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Relation between the periodical variations in the average size of the skrei and the fluctua- 
TON SÉO fee tee dS ING SR RE ee le ee ee ee ee 161 
Investigations of cod and haddock in the North Sea and southern Norwegian waters... 164 
CHAPTER V 
Eluetuationsjintqualityar ee ee Eee ee Ele er ee ee he 168 
SCO the WORKOUT A IE N Ren ee LE ep ee eo CN 168 
Importance of fat as a determining factor in the quality BF a See sas ne tebe etc ee RNA 168 
Variation in quality of the herring: FAAAMS AMOUNE Où SEP cococosccncscc000unc000 169 
Amounbonlabinghertinen.. en ee nn nee aies ete ne en ee ee 170 
Amountgolatateinkthel Sp tarts sera ee alter ven celte cer teen ee EAU 171 
Variations in the composition in point of age and size of the sprat................... 172 
Comparison of different species of Clupeides . 0.8 ONG REY MOO MOBO dO 10,010 60 ARE. 15 174 
Variations 10 the quais OÙ Une Giono cb éacoodooaucacdedbotostosaose ed odoeoocous 176 
Hluctuations im the quantity of liver trom! year to year. EN EE EE ae ee 177 
Hluctuationsmne the vcurrents ieee ee es ers ee here ie tee 179 
Helland-Hansen’s and Nansen’s comparison of fluctuations in the ocean currents with those 
OfenteMehiS Me reas REN te ne DO ie shale TE A oe eo le ee ee es 179 
Later observations as to the theories of Helland-Hansen and Nansen.................. 183 
Waring: ec oi ung Coal Mens CHAN » 0.0000 cco ccnaesassacnddn00000050eeqRa00nC 183 
Variation in GUanEyROR LENS ta seine dee 184 
No relation between the number of sun spots and quantity of liver................... 186 
Einar Lea’s hydrographical investigations, 1910—1912................................ 187 
Biological investigations as to the ‘fluctuations in quantity of cod liver and roe........ 192 
Comparison between size of fish and WEICHE Ole er eo connie moe alse imeem eee 192 
Study of the influence of nourishment on the quantity of liver; necessary preliminaries. 194 
Gta OF liver for tie Cent GWA Lou p SE 195 
Varying quantity of liver in the size groups compared with fluctuations in the average amount 
of Miversin the skreimiromltyear tol yeat rss saa ee ee: 196 
Comparison of the quantity of liver in the first and last week of the skrei fishery ..... 197 
Tine: Loioten tislvery iin 10 and) WN. Ee oceoccoesdoocoocdcosopcodoceooodvovonatoo 199 
K. Dahl’s investigations as to the fluctuations in the salmon fisheries ................. 201 
CHAPTER VI 
Review of the present position of the Investigations .................................... 202 
Results hitherto tobitaime dacs tere ee ee re ua tre oem mieten 202 
Origin OF the lucinations in menewall où Wine SHOCK oo. canocesncasnacsovacsansonnDcCEse 202 
Stage at which the numerical value of a year class is determined..................... 203 
Extent of spawning and numerical value of year classes ..................---+-++---- 204 
LAINE GING! VOUS WAY SIRES 0.6.0 0.0.00 00800800000 0.0.0 0.0.0.0 0.0.06.0.08000.00800000000.50000.000 204 
NON Sen RO EMA a Ne ee tp Mic One EE PRET Lies Eon ot 204 
Dani OH Wie lewd euvel youn iieyy yim WOE (UVARSNIS . oa caccnangccagndcnscausooosencee 206 
Matter sStamesie une ne ie er Los edel cree eee ae ON ene oi mere le 21 Re stesso eter ee 206 
C. G. Joh. Petersen: Fluctuations in the annual numbers of certain Invertebrata........ 207 
Great mortality of older stages where cold and warmer currents meet................. 208 
Fluctuations among the earlier stages probably of greater importance ................. 208 
Importance of future investigations as to the causes of numerical variation............ 209 
Knowledge required for predictions as to future composition of the stock and consequent yield 210 
Mariner: OF Gmployine Une mano oo cococgccndeacdoonnevesnabonadcoavacccadoogooo bo 210 
Possibility of obtaining samples truly representative of the composition of the stock in point 
ORTEN ee Det yo ER ee atten A har Sve nate Rey Rica aa NC EN eee east 211 
Possibility of general knowledge as to the longevity of different species ............... 211 
Possibility of deducing amount of yield from the composition of year classes .......... 212 
Investigations as to the Norwegian fisheries in the spring of 1914....................... 217 
Future prospects of the Norwegian Inge GUNG COC! WENEAES o.oecccecoccnccoo00d0boncnse 227 
