This report briefly documents the fishing gear commonly used by local fishers in Lake Alau (Nigeria). Five types of gears are described: gill-net, cast net, Gura trap, longlines, and Clap ne

Adikwu, I.A.

Bankole, N.O.

Okwundu, E.C.

Raji, A.

Aquatic Commons

INTRODUCTION
'Due to the varied habits and habitats of the arrays
offish species peculiar to water bodies, an assorted array
of fishing gears are equally employed to catch them (fish).
Also, seasonal changes both in species diversity and
abundance necessitates changing over to varied gear
several times in the year. Different gears are thus used
to fish by different fishermen depending upon the season
and period (du feu et al 1997).
Recent advances have also led to improvement
in the types of fishing gears employed by the artisanal
fisherfolks (Reed et al 1967). These gears are mostly
imported and invariably more expensive than the locally
available or 'primitive ones'. Nonetheless they are more
efficient in catching the target fish species. 'FIlis hovvever,
is not to say that the so called 'primitive' gears are not
effective. In-fact they could st i I I complete most favourably
with the modern or new gears. Gears could be distributed
according to tribal pattern or tribal lines. Gears employed
could also be attributed to the peculiarity of the physical
characteristics of the reservoir on which they are used
as evidenced by Alau Lake. It could also be used to
target particular species (du Feu et al (1996). Omorinkoba
and du feu, (1996) reported cupeids as the target species
for the Beach seine net while du feu et al (1996) also
reported long lines to target clupeids on Kainji lake. The
aim of this study is to assess the diversity of gears
employed by the fishermen as well as the contribution of
each to the overall fish catch on the reservoir.
MATERRIALS AND METHODS
Three landing sites on the reservoir WerC assessed, which
were chosen from earlier frame and catch assessinents.
These were Abari, Kedari and Alau Ngaufate. They w-ere
assessed twice. One during low water (may) and the
other at high water (Sept) of the year 2000. The number
of fishermen were assessed in frame while the diversity
and number of gears used and the catches were recorded.
The contribution of each gears was estimated with their
seasonal contribution to the catch efficiency of each gears
used. Gear performances at the different seasons were
also observed.
RESEARCH AREA
Lake Alan is located between latitudes II 0 40'
and 120 05 N and longitudes 130 05' and 13020' E. the
inflow of water into the lake depends mainly on runoff
and annual seasonal flow of river Nyadda which has a
tenuous connection with the Yebrerarn in the Sambisa
Swamps area. In years of low rainfall, the contribution
FISHING GE ' SUR Y OF LAKE ALAU
BY
N.O. ANKOLE, A. RAM, I.A. ADIKWU AND E.C. OKWUNDU
NATIONAL INSTITUTE FOR FRESH WATER FISHERIES
SEARCH P. M. B. 6006 NEW BUSSA NIGER STATE.
99
from these sources are greatly reduced. Based on a 14
y-ear record (1964-1978). -Fhe average annual inflow into
lake Alau was calculated to be 329 thousand cubic metres
of water (Mshelizah, 1986).
The Alau lake is about 20 km away from
Maiduguri the capital of Borno State.
RESULTS AND DISC USION
The list of gears identified in the three sites on
the lake is given in Table 1. The contribution of each
gears is also given in Table 2. The most coinmonly
employed fishing gears on the lake is the gill-net which
produced over 60% of the catches particularly the
monofi lament gill-net. All the fishermen employ it for
fishing. It was found to be available in meshes ranging
from 50mm-100intn. The most widely used mesh is
76mm. As catches reduced, the mesh sizes also reduces.
This particularly results in generally stnal I sized catches
and the inost, susceptible species with the gill-net was
the Tilapia spp Sarotherodon gal ilaeus, Oreochromis
niloticus and 'Filapia zillf) and of recent Hetarotis niloticus
a newly emerged species in the reservior.
The Malian gura rank. next .to the gill-net
(23.20%). Other gears used on the lake included the
longlines, castnet and drag nets. In terms of ranking the
Malian gura was next to the gill net during the low water
but longline contributed more during the high water. Both
gears targeted charlas species while the Tilapia species
constituted the secondary target.
The Mallan gura had a great toll on small sized
fish. It could serve both as a qualitative and quantitative
gears for sampling the take. It had a veritable fishing
gears for the collection of live fingerling of both elarias
and Tilapias (the choice aquacultural species in the
country). Most of the fish caught with the gears remained
alive. As stated earlier the contribution of the longline
was more during the high water. The most abundant hook
size was size number 14, other sizes were in descending
order of application were 13, 12, I 0 and 9. The longlines
also targeted clarias species as observed by du feu eta.
(1997). The success of the mallan gura was due to the
generally shallow depth of the lake. Its mean depth is
about 4.3rn while most of its areas fall within the ranges
of I .5in to 2.8in.
Clap nets featured mostly during the high water
and was employed only downstreain of the lake. With
the reservoirs spill ways being opened to spill, a lot of
fish get flushed to the downstream of the reservoirs and
attract fishermen who migrate to other places like Lake
Chad, Kiri, Dadinkowa, and as far away as Goronyo in
Sokoto State for fishing with clap nets.
Description of gears and their Desi n
characteristics.
Gill-Net:
Nylon gill nets were the dominant gears
used by lake Alau fishers. Net webbing of mesh sizes
are 75 to 114mm arki twine of 210/3 to 210/6, were in
use. They were mounted by passing the head and foot
ropes through the marginal meshes at each side of the
webbing. and fastening. Styrofram/cork floats and sinkers
such as lead and heavy object were fastened at the foot
ropes. This is to keep the gear up right in the water body.
The minimum and Maximinn length of the gill
net. Ranges from 100m to 300m. This were set across
the water body as a passive gear (i.e the set in the evening
time and check the catch in the morning hours of the
day).
Gill-net design is as a result of tapering ratio. The
cutting in to desire shape of the net webbing them
mounting it on the required length of head rope and the
foot rope with the presence of other assessories as float
sinkers (Fig. I).
Cast net:
Cast nets which is otherwise known as throw
nets is common in lake Alau. The size of cast net varies'
according to individual preference and type of fish
designed to catch. The sizes prages from 3m diameter
and 10mm. Mesh size to 6m and 9m diameters and 25mm
mesh size.
Cast net are occasionally braided by hand, but
nowadays most are made from machine rnade webbing
and only the centre or crown is hand-braided. Most of
the fishermen do the braiding work themselves.
Cast net is conical in shape. Great skill is required
to throw a cast net in such a way that it will unfold in the
form of a large circle and cover the greater possible area.
It is an active gear that can be operated by one person
when at the bank of the river, lake or stream while on
board, the crew member are two (I.e the net caster and
the boat/ canoe paddler).
Gat ra-tra
The malian gura trap is mostly 1.5 to 2.5 metres
long. 60 to 100cm, diameter and the size of the square
meshes is about 6mrn to 9mm. Gura are made from many
fine strips liane or vine, bound together into twines, which
makes them rigid and strong. The principle of non-return
valve is used. This allow fish to enter and disallow fish
from escaping. The materials, for the construction are
fine mesh size of net webbing and liana or Rana woods.
It is a model of the mallan 'fishermen. It is either baited or
unbaited when used,
Lop. Line:
This is characterised by a major rope (head rope)
being attached at every interval of 30cm to several twine
210/3-6 attached to a hook each at the end of each branch
twine (snood).
The design of long line varies according to the
size of hooks used. When using Ille smallest hook of"No_
100
14 the space between hooks is usually about 100mm.
And the snoods are 60 cm long. While larger hooks as
No. 2,3,9, etc were spaced 120mm. The smaller type is
the most commonly use in lake Alau its has small weak
floats at intervals of about each twenty hooks the float
are made from either synthetic materials such as
Styrofoam or cork, long line can be baited or unbaited.
Clap net:
Clap net is mostly utilised during high water
period at Late Alua down stream by swimming fishen-nen.
Clap net varies in size from 50cm to 2 metres across the
month, smaller ones being used mainly by children. The
nets are tailored fronn machine-made webbing of 10 to
30mm. Mesh size. It can be made in few hours.
They are used in a variety of different ways either
alone or together with certain traps and fish fence.
CONCLUSION
Gill nets. Cost nets. Malian gura trap and long
lines are typical gears employed on the Alau lake. The
most prominent among them is the Gill-net. The clap net
which is used during the high water and down stream of
the lake can encourage a fishing festiva/ to be introduced
during high water period.
The gill net at appropriate mesh size (50-100imn)
proof highly efficient and it is durable when properly
maintain. It has no discrimination in selecting species to
be entangle or gilled in to net, hence fishermen enjoy the
usage. As a passive gear it can be set and other daily
activities can be possible for the fishermen such as farm
and marketing. Long line is an efficient gears, it hook
mostly the carnivorous fishes. But it is labour intensive,
time waisting, both during construction and operation.
But the fishermen enjoyed the high market value of the
catch. Cast net (an active gear) the usage is seasonal
and it select suitable water body. Fishermen at lake Alau
enjoyed the usage during the high water level with low
current. It catches species such as Tilapia, mormyrus
and heterotis species. Clap net vere use during the high
water period at the down stream to collect pelagic fish
species such as Tilapia nilotics and Momyrus rume.
ecommendation
The government should encourage the use of large
mesh sizes to avoid future over exploitation of lake
More future research work on lake Alan should be
encourage to study the distribution and abundance
of fish and fisheries activities taken place around
the lake Alau.
TABLE 1. DISTRIBUTION OF FISHERIES, BOATS AN GEARS ALONG THE SHORES OF
ALAU LAKE IN SEPTEMBER, 2000
101
The composition of fish caught by clap net at downstream were 100% compared to other gears type.
Table: 2 Percentage contribution of fish caught gears type in lake Alau
Fish spp Total weight
(kg) offish
Gear Used
Fish caught by gears type
Gill net Cash net Mallan
gura
Long
line
Clap net
Clarias spp 348.90 15.80 O 43.985 40.25 0
Tilapias spp 581.33 80.15 0.05 15.06 4.20 0
Synodontis 11.60 90.35 O 9.65 0 0
Biycinus spp 11,19 97.80 0,20 2.0 0 0
Schilbe spp 92.01 91.35 0.15 0 8.50 0
Gnathonemus spp 5.33 100.00 o O 0 0
Protopterus spp 7.05 100.00 o o 0 0
Polypterus spp 0 0 O O 0 0
Total 1057.41 575.45 9.4 71.235 52.95
Downsstream Clap Net
Clarias spp 100%
Tilapias spp 100%
100%spp
Schilbe spp 100%
Landing Site Type of fishing Site No of Fishermen Types of Gear
Boat o 'tiers A ssistants Gill net Cast net Gura traps Long Clap
Lines Net
Lanyeri Village 8
Abari Fishing Camp 84 16 X X
Kedari Fishing Camp 12 3
Aligunan Village 10 X X
Kulomari Village 6 X X
Binnan Village 5 0 X X
Burteri Village 5 A X
A I au Ngaufate Resttlement
Village 14 X X
Total 144 19
Below other 35
The Dam
Foot note: -stand for absent of type of gears
x stand for present of type of gears
Table : 3 Weight (kg) contribution of fish caught by gear types
REFERENCE
I. Du Feu, T.A. Abayomi, OS., and Seisay M.D.B (1997). Fishing gear seisay, Kainji Lake, Northern Nigeria,
1996. Report submitted to Nigeria German Kainji Lake fisheries promotion project NCKLEPP. Technical
report series No.6 Page 46-50.
Omorinkoba W.S. and du feu T. (1996). The beach seine fishery, Kainj i Lake. Unpublished report submitted
to Kainji Lake fishery promotion project 26.
Mshelizah D.1. (1986) Alau Dam case study in Born° State Nigeria M.S.0 thesis Loughborough University
of Technology.
Reed, W. Burchard, J., Hopson, A. J., Jenness, J. and Yaro Ibrahim. (1967) fish and fisheries of Northern
Nigerian published by Ministry of Agrie, Northern Nigeria, 226p
102
Gill net Cast net Malian lura Lon . Line Total
638.92kg
60.42%
0.45kg
0.40%
245.37kg
23.20%
172.67kg 1057.41kg
16.33% 100%
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Fishing gear survey of Lake Alau

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Fishing gear survey of Lake Alau

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