Fish monitoring report 1995/96: Sierra Leone

f I I i I ONC}IOCERCIASIS CONTROL PROGRA},TME WORLD HEALTH ORGANIZATIO!{ FISH !'!ONITOB.ING REPORT 1qq5lq6 SIERRA LEOIIE ZAC BAH DEPARTMEI{T OF BIOLOGICAL SCIENCES NJATA UNTVERSITY COLTEGE (LrSt) P.M.B. FREETOWN SIERRA LEONE NOVEMBER, ].996 CONTENTS LIS? OF FIGURES SUM},!ARY IlqTRODLICTIOS RIVER F.OKEL CATCH PER LINIT EI,FORT (CPLIE} I{O/WT. RICHNESS OF SPECIES CPUE GRADtrS OI' MtrSH SIZES COEFFICIENT OF COI{DITION MAII* SPECIES CPLIE PRI$CIPAT. I'ISH SPECTES Peolro,'{P RIVEB *AEXL - CATCII PER UNIT EI,FORT { CPUE ) I{O/WT. RICHNESS OF SPECIES CPUE GRADES OF MESI{ SIZES COEFFICIENT CIF COND]TIOI{ MAII{ SPECTES CPLIE PRINCIPAL FISE SPECIES CONCLUSIOI{ TABT.ES E'TGIIRE <: APPEI{D]X PAGE I I 3 f s -r *r ( T 6 L I 7 x q lt, 2'r LIST OF FIGLIRES 1 . a. L' \./ARIATION IN TOTAL CPUE IN ROKEL C. _ RICHNESS oF SPECIES IN ROKEL 2.a'b CPLIE \./ARIA?I.N* IN GRADES oF MESH sIzES IN R.KEL c. - COEFF'ICIENT OF CONDITIOI; ( K ) IN B.OKEL -? . A ' b ' C. - CPLIE OF PRINCIPAL FISH SPECIES IIY ROKEL 4. a. b VARIATION IN TOTAL CPL}E IN PANPANA C. _ RICHNESS oF SPECIES IN PANPANA 5'a'b CPLIE vARrATroNs rN cRADES oF MESH sIzES rN pANpANA C. COEFFICIENT OF CONDITION (K) IN PANPAN.A- 5 ' A. b ' C. - CPL]E OF PRINCIPAL FISH SPECIES IN PANPANA 3. CATCH PER LINIT ET'I'ORT CPUE The average CPUE harre been cal-culated for at1 sampl-es. They harzebeen used j-n the anaJ-ysrc and interpretatron oi the aata:ol-Lecteddurrng the monrtorrng per:-od. Catches were hrghest during thepref lood perrods. The total- CPLIE r ncreased sJ-rghtJ-y during theearLy rnonrtorrng perrod except f or a drop j-n ,ruly. splcres anaLys:_s of the CPLItr's shows that the remarka.b]e reauctron of thetotaL CPUE's may Lre attr:-buted to the l-eve1 of the catch of specl-es whrch were dom.:-natrng some years back. ( Schrl_le mandrbutarl-s ,Brycinus macrot eprdotus, petrocephal.us Sp. Etc ) . 4. CPUE - GRADES OF UESH SIZE The CPLIE's expressed in relatron to the category of grade of mesh sr-ze rndrcated that the medrunn slze mg.sL (l-7.5 , 20.o and 22.5mm)recorded consrqtentf y higher CPLIE's (vierght and nurnL,ers ) rn theRok-el- Runbuna throughout the monrtorl-ng perrod, r^rith the rnceptronthat the recolonrzat:.on potential- of the L',rota l-s not drsrupted,because the medrum s:-zed mesh (17.5, zo.0 and 2.5rnn) made the besr_resul-ts compared vrrth the bigger mesh ( Z 5 , *?0 , 40rnn ) . 5. PRI!{CIPAL SPECIES lalrth respect to the reguJ-arJ-y occurl-ng specles l-n the two rl-vers,Rokel and Panpa.na, the pattern of f luctuatl-on l-n CPLIE recorded ivasgeneralJ-y hrgher than that of Lhe Dra\.zrnu-q vaar 5- FISH CONDITION (Xi The seasonal- mean condrtrons of al-l- the reguLarJ-y occurl-ng specl-esrn the Rokel Runbuna were conparabJ.e to that of the prerrLous year.The Same ti en{ yiag ObSef rZed 'r n the Panoana _ Evcent pot rnr.onha I rrq: Y.;'; : u:ri.,u___- taenurcauda rn the Rokel- uihrch showed l-m.provement orler that of thep:el/l-ous year. The rnsuf f :-crent number of data does not al-Lovr usto draw reLevant concl-usrons. cot{cLLrsIot{ Sprayrng of antrblackf l-y rnsectrcrdes has a l-rm:-ted ef f ect on thef rsh f auna, hence the suspension of l arr.rl-cidrng rn the two rl-vers.Horgerrer, 1t must be certa:-n that ser/era.r f actors that had been observed over the years could contrrbute to the decrease of theCPUEis. Apparentl-y, l-ocaL frshers to rntrude the mar_n water courses w:-th the:-r sophrstrcated gear, out compete our researchf rshrng technrques as well- as the smal-l scal-e f ishers. rt may L,ea reason why the l-ater resort to dynamrte f l-sh1ng or us t-ngIchthytoxrns. Settrng boundaries between sm.aLl- scale research andrndustrial- frsherres woul-d reduce such confLrct and m.:-oht '!mDrovtrthe CPUErs. II{?RODUCTIOI-S The onchocerc:.asr-s contror. programme (ocp) rn therr b,id toreduee transm:-ss:-on of onchocercj-asrl i" the Regron, has embarkedon reducrng the bl_ackf Ly rrector popupJ-ation to-i --*r, l_ow Lerrel-thereb;'r makrng transmission r*po=i.bi;-untri the rnrcrof r r lar:_e :-nthe human popuJ-atron dre out. Thrs ls achreved by aeiret sprayr-ngr nsect:-crdes rnto b'reedrng srtes r^lrtn bJ-ackf J-y rirvae regularJ.y. The rntroductron of such toxrc m.aterrar. rnto the basrn wrl_l_hai're some adverse e f f ect on the f Lora and f auna of the rlversespecrall-y the f rshes. The. present study in:_tiatea ,rr-sr-"r.a Leone .r-n 1992, has been carr:-ed out on ttre' nyarob,:.oJ-ogicar- and f :_shm'onl-torrng of the aquattc en./ironment of the Rrver Roke-L at Rumbuna?nd t.h." P_anpana at Matotoka to ensure that the a.opJ_rcatron oft nsectrcrdes has no damagrng ef f ects on the rnr.rertebrates and f rshpopulat ron . METHOD OF WORK The present study v/as carrred out dur rng June Lggz .ndSeptenber 1996 under the protocol and mon:-toring facrl-r+.res larddoiqn L'y ocp ecologrcal- group f or monr.t.orrng f :_sh catches. Crur seq were made brmonthly t.o estrm.ate the Catch per LrnitEf fort of each specles present ai tr,,.ro srtes surveye,l. F,ach cruiseset out at 4-5pm on the day of surrrey to 1ay grJ_i- nets whrch werelef t orrernrght, and cor-telctea the next day at 6am. The unrt of frshrng effort 1s defrned as one fishrng grrp bycrul-se . slnce the cruise nade only one f rshrng trrp everl/ tr.nromonths, the unit f rshrng ef f ort is normaJ.ly equ:-rraJ_ent to har_fcruise per two months. The g:.L1 nets al/a1l-abLe were of12. 5+15rr.rm, L7 .5+ZO+22. 5mm and 25+_10+4Omm_each crul_se r^/Lth these nets were countedhas been carrred out for 4 vearq. In ! -qgZ , 4 cruLses made l_n all richr-le t-rr 1994 tr^lo cruLses were made l-nRrrrer Rokel_. 'l gqq/1996.j 4-.J'_. three mesh sL Tes; tneCatches collected. from and weighed, Thrs work r_vers. In 199_?, f t was GRr-rrer Panpana and 4 at the a- ---) SUMMARY Durrng the year under revl-ew, rl-vers Rokel/Sel-r and Panpana were m.onrtored at Bunbuna and Matotoka respecttvely. The a:"m of the m.onitor i-ng , wh j.ch f orms part of broJ-ogrcaJ- stud:.es of theprogramme, rs to assess l-ong term effects of the l-arrl:-crdeq on the f ish and rts populatron in the rivers concerned . I t should be noted that mc-''nitorr-ng on the Moa Rr-rrer was suspended:-n 199*1 due to the soc:-al- unrest rn the area. HYDROLOGY O!' RIVERS The f irst regl-me f or b'oth Rokel and Panpana shovied a remarkable importance. The rl-vers experrenced seasonal- r.rarratron 1n water l-elzeJ- throughout the year. Low water ref erred to as "dry" occured betureen January and March. Rrsrng r.sater (pref 1-ow ) was obserlred betr,qeen Jul-y and September and October and Decem.ber respectl-lrely. Erren t-hough no gauge was avail-abl-e at Matotoka due to mr nlng actrvrtres on the rl-ver srde, f reld observatton showed an equaJ-J-y f I nnrl reo'! me drrrr no the rreak of the f lood.r-* 2. SPECIES RICHNESS The spec:.es richness has not changed si.gnr-f rcantly r-n the tvro statinns- The vAr'!cr'ris frshe-q. car-roht.- bv the cruise rn each rl-vgr durrng the perrod under consrderatfon are presented rn the frgure. In effect the tabl-e here after sums up the number of specres caught rlrrrrnrr tho mnnrfnrtnaf MONITORING PERIOD tlI qTTE 1 PNT{III. I STTE ? PANPANA 1-996 1996 1995 SEPT 1996 | ?4?i---I 1nq I qq|" Ii ror L!! !41 ?3_ 58 The species rrchness recorded at Rrrrer Panpana vlere hrgher than that of the River Rokel-. Mosi frsh spec:.es rdentrfred were common to both rl-vers L,ut T. Louka, C. Guentherr and E. Rectrculatus $iere onlw fnrrnd :t tho Rokal PrvAr R Sacratr-t-q- S Ohequq- I-4 .|_. .L ,Quadrrll-ineatus, t. Coubie were onJ-y present l-n the Panpana. Condition Factor The condition factor rneasures the var:.atron from the general I enoth-rrra iclhl- rr:l ef r nnqhr n Tf i q rrqorl tn r-.)m11era tha r^rol I hai nrv ,. - L.' j of the f rsh. Condr.tt-on f actor can change throughout the year Aqnlrr-r al lw ritrrrnrr q?lel"r?1rnar "r-" Resul-ts Pre l-arvrcrdal- clrcJ-e studY Water tevel-s of Study Sites ?he rr vers surveyed experrenced seasonal var:-atr-on r-n uraterIerlel throuchoirt the vear - r.ow water referred to as rdrv' occured*_ Ibetween January and March. Rr-sl-ng v\rater (pref .l-or^l ) was obserrzedbetween Aprrl and June. Floori { f low } anrl rlrawn down lnoqt f lood .! 'I- - * - - - v Y 5 i occured between .luly and Septernb'er and October and Decer.nber roqnocl- i rro I w - - -t_ Species lrst and species rtchness ?he snecie l-rst of the rrart-ous f rshec cauoht- trv the c?'r.r'r se -'r n each water during the perrod under cons:-derat:.on are presented tn Tabl-e 1. The specr-es rj-chness recorded at Rrrrer Panpana (.?S) were hrqher than that of the Rokel- Rrver. Most frsh qDecres rdentrfred r."/ere common to b,oth rl-vers but T. louka , C. gueutherr andEthromastercembrelus recticul-atus were only found at the Ro]<elRrrrer. Barbus sacratus, Synodontis obesus and J-cthyb,orus ottadrr I I t noalrrs. urprA nnl w nroq.enf 1n tho Pann:n: Rr rrer F-oke'l F-i ver Total Catch Der unrt sff6r'l nar The unrt of frshrng effort the crur-se. Srnce crul-ses uere of f rshi no ef f ort used l-n thisa --- nAr tr^rcr monf hq r{rtI l q.ct 'lq do'frnorl .aq maria r-rn'l w nna wnrk 'r q orrrr i rza nna f rqhrnrr frrn hw hrmonthlv thp irrrrt Lent to half crur-se The average CPLIE have been cal-culated f or al-L sarnpl-es. They harle been used r-n the analysrs and r-nterpretat ron of the data col-lect:-on durrng the m.onitorrng perl-od. Catches were hrghest rirrri nr: nrA-f I nnr'l anrl f I nnri nerr nrlq I :nnanri i :e a ) Total- CPUE rncreased sIrohtIv rir.irrno t-he mon-ri,orrno oerrr-rr!2 E-fron 1992-1996 except for a drop 1n catch in 1994 (appendrx a). -rl CPIIE nor mesh q.r zAr-- The mesh sr.zes used have been descrr-bed earl-rer. The mesh sr-zes 1-2.5+15m.m recorded h:-gh catches during- May (appendrx L'). The L7 .5+24+22.5mm recorded another r-ncrease rn total catch l-n March and NotremL'er (appendrx c). The m.esh sr-ze 25+30+40mm had the same trend as those of the total CPUE mentroned in the earlrer sectron f annanrl r rz ri )*)' Frsh catches durrng the monrtorrng per:.od f or al-L three mesh slzes recorded marked f.luctuatron in CPLIF'. No definrte trend i"ras obserrzed. Data f rom 1994 and 1995 rnust be treated w:.th cautron. Catches l-n !994 were concentrated durrng the l-ovr water and rr-sr-ng water nerr od - Thiq perlod f rom the data set i s .'eunDo.'ee11 rlomr nnated bv -*!-r < jf rshes of Lower r^leiqht . Tn 1qq5 nnlw nno airrl'rqA r,raq rlono Therefore f rom the onset, these data set were not comparab,Le r.drth the prerrr-ouq twr,r vearc because of t-he aDDarent drfference in catch -__- 5 *t-r rlttr t ncl t ho wat ar I orro I r.wr" I o o.ar"h wo:'r^ , v..v CPUn of the PrincipaJ- Fish Species The nri nni ne I f i eh qna.i eq. woro S M'l r,*r^11.)d^n R Ma,-rnl ani dr dnf rrq anrl H f nr"qka I I r "i [,a rrra recorded tn March, -Tul w and October f or H. f orskall-rr Nor.zember f or S. mi-cropogon ( appendrx f ) and July and R mat-rnl onrrlidntrrq { annondr rr n)\ vrE5 v-.vt*-- ? I . No defrnrte trend was obserrred r-n catches of alL prr-nc:-paL f rsh specr-es of the Rlrler Rok-e l durr no the monrtc,ri no ner:rod3 t--H. f orskaLl-rr was a key f actor l-n determ.i-nrng the shape of the total CPLIE of the frsh stock at the Rrrrer Rokei- durrng the months of -Tanuarv t-hrnr:oh lnl:reh wh:-l-e B. macrolenrdrdotr:s f rom A.nrr I +hrnrtoh Artr:trqt S mi ernnnrrnn r^riq : kaw f ar.tnr f rnm S,ontomhor t hrnrroh Danomtror Coeffieient of Condition (k) The mean monthly rral-ues of condrtron factor for the prrncrpal-fish specles qho$ied that the fishes m.arntarned a constani E throughout the seasons they v,rere caught durrng the monrtorrng nar r nri Post T.arvicide CycJ-e S:-r- types of :-nsectrcrdes were used :-n thrs study. They wereBT pY CA pE AB anrl pI{ Thev were used erther sl-ndl e l v or" 'r n eombtnat-1onq (aDnFnritv k). Aonend'!ces h & r nrnvido rnformatlon on\.El--.Jtthe date of qDravrno and the number of trmas -qDravlno was carrredc,ut durrno the monr torlncr Deriods 1992-L995.E catehes were I:nnondrv ol Santomhar fnr -(- Total- catch per unit effort and the catch per unit effort per meshsize during each crulse during tne monrtoi=.ng p".roa- The data rn thrs section were anaJ-ysed drfferently from thosepresented l-n the ear-Lter sectron rn ord-e, to rl:.sua1:.se the effectof the rnsecttc:-des used on the CPLIE of f rshes specr-es present. At the Rokel- Rirrer, the total CPLIE together wrth the rneshsr-zes of L7 '5+20+22-5mm (Mesh 2) and 25. +30+40nnm. (mesh 3) recordedevery catch per unrt effort were very hrgh before the rntroduetronof the rnsectrcides except f or the 1z . d+tSmm m.esh size (mesh i_ ) .A Si-gnlficant drop rn CPUE i^ras obserrred on the applrcatron of the:-nseetrcrde BT In 15 / 3 94 . The CPLIE through out the j.arrrrcrdecycle durrng the monitorrng perrod harze remii.ned ratner l-ow, butal1 trends reported earLi-er remaln lra.LLd for ]:oth the total_ catchper unrt effort and the CPLIE with respect to the mesh sr.zes of the911L nets (appendrx h). CPUE of the principal Fish SpeciesThe trend obserrzed before the introductron were apparent evenwrth the rntroduction of the :-nsectrcrdes. The cplrE observedappeared to bre unaf f ected by the introductron of the rnsectl-cl-des,regardless of - the .type, the com.brnat r on and the number of trmessprayl_ng was done {appendrx r ) . Coeff,iclent of Condition (ki The mean m.onthly conditr.ons of the principar- f rsh speer-es r-nthe Roker R:-lrer post r-arvrcrde cycr_e was constant through themon:.tor:_ng per:_od (1992-1996 ) . Rrver panpanaTotal Catch per unit effortAverage monthJ-y catches constant tliroughout the yearMarch rluring the Low w-aterthroughout the nonr toring per durrng the perrod un,3er surr./ey u.rere . Hrghest catches were ob,ta:_ned inmark. CPUF, rncreased gradual_ly rod (appendix L). per cruise CPLIE per mesh size The mesh sr.ze 12.5+15mm recorded hrgh average catches:.n May,September and Norrenber (appendrx m). Th-; l-ncreased ca.tches J_agge,Ci-rehrnd r-ncreaqed catches of the 25+30+4Omm mesh sr_ze (appendrx o).Thrq obserr'ra-tron m:ght halre some bearrng t" - irr. 'reproductrvebrol0gy of the key specr-es responsrbr-e for these peaks. The meshsizes 17 .5+20+22 . 5mn ( appendrx n )- ina - 25+30++0mm recorded hr.ghcatches dur:-ng "Tuly and october. Additional lncreased catches wereobserved r-n May and March f or the !7 .5+20+22 . 5mm and 2 5+*?0+40nmmesh sl-zes respectirzel_y. :(o CPLIE of the principal Fish SpeciesThe priclp:r, .f ish specles of the panpana rr_ver i^/ereH ' f ors]<alr-ir, B. Macro and c. Maurus . Catches f or H. f orskar..r.rr ,B. Maero increased throughout the mon:.torrng period untrr 1994(append:_ces p & r). A drop J-n CpLrE-was recorded Ln L995. C.maurus fr-uctuated throughout the monrtorrng years (appendrx q).High catches were recorded at d:-ffeient t:_mes for each of thesepi:incipar- specr-es . c. maurus recorded hrgh carci:qs r.n May, H.f orskal-r-rr, recorded hrgh catches rn March and August and B. Macrowere caught rn hrgh werghts in March, ,iur-y and Norrember- Coeff:.eient of Condition (k)?he n1'ean rnonthJ.y condrt:-ons of the prr_ncrpaJ_ f rsh specles r.n ii;r;:ifffi Rlr.zer wele constanr tnrougi:out the nonr-rorrng per:_od -r;Jj. Post T.arvrcrde CycJ_eThe sl--x types of rnsectr crdes used at the Rrrrer Rokel_ wereused at t.he panpana Rrrrer . They *"." - St, py, CA, pE , AB, and pH.The sane treatment regrme was empJ_oyed (appendrx .,r). The date ofsprayr-ng and the nu.nber ot^ trmei =j."yr_r.,g was carried out durrngthe m'oni-torr-ng perrods 19gz-1996 u." p.o.,rrded rn Appedlces & u. Total- catch per unrt effort and the catch per unrt effort per nneshsize duri-ng each crui-se aurrng trr" *o".torr-ng per:.od- Total CPLIE and the CPLIE wrth respect to the various rnesh sr-zesused were rzery high inrtrai.J-y ierore the rntroductron ofinqeetrc:-deq r nto the rirrer bas:-n to -uarget the bJ-ackf J_y .r-arrraeexcept f cr the 2I+,?0+4Omm mesh s:-zes (appenorx s ) . ?he iniroduction of the rnsect j.ci.des s:.gnr-f :.cant j_y* reduced thetotal cpLIE and the catches ob,ta:-ned rrom the .rurr.ori' mesh s r zes ,but hrgh catch per unr-t effort cont:-nued to h,e recorded durrng thel-ow water m.ark as descrrbed ear-Lrer. CPLIE of the prrncipal. Fish SpeciesThe resuLts are consrstent wrth earlrer f :_nd:.ng. The CpLrEwere in:-fraJ-J"y hrgh before the adrrent of the sprayr_ng exercr-secarrred out by ocp. The decreased r_n cpuE drd not howerzeradtzersely affect the total- CPLIE or ine pir-n"rpai- specres of fishesat the Panpana F'tr'rer . The usuaL peaks ,iere obserrred but at a LowerCPLIE rral_ue (appendrx t). *? Coef f rci-ent of Conditron i k )The rnean nnonthJ-y condrt:.ons of thethe Parrpana. Rrrler was constant throughoutLarrrrctde use. Concl_usi on The :-ntrodr.letron of rnsectr cr des :-nto the Rrrzers F.okel_ andPanpana har.ze rerzeal-ed onl-y s j-:-ght decreases r-n t.he tot_al_ cpuE ofthe totaL numi:er of f :-shes and ther-r principal ir-=n =p""r."=. Thesedecrease'] of CPLIE has howerzer not lead to any ob,ser.zatron change r-nthe condrti-on f actors of the f ish dur:-ng the perrod under study. The cont:-nuatron of thrs programme woulrf Lre rrrtal. The total_number of healthy days l-ost and the economlc rmpli.catron ofonchocercl-asl-s to the region outwerghs the sJ.rght dedrease r.n theCPUE ln total f:-sh specles and the prrncipal i;;h =p""."= rn bothr].verq, prl-ncLpal frsh specl-es :-nthe perrod ( 1992-199G ) of Monthly variatioa in CpUE per cruise during 1992-96 at Rokel River Monthtv variation in CPUE per mesh ,o"'??lil r5 mm) duriag l99z-1986 ar River Roker Monthlv variation in cPUE per mesh .rr" (li!1i;*22.5 mm) during rssz-tss1at River Roker Monthy variatioo in CpUE per mesh Table d size (25,30,40 mm) during at River Rokel All years Monthly variatron in CPLIE of Principat fish species t E fors*allit\ at the River Rokel 1992- 1996 Table fMonthly variation in CPLrE of Principal fish species (.f, micrqtogzra) at the River Rokel l99Z_ 19.)6 1996' Monthlv variation in GPUE of Principal trrn ,r"l?li"{b. -or*t pr'r**r/ul althe River Rokel leez-1e96 *lo'- Total CPUE aod CPUE per roesh size ar the Rokel River 1992_1996 GPUE of principal firh ,#:i:"r'"r River Rokel l99z-t996 Frequencv on insecricid" ,r""*"llojiJ ,r, ar rhe River Rokel tegz-r996 u, fl- Insecticides used aod Larvicide cycle at the River Rokel Monthtv variaiion in cpuE 0"" lrtnlil3'i,l* ,rrr-16 a*he paapana River Monthy variation io CpUE per mesh Table m size (12 5* 15,0 mm) during 1992-96 at River panpana Monthy variarion in CpUE per rnesh ,ir" ( l;if.t;0l ZZ j mm)duriag tsg!-96ar River panpana *1?: - Monthy variation in CPIIE per mesh size (2r.30r40 mm) during 1992-96 at River panpana Monthly variation in GPLIE of Principal ,rrn .l3fr'i.'t H fon-kalLt)ar the panpana River tggz- 1996 Monthlv variation GPIJE of Principal rist sfSSilisqt c mautwgar the panpana River tggz-rg96 Monthly variation in CpLIE of Table r Principal fish species ( B maut./ept*e/rtlus) at the panpana Riverr992- 1996 Total CPUE and CPUE per oesh size atthe PanapaoaRiver l99Z-1996 Frequencv on insecticide useage tl"lJ:8ao o, rhe River panpana 1992-1996 Table r Principal fish species at River panpana lc)g}-1996 Insecticides iBf IEy--------?f,..i.;:;:.:_."_....___--__.t_.;;_-._..._-._.......i..i...:......,.,...............i..y:... 1..?,.!..q .....:..P..e..s-p_e..{.e.i9..1...i..1sln.e'-,sj.s.t...i.$lr..s1989 i r igii"-----:::i--: ieez--""-""-?')-**- *-- "it- -*----' "il- -i?oi"-::---:-:: l.?.?..1 ...-i.-s--,..:p-....t..-..ig'..tt...i.tusp.p.ttsi.eg...i.Sgsl??_? ....i.$.-u._sp.-"_'Nr-on...!...s..usp_emip..q....!.-s..e.clrrr)6 iSuspension isusoension lsus ?.!]il.qrJ.... i)._u..9.p..e..{r..-s.!.g..q_..i..Lu.s_p.9,.+.:.il ,nsion iSusoension ilr.r.,-.ir-.nq__.-n6r.--..-.-;__*9...._,.....,.,..... rnsion i4 it? "-""--*'!":---"--"----'-i'a'Y'--"---.... -lv - Insectrcrdes used and Larvrcide c1'cle at the Rirer Panpana 1995- 1996 Total CPUE variation at Bumbuna during the period 1992 to 19g6 160 140 120 100 BO 60 40 20 0 9.oIt E az $$$$EEEEEEEs$44 H $SSS s = dt i5 j gi s"g i6 } 9= g ! $\g Samp!ing dates Total CPUE variation at Bumbuna during the period 1992 to 1996 4500 4000 ? 35oog 3000g 2soo :g, 2ooo s l::: 500 0 (o@()(o o) oJ o) cD!gqsC.l N ol C{ (f) r, A O (!) (r) (, $ $ $ r ro? ? ? q, ? q o or o) 6 di d o cr o dis=d"9s!g;fitisggi $ Sampling dates Species richness at Bumbuna: 1992 to 1996 18 816 '6 14#nb10g8 t6E, 4 zz 0 C.l O,l C\ C{ (o A O (O r, (O (f, g S .+ $ l.c) (o (c) (O (o? ? ? ? ? I ? E ? E ? q, o' ol o) dt + + + +c=o.>E!i E,f I ! s g = $ S i ! ! g = g E g i da CPUE variations in grades of mesh sizes at Bumbuna: 19g2 to 1996 70 60 50 o 3' 40 5soz 20 10 0 @ 12.5 + 15 mm '17.5 +20 +2.5 25+30+40mm ggBgSEEgB33EEEg E EEEEg $g=$ Sampllng dates CPUE variations in grades of mesh sizes at Bumbuna: period 1992 to 1gg6 3000 2500 tnE 2000 .! f rsoostllE 1000 3 500 0 E 12.5 + 15 mm 417.5+20+22.5 O25+30+40mm ggBSEEBs sEESrrr ,8"8 i 5$gE Sampllng dates E EEEEg s'g= h Coefficlent of condition for main species at Bumbuna 2.5c,' o EIE, o a, E 1,s o(Jr EI G,\ oo o,s s a fio o E o rm <- P. taenuicauda ..*-C. maurus Jun-92 Dec-92 Jun-93 Dec-93 Jun-94 Dec-94 Jun-9s Dec-9s Jun-96 Deog6 Dates *t? - o E IE cD t ED '6 = CPUEs per fish species at Bumbuna in river Rokel from 1gg2 to 1gg6 H. forskalii 700 600 500 400 300 200 100 0 Jun-92 Dec-92 Jun-93 Dec-93 Jun-94 Dec-94 Jun-95 Dec-95 Jun-96 Dec-96 S. micropogon 2000 1 800 1600 1400 1200 1 000 800 600 400 200 0 Jun-92 Dec-92 Jun-93 Dec-93 Jun-94 Dec-94 Jun-95 Dec-95 Jun-96 Dec-96 B. macrolepidotus o E E c,, .c o) o = o E E cD E') o = 1 000 900 800 700 600 500 400 300 200 100 0 I Jun-92 Dec-92 Jun-93 Dec-93 Jun-94 Dec-94 Jun-95 Dec-95 Jun-96 Dec-96 IY Total GPUE variation at Matotoka during the period 1992 to 1996 80 70 60t,bs0 €40 =30z20 10 0 N N C\l c\r (fr c, (Y, (o G) (o c, (,o (o $ $ (o (o (o (oBSBEEEBESsBS r EE EgsB Sampling dates (\NNNOOo, o, o, o, o)$ E E'9 s s $s l gBs 3E E Sampling dates (o@(o(oo, o, cD ct$ gt E' Total CPUE variation at Matotoka during the period 1992 to 1g96 6000 G sooo EE 4000 E" E 3000 E 2ooog looo o (o@(o cD cD cnE+ Ao<o) Species richness at Matotoka: 1992 to 1996 N N c\t c\I 6.r q, (p (9 (Y, (r, o (') oD t \f (oo) cD cD o, cn O O of it it qr qr g, q, o, o,#il+a*$gg=FhsZ6E E Dates .g 20 oOqE cL rvo o10 o oll5 E2o -!1- $$$$q s532q CPUE variations in grades of mesh sizes at Matotoka: period 1992 to 1996 qqsqEsqEEg€EgSBE Sampling dates CPUE variations in gradei of mesh sizes at Matotoka: period 1992 to i996 {$ qqsEEi EgEE 4100 4000 G 3500I sooo; 2soo ; 2ooo ,B ,soo = looo 500 0 NN6IN(no)cDoj.+a_gE532 (t G, (.,(, cn d)$$E (rt\t9qqB EE (, (r) lY1 6o)o)oat =P$S Sampling dates EEEEE$qg ! 17.5 + 20 + 22\S mm tr 25+30+40mm &- -tu oT t 3,s+ =alE s-1-EII2,s+ : 2+ ffi E ,,u tE 1t6'I 6o,sl I o 'l-'-- --- -J Jul-92 Jan-93 Coefficient of condition for C. maurus at Matotoka Jlrl{ Sep-94 Apr-95 Oct-95 May-96 Dec-96 Dates t I -2_o - cPUEs per main fish species at Matotoka in river pampana H. forskalii C.l N Ol N (.) A q) (I, !t V t !. (o ro roo) o) o) cD o,E3B33gBEE3B3E3B3Egp3 C. maurus B. macrolepidotus T. brevimanus C.l C.! C{ (\l (f) q? (9 (r) S t S $ ro ro ro? ? ? q, e ? ? qt + + + + E b,, qr B E E E Es 5 SA E 5,fr9 S 5 sa S; fra g i P i 700O 600I soob 4oo E 300 .9 200 * ,oB 2000 6 I rsooy looo .B soo = 0 400 o I aoo I 2oo .f 1oo =o 4d+qBqBEEEE5 AE! i e$i * eB (Y) (O (O (O o) cD (D (,)i g #*i2'1 U)O OINNNo, o, o, (Dgia6 lyfoo -l .(. o) J- o $qa$s$fiqs4ddEEEBEsdoAEEdo8sgSA!5.frA (o(o(o(()o, o, (D O)t * et RICHNESS OT SPECIES PER STATION FOR PERIOD 1-992-1996 CODE ll fi lt ,l t1il ilil !tIt t, tl u illl l1ii ,llt lt ilIIll t!lt !lltillltr il 1l titl tgI !ittilil lt ilu ltIillt fill Hll ,ltlitilllt!Itti ilti II ittlil u iltln It iltt illt ilil 501 904 10 01 1111 111 _? 1246 L2A7 L209 !-"a2 1-?09 1203 1 50L 1604 L704 L7 A8 2202 300-? -1005 _? 3 01_ 324! 3406 3600 -? 9 01_ _?902 3903 4 501 4502 450*? 4505 4901 5422 542 5 5427 5433 5701 6!02 620! 5401 6502 65l-7 5 51-8 6 519 6522 680 1 6901 7 302 i BUNRUT{.A i ueroror-e I r* r r... r- r-r = * il--_- --]---l-- i - -::-- -:'- t-- iMoRMYF.usrAprEUS i : i i ioRMYF.USTAPIEUS I + | * iiMOF.MYRoPSANGUTLoTDES i * i " iiMARCUSENILISTHOMAS, i * i * i; sPECrEs inor.sr jpaupeue| -rr*t-trrtt i ..' -^-^-- MARCLTSENIUSMENTO i + i * ilt i rrPETROCEPHATUS LEi/EQLIEI i + i * i!__r__!ri ! - i 1. lrPETRoCEPHALUSTANLIICALIDA j * i * ii PETROCEPHALLIS PATTIIDOMACLILATLIS i * i + iiRRIENOMYRLIS BRACHYISTLIS i * i - iiHIPPOPoTAMYF.L]sPAUE{I i + i * iiPETROCEPHALILUSBovEI I - | * iiI i ' il LABEOCOLIBIE i - i * iiLABE0PARVLIS I * i * iiRARtrus wriprzr i i . ii"=,. i * iiBARBL]SSACRATLIS i - i + iiR.A.IAMASNIGERIENSIS i * i * li . YROPSANGUILOIDES i I o !iii! i ii * I _______j_-*__=____-_. j!r T--*----------]iTOTAT i :Z i HEPSETL]S0DOE i + i + iiHYDROCYNUSTORSKAII i " i * iiBRYCINLISMACROLEPIDOTLIS ! . I ." ii TTLApTAr.orrka ' i iii+r-rlLATESNILoTICLIS I * I * iir i - ll ,!!i :L"* l'-,J I J- iiBRYCINLISLONPIPINIS i * i * ii ICTHYBORUS QLIADRILLINEATUS i - i * iir.l! TILAPIABREVIMANUS I + | * l;SARoTHERoDoNCALIDOMAF-BINATUS i * i _ iiSAROTHERODONOCCIDENTALIS i - i iITILAPIABLITTIXOFERI i ; i I ii CHRYSICHTHYSI.IIGRODI&ITATUS i " i * ilCHRYSICHTHYSMAURUS i * | * iiCHRYSICHTHYSJoHNELst i * i - iiALICHEN0GLANISoCCIDENTALIS i - i * iiSYNoDONTISoBESLIS I - i " i; 5.F.Ll1.1vtf\:I{1rits!(LEN515i+i+iiCLARIASANGLILLARIS i " i - ii! + i _ iiSCHILBEMYSTUS I " i * il!r! i.:urui | + ! + itSCHILBEMANDIBULARIS i * i * iiSCHIBEMICROPOGON i * i * iiLIHRYSICHTHYSALIRATUS [ * i " !! JIr(YNoDoNTISANNECTENS i - i * iiSYNoDONTISTHYSI i " i * iiSYNOD0NTISW.ATERL0?I i * i * !iMALAPTERLIRUSELECTRICLIS i * i _ iIHEMICHROMISFASCIATLIS I * i - ii| | iiTYLOCHR0MISJENTINKI i * i * !iCHF.OMIDOTILAPIAGLIENTHERI i + i _ ii CTEISoPoMAKINE6LAYE i _ i * iiI t trAETHIOMASTACEMBELUSLIBERIENSIS i + i - iiIil L>+L