Transcript symposium-waya

THE IMPORTANCE OF TAXONOMIC
PROJECT OF ZOOPLANKTON TO SOCIETY
Waya R.K.
TANZANIA FISHERIES RESEARCH
INSTITUTE
THE IMPORTANCE OF TAXONOMIC
PROJECT TO SOCIETY
Waya R.K.
TANZANIA FISHERIES RESEARCH
INSTITUTE
Introduction
• Biodiversity in Lake Victoria is increasingly
at risk from human activity such as
pollution, overexploitation and widespread
catchment deforestation resulting in excess
sedimentation
• In order to predict ecosystem responses to
environmental perturbations, it is essential
to have an enhanced understanding of the
diversity of various key components of the
lake ecosystem.
Introduction
• Zooplankton is one of them having a
potentially important function in aquatic
food webs.
• Zooplankton community of Lake Victoria
consists of Copepoda, Cladocera and
Rotifers but Copepoda comprised of 80 %
of the community
What is a copepod ?
a forked tail:
the caudal rami
5 pairs of mouthparts
5 pairs of
bi-ramous
swimming legs
Eucyclops macruroides (Lilljeborg, 1901)
Cyclopoida
Importance of the study
• Zooplankton as one of the important
ecological factors governing production,
abundance and sustainability of key
commercial fisheries
• evaluation of zooplankton occurrence,
taxonomy, distribution and abundance
patterns is of utmost importance
• because to a great extent it can be used as
a tool to interpret trends in fish spatial and
temporal dynamics and for management
decisions
Importance Cont.’
• In order to monitor and maintaining
biodiversity, the knowledge on the
taxonomy is necessary
• when biodiversity is maintained the
outcome will be a health ecosystem with
sustainable resources.
Importance Cont.’
• Zooplankton are important to fisheries as
they graze on phytoplankton and detritus
converting it into animal protein for use by
fishes
• Fish larvae (baby fishes) regardless of
species, are obligate zooplanktivores,
ingesting zooplankton as the first external
food.
Importance Cont.’
• Their presence in good amount will sustain
the fish production, since the fishing
communities are said to be dependent
upon the fishery for their livelihood and
well-being
• millions of people will have enough fish as
the major source of protein
• and the fishery industry will provide
employment to fishermen and people in
secondary associated occupations
• Eventually poverty will be alleviated.
THE INTRODUCTION OF ALIEN SPECIES
• Detailed zooplankton taxonomic study will
provide information on the introduction of
alien species, for example Copepod
parasites
• They are found on the general body
surface, fins, and gills, and obtain
nourishment from the tissues of the host.
• Under
natural
conditions
parasitic
copepods are rarely present in sufficient
numbers to cause serious injury to the
host.
• In hatchery ponds, however, where fish are
crowded in a limited area, there is much
greater opportunity for the free-swimming
immature stages to find a host, and, as a
result, heavy and serious infections may
break out.
• When firmly establish copepod parasites
are difficult to control, chiefly because the
sclerotized exoskeleton of the adult is
resistant to chemical solutions.
• Newly attached larval parasites are relatively
delicate, however, and sometimes it is
feasible to combat infections by giving the fish
frequent salt or acid baths.
• In extreme cases there is no alternative but to
get rid of the parasitized fish, clean the
hatchery ponds, and start a new
• Tapeworms
• Fresh water cyclopoids play an important role
as intermediary host in the development of
tape worms.
• When the copepod eats the free swimming
larvae of the tape worm it become infected
and the (planktonivorous) fish becomes
infected by eating the cyclopoids.
• Heavy infection of the tapeworm leads to
dwarf growth of the host.
• Other tapeworms (example Diphyllobothrium
latum) remains as a plerocercoid in the
mussels of the fish (which act as a second
intermediary host) and develops further in the
intestine only in fish eating mammals
(examples: bears and humans).
Dibothriocephalus
latus
Coracidium
Procercoid
Aquaculture production
• Aquaculture is being promoted as an
alternative income generating activity for
those affected by declining open water
resources.
• It attempts to bridge the gap between
supply and demand for fish
• With greater emphasis on promoting
aquaculture production on the region to
bridge the shortfall in fish production,
provision of high quality protein live fish
feeds has come into the limelight.
• Rearing and mass production of desirable
zooplankton
species
will
become
increasingly
important
in
hatchery
operations.
• Owing to that the gained taxonomic
capacity will alleviate poverty in the way
that, it will be possible to identify the
required species of zooplankton required in
the fish farms in order to control
cannibalism.
• Results will be high fish production in fish
farms and the problem of over exploitation
of fish in Lake Victoria will be solved
PLANKTON MANAGEMENT FOR FISH
CULTURE PONDS
• In the culture of larval fish of various
species, management of the zooplankton
forage base is critical to successful
transition of larvae to the fingerling stage.
• in most cases Cladocerans are desirable
fish prey since they have high energetic
caloric value and are readily consumed by
most fry.
• However, cladoceran populations usually
decline rapidly when subjected to predation
in culture ponds
• On the other hand, copepods, because
they are swift, powerful swimmers are
better able to maintain their populations
during the later stages of a culture season
• Therefore the taxonomy study is important
to the society because it will lead
researchers to use particular fertilization
techniques
and
species-specific
zooplankton inoculations in culture ponds
• These management techniques will
maintain high densities of desirable
zooplankton species in culture ponds until
fish will be harvested or able to consume
commercial feeds
• and eventually the plankton management
for fish culture ponds will be possible
Conclusion
• Zooplankton taxonomic analyses will
provide the society
with
practical
applications to a range of policy issues
such as climate change, biodiversity, the
introduction of alien species, pollution and
eutrophication in addition to fisheries.