Aspects of the fishery resources of Alau Reservoir in Maiduguri are reported upon in this paper. It focuses attention on the fishery in terms of fish abundance and potential. It also discusses other resources associated with the fish production. Various other possible uses of the reservoir are discussed too. The reservoir is thus revealed to be a most useful and versatile one in terms of fishery resources and fund generatio

Bankole, N.O.

Okaeme, A.N.

English

Aquatic Commons

ALAU RESERVOIR: A MULTI-DIMENSIONAL
SOURCE BASE IN BORNO STATE.
N.O. BANKOLE and A. N. OKAENJE.
National Institute for freshwater Fisheries Research (NIFFR)
PMB 6006, New Bussa, Niger State, Nigeria
INTRODUCTION
The fisheries of the North East Zone which has
been dependent majorly on the Lake Chad and
which is mainly and predominantly artisanal in
nature has been experiencing a downturn. This is
due to the recession of the Lake resultant from the
droughts that hit the zone in the 1970s and 1980s.
(Bankole, 1995). However the creation of the Alau
has been a welcorae relief to fishermen.
The Alau reservoir was created in 1987 by
damming river Ngadda which takes its source
from the Mandara Plateau and is one of the three
confluent rivers that formed the Sambisa
floodplains in the semi-arid North East of Nigeria.
The reservoir was formed primarily for the
provision of potable water for the Maiduguri
Metropolis as well as to irrigate over 8,000 ha of
farmlands within and around the reservoir basin
(C B DA , 1984) . Although no fisheries
consideration was given from the onset of its
creation, the reservoir contributes immensely to
the fisheries of the north-eastern region of the
country.
Sorae of the few information available on the
fisheries of the reservoir include those of Odunze
et. al (1995), Bankore et al (1995) and Bankole
and Mbagwu (1996). Odunze et. a/ (1990) gave
information on the catch composition abundance
and distribution of fish as surveyed in 1990, three
years after impoundment. Bankole et al (1995)
and Bankole and Mbagwu (1996) reported on the
fishing, fishing community, catch characteristics,
processing and marketing on the lake. All these
ABSTRACT
Aspects of the fishery resources of Alau Reservoir in Maiduguri are repotted upon in this paper. It focuses attention
on the fishery in terms of fish abundance and potential. It also discusses other resources associated with the fish
production. Various other uses to which the reservoir is put and to which it could still be put are discussed too. The
reservoir is thus revealed to be a most useful and versatile one in terms of fishery resources and fund generation.
215
information came years after the impoundment of
the reservoir. The objective of this paper is to
highlight the multiple uses to which the Alau
Reservoir could be put for a more effective
utilization in the semi-arid zone of Nigeria.
MATERIALS AND METHODS
A Catch Assessment Survey was carried out in
September, 1994 using the method of stratified
random sampling as in (Ekwemalor, 1977). Three
fishing sites were randomly selected out of eight
identified. These selected sites were sampled
within. a 10-day sarapling period. Six fishing boats
were randomly selected from each fishing site and
were sampled for 3 days consecutively. Fish
huided by each boat were collected, sorted into
species, counted and their weights taken. The
weight recorded for each boat and fishing site
were then used to estimate the total monthly and
ammal fish landings for the entire lake The
landing were assessed during the flood season
which usually occurs between September and
November.
RESULTS AND DISCUSSION
Frame Survey
Fishing Sites
Eight fishing sites were identified along the shores
of the reservoir (Fig.1). Of these the Damsite,
Laujeri and Alau Ngaufate are located towards the
northern shore. Kedari, Aliganari ard Kulomari are
located towards the southern shore. The remaining
sites - Birmari and Burteri - are located to the east
of the reservoir. Due to its overflooding
September, 1994, most of the villages and fishing
sites that existed were evacuated and banned from
re-establishing in those sites. This accounted for
the fewer number of sites identified. Chalmari, a
village displaced by the flood on the northern
shore had to move to Alan Ngaufate, a
resettlement village. Two of the fish landing sites
are fishing camps while the remaining five are
villages.
Fishermen, Crafts and Gears
One hundred and seventy seven (177) boats were
counted. None of these was motorized. About
66% of these were found at the Damsite fishing
camp (Tabla 1). Out of the 177 boats only 30 had
assistants; 67% of which came from the Damsite
fishing canap.
Due to the general shallowness of the lake a third
type of fishermen abound in the reservoir. These
are part-time fishermen whose main occupation is
arable fanning. Their fishing activity is for a short
duration within the year. They do not own boats
so they set their traps and hooks by wading
through the water. They Out-number the
fishermen by far; numbering 883 in all during this
survey.
Two hundred and seven full-time fishermen were
enomerated. These were migrant fishermen
comprising Nigerian Nationals such as Kamnis,
Marghis, Junkuns and Hausas as well as Nationals
of neighbouring countries such as Chadians,
Cameroonians and Malians.
Four types of fishing gears were identified on the
Lake. These were the Gill-nets, Cast nets, Malian
gura traps and Hooks. The commonest of these is
the Malian gura trap followed by the Hook and
Gill-nets. The gura trap (Fig.2), introduced by the
Matins, is extensively used in North East Zone of
Nigeria. Its intensive use on the Alau Lake is
possible because of the shallowmess of the Lake
(Mean depth 4.25m). The trap catches fish
in.discriminately and juveniles are as susceptible to
it as adult fish. Fish caught in gura traps remain
alive until they are retrieved unless preyed upon
by carnivores. The bait commonly employed for
the trap is boiled husk removed from grains in
grain mills. After boiling, the husk is shaped into
block forms or any other shape suitable to the user
and dried. It is placed in the trap when setting to
216
attract fish into the trap. The trap is particularly
efficient in catching Clari as.
Hooks are also prominently used on the lake. Gill-
nets are used in all the stations except in Laujeri.
Cast nets are the least common of the gears and
are used only to catch live baits for hooks.
CATCH ASSESSMENT
Species Composition and Distribution
Table 2 shows the distribution of fish species
identified in the landings along the Lake Alau
shore. Sixteen species belonging to nine families
were identified. Protopterus annectes and
Polypterus senegalus were recorded only at the
Damsite. Grzathonemus senegalensis, Marcusenius
isidori, Micralestes acutidens and Lobeo pan/us
were recorded at both damsite and Kedari, but not
at Alau Ngaufate. The remaining 11 species were
common to all the three landing sites. A
comparison of the species diversity with the
earlier work of Odoo7e et al. (1995) showed that
more species and fish families were recorded
during this survey (Table 2). This is probably
because the report of Odunze et al (1995) was
based on experimental gill-net catches while
catches in this report are from assorted gears
employed by fishermen.
A further comparison with Tiga, anoth.er snaall
reservoir within the same-arid zone shows a
closeness in the number of species (Table 3).
However there is considerable dissimilarity in the
species composition of both reservoirs. This could
probably be due to the characteristics of the
catchments of both reservoirs which are
completely different and widely separated.
Fish Catch
The fish landed by each of six boats for the three
consecutive, days and for the three landing sites is
shown in Table 4.81.11% of the fish landed by
number were Tilapias. This was followed by
Claras spp. (8.41%) and Schilbe (5.96%). These
three are the most important species to the fishery
of this reservoir. The rest are not conamercially
important. In terms of weight the trend is the
same with Tilapias constituting (56.02%) of the
catch. Claras spp. formed (32.43 %) while Schilbe
formed 8.87%. In the report of Odunze et. al,
Table 1: Distribution of Fishermen, Boats andGear along the Shores of Alan Reservoir in November 1994
V =Village; C =Fishing camp RV =Resettledvillage
1 =All boats are non-motorised and operated by the fishermen owners.
Table 2: Species Occurence and Distribuilon among the Sampled Fish Landing Sites along Alan Reservoir in November 1994, and
in Experimental Gill-net Catches(A) in 1990 (Odunze, et aI., 1995).
FISH LANDING SITES
217
Landing Sites
-
Type of
Fishing
Site
Boat
OWIlerS
Fishertnen:
Assistants
Fishermen:
Part-time
Gill-net Cast net Gura trap Hooks
Laujeri V 8 - (150) - - x x
Dam site C 116 20 (20) x x x x
Kedari C 14 4 12 x - x x
Aliganari V lo - (200) x - x x
Kulomari V 5 - (100) x - x x
Birmari V 4 - (100) x x x
Burteri v 4 - (120) x x x
Alau-Ngaufate R.V 16 6 (180) x x x
177 30 883
SPECIES Dam Site Kedari Alan Ngaufate (A)
FAMFLY LEPIDOSIRENIDAE
Proropterus annectens
FAMILY POLYPTERIDAE
Polypterus senegalus
FAMILY MORMYR1DAE
Marcusenius isidori
FAMILY CHARACIDAE
Alestes nurse
Micralestes acutidens
FAMILY CYPRINIDAE
Labeo parvus
FAMILY SCHILBEIDAE
Se/silbe mystus
FAMILY CLARIDAE
Clarias spp.
FAMILY MOCHOKIDAE
Synodontis barensoda
Synodontis nigrita
Synodotais eupterus
FAMILY CHCEILTDAE
Tilapia zilli
Tilapia aurea
Oreochromis niloneus
Sarotizerodon galilaeus
Hernichromis bimaculatus
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
-
-
-
x
x
x
x
x
x
x
x
x
x
x
x
x
-
x
-
-
x
x
x
x
x
x
x
x
x
x
-
x
x
x
x
x
x
x
Tabie 3: comparison of the Specis Diversity of Alan and Tiga Reservoirs in the Semi-Arid Zone.
Source: Ira (1993).
218
SPECIES ALAIT 110A*
FAMILY LEPIDOSIRENIDAE
Protopterus annectens
FAMILY POLYPTERIDAE
Polypterus senegalus
FAMILY MORMYRIDA_E
Marcu.venius isidori
Mormyrops deliciosus
Gnathonenus senegalensís
FAMILY CHARACIDAE
Micralestes acutidens
Alestes nurse
Aiestes denstex
Alestes baremose
Hydrocynus forskalí
FAMILY CYPRINIDAE
Labeo parvu.v
Barnum senegalensts
FAMILY I3AGRIDAE
Chtysichthys auratus
Auchenoglanis occidentials
Bagrus bayad
Bagrus doctnac
FAMILY SCHILBEIDAE
Schilbe 'masts
FAMILY CLARIDAE
Ciarías Iazera
Clarias sp,
FAMILY MALAPTERURIDAE
Malapterurus electricus
FAMILY MOCHOKIDAE
Synodontis batensoda
Synodonds nigrita
Synodonfis eupterus
Syttod.nats gambiense
FAMILY CICLIDAE
Tilapia vlii
Tilapia aureu
Oreochromis niloticus
Sarotherodon g,alilaeus
Ilemichromis bimaculatus
x
x
x
-
x
x
-
-
-
x
-
-
X
-
x
x
x
-
x
x
x
x
x
x
x
-
x
x
x
x
x
x
x
x
x
x
x
-
x
-
x
-
x
x
-
Table 4: Catch by Species for Selected Villages for 3 Days Each in November, 1994.
219
ALAU DAMSITE KEDARI ALAU
NGAUFATE
TOTAL
SPECIES NO. WT(kg) No Wt(kg) No Wt(kg) Wt (kg) % Mean
Wt (g)
Claris spp 1222 81.95 480 105.81 332 52.55 2034 8.41 240.31 32.43 118.15
Tilapia spp 16193 275.47 128 14.60 3305 125.02 19626 81.11 415.09 56.02 21.15
Synodontis spp
Mestes spp 747 8.00 2 0.010 8 0.15 757 3.13 8.16 1.10 10.78
Schilbe sp 270 7.66 0.12 2 0.11 279 1.15 7.89 1.06 28.28
Mormyrid 1202 55.35 171 7.17 69 3.18 1442 5.96 65.70 8.87 45.56
Protopterus sp 51 2.25 4 0.10 4 0.21 59 0.24 2.56 0.35 43.39
- 1 1.20 - 1 0.00 1.20 0.16 1200.00
Total for 3
days 19685 430.68 793 129.01 3720 181.22 24198 100 740.91 100 30.62
_
58.13% 17.41% 24.46%
No of boats
sampled per day 6 6 6
Total No of boats
sampled for 3
days 18 18
Catch per boat
(kg) 2393 7.17 10.07
Mean catch per
boat (kg) 13.72
1995, the catches were dominated by Tilapias both
by number and weight (48.39% and 54.01%
respectively) followed by Characids and Schilbe.
This differs from the present trend where Clarias
spp. ranks second both in temls of number and
weight.
The catch per boat for each of the three landing
sites is 23.93kg for Damsite, 10.07 kg for Alau
Ngaufate and 7.17kg for Kedari (Table 4), 58% of
the fish caught (by weight) comes from the
Damsite. This is not unexpected since the highest
concentration of fishermen and boats were found
here. The sizes of fish caught in all the diree
landing sites were small (Table 5). The generally
small sizes could be attributed to the
indiscriminate fish catch of the most popular gear
- the Malian gura trap, the shallowness of the
reservoir and the gregariousness associated with
the breeding activities of most of the species
during the floods.
Estimated Landing
The estimated fish limded for the month of
November 1994 (coinciding with the flood season)
is 72,489kg or 72.49mt (Table 6). This gives an
annual production of 869.84 metric tons and a
standing stock of 155.33kg ha.' This figure
indicates that the reservoir is highly productive.
The production estimate obtained for the Tiga
Lake in Kano State ranged between 1526.0 and
1840.8mg yr. (Bankole 1988). In comparison
with Tiga therefore, (a reservoir which is over 3
times bigger than the Mau) the productivity of the
latter is remarkable. The bulk of the fish landed
was recorded at the Damsite.
Economic Considerations
With an estimated standing stock of 155.33 ha',
this reservoir has a great potential for fish
production if properly managed. At a modest
#50kg-1, the annual fish prod-action of 870mt could
fetch over #43.5 million ye'.
However, the concentration of fishermen in the
reservoir at present is 3.701ma. This figure is
85% higher than the maximum of two fishermen
per square kilometer of reservoir recoramended by
Henderson and Welcome (1974). It is therefore
imperative that management programmes be
220
introduced to sustain fish production in the
reservoir.
MANAGEMENT CONSIDERATIONS
Multi-purpose use of Alau Reservoir
The most effective way of utilizing our water
bodies could involve a multi-faceted approach.
This could involve utilization of the water body
for purposes like irrigation among others. This
happens to be one of the major purposes for
which the Alau was created apart from potable
water supply. This study has revealed that a lot of
revenue could be generated by the fisherfolk,
operating on this waterbody through artisanal
fishing.
One other revelation of great importance in the
course of the study is the fact that the reservoir is
generally shallow. This holds a good promise for
pen, cage, and enclosure fish farming practices.
This is worth looking into and is greatly
recommended.
All legislation for the management of the
fisheries, including regulation of fishermen's
numbers and gear should be enforced tiu-ough the
Chief Fisherman of the Lake. These Chiefs are
known to command immense authority among the
fisherfolk in this region.. These measures if
implemented Gould rurn this reservoir into an
important source of fish and fish products in the
North East semi-arid zone of Nigeria especially
with the dwindling fortunes of the fishery of Lake
Chad. It is also recommended that fish farming in
flood ponds around the reservoir be developed and
encouraged among the fishermen. This will
require some extension work through
enlightenment campaigns. The prevailing gear, the
Malian gura trap could be of tremendous
assistance in cropping fish fingerlings from the
lake for stocking the ponds. The water body loolcs
very promising in terms of richness in natural fish
food to support fish even without fertilization.
This could have been derived from the fertilizer
draining into the reservoir from the adjacent
farmlands and from the cattle dungs dropped by
cattle that come to drink from the lake from time
to time. The zone is big in cattle rearing in the
country.
Table 5: Estimated Fish Lauding from catch Assessment Survey Conducted along the Shore of Lake Alatt in November, 1994*
a =Name of sampled village
b =No of boats sampled per day
d =Sum of daily catch for 3 days
e = Raitiing factor (Rfi) =No of boats in the village
No of selected boats per day
f =d " e
g =Inverse probability raising factor (1/p)=Totat No of boats M the temor stratum
Total No of boats in the selected village
(The entire lake was taken as the minor stratum)
h = Month raising factor --,--Total No of fishing days in the month (Da)
Total No of sampling days in the month (ds)
i = f g
j = Sum of i
= Mean of i
I Catch per annum =1 * 12
n Catch per hectare (56-00 ha)
221
1
Dam site 6 116 425.18 19.33 8218.73 1.53 10 12574.66 21746.00 7248.67 72486.7 869.8 155.33
(kg) (kg) (kg) (mt) (kg 11-1
Kedari 6 14 181.37 2.33 422.59 12.64 10 5341.56
Alau
Ngaufate 6 16 129.69 2.67 346.27 11.06 10 3829.77
Water retention in the zone is for a period ranging
between 6 - 8 months within which fish would
have grown to table size, harvested and sold.
CONCLUSION
The study though brief has shown that the Alau
Reservoir was primarily created for the purposes
of supplying water and to irrigate surrounding
farmlands. The results has further revealed that the
lake offers such a great potential for artisanal
fisheries with adequate management, as well as
pen, cage and enclosure culture practices. The
latter has to be introduced and encouraged with
inputs and technical know-how.
With the location of the reservoir, it is pertinent to
note that water preservation is of paxamount
importance. Hence with such an appealing
potential the reservoir could be put to a multi-
purpose use as highlighted. The benefit of
combining all these uses will be of tremendous
importance towards the improvement of the
overall utilization of this reservoir which is
located in a semi-arid environment.
RE!, hItENCES
Bankole N.O. (1995). Fish species diversity and succession in
Lake Chad. Paper presented at the workshop on
sustenance and conservation of fisheries and other
aquatic resources of Lake Chad and (he Arid Zone of
Nigeria. Maiduguri 15th - 17th January 1995.
Bankole, N.O. et. al (1994). Preliminary investigations on the
frame and catch assessment survey of Alau Lake,
Maiduguri Borno State. National institute for
Freshwater Fisheries Research Annual Report 1994. p.
134 - 146.
222
Bankole, N.O. and Mbagwu 1.G. (1995). Aspects of the
fisheries of Lake Alau in the Nigerian North East Arid
Zone. Paper presented at the 9t11/10th Annual
Conference of the Nigerian Association for Aquatic
Sciences. 30th November - 2nd December 1995.
13ankole, N.O. (1988). The fish and fisheries of Lake Tiga (a
man-made Lake) in Kano State. NIFFR Ann. Rep. pp.
12-22.
CBDA, (1984). A resettlement plan for the Lake Alau Dam
and Jere Bowl Scheme Agricultural Survey and
Background Studies. Askoning Nigeria L'ID. 59 pp.
Diyam Consultants (1990). Feasibility study of options to
improve inflow into Alau Reservoir and preliminary
design of the recommended option. Report to Borno
State Water Board. 77pp.
Ekwmalor, Al. (1977). Catch Assessment Survey of Kainji
Lake Nigeria M. Sc. Thesis. University of New South
Wales, Sydney. Australia. 49pp.
Henderson, A.F. and Welcome R. L. (1974). 'Thc relationship
of yield to Morpho-edaphic Index and numbers of
fishermen in African Inland Fisheries, C1FA Occasional
Paper No. 1 FAO, Rome, Italy. 19pp.
ha, E.O. (1993). Inland Fisheries Resources of Nigeria. CIFA
Occasional paper No. 20. FAO, Rome. Italy. 120p.
ODNRI (1989) Nigeria: A. Profile of Agricultural Potential.
Overseas Development Administration, United
Kingdom. 15pp.
Odunze, F. C., Awojebi, R. and Ntakil, N. (1995). Preliminary
fisheries resources survey of Lake Alau Maiduguri.
Paper presented at Me workshop on Su.stenance,
Management and Conservation of Fisheries and Other
Aquatic Resources of Lake Chad and the Arid Zone of
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Lake Chad Reserch Institute, Maiduguri.3


Alau reservoir: a multi-dimensional resource base in Borno State

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Alau reservoir: a multi-dimensional resource base in Borno State

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