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409 Verf. weist darauf hin, dass L e a die Proportionalitat des Wachstums von Korper und Schuppe beim Hering fiir den dorsoventralen Durchmesser einer Normalschuppe nachgewiesen hat, dass aber fiir die Messungen und Langenberechnungen der oral vom Schuppenzentrum gelegene Abschnitt des Ldngsdurchmessers benutzt wird, der, wie M o l a n d e r nachgewiesen hat, nicht genau proportional zum Korper wachst. Es wird sodann nachgewiesen, dass bei den drei im Titel genannten Arten der Langsdurchmesser der Schuppe und dessen oraler und caudaler Radius nicht proportional zur Korperlange wachsen. Das wird bewiesen durch Messungen an Normalschuppen, die an bestimmter Stelle der Korperseite genommen werden. Die Schuppe wachst entweder dauernd oder doch anfangs schneller als der Korper. Das Missverhaltnis ist beim oralen Radius sehr gross, beim caudalen dagegen viel kleiner, sodass man z. B. bei Leuciscus idus durch Messung des caudalen Radius ziemlich richtige Resultate erhalt. Bei Messung des oralen Radius erhalt man aber sehr deutlich "verandertes Wachstum", das demnach auf einen methodischen Fehler zuriickzufiihren ist. Die Korrektion durch eine additive Konstante, wie verschiedene Autoren sie vorgeschlagen haben, fuhrt auch in diesem Falle zu einer Verbesserung der berechneten Langen. Doch hat die Grosse der Konstante nichts zu tun mit der Korperlange bei der Anlage der Schuppen. Der Verf. schlagt nun eine viel besser begrundete Korrektion vor. Er verwendet dazu sein grosses Material von zusammengehorigen Korper- und Normalschuppenmessungen in folgender Weise: Die Schuppengrossen werden als Ordinaten in einem bestimmten Punkt der Abscisse eingezeichnet. Von einem anderen festen Punkt der Abscisse werden Strahlen durch die Endpunkte der Ordinaten gezogen. Auf jedem Strahl wird der Punkt gesucht, der von der Abscisse den Abstand hat, der der mittleren Korperlange bei der gegebenen Schuppengrosse entspricht. Waren Schuppen- und Korperwachstum einander durchaus proportional, so wiirden alle diese Punkte auf einer Parallelen zur Ordinate der Schuppenlangen liegen, denn durch ein Strahlenbiischel werden parallele Geraden in proportionale Abschnitte zerlegt. Da aber keine geradlinige Proportion besteht, so liegen die gesuchten Punkte auf einer von der Parallelen abweichenden gekriimmten Linie, der "Korrektionskurve". Da die Schuppe anfangs schneller wachst als der Korper, so hat die Korrektionskurve fiir kleine Langen grosseren Abstand von der Ordinate als fiir grossere Fische. Die Korrektionskurve kann nun, ganz wie bei L e a der parallele Masstab, zur geometrischen Bestimmung der Fischlange zur Zeit der Bildung der einzelnen Winterlinien benutzt werden. Das Verfahren setzt allerdings eine betrachtliche Vorarbeit fiir jede Art (vielleicht auch fiir jede Rasse, jeden Wachstumstyp?) voraus, liefert aber dann einwandfreie Korrektionen. Wo biologische Selektion die Ursache des "veranderten Wachstums" ist, wird es durch diese Korrektion nicht verdeckt A. Biickmann. L. B e a u g 6 . "Rapport de mission au Greenland (campagne 1931)." Rev. des Trav. de l'Off. des Peches Mar. T.V, Fasc. 1, No. 17, Paris, 1932. The author of this report adduces further, but naturally still incomplete, evidence in support of his bold and important hypothesis of correlation between the succession of events in the spheres of meteorology, hydrology and the fisheries. We witness an attempt to fill in supporting data for the validity of the lesser phases of the range (41/2—9—18—111 years, in relation to sunspot variation), hitherto drawn attention t o b y L e D a n o i s and linked
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410 to the variations in the time of occurrence of warm and cold transgressions in the northern hemisphere. The author traces these variations to their meteorological sources, defining four cold and four warm regions (anticyclonic zones and zones of depression) in the northern hemisphere, and showing how the displacement of these centres during the year determines the chief air movements, which in turn, directly and indirectly, have a considerable influence on the movements of water masses. There occur quite a number of different combinations of the effects of ordinary superficial summer heating of the water and of cold (from the north) and warm (from the south) water influxes, or transgressions, into the Newfoundland—Greenland area. The most constant factor is; that of the solar heating of the surface layers; in the north, at Greenland (and probably also at Jan Mayen and Spitzbergen) the water becomes suitably warm for large masses of cod only during alternate periods of 4 % years when solar heating synchronises with a strong northerly transgression of warm water of Atlantic origin. It is claimed that this has occurred at regular intervals, the most recent favourable period being from 1927 to 1930. A progressive delay in the time of incidence of the warm transgression led, in 1931, to the occurrence of the latter near the close of the year — too late to combine with the ordinary summer-heating effect. The 1931 fishing season was therefore a short one; trawler catches diminished by 30 %, since water conditions soon became too cold for cod. The author's forecast that this would occur was therefore borne out, and he anticipates diminishing fishery returns from Greenland, and increasing returns from the Newfoundland area, during the ensuing 4 % years. In other words, good periods for the cod fishery alternate between Greenland and Newfoundland and can be anticipated. In contradistinction to what must occur at Greenland in order that a good fishery may ensue, the most favourable conditions exist at the more southerly latitude of Newfoundland when the influx of cold water from the north is in sufficient volume to temper the warmer and more regular influx from the south. The catches of cod are greatest in years when the combined heating effect, so favourable at Greenland, is absent, and when lower average temperatures are maintained. The author anticipates that the period 1932—1935 will be favourable at Newfoundland. The abundance of cod, he states, is bound up with that of the polar water in the Newfoundland region. Cod spawn in water having a temperature of between 3° and 5° and a salinity between 33 and 34 °/ooSuch water last abounded in the period 1923 to 1926. In 1927 the warm transgression greatly exceeded the cold in effect, and polar water remained deficient in amount till 1931. A period of remarkably mild winters occurred at Newfoundland. The author favours the view that great masses of cod move from Newfoundland to Greenland when conditions become more favourable in the latter than in the former region. It is essential to confirm this theory by tagging experiments. Tagging experiments off the coast of the United States have tended to show that cod populations are largely localised, and this finding can be supported, at least for young and medium-sized fish, by biological evidence, which does however leave room for deducing that there are very extensive migrations made by large cod. Such movements have recently been demonstrated by tagging to occur between Greenland and Iceland, and the author neatly shows that the migration became more intensive as conditions at Greenland became less suitable. Since a return migration to Greenland can occur, this is not merely a general northerly migration with increasing age. If in places the specific evidence is on the weak side that the. yield of
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411 cod agrees entirely with the author's forecasts and what is to be expected of certain hydrographic conditions, he is to be congratulated on giving us a hypothesis which is broadly applicable and something of a godsend to the practical fishery biologist. H. T. L. V e r b r u g g h e . "Die belgische Seefischerei." Handbuch der Seefischerei Nordeuropas, herausgeg. von H . L i i b b e r t und E. E h r e n b a u m . Bd. VII, Heft 3, E. Schweizerbart'sche Verlagsbuchh., Stuttgart, 1932. It is well known that in earlier times the sea fisheries of the two countries which are now separated, Belgium and Holland, were similar, if not identical. In Flanders we find in later mediaeval times the same relation with the powerful Hansa League and the same active part in the Skania fishery as in the Dutch province of Zeeland; indeed, Flanders took the lead in this line. At a time when Ostend scarcely existed Newport was the principal fishing port. The discoverer of proper herring curing, B e u k e 1 s, belongs, it would seem, as well to Flanders as to Holland. In the fifteenth century Belgium had herring busses similar to those in Holland. From the year 1579, when the northern provinces in their revolt against the Spanish King declared themselves independent, the Flandrian fisheries took a different — and on the whole downward — trend owing to political difficulties. In the repeated wars the Flandrian fishermen took to privateering and piracy. The peace of Miinster (1648) was disastrous to the Southern (then Spanish) Netherlands; the Scheldt and the Zwin (which silted up) were closed to their subjects, and in the later part of the seventeenth century Dunkirk, the cradle of rather lucrative sea-roving in jhese troublous times, was taken by the French. Newport was doomed to unimportance, and Ostend occupied herself occasionally with some whaling. Under the sway of Austria, to which the Southern Netherlands had fallen in the beginning of the eighteenth century, some efforts were made to revive sea fisheries by instituting prohibitive tariffs on foreign imports of fish. Yet there was always some drift net fishing in the North Sea and line fishing at Iceland. After the Napoleonic wars Belgium was incorporated in the kingdom of the Netherlands. In this period the beam trawl was introduced at Ostend; protestations in Holland against this new method brought about a close time from November 15th to February 15th in this country, but were ineffective in Belgium. After the separation of 1830 a slow improvement began, and premiums for sea fisheries were instituted (up to 1500 fr. for herring busses). Small coastal vessels, fishing for autumn herring, were allowed by a special license to cure, their herrings as the busses did, so they were not strictly excluded from doing so, as was the case in Holland. Premiums were abandoned in 1867. Towards the close of the nineteenth century the Belgian fishermen, who were excessively poor, found it necessary to engage their wives and children actively in all sorts of industries, to raise the meagre earnings. The first small steam trawler was introduced into Ostend in 1884, but the gradual development of steam trawling, beneficient though it was to the sturdier fishermen, was on the whole a blow to the modest sailing craft. During the war years many Belgian fishermen emigrated to England and made accquaintance with new fishing grounds. After the return of peace a rapid development set in. The number of steam trawlers, which was 24 in 1919, increased td 57 in 1928, then fell, however, to 36 in 1931. Motor
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