Translation Series No.1211

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6.2. Amount and kind of food according to my own investigations 1957 to 19 6 4 - 180 - ' The present investigations were carried out between 1957 and 1964 on 2400 salmon (Table 47). More than one-half of the stomachs have been analysed on'land in the laboratory. For the collection of the mat- erial several salmon cutters were supplied with plastic pails that held about 70 to'80 stomachs each. After gutting, the fishermen put the entire intestines in formaldehyde on board. In this way it was possible to det- ermine also the sex of the fish. No exact statements of length could be obtained. Instead the length of the stomach was measured. The comparison Table 47. Number of salmon investigated and their times of capture Month Time of capture 1957/8 '1958/9 1959/60 1961/2 1962/3 1963/4 September . 25 23 Oktober - 91 71 66 November • • 221 151 . Dezember 122 151 . Janua'r 156 71 54 Februar 36 Mârz • . 210 . 77 280 April . 157 71 159 . • Mai 151 • Juni 63 . •of the frequency distribution of these values with the series of measure- ments of coMplete catches df'salmon (Fig. 54) shows that a stomach length of 10 cm corresponds about to a tdtal length of fish of 66 cm and each further cm to a body length of 2.5 cm. In every case thé totarweight of the stomach content was ascertained first and then the weight and number of the individual prey. It 'was in general possible to identify food items that.had been strongly . digested with the aid of ooliths or by counts of vertebrae. That.was • • • [p. 336]
- 181 - especially decisive in, the „separation of clupeids into sprat and herring. Nevertheless, there remained a small percentage Of clupeids that could not . be identified and a further part of fish that could. no longer be determined.. . The former have been assigned to sprat and herring according to the shares of these two species that had already been ascertained. In the investigations of food at sea ia was only possible to count and measure the prey. These figures have later been recalculated into weightS with the 'aid of the relations that had been established in the laboratory. • Of the 2406 stomachs of salmon that have been examined,1198 49.8 per cent contained food with a total weight of 36,139 g. Of this 1416 g consisted of a slimy food mash. The remaining food constituents have been listed in Table 48. They amountto 34,723 g. Notwithstanding the rather long list of foo&constituents it is seen that only five specieS of fish and one crustacean species are of decisive importance. The clupeidP, especially the sprat, alone made up over 88 per cent of the food,weight, The sprat was found in 60 per cent of all .salmon that had taken food and herring in 20 per cent. Besides these two species of fish should be mentioned in the order . of their .importance, (2.8 per cent of the food weight), Ammodytes (2.6 per cent), and stickleback (Gasterosteus, 0.9 per cent). These fish Were found in 5 to 10 per cent of all salmon that had food in their stomachs. As a last group of importance have to be mentioned the mYsids, which made up 2 per cent of the weight and had been eaten by 9 per cent of the salmon. [1" 337] Cod, amphipods and Crangon were present in 1 per cent of the salmon. With the exception of the cod they do nàt play any role, in regard • to Weight, «nor as to the number of individuals (Table 48).
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FISHERIES RESEARCH BOARD OF CANADA
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sos-2cto—lo-31 DEPARTMENTOFTHESEC
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• 6.1. Previous investigations 17
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-5-. and Kerr very much later menti
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treated as a quality, a special pop
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• -9-- per cent). Furthermore, th
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• - 11 - fishery, mentions the gr
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• - 13 - in LiepUva. These voyage
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• 1948/49 545 1949/50 730 1950/51
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• 2.2.1. River fishing - 16- The
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- 18- are 50 norsels, 60 to 80 cm l
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• nets give better results is onl
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• • G Fig. 4. End buoy for salm
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• with • Total length (cm) Mout
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• • - 25- of Bothnia. In the fa
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• • - 27- increase the catch. S
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• of • fishing representsavalue
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• to lower figures than in the fa
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• • Umfang = Cire umference - 3
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• - 35 - and nape corresponds to
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• • / 100 50 Selektion Selectio
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- 39 - In Table 9 have been calcula
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. Table 10. Number of salmon per 10
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• Table 11. Number of salmon per.
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• - 45 - cza-ci, es When consider
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- 47 - If We examine once more the
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- 49 - German fishermen work during
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• - 51 - is true, have to be corr
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Table 16. Seasonal yields of the fi
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Table 17. Monthly average weights o
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- 57 - In February and March hardly
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• Table 20. Additional catch of c
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• 100 50 60 100 cm Totallarle . 2
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• subject to an error of ± o.op9
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cycle) during the second . period o
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• their third year. , Recruitment
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50 r-■ 2 / bet; 56cm = 1 fis 1 li
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• - 71 - ovary that has already b
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5 - 73 - April 1960 the diameter of
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- 75 - oocytes can be demonstrated
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. ineftlerer Mean OocytendurcArness
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- 79 - furnish the energy fer the s
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' 1741 salmon, which were.caught be
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• - 83- the series of measurement
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- 85 - the relative amount of eggs
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- 87 - The calculation of a formula
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- 89 - area of distribution is form
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- 91 - as percentages of thé recov
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Table 22. The recapture of tagged s
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• II> Three conclusions can be dr
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• 6 65- 64 - 62-. 61 - 6 . 5 . 59
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• - 99 - fish. The tagging does n
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- 101 - tagging experiments'that sa
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- 103- Renne Bank in about 60 m dep
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• 9:1 0 a) el-4 o (XI -P CNI 4- o
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14,3 14,3 30,7 31,3 27,7 6,0 15,0 1
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Table 26. Catches of salmon in the
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- 111 - between Hela and Kahlberg r
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• - 113- 5 .. Age and growth of t
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cm 100 80 60 40 - 1 15- customarily
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found can be used for the recalcula
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v 0 00 0 I I - 119- of the scales.
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- 121 - The interpretation of the y
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• - 1 23 - the age groups 2.B to
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• L s - L c r s 0.85 Smolt Ls = l
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5.3. The'age composition of the Ger
Page 133 and 134: -129- with shares in the catch of o
Page 135 and 136: "ervoct. Yeer-Le- -e-t. '4.y-c.1*.e
Page 137 and 138: 1955 1 2 3 4 23 3 61 506 7 3 135 21
Page 139 and 140: - 135 - yeAy-ctt4 thé explanation
Page 141 and 142: • • _ Table 33. The composition
Page 143 and 144: Table 34. Composition by age of cat
Page 145 and 146: - 141 - yeAy-cle..es Table 35. The
Page 147 and 148: - 143 - • U7,) tdL comparablenece
Page 149 and 150: • whereas the present data .(1957
Page 151 and 152: Sin% 0,1 2,8 37,0 96,8 100,0 - 147-
Page 153 and 154: • - 149 - these results 38 per ce
Page 155 and 156: • • Number of salmon J. en1967
Page 157 and 158: 4. number 50 e" • ); e e , lot nb
Page 159 and 160: they take account of the annual cha
Page 161 and 162: • -157- and in the stock are bein
Page 163 and 164: Table 43. Mean lengths of age group
Page 165 and 166: • - 161 - of these catches has be
Page 167 and 168: - 163 - of enolt in Fig. 36. From a
Page 169 and 170: --165 - increase'in weight is more
Page 171 and 172: • rl -P b..0 -e nzi -ri r-1 gl a)
Page 173 and 174: - 169 - CLA‘s set of smolt of 193
Page 175 and 176: Year's sets of smolt CILS present 7
Page 177 and 178: - 173 - necessary to follow the gro
Page 179 and 180: - 175 - • been ascertained from t
Page 181 and 182: (after K. A. Pyefinch 1955). — 17
Page 183: • gadids and sticklebacks (after
Page 187 and 188: 6.3.1. Seasonal fluctuations 36,9 2
Page 189 and 190: • Number of Months Gear salmon in
Page 191 and 192: MagerdW hing 40 , 20 Filling of Sto
Page 193 and 194: Deep could be examined. - 188 - Chr
Page 195 and 196: - 190 - salmon . switch over to the
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Page 199 and 200: - 194 - amount of food. Under-consi
Page 201 and 202: - 196- expenditure, composition in
Page 203 and 204: • - 1 98- the stock losses are co
Page 205 and 206: NUmber of salmon per Z Weigh- Seaso
Page 207 and 208: • 'Table 55. Values of the total
Page 209 and 210: - 204 experiment were about 40 per
Page 211 and 212: - 206- strength of the stock N pert
Page 213 and 214: • N„ Z o = cf„ (M1- T) -- In
Page 215 and 216: — 210— the coefficient for the
Page 217 and 218: - 212- In a further paper Piggins (
Page 219 and 220: - 214- shifted and the fOod supply
Page 221 and 222: - 216 - concerns the yield of captu
Page 223 and 224: nachafter 00 04 0,3 0,4 2 1 0,5 6 9
Page 225 and 226: • 1. (5 100 000) (4 250 000) 4 25
Page 227 and 228: • •em.ilts - 222 - in an error
Page 229 and 230: • - 224- BRANDT, A. y. , 1959: Fa
Page 231 and 232: - 226 - Paw, T. H., 1938: Fluctuati
Page 233 and 234: - 228- PETERSEN, C. G. .11, and Orr
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Table I. Captures per unit effort w
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Table II. Captures per unit effort
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• Yea.r Sweden Continuation Table
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Table VI. Ratio between fork le . B
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Translation Series No.1211

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