Translation Series No.1211
Total Page:16
File Type:pdf, Size:1020Kb
FISHERIES RESEARCH BOARD OF CANADA Translation Series No. 1211 Contributions to the biology and study of the stock of the Atlantic salmon (Salmo salar L.) in the Baltic Sea . • 4e. re By . Fritz • • ' OEriginal title .Beitraege 2ùr Biologie und. Bestandkundé ' - dee'AtlantisChen LaChses: (Salmi salarL) in der .0stsee. •From. : Berichte der deutschen wissenschaftlichen Kommission d. Meeresforschung, 18(3/4): 223-379, 1966. Translated. , by the Translation. Bureaù . • Foreign Languages Division' :Department of the Secretary of State Of Canada- Fisheries Research Board of Canada - Biological Station ..- St. John's,r fld'. • 1969,: 1K 1'1,1 ■ DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU BUREAU DES TRADUCTIONS • FOREIGN LANGUAGES DIVISION DES LANGUES DIVISION CANADA ÉTRANGÈRES TRANSLATED FROM — TRADUCTION DE INTO — EN German Ehglish - AUTHOR — AUTEUR Fritz Thurow TIT.LE IN ECNGLISH TITRE ANGLAIS • • Contributions to the Biology and Study of the Stock of. the Atlantic Salmon (Salmo salar L.) in the Baltic Sea Beitrgge zur Biologie und Bestandskunde des Atlantischen Lachses (Salmo saler L.) in der betseC R5F5RENCE IN FOREIGN I,ANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHA,RACTERS. REFERENCE EN LANGUE ETRANGERE (NOM DU LIVRE OU PUBLICATION), AU COMPLET.TRANSCRIRE EN CARACTERES PHONÉTIQUES. Berichte der deutschen wissenschaftlichen Kommission der MeeresforschUng •REFERENCE IN ENGL ISH RÉFÉRENCE EN ANGLAIS Reports of the .German Scientific Commission for Oceanography PUBL ISH ER — ÉDIT EUR PAGE,NUMBERS IN ORIGINAL Verlag Paul Paxey DATE OF PUBLICATION NUMEROS DES PAGES DANS DATE DE PUBLICATION L'ORIGINAL. YEAR ISSUE NO. 223 - 379 VOLUME AN N ÉE • NUMÉRO PLACE OF PUBLICATION NUMBER OF TYPED PAGES .LIEU DE PUBLICATION , HOMBRE DE PAG,ES DACTYLOGRAPHIEES Hambilrg 1966 XVIII 3/4 237 REQUE,FING DEPARTMENT. TRANSLATION BUREAU NO. Fisheries MIN ISTERE-CLIENT NOTRE DOSSIER NO 5660 TRANSLATOR (INITIALS) BRANCH OR DIVISION Office of the Editor p , p B. DIRECTION OU-DIVISION TRADUCTEUR (INITIALES) PERSON FEQUESTINGDr . A. W. May,y St. John's, Nfld. DATE COMPLETED Fehr. 22, 1969 DEMANDE PAR ACHEVE LE YOUR NUMBER VQT Ft E DOSSIER N ° 769-18-14 DATE OF REQUEST DATE DE LA DEMANDE No . , 1968 ZucevY etold . S05-20 0-10.6 (REV. 2/4s8) ' 13 f DEPARTMENTOFTHESECRETARYOFSTATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU BUREAU DES TRADUCTIONS FOREIGN LANGUAGES DIVISION DIVISION DES LANGUES ÉTRANGÈRES CANADA VOURNO. DEPARTMENT . oivisioN/smANcH CITY VOTRE N ° MINISTRE DIVISION/DIRECTION VILLE 769-18-14 Fisheries Office of the Editor ' Ottawa OUR NO. LANGUAGE TRANSLATOR(MITIALS) DATE NOTREN ° LANGUE TRADUCTEUR(INITIALES) 5660 'German P.F.B. February 22, 19 69 Reprint from Vol. XVIII (1966), Heft 3/4, PP. 223-379 Reports of the German Scientific Commission for Oceanography CONTRIBUTIONS TO THE BIOLOGY AND STUDY OF THE STOCK OF THE ATLANTIC SALMON ( Salmo salar L.) IN THE BALTIb SEA By Fritz Thurow Federal Research Institution for Fishery Institute for Shore- and Inland-Fishery Cont.ents I. Introduction 3 2. The salmon fishery in the Baltic Sea 2.1. The historic development 10 2.2. The fishing technique • • . .. .. 15 2.2.1. River fishery *16 2.2.2. Shore fishery 16 2.2.3. Pelagic salmon fishery. 17 2.2.3.1. Vessels 17 *2.2.3.2. Fishing gear 11 sos-2 cto—lo-31 2 2.3. The extent of the pelagic salmon fishery 24 2.3.1. The fishing grounds 24 2.3.2. The fishing season 25 2.3.3. The yield of the stock 26 2.3.3.1. Fishing effort 27 2.3.3.2. Catch per unit effort 28 2.3.4. The yields of the salmon fishery 52 2.3.5. The composition of the catch in the pelagic fishery 57 •3. The sexual maturation of the Baltic Sea salmon in the ocean . 60 3.1. The sexual composition of the exploited stock 62 3.2. The condition of the gonads 64 3.2.1. The ovary 66 3.2.2. The maturing of the oocytes 7 0 3.2.3. Comparative discussion of the findings about the sexual maturation 77 3.3. The fertility of the salmon 84 4. The migrations of the Baltid Sea salmon 87 4.1. The sections of the periodic migration 89 4.1.1. The smolt migration 89 4.1.2. The feeding migration 90 4.1.3. The spawning Migration 95 4.2. Small-scale movements 101 5. Age and growth of the salmon in the main basin of the Baltic Sea 113 5.1. On the terminology of the analyses of age and growth . 113 5.1.1. The relation between total length and. fork length . 114 5.1.2. The gutted weight 11 6 5.2. Material and method 118 5.2.1. The arrangement of the scales 119 - 5.2.2. The significance of the sclerite rings for age determination ............ .120 5.3. The age composition of the German catches 127 5.3.1. The results of the age analyses of January catches 127 5.3.1.1. The brood year t s sets 128 5.5.1.2. The sea year classes 138 5.3.1.3. The salmon with spawning marks 143 5.3.2. Seasonal .changes in age composition 149 5.3.3. The age composition of the exploited stock in the main basin of the Baltic Sea 1 54 5.4. The growth relations 161 5.4.1. Results of the investigations • 161 5.4.2. Discussion of the findings 166 5-4.2.1. The rate of growth • 166 5.4.2.2. The growth of the smelt of the year 1959.• 168 5.4.2.3. The effect of the size of smolt on the • growth in the sea 173 6. The food of the Baltic Sea salmon 175 6.1. Previous investigations 175 • 6.1.1. The nutrition of the juvenile stages 175 6.1.2. The food in the main basin of the Baltic Sea 177 6.2. Amount and kind of food according to my investigations 1957-64 180 6.3. Differences in the composition of the food 182 6.3.1. Seasonal variation 183 6.3.2. Differences on the fishing grounds 186 6.3.3. Differences depending on the kind of fishing gear . 187 6.3.4. Differences depending on sex 188 6.3.5. Differences in food related to the size or the salmon 189 6.4. The relation between the behaviour of the prey and the composition of the food of the salmon 190 6.5. The food consumption of the salmon 191 7. Attempt at a quantitative analysis of the stock in the main basin of the Baltic Sea 194 7.1. The characterization of the stock 195 7.2. Losses in the exploited stock 197 7.2.1. Total mortality 198 7.2.2. Wasting through fishing and natural mortality . 203 7.2.2.1. Results of tagging 203 7.2.2.2. Determination with the aid of the fishing intensity 205 7.3. Losses in the recruitment phase 211 7.3.1. The natural enemies 211 7.3.2. The mortality until the beginning of exploitation, . 213 7.4. Models for the stock of salmon in the Baltic Sea 215 Summary 221 References 223 Appendix 230 1 • Introduction The genUs Salmo belongs together with the genus Oncorhynchus to the subfamily Salmonininae (Family Salmonidae, Suborder Salmonoidè4 Order Clupeiformes) (L.S.Berg 1958). The Atlantic salmon,'Salmo-salar occurs in the northern part of the .Altantic Ocean. The distribution reaches from Cape Cod to the Duero River (Spain) in the south and,from West Green- land to the Kara River (east of Novaya Zemlya) in the north (G. W. Nikolski . 1957). . The lifè cycle runs'a very uniform course everyWhere in the . 'entire area of distribution. After a period of ,feeding in the beal:the • maturing salmon seek out the rivers in which they were spawned, in order to spawn. The females make two- .:10 three-meter long depressions in the . gravel and shingle bottom in which they deposit their eggs and colter them afterwards. The duration of the egg development is dependent on the tem- perature and amounts on an average to about 180 days. After spending from one to five years in the rivers, the young salmon migrate to the sea, where they grow very rapidly. A large number of scientific papers have been written about the life history of the salmon. J. Bergeron (1962) lists in his bibliography of the Atlantic salmon for the time from 1800 to about 1960 a total of 1800 references. The scientific research of the salmon received its first stimulus through the great economic growth of the fishery for the species [P. 225] of Oncorhynchus in the Pacific Ocean at about 1860. This led alsoto num- erous investigations of the Atlantic salmon of the North American coast of the Atlantic Ocean between 1870 and1880. In Europe a substantial in- crease in the.scientific activities took place only after 1900 through eXe ô1 ee Sea . the founding of the international Council for-Geettnegraphy. In a partial review of the literature on the Atlantic salmon K. A. Pyefinch (1955) e‘tablished the fact that the fundamental biological knowledge has hardly increased since the earliest times. He cites H. Boece (1527) and P. Olauen (1545. -1614), who already knew the life history of the salmon in its main features. A. Fritsch arrives at a similar result in regard to the works of J. Johnstoni (1633) and Balbin (1679), who deacribed the life history of the salmon of the Elbe and mentioned the period spent in the ocean. C. Gessner (1958) Published.among other_things eready .'illustrations of the male and female salmon (Fig.