIGHT-SPECIFIC GROWTH-RATES BODY-SIZE INDEPENDENT IN MARINE PLANKTONIC COPEPODS - A REANALYSIS OF THE GLOBAL SYNTHESES AND A NEW EMPIRICAL-MODEL
Ag. Hirst et M. Sheader, ARE IN-SITU WEIGHT-SPECIFIC GROWTH-RATES BODY-SIZE INDEPENDENT IN MARINE PLANKTONIC COPEPODS - A REANALYSIS OF THE GLOBAL SYNTHESES AND A NEW EMPIRICAL-MODEL, Marine ecology. Progress series, 154, 1997, pp. 155-165
The dependency of in situ weight-specific growth rates of marine copep
ods upon individual body size (weight) was examined by compiling liter
ature values. Two predictive models were compared to the compiled valu
es, one in which weight-specific growth rate of individuals is depende
nt upon body size and temperature, and another in which weight-specifi
c growth rate is dependent upon temperature but independent of individ
ual body size. By comparing predictions from the models with the compi
led values, it is shown that the former model is a better predictor of
weight-specific growth rates for marine copepods under most condition
s. Temperature and body weight are of influence upon weight-specific g
rowth rates for the whole data set (which includes adult, juvenile and
mixed growth types), rates declining with increasing size. Allometric
scaling coefficients of b = 0.581 to 0.737 were found when adult weig
ht-specific fecundity and juvenile weight-specific growth are consider
ed together, while the significant relationships give b values of 0.70
6 and 0.739 when juvenile growth was considered alone. These are simil
ar to those describing other metabolic rates. No significant relations
hip was found for weight-specific fecundity and body weight, although
the data set was very Limited. Copepod generation times were shown to
be weight dependent when compared to the combined geometric mean of eg
g and adult weights rather than adult weight alone. By combining data
from the literature, a new globally applicable empirical equation was
constructed which allows predictions of the weight-specific growth rat
es of copepods from body weight and temperature. Given that many meso-
and macrozooplankton samples are dominated by copepods, it is suggest
ed that this equation may be the most appropriate for estimation of gr
owth and production for suites of such organisms when there is a lack
of growth rate data available.