Ocean Research and the Great FisheriesClarendon Press, 1921 - 220 pagine |
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Parole e frasi comuni
100 fathoms 1920 the landings 20 fathoms appear April Atlantic August average baby Bay of Biscay bottom British Catch Catch Analysed caught cent coalfish copepods Danois deep-sea Depths of Ocean Dogger Bank drifters east coast eggs England Scotland English Channel European Catch Faeroe feed fishermen Fleetwood fluctuations follows Garstang Grimsby growth haddock hake halibut hatched Hjort Horn Reef inches long inshore investigations Ireland Irish Sea July large number larvae Lebour lemon soles life-history ling mackerel miles millimetres Morocco naturalists North Sea North Shields northern Norway Norwegian ocean research period Plaice Grounds Plymouth ports Sailing trawlers scales Science Scotland shallows Shetland shoals shrimp Skagerrak skate skippers small fish small plaice small-plaice grounds south-west southern spawners spawning grounds species statistics steam trawlers Storrow summer surface Tees-Skaw line temperature Tons Total transplanted trawl turbot Westward of Scotland writer yolk-sac young fish
Brani popolari
Pagina 201 - ... points out, is obviously contributing generously to high taxation. It stands to reason, as night follows day, that it will continue to add to our financial burden as long as it proceeds unchecked. Such evils do not disappear of themselves. England took warning of conditions, for its experts in 1919 believed that the population of the sea varied more or less in inverse ratio to the number of fish killed by fishermen, and that nature left to herself would add an even approximate accretion to the...
Pagina 199 - British coasts have been carried out for the Ministry of Agriculture and Fisheries and the- Fishery Board for Scotland.
Pagina 157 - ... inches in length. After remaining on the coast for a certain number of weeks, the herring deposits its spawn on hard, clayey, or rocky ground, or gravel, before leaving the bays or estuaries where it resorts. The female first ejects the roe, which is afterwards impregnated by the ejection of the milt of the male. Sauer describes the mode of impregnation from actual observation, and states that in the inner harbour of St Peter and St Paul, Kamschatka...
Pagina 15 - ... were the reverse of easy, as the metre-wheels froze up, and we had to keep them warm with thick red-hot iron bars that were brought from the engineroom and held close to the wheel axles.
Pagina 15 - ... about nine o'clock that evening we had a hard job to get the ship round against the wind, her sails being so stiff with ice that it was impossible to take them in.
Pagina 24 - ... is, not that so little, but that so much, has been accomplished. We must
Pagina 70 - ... manipulations of the attendant who went amongst them and removed from the dead fishes the ripe eggs and milt, placed them in sea-water and showed them how the former floated as minute spheres of glassy transparency, soon altered their opinions. Many of them were by and by provided with earthenware jars which they took to sea, and in some instances were successful in bringing to the laboratory fertilized and floating eggs of forms not yet examined.
Pagina 145 - ... after immersion in spirit) along the ventral edge of the abdomen and clavicle. The lemon-dab has thus a very hardy larva, almost as hardy as the plaice, and little difficulty would be encountered in hatching and rearing it for a considerable time under artificial circumstances. So hardy are the larvae that a number lived about six days in a small glass cell 2 inches by £ inch deep, the water being filled up as it evaporated. The early post-larval condition of the lemon-dab is probably that represented...
Pagina 78 - The eggs are about ,L-- inch in diameter, and are quite delicate and tender. The spawning time extends from January to June. The average production of eggs per fish is about 100,000. The eggs are slightly glutinous and have a tendency to form into small lumps during hatching. At a mean temperature of 37° they hatch in 15 days, and at 41° in 13 days. The yolk-sac is absorbed in 10 days at a temperature of 41°. The tomcod or frostfish (Microgadtts tomcoil) has been extensively propagated by the...
Pagina 70 - ... floating eggs of forms not yet examined. Thus a change was speedily brought about without much notice, so that in July of the same year (1885) when, with Prof. Ray Lankester, at Oxford, urging the University to support the scheme for the proposed Marine Biological Laboratory at Plymouth, one of us was able to adduce this fact as an instance of the effect of such institutions even on the opinions of the fishing population. 1 Now Commissioner of Fisheries in Canada. Floating w Pelagic Eggs.