Methods
Summary
Research Design
Purposive sampling protocol will be followed, at the discretion of fishing company vessels at pre-determined fishing sites. Environmental data will be inferred using secondary data from fishing activities within Namibia's EEZ. Sampling will be done within hake fishing grounds in Namibian waters between 17°12' S and 29°30' S.
Procedures
Two sampling bins, each approximately 30 kg will be collected from each hake trawl station, onboard the hake fishing vessels during commercial fishing activities between May and August 2022. Daily, on average, two stations will be surveyed, depending on the number of fishing trawls. Where possible, trawls set at daylight and night time will be recorded, to cater for diel migrating species. Species regarded as by-catch will be sorted and identified up to species level using a species identification guide.
Challenges
Anticipated project challenges
To fully determine the spatial-temporal composition of fish by-catch species in the Namibian hake trawl fishery, sampling should preferably be done over a year, as some fish species may be available seasonally. In contrast, sampling will be specifically done between May and August in the year 2022. Therefore, this does not allow for seasonal sampling of the study area.
How I plan to overcome this challenge
Only the hake trawl fishery will be considered. Consequently, information on fish species by-catch will be obtained specifically pertaining to the hake trawl fishery
Pre Analysis Plan
My research hypotheses are:
a) There is no significant difference in the composition of marine species caught as by-catch overtime at different geographic locations
b) Environmental factors have no significant influence on the spatial and temporal variation of marine species caught as by-catch within the hake trawl fishery
c) Changes in environmental factors overtime have no significant effect on the species richness and diversity of marine species caught as by-catch within the hake trawl fishery
Protocols
Browse the protocols that are part of the experimental methods.