'~TUDIES
ON THE PROFUNDAL
PRODUCTIVITY
BENTHIC
MACRO INVERTEBRATE
IN LAKE NAIVASHA,
KENYA}'
BY
lRABUR~'
PHILLIP
OKOTH.
M.Sc.
THIS THESIS
HAS BEEN SUBMITTED
FOR THE DEGREE OF MASTER
(HYDROBIOLOGY)
IN PART FULFILMENT
OF SCIENCE
OF THE UNIVERSITY
1991
IN ZOOLOGY
OF NAIROBI.
(xvii)
ABSTRACT
STUDIES ON THE PROFUNDAL
PRODUCTIVITY
BENTHIC
MACRO INVERTEBRATE
IN LAKE NAIVASHA,
The study aimed at establishing
abundance,
biomass
the population
abundant
of benthic
structure
and
tubificid
oligochaetes
Claparede,
Branchiura
Bretscher
microtubellarian
by
and widespread
interspecific
of
rainfall
sowerbyi
with
a
Limnodrilus
sowerbyi
the most
are
clumped
,
association.
was
in the Naivasha
reproduce
February
and
July.
biomass
annual
larvae dominated
Kieffer.
The
type of the sediment
hoffmeisteri
in
strongly
and
hoffmeisteri
throughout
adults peaks twice
of 4.07 g
secondary
and B.
a
dry weight!
of
by
the year
while
year in
contributes
productivity
life
influenced
and March respectively
B. sowerbyi
and
is the most
abundance
basin.L.
in October
include
in their distribution
continuously
of Chironomid
total benthic
L.
-
Variations
macrobenthos
peak
Potamothrix
the lake. Their distribution
by substrate
species.
by
hoffmeisteri
Beddard,
formosipennis
emergence
The
of
and
was found to be dominated
throughout
influenced
cycle
production
worm and chironomid
Chironomus
abundant
macroinvertebrates,
and a naid Dero sp. Others
macro invertebrates
is
the distribution,
species.
The profunda 1 benthos
heuscheri
KENYA.
58% of a
2
m
L.
(xviii)
hoffmeisteri
of
year
Lake
and B.
Naivasha
sowerbyi
belonging
benthic
to
the
region
are 0.65 and 7.43 g dry weight/
respectively.
important
in the profundal
Introduction
feeding
genus
exploit the profundal
fish,
Mormyrus
benthic
'-..
of
a
commercially
especially,
is
~ /
those
recommended
production.
to