Item Details

Title: Acoustic estimates of commercial fish species in Lake Victoria: Moving towards ecosystem-based fisheries management

Date Published: 2012
Author/s: Inigo Eversona, Anthony Taabu-Munyaho, Robert Kayanda
Data publication:
Funding Agency :
Copyright/patents/trade marks: Elsevier B.V.
Journal Publisher: Elsevier B.V.
Affiliation: Animal and Environment Research Group, Faculty of Science and Technology, Anglia Ruskin University, Cambridge, UK
b National Fisheries Resources Research Institute (NaFIRRI), P.O. Box 343, Jinja, Uganda
c Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 475, Mwanza, Tanzania
Keywords: Nile perch
Lake Victoria
Ecosystem-based management


Data from the first series of lakewide fisheries acoustic surveys of Lake Victoria, East Africa, have been
re-analysed according to current protocols. Surveys took place in February and August each year between
1999 and 2002. The primary aim has been to estimate the standing stock of Nile perch and dagaa, the
main species taken in commercial fisheries on the lake. The results show that over the period of the
surveys from 1999 to 2002 there was no significant trend in the standing stock of either species with
time although there was a significant seasonal effect higher values in February as compared to August.
Information from bottom trawls during the surveys supports these conclusions. The results have been
considered in the context of a food web from which it is concluded that in order for sufficient food to
be present for the Nile perch there must be a significant proportion of the decapod crustacean Caridina
present. It is noted that this species can be estimated acoustically using multifrequency echosounders
but is very difficult with the single frequency system used on the 1999–2002 surveys. Refinements in the
methodology will permit the simultaneous assessment of several key components in the food web and
open the way to effective ecosystem-based fisheries management.