IDEAS home Printed from https://ideas.repec.org/a/spr/endesu/v27y2025i7d10.1007_s10668-024-04649-8.html
   My bibliography  Save this article

Changes in fish species diversity, size structure and distribution in the trawlable demersal zones of Lake Malawi, Malawi

Author

Listed:
  • Mwamad S. M’balaka

    (Lilongwe University of Agriculture and Natural Resources
    Ministry of Natural Resources and Climate Change)

  • Emmanuel Kaunda

    (Lilongwe University of Agriculture and Natural Resources)

  • Geoffrey Z. Kanyerere

    (Ministry of Natural Resources and Climate Change)

  • Daniel Jamu

    (The University of Rhode Island)

  • Amulike Msukwa

    (Lilongwe University of Agriculture and Natural Resources)

Abstract

A study was conducted to assess temporal and spatial changes in the trawlable demersal zones of Lake Malawi. Data from surveys conducted in 1998 and 2020 targeting 120 stations covering a surface area of 9647.97 km2 was used. Trawling speed of Research Vessel Ndunduma was restricted to 4.6 km/hr. Length frequency distribution was modelled with the probability density function for determining the likelihoods in the gamma distribution. Parameters for modal length and logistic modelling were guessed and Solver in Microsoft Excel 2021 was used to generate the best of fit values through iteration with GRG Nonlinear approach. The study determined fish diversity using the Shannon and Weiner relationship. The recent survey recorded fewer fish species (149) against 158 sampled in the previous survey. The overall catch rates in 2020 and 1998 ranged from 3.8 kg/0.5 h to 2003.8 kg/0.5 h and 28.7 kg/0.5 to 1,884.3 kg/0.5 h, respectively. Overall fish density in the 2020 and 1998 surveys was calculated at 11.7 tons/km2 and 7.5 tons/km2, respectively representing a 35.6% drop. The study has revealed temporal and spatial shifts in the fish stock composition, distribution and abundance which necessitates urgent management interventions to prevent further fisheries resource losses. Efforts to regulate mesh sizes of the cod-ends of trawlers are encouraged just like the initiative of introducing a closed season for the commercial operators.

Suggested Citation

  • Mwamad S. M’balaka & Emmanuel Kaunda & Geoffrey Z. Kanyerere & Daniel Jamu & Amulike Msukwa, 2025. "Changes in fish species diversity, size structure and distribution in the trawlable demersal zones of Lake Malawi, Malawi," Environment, Development and Sustainability: A Multidisciplinary Approach to the Theory and Practice of Sustainable Development, Springer, vol. 27(7), pages 17239-17259, July.
    • Handle: RePEc:spr:endesu:v:27:y:2025:i:7:d:10.1007_s10668-024-04649-8
    DOI: 10.1007/s10668-024-04649-8
    as

    Download full text from publisher

    File URL: http://link.springer.com/10.1007/s10668-024-04649-8
    File Function: Abstract
    Download Restriction: Access to the full text of the articles in this series is restricted.
    File URL: https://libkey.io/10.1007/s10668-024-04649-8?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    As the access to this document is restricted, you may want to search for a different version of it.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:spr:endesu:v:27:y:2025:i:7:d:10.1007_s10668-024-04649-8. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Sonal Shukla or Springer Nature Abstracting and Indexing (email available below). General contact details of provider: http://www.springer.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.