Gundersen, Kaare R.

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International Council for the Exploration of the Sea C .M.1973/K: ~~2 Shellfish and Benthos Committee Catch stat.istics of lobster (Homarus vulgaris L.) by . x) Kaare R. Gundersen INTRODUCTION The lobster fishery is rather young among the Norwegian fisheries. The increasing demand for lobster in the Netherlands around the year 1600 gave the impuls to the Norwegian lobster fishery and export. At the beginning the lobster stock must have been very rich along the Norwegian coast. During the first 100 years of the fishery the whole catch was taken only by pinchers. tines two or three fathoms long. By ~eans of this tool it was possible to take about 240 lobsters du-ring an early morning. Later, lobster pots were used and it was poss-ible to catch lobsters on greater depths. During the following cen-turies the catch flucturated. partly because of varied demand from other countries or due to natural protection caused by different wars in Europe which stopped the export. STATISTICS The first statistics of lobster in Norway only deals with the number of and goes back to 1815. From 1933 onwards the co.mmercial catch ,of lobster is given in metric tons. The highest catch recorded in this. country was taken in 1932 and amounted to about 1300 tons. The lan-dings decreased a little during 1930 -39, but the average catch these years reached about 1000 tons. During the World-war 11 the statistics is more or less inreliable. From 1946 to 1960 the landings only shows small variations with a average yearly catch about 700.tons. From 1960, however, the Norwegi-x) Institute of Marine Research Bergen, Norway .. . 2. an landings of lobster have declined steadily from year to year and reached the lowest record in 1972 with only 150 tons. DISCUSSION The variations in the catch from 1946-1960 may be due to natural fluctuations in the stock. recruitment and fishing intensity~ but it is difficult to explain the steady decreasing in landings from 1960-1972. The main fishery in Europe take place in the countries around t~e North Sea.. In Fig. 1 the landings of lobster in Denmark, S''leden and Norway from 1946 to 1970 are given graphically. Fig. 2 shoW's the landings in Ireland, England and Scotland in the same interval. .. I 1300 r '·,200 . .11CO r 1000 r. 900 ~ I SCD I ". 500 400 300 200 100 Fig. 1 Dcnr.:ark Swoden ~cE'way Annual lobster landinSs in Ireland, Ev&land ~ Scotland 1946-79 1700 1600 . {soo R Ireland ~;' England U Scotland 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 1946 40 50 52 54 56 58 GO 62 64 66 '68 70' Fig. 2 The figures shows a marked difference in catches on the east and west side of the North Sea. The explanation for this difference is rather difficult to find. However, with the last yearsl problems of pollut~on in mind, it is natural to start by looking at the water currents on the two sides of the North Sea. Lee (1970) gives two figures of water types and cur-rents of the North Sea in winter and summer reproduced here as Fig. 3, and Sretre (1973) gives a detailed figure of the water current along the Norwegian coast, Fig. 4. " t '0' 10' rt 60' SI' \1' o 2' 10 -Water types and currents of the North Sea in winter according to Bohnecke (1927.) nnd Laevastu (1963). ' Prlmary water types 1. North Atlantic. 2. Channel. 3. Skagerrak, 4. r r r ~ 6 r r -Water types nnd currents of the North Sea in summer according to Dohnecke (1922) and Laevastu (1963), Secondary (mixed) water types 4, Scottish Coastal. 5, English Coastal. 6. Continental Coastal. 7, Northern North Sea, 8. Central North Sea, ' Fig. J. After Lee (1970, Fig. la and 1b). 76' 6S' 66' 6~' Fig. 4. After'Smtre (1973, Fig.l). 1-2<-3 <lo= 68' 66' 60' According to these figures the water masses on the west .sideof the north sea originate from the-Atlantic, with the coastal current along Sweden and Norway is dominated by water from the Baltic. Investigations in the Baltic the last years have shown a higher de-gree of pollution than in the Atlanti~ and the North Sea {Jensen,S., _Johnels,A.G., Ohlson,M. and Otterlind,G. 1969). CONCLUSIONS From the material presented it is not possible to give any explanati-on of the marked difference in landings of lobster at-the coast on the east and west side of the North Sea. The high degree of polluti-on in the Baltic, especially of insecticides may influence the recrui t-ment of lobster along the coastline in Sweden and Norway, and perhaps investigations of this problem would be of value. REFERENCES --Jensen,S., Johnels ,A.G., .. Ohlson,M. and Otterlind,G. Lee ,A. Scetre,R. 1969. DDT and PCB in Marine Animals from Swedish waters. Nature, 224 (5216): 247-250. 1970. The currents and water masses of the North Sea. Oceanogr. Mar. BioI. ~ Rev, 8: 33-71. 1973. Temperatur- og saltholdighetsnormaler for overflatelaget i norske kystfar-vann. Fiskets Gang, ~ 166-172. 

Catch statistics of lobster (Homarus vulgaris L.)

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