Estimating macrobenthic secondary production from body weight and biomass: a field test in a non-boreal intertidal habitat

M Sprung

doi:10.3354/meps100103

Abstract

Production (P) and biomass (B) data of different species from 3 stations in the intertidal zone of the Ria Formosa (southern Portugal, 37 N) were analysed. They were compared with equations from the literature to estimate P/B ratios from body weight. A clear distinction must be made between (1) an intraspecific and (2) an interspecific comparison. (1) Results from 3 species supported a body weight exponent of -0.25 for the P/B ratio, as is to be expected from a linear relationship between growth and respiration. (2) In an interspecific comparison, the weight exponent depends on the contribution of age or growth rate to the presence of large specimens in a sample. It is concluded that production in the specific habitat examined cannot be calculated properly from body weight and biomass by 1 simple equation which mixes interspecific and intraspecific effects, rather that both aspects should be separated into 2 different calculation steps.

Highlights

Since the first attempts to estimate secondary production by Boysen Jensen (1919), techniques have improved continuously (Winberg 1971, Waters 1977, Crisp 1984).At present, the most common methods are the increment summation method, the removal summation method, the instantaneous growth method and a production estimate by the Allen curve
(1) Results from 3 species supported a body weight exponent of -0.25 for the P/B ratio, as is to be expected from a linear relationship between growth and respiration. (2)In a n interspecific comparison, the weight exponent depends on the contribution of age or growth rate to the presence of large specimens in a sample
It is concluded that production in the specific habitat examined cannot be calculated properly from body weight and biomass by 1simple equation which mixes interspecific and intraspecific effects, rather that both aspects should be separated into 2 different calculation steps

Summary

INTRODUCTION

Since the first attempts to estimate secondary production by Boysen Jensen (1919), techniques have improved continuously (Winberg 1971, Waters 1977, Crisp 1984).At present, the most common methods are the increment summation method, the removal summation method, the instantaneous growth method and a production estimate by the Allen curve All these methods are based on analysis of body weight and abundance of cohorts sampled at regular time intervals. An even extended analysis of 337 data sets of production, mean annual biomass and mean individual weight figures has been published by Brey (1990) Both equations imply that the PIE ratio depends on body size in a characteristic way. Are the empirical equations by Banse & Mosher (1980)and Schwinghamer et al (1986) valid under these conditions?

MATERIAL AND METHODS

Findings

RESULTS