Distribution of Freshwater Fishes in the Whakapohai River to Waita River Area, South Westland
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Distribution of freshwater fishes in the Whakapohai River to Waita River area, South Westland Fisheries Environmental Report No. 77 Fisheries Research Division N.Z. Ministry ofFisheries Agriculture environmental report no. 77 (1987)and Fisheries lssN 0111-4794 Fisheries Environmental Report No. 77 D'i stri buti on of f reshwaten f i shes i n the Whakapohai River to Waìta River area' South Westl and Repont to: New Zealand Forest Servìce South Westland Management Evaluation Programme Fi sheri es Research Di v'i s'ion N.Z. Ministry of Agricu'lture and Fisheries Chri stchurch Fisheries environmental report no. 77 (1987) FISHERIES ENVIRONMENTAL REPORTS This r"epont is one of a senies of reports issued by F'isheries Research Djvisjon on ìmpor"tant ìssues related to environmental matters. They are issued under the following criteria: (1) They are informal and should not be cjted w'ithout the author's permission. (2) They are for lìmited circulation, so that persons and onganisations nonmaì1y receivìng Fisheries Research Division publ ications should not expect to receive copies automatical ly. (3) Copìes wi 1ì be 'issued in jtia'lly to onganisations to wh jch the repont ìs djrectly relevant. (4) Copies wì1.l be 'issued to other appropriate organisatìons on request to Fjsheries Research Div'ision, Ministry of Agricuìture and Fjsheries, P.0. Box 8324, Riccarton, Christchurch. (5) These reponts will be issued whene a substantial report is requi red with a t'ime constraint, e.g., a subm'ission for a trjbunal heari ng. (6) They wì'll also be'issued as interim reports of on-go'ing environmental studies for wh'ich year by year olintenm'ittent reportì ng i s advantageous. These 'i nteri m neports wi ì 1 not precl ude formal scient'if ic publ ication. ISBN 0477031692 Fisheries environmental report no. 77 (1987) CONTENTS P age 7 S umma ny 1. I nt roduct'i on 7 2. Study area 9 2.I Mataketake State Forest 11 2.2 Catchments l2 2.2.I Whakapohai Ri ver I2 2.2.2 Shìp Creek 13 2.2.3 Waita R'iver T4 3. Materi al s 16 4. Methods 1B 5. Habitat, Ecology, and Distribut'ion of the Fjshes 18 5.1 Habitat Features 2I 5 . 1 .1 l^late r Tempe ratu re 27 5.I.2 pH 27 5.2 Native Fishes 25 5 .2 .I Long-f i nned Eel (an¡uíIla aief fenbachii ) 25 5.2.2 Shont-finned Eel (ensuilLa austraiis) 30 5 .2 .3 Wh'itebai t Speci es 31 5.2.3.1 Inanga (calaxias macufatus) 31 5 .2.3 .2 Koaro (Galaxias .brevipinnis) 35 5.2.3.3 Banded Kokopu (caLaxias fasciatus) 39 5.2.3.4 Gìant Kokopu (GaLaxias argenteus) 4I 5.2.3.5 Short-iawed Kokopu (caLaxias 42 postvectis) 5.2.4 Torrentfjsh (ch"i*urrichthgs fosteri) 42 5.2.5 Red-f i nned Buì 1y (cobiomorphus huÈtoni) 46 5.2.6 Common Bu'l1y (cobio orphus cotidianus) 48 Fisheries environmental report no. 77 (1987) P age 5.2.7 81 ue-gì I ì ed Bu1 ly (cobionorpnus hubbsi ) 50 5.2.8 Bl ack Fl ounden (RhombosoJ.ea retia¡ia ) 52 5.3 Int noduced Fì shes 52 5.3.1 Brown Trout (salmo trutta) 52 5.4 Crustacea 54 5.4.1 Freshwater Crayfìsh (Paranephrops 54 planifrons) 6. Di scussi on 55 6.1 Factors Affecti ng Fi sh Di stri buti ons 55 6.1.1 Dìstance From the Sea and Alt'itude 55 6.1.2 F'ìow Type 57 6.1 .3 Cove n 59 6 .I .4 Bank Vegetat i on 61 6.1.5 Water Colour and pH 63 6 .1 .6 Temperatu re 65 6.I.7 Presence of Brown Tnout 66 6 .2 The F'i she ri es 68 6.2.I Rare Specì es 68 6 .2 .2 tlh'i teba'i t F ì s he ry 68 6.2.3 Eel Fishery 70 6.3 Impì ications for Management 7T 6.3.1 Possjble Effects of Forest Harvesting 7T 6.3.1.1 Sedimentat'ion 7T 6.3.I.2 Obstruct'ions to Upstream Mi grati on 72 6.3.2 Effects of Land Uses 72 6 .3 .2.1 Ag t'i cu I tu re 72 7. Recommendati ons 73 8. Acknowl edgments 74 Fisheries environmental report no. 77 (1987) P age o Li teratu re C'ited 74 Appendìx I. Distribut'ion of fjshes by catchment 78 TABLES 'in 1. Number of each species of fish recorded each catchment, 20 nencentaqe of catchment sites from which each species was iecorded] and percentage of the total fish recorded in each catchment 2. Tempenatune data for habitats fnom which fjshes were 22 reco nded 3. pH data for habitats from which fìshes were recorded 23 F IGURES 1. Study area, showing samplìng s'ites, rivers, and 10 localities mentioned 'in the text 2. A coastal dune lake near the mouth of the V'laita River I7 3. A forested dune lake in the Waita catchment I7 4. Mean and 957" confidence Iimits of pH fnom habìtats 24 of LZ fish species in South Westland, November 1984 - February 1985 5. Sites fnom whjch long-finned eels (ensuirla 26 dieffenbachii) and sñort-finned eels (a. australis) were recorded 6. Habitat profile for the long-fìnned eel 28 29 7 . Habitat profì le for the short-fi nned eel 8. Sites f nom which inanga (calaxias macul.aÉus), banded 33 kokopu (c. rascja¿us), giant kokopu (c. arg"nteus) and short-iawed kokopu (c. postvectis) wene necorded 9. Hab'itat prof i le for inanga 34 10. Sites fnom wh'ich koaro (Galaxias brevipinnis) was 36 reco rded i1. Habitat pnofile for koaro 37 12. Habitat profile for banded kokopu 40 13. Habitat profile for gìant kokopu 43 Fisheries environmental report no. 77 (1987) 14. Sites from which tonrentfish (cnei*urtichthgs fosteri), þlack flounder (Rhombosorea retiaria),. and fresñwater crayfish (naranephrops pranif¡ons) were recorded 15. Habitat profile for torrentfish 16. Sites fnom wh'ich red-fÍnned bully (cobiomorphus common bulìy (G. cotidianus) and huttoní),'led bl ue'gi 1 bul 1y (c. hubbsi ) were recorded 17. Habitat profì'le for the red-finned bully 18. Habitat pnofile for the common bully 19. Sites from wh'ich brown trout (s"mo trutta) was recorded 20. A tributary of Ship Creek where banded kokopu was partìcul arly abundant Fisheries environmental report no. 77 (1987) 7 SUMMARY The distribution and compositjon of the freshwater fish fauna wìthìn the Whakapoha'i , Sh'ip Creek, and t^Ja'ita Ri ver catchments was studi ed f rom November 1984 to mid February 1985. The methods and objectives of this survey were s'imilar to those described by Main, Nicoll, and E.ìdon (1985). Habitat data were necorded at all sampling sites and the eco'logy of the fish fauna is d'iscussed in relation to these. Twelve nat'ive fishes and one intnoduced species, the brown trout, were recorded from the study area. Among the native fjshes, the giant kokopu was widely distributed; it was reconded from each of the three studi ed catchments, though it 'is rare on absent 'in more devel oped regions of New Zealand. Ship Creek, ìn partìcular, contains a rich native fish fauna,'including the scarce short-jawed kokopu, and the f,Jaita River conta'ins commercìaì'ly utilised eel and whjtebaìt fisheries. Both of these waters are recommended for consenvation. Impl i cati ons for freshwater f i sheri es i n the study area are discussed and recommendations about futune land use are made. 1. INTRODUCTION In late 1984 the New Zealand Forest Service (NZFS) granted further f.inanc'ial support for Fisheries Research Divis'ion (FRD) of the M'inistry of Ag¡iculture and Fìsherìes (MAF) to participate'in the South l.,lestland Management Evaluatjon Programme (SldMEP). In response to the extended financial support, further field work was undertaken in South Westland sim'ilan to that described in the finst Fisheries environmental report no. 77 (1987) 8 stage of the SWEMP fl'sh survey (Uai n, Ni col I , and El don 1985) . Two employees, unden the d'irectjon of FRD, conducted field work in the anea from the Whakapohai Rìver in the north to the Waita Riven in the south. Dunation of the field work was from 4 November to 21 December 1984 and from 13 January to 16 February 1985. Ecologicaì data nelevant to the j d j stni but'ion of nati ve f reshwaten f i sh wet'e obta ned wj thi n the study a rea. Ëldon (1985) The objectives of FRD, outlined by Maìn, Nicoll, and ' remained unchanged for the second stage of the Survey. These were to determine the d'istributjon, relative abundance, and hab'itat requìrements of nat'ive freshwater fishes and the probable impact of varìous forest management reg'imes upon f i shery val ues. 1¡ithin the study area three catchments, Whakapohaì, Ship Creek, and Waita, were identifìed as priority areas. The fi rst catchment was selected fon jts potentially hjgh value for native fish, owing to jts reportedly low trout population (Coker and Imboden n.d.). This catchment was al so chosen because of its elevated terra'in companed w'ith the other two systems. The Ship Creek catchment was selected because analysìs of wh'itebait samples indicated that koaro were mone common than expected fnom a "brown-water stream", and that banded kokopu were pant'icular'ly common in the system (McDowaì1 and tldon 1980).