Abstract:

Trawl surveys are among the popular methods used to estimate the abundance of fish in an ecosystem, with the aim of determining how much fish can be harvested while allowing the remaining fish populations to stay viable. The National Fisheries Resources Research Institute (NaFIRRI) has a long history of undertaking bottom trawl surveys, and data collected from these surveys forms a time series that dates from around 1969. These surveys, because of their nature, are conducted with funding from major projects on the lake i.e. Lake Victoria Fisheries Research Project (LVFRP), 1997 – 2002, Implementation of Fisheries Management Plan (IFMP), 2003 – 2010, and ATAAS 2012—2017. Here, we report results of the survey that was funded by a National Science Foundation (NSF) grant to the University of Denver and the Lake Victoria Fisheries Organization (LVFO). The objectives of the survey were 1) to determine the distribution and relative abundance of fish, with major emphasis on haplochromine cichlids, and size composition of commercial fisheries, and 2) to collect biological samples for Mercury, DNA, and stable isotope analysis. Standard bottom trawl survey techniques were used when processing the catch. Specimens were also saved to fulfil requests. Environmental sampling was concurrently done using a submersible Conductivity-Temperature-Depth profiling system (CTD).