Page 26 - UNAM Virtual Graduation 2020 e-Book

FACULTY OF SCIENCE

DOCTOR OF PHILOSOPHY IN SCIENCE
(BIOLOGICAL SCIENCES)

CANDIDATE: SIMASIKU Evans Kamwi

CURRICULUM VITAE

Evans Kamwi Simasiku was born in the Zambezi Region. He matriculated from
Noordgrens Secondary School in the Kavango East Region. His qualifications
include Bachelor of Science in Aquatic Fisheries & Natural Resources
(University of Namibia); Post Graduate Honours degree in Zoology (University
of Cape Town); Masters in Fisheries Ichthyology (Rhodes University). His professional career includes working
as a fisheries technician, Biologist and Senior Biologist with the Ministry of Fisheries and Marine Resources
(MFMR) and currently serving as a senior Lecturer at the University of Namibia, Department of Wildlife
Management & Ecotourism, Katima Mulilo Campus. His research interest focus is based on freshwater fish
biology, ecology and social economic aspects of the riparian fish communities.

CANDIDATE’S DISSERTATION

DYNAMICS OF THE FLOODPLAIN FISHERIES OF THE ZAMBEZI AND CHOBE FLOODPLAIN, ZAMBEZI REGION,
NAMIBIA

The doctoral study was undertaken and completed under the supervision of Dr. Clinton Hay (University of
Namibia) as Main-Supervisor and Pro. Grzegorz Kopij (University of Namibia) as Co-Supervisor.

Floodplain fisheries are typically multi-species and in most cases harvested with a variety of fishing gears.
In the Zambezi/Chobe River, artisanal gillnet fishers mainly target three cichlids: Oreochromis andersonii,
Oreochromis macrochir and Coptodon rendalli. However, their abundance is declining because of
increased fishing pressure and are becoming vulnerable to overfishing. In response to this dilemma, the
candidate assessed the fish population dynamics of the Zambezi/Chobe floodplain with an intent to initiate
management guidelines for fishery. The study employed a multidisciplinary sampling approach based on
seining for littoral fish communities and experimental gillnetting surveys.

Littoral fish densities of small fishes showed spatiotemporal variations among the different stages of flooding
with a marked increase in juvenile cichlids; O. andersonii, O. macrochir and C. rendalli during the peak flooding
phase. The prevalence of cichlids during the peak flooding phase was related to their spawning periodicity,
enhanced microhabitats, and the abundance of food suitable for larvae and juvenile productivity. Among
other environmental factors, dissolved oxygen and water level had a marked influence on the distribution
and abundance of the littoral fish species. The study further showed successful recruitment in juvenile O.
andersonii, O. macrochir and C. rendalli into the main river channels after attaining a size between 75mm and
80mm SL. However, the newly recruits were still vulnerable to natural mortality (predation) and fishing mortality
imposed by the riparian fishing communities. Further investigation centered on the riparian fishing patterns
and fishing techniques revealed that the current floodplain fishery employs destructive fishing methods and
gears in form of monofilament nets and the frequent use of small illegal mesh sizes (<76mm). These innovations
may have led to economic opportunities for the riparian fishing communities but has eventually resulted into
fish depletion of the three commercially target species; O. andersonii, O. macrochir and C. rendalli in the
Zambezi/Chobe floodplain. As a result, the role of the recently established Fish Protected Area (FPA) on the
Zambezi/Chobe River (i.e. the Kalimbeza Channel) to protect and conserve the reaming fish stocks of the
Zambezi/Chobe River was assessed. Experimental fishing trials showed higher CPUE by weight and number (p
< 0.05) of the five dominant species (Hydrocynus vittatus, Schilbe intermedius, Pharyngochromis acuticeps,
Micralestes acutidens and Brycinus lateralis) in the FPA than non-FPA. Recommendations were made to
manage the fish stocks of the Zambezi/Chobe floodplain by imposing restrictions on gear type, establishing
more fish reserves (FPA) and advocate for community engagement in managing their own resources under
strict guidance from government.
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