---~ ~ ~- ~-~,~~~

--~~

for females). The slope for males is not signifi- Gayanilo, F.C.]r., M. Soriano and O. Pauly. 1989. A draft guide to th e1 .-Compleat ELEFAN. ICLARM Software 2, 70 p.

-c:;ant y dIfferent from females (t -2.02 di. 37 P Jones. C.M. 1992. Development and application of the otolith incre-'~;O.O.1). menttechniques. In O.K. Stevenson and S.E. Campana (eds.)

.'~ ' Otolith microstructure examination and analysis. Can. Spec.,; ~;, Publ.Fish.Aquat.Sci.117:1-11..i Acknowledgements Longhurs~, A.R. and D. Pauly. 1987. Ecology of tropical oceans. Aca-.,'+' demlc Press., New York. 407 p.

.' Pannella, G. 1971. Fish otoliths: daily growth layers and periodical, ,'f 'rhe author thankS Dr. Armando B. Cortes Mr.. patterns. Science 173:1124-1127." " ." Pauly, O. 1984. Fish population dynamics in tropical waters: a manual';Mauro Costales, and Mr. Cabutln for theIr sup- for use with programmable calculators. ICLARM Stud. Rev.8,"-port during the course of the study. 325 p.. .,

Pauly, O. 1986. On Improving operation and use of the ELEFAN. programs. Part II: Improving the estimation of L.. FishbyteReferences 4(1):18-20,

Arellano, R.V. 1988. Spiny lobster fishery in San Vicente; Cagayan,..and population dynamics of Panulirll! penicillatu!. College of

F1sheries, University of the Philippines in the Visayas, Miag-ao, Iloilo. 98 po M.Sc. thesis, ." ..

Campana, S.E. and ].D, Neilson. 1985. Microstructure of ,fish ~toliths. R. V. AREllANO IS from the Cagayan State University College of fisheries,Can.l.Fish. Aquat. Sci; 42:.1014-1032. c Aparri, Cagayan, Philippines.

Length-Weight Relationshipss

~.. of Nigeria~ Coastal Water Fishes

Rapports de poids pour longueur des poissons du littoral nigerian

R.P, King ,

Abstract

Length-weight relationships (LWR) of76 flSh popUlations, distributed among 11 families, 18 genera and 22 species,inhabiting coastal (marine/brackish water )_ecosystems in Nigeria were estimated (39 cases) or assembled from theliteratllfe (37 cases). The mean exponent (b = 2.912) is significantly less tha113. While the frequency distribution ofa was positively skewed, that of b was approximately normal. The mean a and b data are also presented by fish genera

, and families.

,.Resume .

.~ Les rapports de poids pour longueur de 76 populations de poissons reparties en 1 Ifamilles, 18genres et 22 especes formant part

des ecosystemes du littoral nigerian (espace marin et saumdtre) ont ete calcules pour 39 cas ou restitues de la litterature pour 37cas. L'exposant moyen (b = 2,912) etait signiftcativement inferieur a 3. Tandis que la distribution des fre'quences de a etaitpositivement biaisee, celle de betait pratiquement nDmfale. Les valeurs moyennes pour a et b sont e'galement repre'sentees par

genre etpar famille.'"

Introduction condition factors (an interpretation of relative

well- being), and conversIon of length -growth

The.1ength-weightrelationships (LWR) of fish models to corresponding \Veight-growthmodelsare important in fisheries biology. Applications (e.g., Tyler and Gallucci .1980; Bolger and

of LWR include: estimation of mean weight of Connolly .1989; Kulbicki. eta!.. .1993; King .1996).

fish of a given body length, determination of body Only a few estimates of species-specific L WR

October 1996 53

p-c f

i

..,~'t:,

i!!I!~ parameters are available for Nigerian fishes. An prised 39 cases analyzed using original data, and '"

~\~~ earlier study by King (1996) provided informa- 37 cases derived from the literature.~if '.. tion on the LWRof 73 populations of inlandwater Interpopulational variability in the value of the

Iii "~~; fishes of Nigeria. The present compilation focuses intercept a was highly heterogenous (CV =~~; :; ~:.. on the ~e~gt.h-W~igh: parameter~ of 76.fish 142.6%) ~nd varied from amin = 1.1 x 10-3 in

I~~..' .-,..J popu~atIons m: r:rlgenan coastal (I,e" manne/ ~seud~tohthus elongatus to ama.'C = 1.533 x. 10-1~i.:;:;r .' brackIsh) waters: ill PenophthaImus barbarus, InterpopulatIonal

i,r,~ "

~~i,!r ..' ~ variability in the exponent b revealed high ho-~;~.!if..., ";,: Materials and Methods mogeneity (CV = 10.1%), with values ranging ""'" , ..;1,[: ' .from b .= 2.168 in Gobioldes ansoro-li. to b =!'" , mtn C:>' max

:i: i Fishes were sampled from Nigerian coastal 3.635 in E.' elongatus. These estimates are mostly

.~::i; waters over an II-year period (1984-1994 in- within the limits reported by Carlander (1969),

~~1: 'clusive), using s.e~ giUnets, beach seine, cast nets, Royce (1972) and Lagler_et al (1977).m: .hooks and tradItIonal valved baskettraps. ~ey The mean exponent (b = 2.912, s.d, = 0.295)i~i: were identified (nomenclature of the taxa con- is significantly less than 3 (t = 2.597, df= 75, P '!if

~ii: formed to Leveque et al. (1992) and Teugels et < 0..:.02). S~milarly, ~orre~ (1991) reported a value .~tjTi:!i al. (1992», measured (cm, total or standard of b < 3 m a multIspecies study of LWR. As an

"'~IJ le~~), and wetghed{g, totalfresh thus, th~ Nigeri~n coastal water..I!~~:! dra~mng water frG>m the buccal ca~tyand blot- fIshes exhI~It allo~etr~c LWR? I..e', they tend toI :ikli dryIng excess water on the body. become thInner wIth IncreasIng length. It may!!:~ For each species or population, the param-", ,therefore be errpneous to generally apply the~i,~~) ~ eter a (proportionalityconstarit or intercepts) and ,"~'cube law (b = 3)' toth~ length-weight function

'::I~ -,. b (exponent) of the L\\tTR of the form: of the fishes. In an earlier compilation of the LWR

' "! ,; of Nigerian freshwater fish~s, King (1996) also! W = .a"Lb ...1) "demonstrated an i~terpopulational negative al-

;' .d hr hb 10 1 . hm lometric function (b = 2.911, s.d. = 0.313). This.,: , were estimate t oug ase- ogant trans- '0'1';" ti t. f 1 ~O+

h ;n-1..t d t . d d.estImate does not sIgnIfIcantly depart from the b' r orma Ion 0 e..'O" -we~l a a paIrs an or 1- .~.; for the coastal water fishes (t = 0.030, df =75, P -R' nary least squares lInear regressIon (I.e., log

o 05) t. th t th t b d t ' :~ .". .>., conno Ing a e wo roa ca egones! .!li transformatIon verSIon of equatIon 1) VIZ.

f t ' t (. f h d . /.'~ 0 aqua IC ecosys ems I.e., res an marIne .., '

" I - 1 b 12 ) brackish waters) are not different in terms of their ' ogW-oga+ ogL h h fth '

f 'h It ' .; Impact on t e s ape 0 elr IS popu a Ions.

" Whenever possible, estimates of length-weight , PoPulation-specifi~values. of? (Table ~!,in-

:1 ,parame~ers w~re made for m~e and female fishes, dlcate ~hat 33, '(43,4~) popula~ons ex_hlbltedI-'~ ..~long WIth estimates for combIned sexes.Th~e es" approxI~ately Isom~tric LWR (b 2,94. 3,28)~., -r timates are treated here as separate populatIons. 40 {~2.6%) popluatIons revealed nega;IVe allo

:, S Additional LWRparameters were derived from metrIC LWR (b < 2.94) and only 3..<4.0%) popu-:"i ." the literature. In some of these cases, important in- lations displaye~ positive ~~ ~b > 3.28). Vari-

;:U formation was missing (e.g., sample sizes, correla- an~e-~ean ratIos were sIgnIfIcantly less. than!1f tion coefficients and size ranges). All results,pre- UnIty (I.e., they tend strongly toward zero) mthej~, sented here are cm for lengths andg for weights. case of a (VMR = 0.038: t = 5.891, df = 75,P <!t 0.005)"and b (VMR -= 0.030: t = 5.940, df = 75, c'

~i Results and Discussion P < 0.~05), thu.s suggesting, that both parameters,~ are unIformly dispersedvariates among the popu-It Table 1 summarizes the LWR parameters for lations studied. King (1996) similarly noted thati~ 76 Nigerian coastal water fish populations from a and b were uniformly dispersed among then 11 families, 18 genera and 22 species. These coni- freshwater fishes of Nigeria.,f

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,'!':- .::II~ ";0 U:~~! = ~ f-o E-o CI) f-o CI) f-o CI) E-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o f-o E-o f-o f-o CI) f-o CI) f-o f-o f-o CI) f-o f-o".,!, U -;,," ~"""I" : rJ!

.', ~" >< ~ ~ ~ ~"'" U!.~!,I '""";,~;!%,1 ,.

Ii "" .~

:~ '" ~ ~ ~ 5 ~ ~ ~ ~ ~ ~ ~ ~!; " ~ ~ ~ ~ ~ t: ~ ,~ ,~ ,~ ~ ~ :3 ::' 'u ~ ~ ~ ~ ~ ~ ~ '" OJ OJ ~ ~ ~ '$;'" ;,.Co ", ~~ ~~~~ ~ u ~ ~ ~ ~ '~~11 Q, ':;:;'"S'~'~,~,~,~,~ ~;;§~'§§§~:,.,:3 ~ '~'~"" ;;~~ ':t;':t; ~ ~ ~~ " '" ~t;E;t;~"t:;: ~~~~~~~~~ S ~ "I~~ ~~~ ',..'", ~":;1 ~Uii; ';;:, ~"I~~"I~~~ ..11 ., t:t:t: u",u ':ii':ii ~ ~ ~~1; := '~:3 ~ ~ :3 ~ :3 ~ :3 'S 'S 'S 'S 'S 'S 'S 'S ~ '~ ~ ~ ~ ~ ~ ~ ~ OS OS ,~:3 ij ij 0 0') "I:! ~ ~ t... '" ". t... 1'" ~ '" ~ ., ., ;: ~ ., ., ., ., t; ~":3 :3 :3:3 ,'" ,'" .". ~ t: ~,,; U = ",,~,~,~,~,~,~,~,~~ ~~';::.!!.~~~~"I "ioS~,,~~~ ~,;;~ ~~~~ ~~

"::' ~ d ~'I3'13'13'13'13'13'13'13u ~~"I~"I"I"I~ 'S"I:!voS:3~;I ,~,~,"" """ ;;~~:3 ';jui~ ...§ ~ 'u~~~~~~~~~ ~~~~~~':S':S,.'g ~~~~~~~OJ~~~'.:;j'~,,~~o~ ~~

\11' § ~ ~~~~~~~~~ OJ~~~~~~~~:~ '.: ~u~ ::~~~oS~~~~~~~ ~ ~~~ '.: ~ ~r u ~ ~ ~ ~ oS '~ ,~ ,0 ,0 ,~ '~ '~ '~ ~ '0 ~. oS ;; 0 ;: ~ ~ ~ ~ :3 ~ -;: ~'- u.Q ~ ~ "I:! ~ ~' ..; :~ ,~ :~ .~ :~ ,~ ,~ ,~ ,§ :~ "I:! ~ ij fi fi ~ ~ ~ ~ r~ ": ~ "I:! ~ "bo':';' r:':- r:':- = P. ~ ~ ~ S Q ~ ~ ~ ,~ ~ .-~ r~f """4""~""~~"""4"";::~~~~~~~~",,-~ o~ o\J' OJ"'~~ s~~ oS~ ,.,E;;; ~G i ~ .Q 0 = = oS ".. ..

! ~ 0 ~ 0 >, 'u oS oS OJi E-o ~ ~~u '" x u ~! ,.I 56 NAGA, THE ICLARMQuARTERLY

-

The frequency distribution of a values (ex-pressed as In (a» is presented in Fig. 1. The coef- A

"\ ficient of skewness (SK = 1.16) portrays a sub- mean

.~~ stantial amount of positive skewness. Fig. 1 also ,

.:~..,~~ illustrates the frequency distribution of b values.~i J( The skeyvnes~ coeffi~ie~t cl~sely appro~ches ~ero...'~ (SK = 0.22), ~thus IndicatIng normalIty. CInCO

, ~ (1982), Torres (1992), and Caillouet (1993} j.~;...:. have also demonstrated normality in the distri- ~ --. b . f b . h d. f h I ..-Reg-es..,., .,Iercepllo)'!-.' uhon 0 In t e stu les 0 ot er mu tIspecles ;.: LWR of marine fishes. § I 8

zTable 2 presents the intergeneric plasticity in

mean length-weight parameters. The interceptswere remarkably heterogenous (CV = 5.2 -106.3%) and rano-ed from a. = 2.4 X 10-3

C mm(Cynoo-lossus) to a = 80.9 x 10-3a max(Periophthalmus). The exponents were homog-enous (CV = 1.6 -16.8%) and ranged from b .L~h exlXJn8nl (b) .

-mm= 2.620 (Gerres) to b = 3.226

max(Pseudotolithus). Negative allometric LWR oc- Fig. 1. Frequency distribution of the regression intercept fA} and

d . 13 h 'I ." f .length exponent fS} of length-weight relationships of fishes fromcurre In genera w I e Isometric unctIons the coastal waters of Nigeria.

I,. were recorded in five genera.~., Interfamilial plasticity in mean length-weight the fish genera and families (Tables 2 and 3), ap-

~ parameters is given in Table '5. Wide variations proximations can be derived when species-spe-~ were recorded in the intercepts (CV = 5..2 -cific parameters are unavailable.

107.8%), with values ranging between amin = 2.4

x 10-3 (Cynoglossi-dae) and a = 76.7

max --x 10-:i (Gobiidae). Table 2. Mean intercept (a) and exponent (b) of the length-weight relationships for 18 genera ofV . t .. th coastal water fishes in Nigeria.

ana Ion In e

exponent ranged Intercept Exponent.from b. = 2.620 -(G .dlnm ) t -b Genera N a s.d. CV b s.d. CV

errel ae 0 =max

3.226 (Sciaenidae). Chrysichfhys 2 0.0077 0.0004 5.2 3.078 0.051 1.7The fish families Pcllonula 8 0.0193 0.0142 73.6 2.745 0.462 16.8

.. t ' t t d I llisha 8 0.0083 0.0066 79.5 3.035 0.315 10.4cons I u e c ose Sardinella 1 0.0140 --2.827 --

homogenous groups EfhmaJosa 12 Q.0205 0.0218 J06.3 3.014 0.206 6.8in terms of mean Mugil 3 0.0241 0,0138 57.3 2.784 0.153 5.5

.,,' Liza 17 0.0186 0.0119 63.9 2.903 0.172 5.9exponents (CV = 1.6 Periophfhalmus 8 0.0809 0.0626 77.4 2.923 0.302 10.3

-15.7%). Isometric Gobioides 1 0.0431 --2.168 --and negative Bosfrychus 1 0.0157 --2.890 --

II tr . L 'lm Monodacfylus' 1 0.048~ --2.799 --a ome IC ,yy 1'- were Cynoglossus 3 0.0024 0.0004 16.7 3.185 0.051 1.6detected in four and Pseudotolifhus 3 0.0"e77 0.0083 107.8 3.226 0.367 11.4seven families pomadasys 2 0.0196 0.0007 3.6 2.921 0.153 5.2,. I Selene 1 0.0520 --2.309 --respectIve y. Chloroscombrus 1" 0.0140 --2.782 --

From the esti- Trachinofus 2 0.0255 0.0035 13.7 2.765 0.295 10.7mates of a and b for Gerres 2 0.0169 0.0057 33.7 2.620 0.410 15.7

57

--=~c~=c~-- --

--Table 3. Mean intercept (a) and exponent (b) of the length-weight relationships for 11 families of coastalwater fishes in Nigeria.

,

"¥.~ Intercept Exponent

.'~:';.; ~ G~nera N a s.d.. CV b s.d. CV...,,¥ ..:--- -,, .r: Bagrida~ ~ 2 0.0077 0.0004 5..2 3.078 0.051 1.7

, , Clupeidae, 29 0.0166 0.0166' 100.0 2.939 0.333 11.3~ Mugilidae 20 0,0195 0.0119 61.0 2.885 0.171 5.9

' I.

~ Gobiidae 9 0..0868 0.0599 78.1 2.839 0.378 13.3" Eleotridae 0.0157 -.2.890 --" Monodactylidae 0.0489 .-2.799 --, Cynoglossiae 3 0..0024 0.0004 16.7 3.185 0.051 1.6

Sciaenidae 3 0.0077 0.0083 107.8 3.226 0;367 1.1.4Haemulidae 2 0.0196 0.0007 3.6 2.921 0.153 5.2Carangidae 4 0.'0293 0.0162 55.3 2.655 0.287 10.8

.Gerreidae 2 0.0169 0.0057 2.620 15.7

References Marcus, O. 1982b. The biology of ~e West African shawa, l~/hlllaloJajilllbriata Q3owdich) found in the Nigerian coastal ,vaters, p. 10-11.

..c 'in Annual Report, Nigeria .Ih~titltte for Oceanography and MarineA/aYI, T.O; 1993. The age and gro,vth of the tongue sole, Cynoglo!111s Research, Lagos.

..anari.nns (Steind.. 1882), p. 228:;235. In Proceedings of tpe 2nd Marcus, O. 1982c. The biology of the clupe!d, I/i.rha afii..ana Q3loch) ofAnnual. Conference of the. Fisheries Society of Nigeria (FiSON), the Nlgerian coa$t. University of .I_'\gos, Lagos.' Ph.D. thesis.25'-27 January 1992,Calabar.. Kainji Lake. ReseatchlnstitUte, New Marcus, 0; 1984. Biology of bonga, Elh,llalo!,) jiulbrialll (Bowdich) .inBussa,. Nigeria. the Nigerian coastal and bra,;kish waters, Project (Mf) 1,2.2. .In

Bolger, T. and P.L. Connolly. 1989.. The selection of suitable indice$ for Annual re:pbtt, Nigerian InstitUte for Oceanography and Marinethe measurement and analysis offish condition. J. Fi$h BioI. Research, Lagos", ,

,34:171-182. , c' Nlewadim. A.A. 1995: The length-~eight relationship and condition ofCaillouet, C. \~; Jr. 1993; On comparing groupt'of fishes based on the mugilids, Uza fal"'pinnis {Valenciennes, [836) and l..iza

;Iength-weight relatiohship$..N~ga, .lCLARM Q. 16(2"3):30-31.. grandisqllaulis (Yillenciennesi1836) in ~ bracki$h,vater environ-Carlander, K. 1969. Handbook of fresh,vater fishery biol9gy. VoL 1. ment, Paper presented at ~h~ First Scientific Conference on tbe

.cIo,va State University PreS$; /\:me$, Iowa. .C Fish and Fisheries of Southeastern Nigeria, 4 October 1995.. Uni-Cinco, E. 1982. Length-weight relationships of fishes, p. 34-37. In D. versity of Uyo, Uyo, Nigeria; 9 p..

Pauly and A.N. Mines (eds.) Small-scale fisheries of SanMiguel Royce, w:r: 1972. Introduction to the fishery sciences. Academic Press,Bay, l?hilippine$: biology and stock assessment. ICURl\{ Tech. New York and I..ondon. 351 p.Rep. 7, 124 p. Tuegel; G.G., G.McG. Reid and R.t'! King. 1992. Fishes of the CroS$

<J{ken~..:I:!.6.1990."L~..ngth-,ve!g~t rela~onslii~and:diet ~qm~ositiO"~of Rj:;;er Basin (Camer.ooi :Ni~ria): taxono~y, ~bogeography, ecol-lC:lhulalosa jilllbnala Q3owdlch) (pI$ces: Clupeldae) In Cross River ogy and con$ervat!on. Mu$ee Royal de "AfCIque Centrale, Ter-J!:stuary, Nigeria.Universiry of Cross River State, Nigeria. B.Sc.. vi1ren, Belgidm. Ann.Sci.Zool.182P:thesis. Torres, E, Jr.i991. Tabular data on marine fishes from southern Africa,

Ikusemiju, K. 1976. Distributi°..n' reproduction and growth of the cat- Part 1: length-weight relationships. Fishbyte 9(1):50-53.fi$h, Ch!'J'si..hlf?:ls ,valken' (Gunther) in the Lekki Lagoon, Nigeria. J. Torres, F., Jr. 1992. Length-weight relationship of Lake Kariba fi$hes.Fish Bioi. 8:453-458. Naga, ICLARM Q. 15(4):42-43.

Ikusemiju, K., A.A. Okiand M. Graham-Douglas. 1983. On the biology Tyler, A.~ and ~r:GaJlucci. 1980. Dynamics of fi$hed stocks, p. 111-of an cstua~ine populatjon of the clupeid., P.llonllia afz.lillsi 147. In R. Lacke.y and L.A. Nielson (eds.) Fisheries management.Oohnels) in Lagos Lagoon, Nigeria. Hydrobiologia 102:55-59. Blackwell Scientific Publications, Oxford.

,. King, R,P. 1996. Length-weight relationships of Nigerian freshwater Udoh, E.E.. 1994. Studie~ on, the occurrence; distribution, gr~wth,fishes. Naga, ICLARM Q. 19(3):49-52. mortallry and potenCIal Yield of catfish of. the genus Chry.r,..hlf?:lS

Kulbicki, M., G. Moutham.. P. Thollot and L. Wantiez. 1993. Length- 'in the Cross River system, Nigeria. University of Uyo, Uyo, Nige-weight relationship$ of fish from the .I~agoon of New Caledonia. ria. M.Sc; thesis.

'" Naga, ICLARMQ.16(2-3):26-30. Udoh, I:':.S. 1992. Occurrence and bionomic~ of the Gu(nean sprat,

L.'\gler. K.F., J.E. Batdach, R.R. Miller and D.R.M. Pa$sino. 1977.. Ichthyol- Ptilonliia I.on.ntis Boulenger, 1916 (Clupeiformes, Clupeidae) inogy (2nd edition). John Wiley and Sons, New York. 506 p. the Imo River f!.stuary, Nigeria. UniversitY of U~, Ufo, Nigeria.

'"eveque, C., D. P:lugyand G.G. Teugels, Editors. 1992. Faune des poissons B.Sc. thesis.d'eaux et saumattes del.'Afrique de l.'Ouest (Tome 2). OF,STOM et Utan, F.U. 1994. A study on beach seine fisheries of the Imo RiverMMC, Patis. 902 p. EstUary at Ikot Abasi, Nigeria. University ofUyo, UfO, Nigeria-

.-.,- Marcus, O. 1982a. The biology and fi$hery of Sardin.1Ia IIladertnm (Lowe, I3..Sc. thesIs.1839) caught off the Nigerian coastal ,vaters, p. 9-10, In AnnualReport, Nigeria InstitUte for Oceanography and Marine Research,La.~os.

R.P. KING is from the Department of Zoology, University of Uyo, P.M.B.

1017 Uyo, Akwa Ibom State, Nigeria.

58 NAGA, THE ICLARMQuARTERLY