Assessment of the impacts of ornamental fish export trade on the exploited ichthyofauna of Lake Malawi

Msukwa, Amulike Victor

Abstract

Globally there are many documented impacts of ornamental fish export trade elsewhere on the exploited populations, on habitats of fish as well as on unequitable distribution of benefits along the ornamental fish export trade value chain. Capture of live cichlid fish of Lake Malawi for ornamental fish export trade started in the 1970s but there have been no studies of the impacts of the trade on the targeted fish species.
This study investigated the potential impacts of ornamental fish export trade on the exploited ornamental fish species of Lake Malawi focusing on: species exported during the past two decades (with respect to export volumes and value, collection localities, export destinations and conservation status); comparison of ornamental fish populations inside and outside the protected areas of Lake Malawi; size at maturity and fecundity of a sample of exploited ornamental fish species; and assessment of the relative risk of the fish to exploitation based on the productivity sustainability analysis (PSA) risk assessment criteria.
The ornamental fish exported from Malawi between 1998 and 2017 were represented by 257 described and 279 undescribed fish species belonging to a total of 64 genera, with the cichlidae family dominating the export volumes at 98.6%. One potentially negative impact of the trade on fish populations was that of the exported fish species, 21 were near threatened species, 12 were critically endangered species, five were endangered species, and five were vulnerable species according to IUCN conservation threat criteria. Underwater visual census of fish showed no significant difference of overall fish abundance between protected and unprotected areas, but large rocky reefs/islands showed significantly higher fish abundance than small rocky reefs/islands. Fish species’ diversity metrics were significantly higher for sites sampled inside protected areas than those in unprotected areas. Fish size at maturity varied between species and between sexes of the fish. Absolute fecundity of fish varied widely amongst the sampled fish species. Some fish species showed significant positive association between absolute fecundity and standard length while other species showed no association between the two variables. Egg sizes significantly varied between fish species and genera. PSA results showed that of the 99 fish species assessed, nine species have high relative risk, 19 species have medium relative risk and 71 species have low relative risk to exploitation for ornamental fish export trade. These results are discussed in relation to management of the ornamental fishery of Lake Malawi and various recommendations are made for further research and fishery management including a proposed framework for the conservation plan for the fishery.

Citation

Msukwa, A. V. Assessment of the impacts of ornamental fish export trade on the exploited ichthyofauna of Lake Malawi. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4224107

• Thesis Type: Thesis
• Deposit Date: Mar 31, 2022
• Publicly Available Date: Feb 24, 2023
• Keywords: Biological sciences; Marine sciences
• Public URL: https://hull-repository.worktribe.com/output/4224107
• Additional Information: Department of Biological & Marine Science, The University of Hull
• Award Date: Mar 1, 2020