EIFAC/ICES WGEEL Report 2008 561 Table SE.i Amounts (kg) of ascending young eels caught in eight rivers along the Swedish coasts. MOTALA RÖNNE GÖTA RIVER DALÄLVEN STRÖM MÖRRUMSÅN KÄVLINGEÅN Å LAGAN VISKAN ÄLV RBD YEAR/RBD RBD 2 RBD 4 RBD 4 RBD 4 RBD 5 RBD 5 RBD 5 5 1900 530,0 1901 5100,0 1902 340,0 1903 858,0 1904 552,0 1905 8700,0 1906 2000,0 1907 275,0 1908 na 1909 na 1910 na 1911 5728,0 1912 6529,0 1913 20,0 1914 2828,0 1915 na 1916 na 1917 45,0 na 1918 4,5 na 1919 na 1465,0 1920 na 800,0 1921 na 1555,0 1922 na 455,0 1923 na 1732,0 1924 na 4551,0 1925 na 331,3 5463,0 1926 49,0 357,8 3893,0 1927 445,0 581,1 4796,0 1928 0,0 211,9 47,0 1929 0,0 4,5 756,0 1930 147,0 268,0 5753,0 1931 na 316,0 2103,0 1932 na 408,0 7238,0 1933 na 303,5 6333,0 1934 na 236,0 6338,0 1935 na 53,5 1336,0 1936 na 24,5 2537,0 1937 na 0,5 8711,0 1938 na 106,5 3879,0 1939 na 36,0 4775,0 562 EIFAC/ICES WGEEL Report 2008 MOTALA RÖNNE GÖTA RIVER DALÄLVEN STRÖM MÖRRUMSÅN KÄVLINGEÅN Å LAGAN VISKAN ÄLV 1940 na 684,0 1894,0 1941 na 321,0 2846,0 1942 14,0 na 454,0 427,0 1943 283,0 na 1248,0 1848,0 1944 773,0 na 1090,0 2342,0 1945 406,0 na 1143,0 2636,0 1946 280,0 29,7 766,5 2452,0 1947 272,5 5,8 440,8 675,0 1948 120,0 6,0 494,7 1702,0 1949 43,0 39,4 603,6 1711,0 1950 304,5 93,5 419,9 2947,0 1951 210,0 2713,0 1,0 281,8 1744,0 1952 324,0 1543,5 9,1 379,1 3662,0 1953 241,5 2698,0 70,0 802,4 5071,0 1954 508,5 1030,0 2,7 511,3 1031,0 1955 550,0 1871,0 42,6 506,9 2732,0 1956 215,0 429,0 14,1 501,6 1622,0 1957 161,5 826,0 46,8 336,1 1915,0 1958 336,7 172,0 73,2 497,2 1675,0 1959 612,6 1837,0 80,0 910,5 1745,0 1960 289,0 799,0 29,0 93,0 552,4 1605,0 1961 303,0 706,0 665,5 143,7 314,8 269,0 1962 289,0 870,0 534,8 113,0 261,9 873,0 1963 445,4 581,0 241,2 32,5 298,1 1469,0 1964 158,0 181,6 177,8 34,7 27,5 622,0 1965 276,4 500,0 292,3 87,1 28,0 746,0 1966 157,5 1423,0 196,3 48,5 216,5 1232,0 1967 331,8 283,0 353,6 6,6 24,4 493,0 1968 265,5 184,0 334,8 398,0 74,4 849,0 1969 333,7 135,0 276,8 85,7 117,1 1595,0 1970 149,8 2,0 80,4 29,8 24,7 1046,0 1971 242,0 1,0 141,1 53,3 45,3 12,0 842,0 1972 87,6 51,0 139,9 249,0 106,2 88,0 810,0 1973 159,7 46,0 375,0 282,3 107,1 177,0 1179,0 1974 49,5 58,5 65,4 120,7 33,6 13,0 631,0 1975 148,7 224,0 93,3 206,7 78,4 99,0 1230,0 1976 44,0 24,0 147,2 17,1 20,2 501,0 798,0 1977 176,4 353,0 89,6 32,1 26,4 850,0 256,0 1978 35,1 266,0 168,4 10,8 75,8 532,6 873,0 1979 34,3 112,0 61,4 56,1 165,9 505,2 190,0 1980 71,2 7,0 36,5 165,7 226,0 72,5 906,0 1981 6,8 31,0 72,8 49,2 78,0 513,1 40,0 1982 0,5 22,0 129,0 40,0 90,8 472,0 882,0 1983 112,1 12,0 204,6 37,6 87,8 308,4 113,0 EIFAC/ICES WGEEL Report 2008 563 MOTALA RÖNNE GÖTA RIVER DALÄLVEN STRÖM MÖRRUMSÅN KÄVLINGEÅN Å LAGAN VISKAN ÄLV 1984 33,9 48,0 189,9 0,5 68,0 20,7 325,0 1985 69,7 15,2 138,1 0,0 234,1 211,5 77,0 1986 28,4 26,0 220,3 8,6 2,5 150,9 143,0 1987 73,5 201,0 54,5 84,8 69,8 140,9 168,0 1988 69,0 169,5 241,0 4,9 191,7 91,9 475,0 1989 na 35,2 30,0 0,0 44,0 32,7 598,0 1990 na 21,0 72,5 32,0 21,6 42,1 149,0 1991 na 2,0 151,0 na na 161,3 0,4 264,0 1992 9,6 108,0 14,0 12,5 na 42,2 70,3 404,0 1993 6,6 89,0 45,7 25,8 na 8,7 43,4 64,0 1994 71,9 650,0 283,0 4,0 na 30,7 76,1 377,0 1995 7,6 32,0 72,4 2,9 na 11,6 5,5 0,0 1996 17,5 14,0 51,9 13,5 na 2,8 10,0 277,0 1997 7,5 8,1 148,0 19,4 10,4 31,7 7,6 180,0 1998 14,7 5,5 12,9 15,3 24,0 62,6 5,0 0,0 1999 15,5 85,0 84,2 22,2 4,2 49,5 1,8 0,0 2000 12,4 270,1 1,0 5,0 na 13,0 14,1 0,0 2001 8,2 177,5 19,3 34,5 1,8 26,8 1,8 0,0 2002 58,6 338,8 37,4 19,3 27,0 102,0 26,2 693,0 2003 126,1 19,0 11,0 9,7 9,1 31,7 45,1 266,0 2004 26,4 42,0 1,5 248,3 2,0 29,0 5,0 125,0 2005 30,9 24,8 2,5 3,4 0,1 20,5 25,8 105,0 2006 35,1 25,9 2,5 94,4 0,1 38,1 2,7 0,04 2007 19 >30 112,6 76 4,45 77 2,1 0 2008 >30,5 na na na na >25 >3,4 >0 The ascent in River Viskan is totally dominated by elvers that arrived as glass eels the same year. Also in River Lagan there is a considerable proportion of “glass eels” but in the remaining rivers there is a mix of year classes, with eels up to more than 300 mm in TL. No data available = na. 0 for River Göta Älv in recent years (except in 2007) is as a consequence of the fact the eel pass was closed in those years. Data for 2008 are only indicated as the season is not over yet. 564 EIFAC/ICES WGEEL Report 2008 Ascending young eels in eight rivers 9000 8000 Göta Älv Dalälven 7000 Motala Ström Viskan Lagan 6000 Mörrumsån Rönneå 5000 Kävlingeån 4000 Catch (kg) Catch 3000 2000 1000 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Year Ascending young eels in eight rivers, from 1950 onw ards 1000 5000 900 4500 Dalälven 800 4000 Viskan 700 Lagan 3500 Mör r ums ån 600 Rönneå 3000 Kävlingeån 500 2500 Göta Älv Catch (kg) Catch Motala Str öm 400 2000 300 1500 RiversGöta Älv andMotala Ström 200 1000 100 500 0 0 1950 1960 1970 1980 1990 2000 Year Figure SE.10 a and b Long‐term trends in the catches of young eels at various places along the Swedish coast. The lower panel is a magnified version of the upper one from 1950 onwards. EIFAC/ICES WGEEL Report 2008 565 Recruitment indices for young eels 1500 2500 1400 1300 Göta Älv Dalälven 1200 Viskan 2000 Lagan 1100 Mörrumsån Rönneå 1000 Aritmetic mean from all seven rivers Motala Ström 900 1500 Geometric mean for all seven rivers 800 700 600 1000 % of average for 1971-80 for average % of 500 400 ström) (Motala 1971-80 for % average of 300 500 200 100 0 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Year Figure SE.11 Recruitment indices from seven Swedish rivers. Data are presented as percentages of the averages for 1971 to 1980 in the same rivers, respectively. SE.G.1.2 Recruitment surveys/marine data The abundance of glass eels in the open sea (Kattegat and Skagerrak) is surveyed by trawling with either an Isaacs‐Kidd Midwater trawl (IKMT) or with a modified Methot‐Isaacs‐Kidd Midwater trawl (MIKT). The former trawl is used in a fixed posi‐ tion in the intake canal for cooling water to the condensers at the Ringhals Nuclear Power Station (e.g. Westerberg, 1998a; 1998b). The latter method is used from RV Ar‐ gos during the ICES‐International Young Fish Survey (since 1993 called the Interna‐ tional Bottom trawl Survey (IBTS Quarter 1) (Hagström and Wickström, 1990).