This paper reviews available past fisheries statistics data and examines the basis of derivation of the estimates and concludes that much needs to be done to establish reliable fisheries data based on well defined methodology. Subsequently, fish consumption data for the ten-year-period 1971-1979 were related to the yearly population that consumes the fis

Okpanefe, M.O.

English

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193
DEMAND ANALYSIS FOR NIGERIAN FISHERIES
by
Moses O. Okpanefe
Nigerian Institute for Oceanography
and Marine Research
Lagos
ABSTRACT
This paper reviews available past fisheries statistics data and
examines the basis of derivation of the estimates and concludes
that much needs to be done to establish reliable isheries data
based on well defined methodology.
Subsequently, fish consumption data for the ten year period 1971-
1979 were related to the yearly population that consumes the fish.
Parameters of the resulting regression equation were tested for
significance to ensure the suitability of the equation for future
prediction.
The suitable equation was used to provide fish demand projections
for the period 1980 - 2000 to meet the needs o fisheries planners,
researchers and administrators.
INTRODUCTION
In Nigeria numerous estimates for fish production and fish demand
have been provided by many authors including non fisheries people.
The authenticity of these estimates is a matter of concern to
fisheries planners, researchers and administrators. Some of these
estimates due to their over ambitious expectation, tended to show
the performance of the fishery sector as retrogresming. Existin
information however, does not lend support to such conclusion.
The objective of this paper therefore, is to review the exinlug
fisheries data, establish demand equation for the fisherien nnd to
provide demand projections up to the year two thousands on n well
defined basis, to serve future needs of planners, researchers and
administrators.
DATA REVIEW
In the second National Development Plan (1970_1974)(fl the volume
of fish available to Nigerians from all sources was estimated at
270,500 metric tonnes. 0f this figure, imports of stock fish
together with landings of chartered vessels accounted for 190,000
metric tonnes.
A high demand for fish in future was anticipated and an optimistic
demand target of one million metric tonnes was set to be nchieved
by the end of the plan. In order to meet thi3 objeci.ve,
capital investment allocation to the fisheries noc.or ic Federal
and State Governments for the plan period was 11,O0Ü 11en. This
investment represented 22.65% of total capital allocation to live-
stock, forestry and fishery.
At end of the plan not even as much as 56% of the ambitious demand
target of one million metric tonnes was achieved.
In a seminar held at Ibadan in 1972(2) Dr. B.N. Okigbo presented a
valuable paper on "Problems and Prospects of increasing food
production in Nigeria". Mr. E.O. Bayagbona then Director of Federal
Department of Fisheries commenting on the fisheries aspect of the
paper and utilising the production data for 1970 projected a demand
:Th i.85 as between 1.3- 1.6 million tonnes and expected that
n:cduction would rise to 1.2 million tonnes in the same year.
01yide et.al (3) estimated desirable demand for fish as 1.356
itilion metric tonnes for 1975, 1.775 million metric tonnes for
I 010 and 2.337 million metric tonnes was proj ected for 1985.
In the third National Development Plan (l975-l980) in response
to changes in policies in favour of the fisheries the volume of
fish production was estimated as 644,300 metric tonnes and a demand
projection of 1.5 million metric tonnes was set againet the end of
the plan (1980).
In the light of this, total capital investment allocation to the
tisheries was R101.554 million, accounting for 18.23% of total
investment on livestock, forestry and fisheries.
In Lerma of quantitative achievement using dais from Federal
Fisheries51ess than 50% of the planned target was achieved by
1950. The picture painted by this analysis is that the future of
the fishery is gloomy and the erroneous conclusion would be that
the fishery sector has been performing below expectation. The
truth is that the fishery sector has been progressing well from
one period to another as could be seen from increases in the number
of fishing trawlers, increase in fish production, increase in the
number of motorised and non motorised fishing canoes and improvement
in craft and gear (Table 1).
The misleading conclusion usually arises during plan review when
comparison of achievements with over ambitious set targets yield a
picture of poor performance. It was therefore, not surprising that
even Progress Reports submitted on the Development Plan later
diverted from comparison of physical achievements to comparison of
financial expenditure with monetary set targets.
It has therefore, become essential to examine the whole process of
projecting demand for the fisheries which will take into account
the realities of the situation. In this light two aspects will be
considered, formulating demand equations and establishing basis for
demand projections.
Table 1 - State of the fisheries 1971 - 1979
Year Nueber of
Trawlers
Number of Canoes
Mo tori z ed
4204
5364
6224
7850
8240
11704
12187
10118
12510
194
Fish Production
from all sources
Non-Motorized (Metric Tonnes)
90923 400537
90523 439971
91732 465075
10632 473220
20381 466236
122633 494766
125256 504014
128129 518567
121218 535435
from Tables 1 & lOof Fisheries Statistics
of Nigeria, let Edition (1980). Federal Department of
Fisheries, Lagos
1971 39
1972 55
1973 57
1974 72
1975 63
1976 59
1977 79
1978 87
1979 92
Source - Compiled
DEMAND EQUATION FOR FISH
195
Planning for the future is a very difficult task especially when
reliable and sufficient data are not readily available, to provide
the basis for projections. However, it is very essential that
targets must be set for the future and it is equally expected that
such targets should be realistic in order to obtain reasonable
allocation of the Nations limited resources. It is obvious from
past trend that the quantity of fish demanded in Nigeria is
continuously increasing. This may be explained by growth in human
population and increased level of income of Nigerians that has
arisen from oil boom income.
In estimating demand for fish in Nigeria therefore, cognizance is
taken of the above factors in addition to the inloce of prices
of other competing commodities auch as meat, beef, pork, chicken
and others. However, the influences of these other substitutes
are reflected in their contribution to consumer price index. And
rather than estimate the quantity of fish perse, the quantity of
fish in relation to the population that consume the fish is
considered as the dependent variable (6). Similarlly, income
level is represented by per capita income deflated by consumer
price index. With all these considerations the most suitable
demand equation was defined as a relationship between fish consump-
tion per capita and price of fish subject to a given level of income,
Symbolically, this is given by:-(P) ( )
C/N = a + b log (CPI) c log (Y/CPI) (1)(N)
W here
C = Volume of fish consumed at a given
time (C = Production + Import of Chartered Vessels)
N = Human Population (or estimation population)
at the given time.
P = Retail price of fish per kilogram
at the given time.
CPI = Consumer price index at the given time.
Y = National incowe (GDP at current factor cost)
at the gíven time.
For ease of exposition the following variables are defined:-
g. = Any point on the regression line for predicting C/N
P. = P
CPI
Y/CP I
N
S = Sum of squares of vertical deviations from the
regression line.
Thus is given by
S
= E (q.- a-b log - e log y.) (2)2
Taking partial derivatives of s with respect to a,b,c snd setting
each to zero, yield:-
ds -2 (q-a-b log p.-c log y.) 0 (3)
da
log y = a log y1
+ C
" perici' 1973 - 1977 was used and dctc on consumption, C, were
o: cinecL f'os Federal Department o' J Theries, data on Price and
Ccoosi ,c consumer price index aid ncne were obtained from
Fi.icisl Office of Statistics Puh' icr.ions (8) while data on
ciulation were obtained from Nciouc1 Population Bureau.
The analysis yielded the following values:-
.63, b -.18 and c 1.23
0g p. log y.)
y.)2 + ........(8)
The ultimate aim of . .......6 analysis is to be able to provide demafld
projections. In or. to .chieve this objective, a much more simpler
function with practi:l application is needed. While equation (1)
provides esti o c1ce and income elasticitiac (' nd c)
respectively. r':': c L ,n of per :ci!ta consumpt:ol deanda on ectinres
of fish price, :o1-:o.,. a :onou:a: unce index, I'1i.tlon:i. Income (GOl?)
and human popo , 6: cc oa 2cn these par'utec are not reodi:
available, tha:aby mc.l n, Sucu.-e o:'orision of co ion per capa r.
very difficult.
Alternative function "c.c there:oe :nsidered by ::':ning the trend
i' :onsumption ova: ca ic.t ja:':. And for hio onclysis the period
1P7 - 1979 was uced 'Ichla 2) . TIe trend exhIbe cad cas apvonniately
E.ced using lease :JijxreC sie, cl cith a linen: eco:,on given by
C/N a + ba .............(10)
Where C and N were r.: ax:lei :io Jened, and X representa any given
year (see graph). Tb: csc!c:o,c '.nalysis yielded the values
a 6.69 and b = 0.26 and hence
C/N 6.69 -- 0.26 n.............Il)
The computed c:wJri u o as's'x.oa, 2 b- ':: O ::r:c:Rra ototal variatI:: ',/r ' - :'T ;cc'uu cc I lic:,:' :aic:rrloo
of C/N on yens' l,:s -ccl ,c a b ,Prl (o: lCIOT 71 Ç cucac ing
196
-2 log
-
n-b log p1-c log y.) o ......(4)
e -2 log y. (q,- zì-b log p-c log y.) 0 (5)
C
T . : the fol:Lowing noi 1, equations resulting from 3 - 5 are
red for the ao1...........of equation ...... (1)
q a n + b :;.og + c log y ........(6)
log p. a log p. + b ' (log
log p. iog y.) ..........(7)
( )
C/N = - 0.63 - 0.18 log ( P
( CPI )
( )
1.23 log (Y/CPI) (9)(N)
DEMAND PROJECTIONS
for
Thus
197
a very good fit and hence the fitted line is very useful for
predicting C/N. Furthermore the coefficient of X is not signi-
ficantly different from zero even at 5% level.
This simple equation enables per capita consumption to be
predicted more readily by using the graph or computing C/N for
given values of X.
With data of estimated human population available, the task of
predicting future fish demand became easy. Table 3 shows projcced
demand for fish for the period 1980 - 2000. A very important £rcor
to observe about these projections is that both growth in fish
consumption and human population are built in them. Again unlihe
previous projections by different people, fish Consumption per
capita for any year is based on analysis which recognised growth
in fish consumption and not arbitrarily assumed.
Table 2 - Population and fish consumption in Nigeria
1971 - 1979
Sources; i - Population estimates adopted from Olayide et.ai
Food Production in Nigeria. Report of Agricultural
Statistics Task Force 1979. pp.165 - 166
2 - Consumption data adopted from Table 1, Fisheries
Statistics of Nigeria, ist Edition 1980, Federal
Department of Fisheries, Lagos.
Year
Projected Human
Population
Million
Total Fish
Consumption
Metric Tonnes
Per Caput
Consumption
Kg.
1971 66.365 463953 6.99
1972 68.356 503034 7.36
1973 70.406 536485 7.62
1974 72.834 548125 7.53
1975 74.693 580422 7.77
1976 76.699 628743 8.20
1977 78.557 668463 8.51
1978 80.563 720775 8.95
1979 82.621 753435 9.12
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Source - Projected human population adopted from Mid-Year
Population Projection, 1963- 2000, National
Population Bureau, Demographic Division, Lagos.
Projected per caput consumption computed from the
function shown on the graph.
AND CONCLUSIONS
198
Th paper has considered two different methods to the problem of
obtaining reliable fiheriee demand data. The first method based
on relationship between fish consumption per caput and prices of
fish, National income, consumer price index and human population
was academically sound but difficult to derive in practice.
84.732 9.29 0.787
86.897 9.55 0.830
39.118 9.81 0.874
91.395 10.07 0.920
93.732 10.33 0.968
96.128 10.59 1.018
98.586 10.85 1.070
101.107 11.11 1,123
103.693 11.37 1.179
106.345 11.63 1.237
109.067 11.89 1.297
111.858 12.15 1.359
114.720 12.41 1.424
117.657 12,67 1.491
120.669 12.93 1.560
123.759 13.19 1.632
126.929 13.45 1.707
130.180 13.71 1.785
133.516 13.97
136.933 14.23 1.949
140.446 14.49 2.035
Table 3 e ct ish demand for Nigeria
O
Projec rua Projected per Projected Fish
'tear Pul.uj Caput Consump-
tion (kg)
Demand
(Million Tonnes)
199
The second method based on regression ot fish cJ1,ni'o
canut on year of consumption yielded a iep10 ¿'na Ce
for predicting per ceput fish consumption each it::;:abioctfuture fish demand projections to be derived ou a well ciCird
method.
The latter method is recommended tor use end it was utl'.ized to
obtain fish demand projections tor the period 1980 - 2000 na
shown in the paper,
REFERENCES
Draper end Smith (1966) Applied Regression Analysis: John
Willey L Sons, New York,
Federa]. Office of Statistics Lagos (1981) Annuti Abotract ofStatistics. p. 169
Federal Office of Statistics Lagos (1979) ReLail prices andConsumer price indices
Federal Republic of Nigeria (1970) Second National DevelonYneal
Plan 1970- 1974. Second Progress hieoort, The Central P1unnig
Office, Federal Ministry of Economic ThuveiopacnL nd lleconstruchion
Lagos. p.332
Federal Republic of Nigeria (1972) Nigerian Council for Seice
and Technology. Proceedings of the First Symposium on Ociamos and
Technology in National Development 10th - 11th January 1972.
Cabinet Office, Lagos, p.1 55
Federal Republic of Nigeria (1975) Third Ntiona1 Developeent
Plan 1975 - 1950 Vol. I: The Centrai Planning Office, Federal
Ministry ot Economic Development, Lagos. p.397
Federal Republic of Nigeria (91130) Fisheries Statistics ut
Nigeria, 1980. Federal Department at Fisheries Lagos. P. EE
Ihempthorne, O. The Design nd Analysia of Eaper:renLs- JoLn
Vv'ìlley & Sons Inc. , New York. p.612
Olayide, S.O. çt.al A Quaatieatve AnalySis of lood Requironenta,
Supplies and Demands in Nigeria 1966 - 1985. Ti e Federa]. Oepartient
of Agriculture, Lagos. p.lO5
United State of America (:1970) Bureau of Commercial F sh'ïe
Economic Research, Working Papers No. 51-60 p.1 - 39
William Feller. An Introduction to erobability theory anl Lt;
Applications, 3rd Edition, Vol.1. John ailicy L Sons I&e.,
New York,
DISCUSSION
Azza The paper should bave ons3 Ocred the FAO ocr
cosumption in the projection to the yess 2000.
V.0. Sagua: Data used for the analysis were samclsd hetwer i.975
to 1977. I this representative of trends from aow to .2000 :1.c.Will it remain linear?
11.0. Okpanole: Consumption information given by FAO oi:iaeçifrom Nigeria. Data for 1975-77 was used :or price calcul ion.It is not possible to forecas t tilo nature of the curv- bet;eau ups,
and year 2000.
Kg
Per. Capitci
14
M.0, Okpanefe: The author ja a member of the Fisheries Statistica
Committee of the National Fisheries Development Committee which
handles statistics.
IlL, Fabiyi: The population figures and per capita income employed
is questionable. There is also specification error because the
structural equation does not include error term and the result
contains no standard error.
MO. Okpanefe: I employed official figures of population and per
capita income. I considered specification error un-important.
0.0. Ladipo: Remarked that error term must be specified to be
sure of the validity of the work otherwise ordinary least square
(OLS) cannot be validly applied.
PER CAPITA CONSUMPTION OF FISH 1971 2000
10
200
5.0E. Odiong: Is there any colaboration between FDF and NIOMR?
S 10 16 20 25 30
1971 1980 1990 2000
Figure I.


Demand analysis for Nigerian fisheries

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Demand analysis for Nigerian fisheries

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