5 Rapp. P.-v. Réun. Cons. int. Explor. Mer, 176: 5. 1979. FOREWORD The concern generated within the main Atlantic salmon producing countries in the North Atlantic following the rapid growth of the West Greenland salmon fishery in the early 1960s, and the great scientific interest in gaining more knowledge of salmon during its sea phase led to steps being taken by the International Commission for the Northwest Atlantic Fisheries (ICNAF) and the International Council for the Exploration of the Sea (ICES) at their Annual Meetings in 1965 to organize an international scientific appraisal of this fishery development, with special reference to its effects on the salmon stocks and fisheries in home waters. A scientific Working Party, the ICES/ICNAF Joint Working Party on North Atlantic Salmon, with member­ ship from all North Atlantic countries with Atlantic salmon interests was established to undertake this task. The first meeting of the Working Party was held in 1966 and subsequent meetings were held each year thereafter up to 1974, their results being reported to the Annual Meetings of ICNAF and ICES respectively (ICES Cooperative Research Report Nos. 8, 12, 24, and 35 and Document CM 1974/M: 2). At the time when the Working Party was established, little was known about the biology of the Atlantic salmon during its sea phase. Hence, in addition to the collection of information on the characteristics and development of the West Greenland fishery itself, one of the Working Party’s most important tasks was the development of coordinated data collection and research programmes on aspects of its biology and population dynamics, especially those of direct relevance to the assessment of fishery effects. These programmes included regular monitoring of the distribution, size, age and sex compositions of catches taken in the West Greenland and home- waters fisheries, smolt tagging in home waters, investigations of scale characteristics and bio­ chemical properties of salmon of different home-waters origin in the West Greenland stock, studies of their feeding and growth, and investigations of their rates of exploitation in the home- waters fisheries. Amongst the most important of these cooperative programmes, however, was the ICES/ICNAF Tagging Experiment at West Greenland in 1972. This experiment which was funded by the countries most concerned and organized by members of the Working Party, provided vitally important information on the home-waters origin and destination of salmon in the West Greenland stock and a much more comprehensive data base for the assessment work. Although the results of these research programmes were presented in working documents to meetings of the Working Party and are summarized in its reports, most of the detailed work has remained unpublished. In view of their important contribution to the advancement of our knowledge of North Atlantic salmon biology and population dynamics, it was decided at the Annual Meeting of ICES in 1974, that the main items of this work should be published by the Council in a volume of the Rapports et Procès-Verbaux series. The contributions in this volume deal with various aspects of the work organized by the Joint Working Party in pursuing its remit. They cover aspects of the West Greenland fishery itself, the biological characteristics and origin of the exploited stock, the ICES/ICNAF Tagging Experiment at West Greenland in 1972 and the assessment of the effects of the West Greenland fishery on home-waters stocks. The volume should be read in conjunction with the reports of the Working Party referred to above. B. B. P a r r is h Sv. Aa. H o r s t e d 82 Rapp. P.-v. Réun. Cons. int. Explor. Mer, 176: 82-92. 1980. REVIEW OF NORTH AMERICAN SMOLT TAGGING TO ASSESS THE ATLANTIC SALMON FISHERY OFF WEST GREENLAND C. P. R u g g l e s Montreal Engineering Co. Ltd. P.O. Box 3478 South, Halifax, Nova Scotia B3J 3J1, Canada and J. A. R i t t e r Fisheries and Marine Service, Resource Development Branch Environment Canada, P.O. 550, Halifax, Nova Scotia B3J 2S7, Canada INTRODUCTION Although occasional smolt tags have been recaptured Horsted (1971), Pyefinch (1969) and Saunders etal. off the east coast of Greenland, this review deals only (1965) have described the development of the Atlantic with smolt tags recovered in the West Greenland salmon (Salmo salar) fishery off West Greenland. The fishery. recapture of tagged salmon from European and North American rivers provided an early indication that the DESCRIPTION OF TAGGED SMOLTS fishery was dependent upon stocks from a variety of Between 1959 and 1971 inclusive, a total of 1894000 rivers in both North America and Europe. Sub­ hatchery and 259800 wild smolts was tagged and sequent tag recaptures have verified that most of the distributed into various rivers in North America rivers contributing to this fishery are located in the (Table 55). Tagged smolts emigrated from rivers British Isles and in Canada. For details about the situated all along the North American Atlantic coast first recaptures and for European tagging experiments, from as far south as the Connecticut River, USA, see A. Swain, 1980. to the Sandhill River in Labrador (Fig. 24). Sixty Early in 1965 the ICES/ICNAF Joint Working per cent of the wild smolts tagged were from the Party on North Atlantic Salmon was established to Miramichi River, New Brunswick. This river was also evaluate the effects of the Greenland fishery on the release site for 224100 or close to 12 per cent of member country salmon stocks. The Working Party the hatchery-reared smolts. has published four reports (Anon., 1967; 1969; 1971; Wild smolts were from 15 different rivers and 1973). One important component of these earlier hatchery-reared smolts were progeny from adults col­ analyses was the information provided by recapture lected in six rivers. Three other sources of hatchery- of salmon tagged in North America and Europe as reared smolts were from adults collected in the Chaleur smolts. The Working Party noted large variations in Bay near New Mills, New Brunswick, and off the recapture rates at West Greenland from different mouth of the Cascapedia River near Maria, Quebec, smolt tagging experiments and concluded that a more and in several rivers in Maine, U.S.A. detailed evaluation of tag returns was urgently needed. The purpose of this paper is to review North American smolt tagging conducted since 1959, with GENERAL REVIEW OF RECAPTURES a view to assessing their relevance in determining The first recapture of a salmon tagged as a smolt stock origins and mixing at West Greenland. Special from a North American river occurred in the Green­ emphasis is placed on smolt tagging experiments con­ land fishery on 10 October 1960. The fish had been ducted in 1970 and 1971, since their recapture in tagged on 22 M ay 1959, in the estuary of the M ira­ West Greenland waters coincided with extensive michi River, New Brunswick (Kerswill and Keenley- sampling of the Greenland catch in 1972 associated side, 1961). Since then 2248 recaptures off West with the ICES/ICNAF Salmon Tagging Experiment. Greenland from tagged salmon smolts originating Review of North American smolt tagging to assess the Atlantic salmon fishery off West Greenland 83 Sand Hill River> LABRADOR 100 20 0 Km >almon River QUEBEC Indian River - yCascapedia NEWFOUNDLAND \River North Harbour River GULF OF ST. LAWRENCE Restigouche Riven New Mills River .Miramichi Riverj ’Margaree River NEW BRUNSWICK s—\ >-> Big Salmon Saint John River River MAINE *-River Philip West Rive] NOVA SCOTIA Medway* River ATLANTIC OCEAN 'Connecticut River Figure 24. Map showing the geographic range of tagged Atlantic salmon smolt releases in North America. from North American rivers between 1959 and 1971 smolts. Similarly, catches in West Greenland waters inclusive have been recorded. Over 90 per cent of are comprised largely of salmon that have spent one these tag recaptures were made approximately 1 year, winter at sea and designated throughout this paper 4 months, following emigration from the rivers as as one-sea-winter fish. Hatchery-reared salmon accounted for 75 per cent Table 55. Summary of tagged smolt releases in North of the North American smolt tags recaptured in the America from 1959 to 1971 inclusive Greenland fishery. Eighty-eight per cent of all the tagged smolts were hatchery reared. Tags returned No. of tagged smolts distributed Area of release from the West Greenland fishery represented 19 per Wild Hatchery cent of the total adult recaptures reported for the smolt releases. Although this figure cannot be taken Massachusetts, USA 0 7 500 as a direct measure of the impact of the West Green­ Maine, USA 0 382 900 land fishery on home-water fisheries, it does indicate Nova Scotia, Canada 21 100 370 100 Prince Edward Island, Canada 300 0 that this fishery accounts for a significant mortality New Brunswick, Canada 188 000 1 022 800 among both hatchery- and wild-tagged salmon. Eastern Quebec, Canada 0 110 700 However, in order to fully evaluate the impact of the Newfoundland, Canada 25 300 0 Greenland fishery, the absolute rather than the Labrador, Canada 25 100 0 relative fishing mortality should be considered in con­ 259 800 1 894 000 Total junction with the natural mortality occurring between 6* 84 C. P. Ruggies and J. A. Ritter West Greenland and home waters. This is done by foundland fisheries. Adult tagging conducted in the various authors in this publication. The recapture same river during 1968 and 1969 yielded 49 recap­ rate of all hatchery-tagged smolts at West Greenland tures, 4 of which were reported from West Greenland. was 0-9 per thousand tagged. The corresponding According to the adult tagging study, salmon of the figure for wild-tagged smolts was 2-2.