SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Time: 4:00:00 PM
Location: Carson A
 
WursterCM, Syracuse University, Syracuse, USA, chwurste@syr.edu
Patterson, W, P, Syracuse University, Syracuse, USA, wppatter@syr.edu
 
VARIATION IN LATE HOLOCENE METABOLIC RATE OF FRESHWATER FISH: EVIDENCE FROM STABLE CARBON ISOTOPE VALUES OF APLODINOTUS GRUNNIENS OTOLITHS
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We hypothesize that intra-otolith variation in stable carbon isotope values of fish otoliths is a proxy for metabolic rate and that metabolic rate varies with climate. A proxy for metabolic rate preserved in otoliths would facilitate the understanding of evolutionary history in physiological traits of fish and improve our understanding of bioenergetics. Stable oxygen isotope values of otoliths are known to precipitate in equilibrium with the environment, however the significance of stable carbon isotope values has remained controversial. Recent advances in technology have permitted extraction of high-resolution carbonate from otoliths. We present stable isotope values of fossil freshwater drum (Aplodinotus grunniens) otoliths to assess a mass balance model where otolith stable carbon isotope values are derived from dissolved inorganic carbon of ambient water mixing with carbon derived from metabolic processes. We find that the proportion of metabolically derived carbon is the dominant component controlling ontogenetic variation in stable carbon isotope values of these otoliths. Thus, total intra-otolith variation in stable carbon isotope values is postulated to reflect the total change in metabolic rate over the lifetime of a fish.