FISHERIES RESEARCH BOARD OF CANADA Translation Series N 2222 Utilization of prawn stocks by Ingvar Hallgrimsson, and Adalsteinn Sigurdsson Original title: Nyting Raekjustofna From: Aegis (Offprint'from Aegir), 9 : 1-4, 1967 Translated by the Translation Bureau JFK) Foreign Languages Division Department of the Secretary.of State of Canada Department of the.environment Fisheries Research Board of Canada -.. Biological Station St. John's, Nfld. 1972 8 pages typescript
SOS-2-1.6 (REV. 2/68/. DEPARTMENT OF THE SECRETARY OF STATE TRANSLATION BUREAU FOREIGN LANGUAGES DIVISION ),13'4Jr SECRÉTARIAT D'ÉTAT BUREAU DES TRADUCTIONS fee,;2_ ` DIVISION DES LANGUES ÉTRANGÈRES TRANSLATED FROM - TRADUCTION DE INTO - EN Icelandic English AUTHOR - AUTEUR Ingvar Hallgrimsson and Adalsteinn Sigurdsson TITLE IN ENGLISH - TITRE ANGLAIS Utilization of prawn stocks Ti tle in f reign. language (transliterate. _f'oreign.--aharaoters Nyting raekjustofna REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHAIRACTERS. REFÉRENCE EN LANGUE ÉTRANG.ERE (NOM DU LIVRE OU PUBLICATION), AU COMPLET. TRANSCRIRE EN CARACTERES PHONETIQUES. Serprentun 9 tbl. Aegis 1967 REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS Offprint from Aegir 1967 issue 9 PUBLISH ER - ÉDITEUR PLACE OF PUBLICATION LIEU DE PUBLICATION YEAR ANNÉE DATE OF PUBLICATION DATE DE PUBLICATION VOLUME ISSUES NO. NUMERO PAGE NUMBERS IN ORIGINAL NUMÉROS DES PAGES DANS L'ORIGINAL 1-4 NUMBER OF TYPED PAGES NOMBRE DE PAGES DACTYLOGRAPHIÉES Reykjavik 1967 9 8 REQUESTING DEPARTMENT MIN IST'ERE-CLIENT BRANCH OR DIVISION DIRECTION OU DIVISION Environmen.t Fisheries Service Office of the Editor TRANSLATION BUREAU NO. NOTRE DOSSIER NO TRANSLATOR (INITIALS) TRADUCTEUR (INITIALES) 165849 JFK PERSON E QU E STI NG John Camp DEMANDE PAR YOUR NUMBER VOTRE DOSSIER N DATE OF REQUEST 12.6.72 DATE DE LA DEMANDE FLD 69A DATE COMPLETED July 1, 1972 ACHEVÉ LE JUL 2 1g72 UNEDITED TRANSLATION For infort-:::-;:.*:1 TRADUCTI..,1N REVI3E5 Information ezulomont
t 'DEPARTMENT OF THE SECRETARY OF STATE TRANSLATION BUREAU FOREIGN LANGUAGES DIVISION SECRÉTARIAT D'ÉTAT BUREAU DES TRADUCTIONS DIVISION DES LANGUES ÉTRANGÈRES CLIENT'S NO. DEPARTMENT DIVISION/BRANCH CITY No DU CLIENT MINISTERE DIVISION/DIRECTION VILLE Environment Fisheries Service Office of the Editor Ottawa BUREAU NO. LANGUAGE TRANSLATOR (INITIALS) DATE No DU BUREAU LANGUE TRADUCTEUR (INITIALES) 165849 Icelandic JFK lt,il 2 1972 e 1.4 C. r. F... I: Ul. W -5 '6 :21 1.2.1 LI. e C Ing IJALlmlnlaÊ2L.:121 Adalsteinn Sigurdsson, ichthyologists: Utilization of prawn stocks Several articles on prawning in Norwegian waters written by Dr. Birgir Rasmussen, have been published in translation here recentlye One of his theses is that overfishing prawn stocks is not possible. Because we disagree with Dr. Rasmussen and consider it proven that prawn stocks have been overfished, we wish to draw attention to some data relating to this subject. Let us first examine prawning in Oslofjord. oldest data we can locate are items written by Alf The Wollebaek, a biologist, that are included in the Annual -5././eport_on_p_2rwegian Fisheries 193, as well as in Norwegian Fishing News 193 and 195. The first trials with a prawn trawl in the fjord, were undertaken in 1898. The results were satisfactory
2 and generated an immense increase in prawning in a short period. Wollebaek indicates that the mean daily catch was generally between 2 anc. 4 k and states that as much as 18 k were obtained in one haul. His work was undertaken because there was even then.concern about overfishing and no data was available on volume of catch, as related to effort during the preceding years. It was therefore not Possible to determine whether or not these fears were well grounded. Wollebaek resumed gathering data in Oslofjord in 195 and continued until August 196. Fig. 1 shows the mean daily catch. JAN. 'E8R. MARZ APR il émi Anil AU 'Aciie SEPT. 1,M WW DES. 1. raynd. Melkarkkjuafli à dag i ôsliffirtéi 195-196 (A. Wollobmk, Norsk Piskeritideede. oa JAY,'; 4, 1tz,uld.LIx9 4_4e4 skrifter Nr an catch per day in the Oslorjord, Norway. Professors J. Hjort and J. T. Rund discuss prawns in the Whalina Authority,Papers 1938. They furnish data 1.
4 4 3 on the Oslofjord mean daily catch for the years 1934-1936, (see Fig.1). This clearly shows how the daily catch dropped between 196 and 1936 although concern about overfishing was evident at the beginning of the period. Dr. Rasmussen collected data on prawning in Oslofjord in 1951-1952, and states that the mean catch per trawl hour was then about 9 k. In spite of more efficient gear introduced shortly before 196, the catch dropped about 5% in the 1962-1965 period (Aftenposten 1/4 1966) and many considered further prawning in the fjord as not worth while (Aftenposten 2/4 1966). The effort on the inner reaches of the fjord dropped until only 4 men were engaged in prawning in April 1966. Such was the development in the fjord where prawning originated about the turn of the century. Dr. J. A. Allan the British ichthyologist states in a 1959 article (J. Mar. Biolg. Assn. U.K.) that prawning in Norwegian waters at least borders on overfishing and that the mean daily catch is about 1 k. The available statistical information on prawns in Norwegian waters is very limited indeed as the foregoing shows. We have reported all the figures we have been able to obtain in literature on the Norwegian prawn, since the turn of the century until the present. There are for instance no figures on effort.
"! 8 7 6 5 v. El 4 3 Effort in licence months. X Leyfir.m6nudir AN itmcustum Catch in tons. vuwam jpring seaso H Houstumeutu mn seas 14 12 1 8 â -J 6.ry at» F H 11 N 1 H 1 4 1 2 VHVHVHVHVHVHVHVHVHVHVHVHVH M55 mes mer 1958 «9 ffl2 4143 tsede mse 19e5 le67 2. mymi... Heitsfar«U i Iscfjrard5(ip 6 ir,r of, keturtvertd.5, ogs ~k,frtratkizetelninee «lea Lsyfirinditd dri (eiese 1eyfiem4n.u.4fee= einn bticr tr..4545 veialejfi.11 einn, tneinzel), (A. Stetrtteecx. Hangr(son, Rapp. Proc. Verb. Vol. 156, 17.'3. ma c) étrtiketilsgar C. 8kelad4ttur). From Isafjord, iv14 Iceland., x)'cne licence month = one boat with fishing licence for one =nth. Swedes introduced gear similar to that used by NOrwegians at about the same time. They also started using larger boats in the Skagerak. Their total catch increased rapidly, peaking in 1962, but has since dropped just as rapidly in spite increased effort. The Swedish ichthyologists Dr. H. Hoeglund and B. I. Dybern, at last fall's meetings of the International Oceanographic Conference estimated
Lt 5 that the largest obtainable catch per trawl hour in 1963 and early 1964 was about 8 k and that maximum per trawl hour catch was 35 k, (in April 1966). It seems unlikely that Dr. Rasmussen was not aware of the Skagerak developments as Norwegian boats also operated there. Considering the foregoing and especially the data shown in Fig. 1, we maintain that Dr. Rasmussen's assurances that prawns can not be overfished, and that the volume of catch in Oslofjord remains constant, rather questionable. Let us now consider prawning in Isafjardardjup. Effort rose immensely in the 1959-1962 period. In the early stages, total catch rose with increased effort but started a downward trend as early as 1961 dropping to 186 tons in the spring season of 1962, omer 4 tons less than in the 1961 spring season. Catch limits were imposed for the 1962 fall season and maintained at 4 tons for the next two seasons. The stock seemed to be recovering in the winter season 1964-1965 and the catch limit was raised to 6 tons. The total catch rose in the 1965 fall season in spite of unchanged effort. Catch limits, both total and daily were abolished starting with the spring season of 1966 and the total
6 catch reached an all time spring season high of 764 tons. Total catch dropped again last winter in spite of an increase in the number of boats from 17 to 23. Although the stock is still reasonably good, this indicates too great an effort during the last two winters. This is in agreement with conclusions drawn by Unnur Skuladottir who estimates optimal mean catch in Isafjardardjup between 7 and 8 tons per year. (See Aegir, 1966, issue 5) 2 18 8 14 12 Me an Catch per trawling hour. iil l 2 ed-h_pf-d_lerelace 'gym vrive4vmv HVItVifY1i 21511 195 tsii Ise *63 ric4 ets teas nnr 3. raynd. litaralaf/i d togtima og rneefaltlefeliarlongd g haustverti5 varhafjarôardpi_ (A,.ioltrthzeon op I. IlcsitgrieLsgon, Rapp. Proc. Ver6.. Vol. 156. 17, 1.965 og sitreikeingar U.Sit-iiiaeiezieue). FrLe Isafjord, W Iceland. Records have been kept on catch per haul hour since 196. (See Fig. 3) The average kept dropping. until the stock began to recover after catch limits
7 were imposed in 1962. (See Fig. 3) Mean catch per trawl hour in the 196 spring season was 142 k, but dropped to 64 k, about 55%, by the spring of 1963. It rose rapidly in 1964-1965 up to 21 k, an increase of 228% from the low point. It has been dropping since and was probably about 85k this spring, but final figures are not yet available. Fig. 3 also shows length of carapace of prawns caught in Isafjardardjup from the fall of 1959 to spring of 1967. It demonstrates deterioration in size until after the peak effort of 1961-1962, when average size and utilization of the prawn increased with the stock. Assuming that the thesis that prawn can not be overfished, is valid, the catch swings in Isafjardardjup should be caused by fluctuations in the stock or variation in migrations. If this were so it seems peculiar that the total catch should have dropped twice in a few years, (See Fig. 2) following a sizeable increase in effort. We may also emphasize that increased effort resulting in reduced total catch is generally regarded as an indication of overfishing. In recent times, the dangers of overfishing have attracted a great deal of attention and its problems will be discussed at a United Nations Conference this summer.
8 In conclusion it may be mentioned that the foregoing.observations on prawning in Oslofjord and Isafjardardjup should be considered in light of the facts that marketing problems and the economics of prawning in Iceland present greater difficulties than in Norway, and that fishing and processing can not be profitable with such poor catches as Norwegian prawners obtain. Catches related to effort must therefore be much higher than in Norway. Offprint from issue 9 Aegir 1965.