A1 Refereed original research article in a scientific journal
Limnothrissa miodon (Boulenger, 1906) in Lake Kariba: daily ration and population food consumption estimates, and potential application to predict the fish stock biomass from prey abundance
Authors: Mandima J, Kortet R, Sarvala J
Publisher: SPRINGER
Publication year: 2016
Journal: Hydrobiologia
Journal name in source: HYDROBIOLOGIA
Journal acronym: HYDROBIOLOGIA
Volume: 780
Issue: 1
First page : 99
Last page: 111
Number of pages: 13
ISSN: 0018-8158
eISSN: 1573-5117
DOI: https://doi.org/10.1007/s10750-016-2732-8
Abstract
The offshore pelagic niche in Lake Kariba is mainly occupied by the Tanganyika sardine, Limnothrissa miodon, commonly called 'kapenta', which is a mainly zooplanktivorous clupeid fish. The population dynamics of kapenta fluctuate seasonally in synchrony with the physical processes that shape the trophic status of the lake. Diel feeding periodicity and mean stomach fullness of L. miodon were used to estimate the daily ration and food consumption rates of the population. The daily ration (R (d)) was estimated from mean stomach contents and evacuation rates calculated using the modified Bajkov (Trans Am Fish Soc 65:288-289, 1935) formula. Data on stomach contents present at different time intervals over continuous feeding cycles under experimental conditions were analysed. The results show a daily ration of 8.8-9.9% of fresh body weight day(-1). The estimated whole population food consumption rate suggests very efficient grazing. The present data enable estimations of the potential standing biomass of L. miodon sustained by the lake under known zooplankton biomass regimes. This basis can be utilised further in future work focusing on spatial and temporal dynamics and climate change scenarios to provide a realistic food consumption estimate for the L. miodon population in Lake Kariba and similar artificial reservoirs.
The offshore pelagic niche in Lake Kariba is mainly occupied by the Tanganyika sardine, Limnothrissa miodon, commonly called 'kapenta', which is a mainly zooplanktivorous clupeid fish. The population dynamics of kapenta fluctuate seasonally in synchrony with the physical processes that shape the trophic status of the lake. Diel feeding periodicity and mean stomach fullness of L. miodon were used to estimate the daily ration and food consumption rates of the population. The daily ration (R (d)) was estimated from mean stomach contents and evacuation rates calculated using the modified Bajkov (Trans Am Fish Soc 65:288-289, 1935) formula. Data on stomach contents present at different time intervals over continuous feeding cycles under experimental conditions were analysed. The results show a daily ration of 8.8-9.9% of fresh body weight day(-1). The estimated whole population food consumption rate suggests very efficient grazing. The present data enable estimations of the potential standing biomass of L. miodon sustained by the lake under known zooplankton biomass regimes. This basis can be utilised further in future work focusing on spatial and temporal dynamics and climate change scenarios to provide a realistic food consumption estimate for the L. miodon population in Lake Kariba and similar artificial reservoirs.
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