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rssN oilt- 1791 FISHERIES ENVIRONMENTAL REPORT NO. 3I SUBMISSION ON THE FISH STOCKS AND FISHER¡ES OF THE BULLER RIVER SYSTEM FISHERIES RESEARCH DIVISION MINISTRY OF AGRICUTTUR.E AND FISHERIES CHRISTCHURCH FISHERIES ENVIRONMENTAL REPORTS Edited by: S.F. Davis This report is one of a series of reports issued by Fisheries Research Division on important issues rel-ated to environmental matters. They are issued under the following criteria: (1) They are informal and shourd not be cited r^rithout the authorrs permission. (2) They are for limited circul-ation so that persons and organisations normally receiving Fisheries Research Division publicaÈions should not expect to receive copíes automatically. (3) copies wilr be issued initiarly to organisations to which the report is directly relevant. (4) Copies will be issued to other appropriate organisations on. request to Fisheries Research Division, Ministry of Agriculture and Fisheries, Prívate Bag, Christchurch. (5) These reports will be issued where a substantiar report is required with a time constraintr e.9. a submission for a tribunar hearing. (6) They will also be issued as interim reports of on-going environ- mentaf stud.ies for which year by year or intermittent reporting is advantageous. These interim reports will not preclude formal scientific publication. CONTENTS Page 1. Introduct'ion 1 2. Catchment Description i 2.I Physica'l descriptìon 1 2.2 Hydro'l ogy 5 2.3 Land use B 2.3.L Forestry I 2.3.2 Mining 9 2.3.3 Farmìng 10 2.3.4 Urban development 10 2.4 Hydro-electric potential 10 3. Fish Stocks 11 3.1 Nati ve fish spec'ies 13 3.1.1 Inanga (Gal-axias maculatus) 13 3 .t.2 Koaro (GaLaxias brevipinnis) 16 3. 1.3 Banded kokopu (GaLaxias fasciatus) 16 3.1.4 Giant kokopu (Gafaxias argenteus) 77 3.1.5 Shortjawed kokopu (Gafaxias postvectis) 17 3.1.6 Common river gaìaxias (GaLaxias vulgaris) T7 3.1,.7 Longjawed gal ax'ias (caLaxìas prognathus) 1B 3.1.8 Alpine galaxias (eaLaxias paucispondgJus) 18 3. 1.9 Dwarf galaxias (caJ-axias divergens) 1B 3. 1. 10 Common smelt (netropinna retropinna) 1B 3.1.11 Lamprey (ceotria austraJ.is) I9 3.1.t2 Shortfinned eel (ensuitla australis) 19 3. 1. 13 Longfinned eel (angui77a d.ieffenbachii) 27 3.1.14 Common bu1ìy (cobio*orphus cotidianus) 21, 3. 1. 15 Redfinned bul 1y (coøiomorphus huttoni) 22 3.1.16 Upland bu11y (eobionorphus brevi"ups) 22 'I 'l Page 3.I.I7 81 ueg'i I I ed bul 1y (coøio^orphus hubbsi) 22 3. 1. 18 Torrentfi sh (cneimurrichthss fosteri) 24 3. 1. 19 Yel l oweyed mul 1et (eurichetta forsteri) 24 3.1.20 Kahawai (arripis trutta) 24 3.L.21 Other marine species 24 3.2 Introduced fish species. 25 3.2.L Brown trout (sutro trutta) 25 3.2.2 Rajnboul trout (sutro gairdnerii) 25 3.2.3 l,rJh'itefish (cotusonus a-Zbus) 27 4. Fi s heri es 27 4.1 l,rlhitebait fishery 27 4.2 Eel fishery 29 4.3 Trout fishery 29 4.3. 1 Upper Bul I er Ri ver 31 4.3.2 Travers Ri ver 33 4.3.3 Lake Rotoiti 33 4.3.4 Howard River 33 4.3.5 Gowan River 34 4.3.6 Lake Rotoroa 35 4.3.7 Sabine and D'UrviJle Rivers 35 4.3.8 Owen River 35 4.3.9 Mangles River 36 4.3. 10 l4ataki taki Ri ver 36 4. 3. 11 l4ati ri Ri ver 37 4.3.1,2 Maru'ia River 37 a1 4.3. 13 Lower Bul I er Ri ver J/ 4.3.14 Inangahua River 38 4.3.15 0hikanui River 39 4.3.16 Other tributaries 39 iii Page 5.. Discussion 39 6. Acknowl edgements 45 7. Literature Cited 45 TABLES 1. Mean annual flow data and maximum recorded floods for the Bul I er Ri ver and ma'in tri butari es. 2. Small hydro potential of the Buller catchment. T2 3. Fish of the Buller River system. t4 4. Annual whitebait catch (in metric tonnes) from Westport, 28 the l^lest Coast and the whole of New Zealand, during 1932 and 1946-48. 5. Spec'ies composition of the wh'itebait catch from l¡lest 28 Coast rivers, 1970. F I GURES 1. The Buller River system and location of flow gaug'ing stati ons. 2. llean month'ly discharge and rainfall at Te Kuha and Murch'i son respecti vely. 3. Records of inanga (caLaxias maculatus), koaro (c. trrevipinnis) 15 and dwarf galaxias (c. dìversens) in the Buller River system. 4. Records of the shortfinned eeì (enguiTta austrafis) and 20 'longfinned eel (a. ai*renbachii) in the Buller River system. (cobionorphus 23 5. Records of the common cotidirnu"),'led redfinned 'ly (c. nuttoni ) , upl and (c. breviceps ) and bl ueg'i1 bul (c. nurasi) in the Buller River system. 1V 6. Records of brown trout (suu,,o rrurra) and rainbow trout (s. gairdnerii) in the Buller River system. 7. Relative usage of the Buller Ríver and its 12 most- fished tributaries by adult, who'le season fishing licence holders from Nelson and West Coast Accl imati satíon districts. 1. INTRODUCTION Increasing and often conflicting demands for water have meant that management plans are required for important river systems throughout New Zealand. tJith'in the terms of reference of the hlater and Soil Conservat,'ion Act 1967, the multiple use of waters is promoted to ensure that both consumptive and non-consumptive users, including "fisheries, wildlife habitats, and all recreational uses of natural water", are taken into account during allocation pìanning. The first stage in preparation of a water management or allocation plan is the compilation of data on the water resources of the catchment and existing uses of the water, into a resource report. The Westland Catchment Board and Reg'ional Water Board have indicated their intention to publish a "Resource Report" on the Buller River in April 1983, and to consider the necessity for a water allocation plan fol I owÍ ng publ i cati on of thi s report. Under the Fisheries Act (1908), Fisheries Research Division (FRD) has responsibility for research and advisory functions related to freshwater fish and fishery values. The M'inistry of Agriculture and Fisheries as a whole also has responsibility for management of these resources both through F'isheries Management and Fisheries Research Divisions. Acclimatisation societies and the two wildlife conservancies of the Department of Internal Affairs have been delegated the management of recreational fisheries involvìng acclimatised fish" The Buller R'iver system'is a fishery resource of considerable importance, with features of national significance. This report has been provided to document the fish stocks and highlight the fishery values of the Buller catchment. 2. CATCHMENT DESCRIPTION 2.1 Physical Description The Buller River is one of the largest rivers in New Zealand. Its 6 500 kmz catchment incrudes the western sropes of the St Arnaud and Spenser Mountaìns 2. (maxìmum elevation 2301 m) and all the ranges to the west, and it is exceeded in area only by the Clutha, I,laikato, [^laitaki and Waiau catchments. I^lith'in the Buller catchment are a number of important sub-catchments, including the two source lakes of the Buller River (Lakes Rotoiti and Rotoroa) and their tributaries, and the Matakjtaki, Maruia and Inangahua Rivers. A map of the Buller catchment is shown in Figure L. The catchment is geologically comp'lex, v'tith a corresponding variety of river forms. The upper reaches of the headwater tributaries lie in areas of schist and greywacke, occupy'ing valleys broadened by glac'ial action and partiaì1y filled by outwash grave'ls. In other areas, such as the two entrenched gorges in the Buller River mainstem, the dominant rock type'is granite. The catchment is also characterised by an active tectonic zone whjch has resulted in major earthquake activity in recent years. The Murchison earthquake in L929 created the Maruia Falls, and also resulted in a large earthsììp which formed a small lake in the Matakitak'i River, although thjs lake has been compìetely filled by sedjment over the ensuing 50 years. A simìlar earthslip resulting from the 1968 Inangahua earthquake established a part'ia'l lake in the Buller River between Lyell and Newton Flat. Most of the catchment is in unmodified beech forest (wotnotusus sÞP.), with some farm'ing and urban development along river flats and at the river mouth. The following is a brief description of the major tributaries; a much fuller description is contained in Egarr and Egarr (1981). Both Lakes Rotoiti and Rotoroa, at the head of the Buller and Gowan Rivers respectively, are of glacjal orig'in. The physical limnology and macrophyte distribution of these lakes were described by Brown (1979). The'ir headwater tributaries - the Travers, Sabine and D'Urville Rivers - are relatjvely small and highly scenic, and the two lakes and their catchments form the Nelson Lakes National Park. From West Bay in Lake Rotoiti, the Buller River flows over a steep, rocky MATIRI R OWEN R HOPE R GOWAN R BUII.ER R LONOFORO LAKE tAKE rotTt MACKTEY R ROTOROA HOWARD R meryç;Les O ) r. RoTollr GORGE MUO LAKE t ROTOROA TUTAKI R .ABTNE R ) BIACKWAI ER R D,URVILLE R MAfAKIIAKI R B t tcKS GLENROY R. D ruow cAUGrNc STATIONS L DANIETS ALFRED R sPRrNcs JUNCfroN a (¡) FIGURE 1. The Buller River system and location of fìow gauging stations. 4. bed to the iunction with the Gowan River, approximately 30 km downstream. The Gowan is a short, swift river, with a current in excess of 7 knots (Egarr and Egarr 1981).