423 E. EHRENBAUM. Der Flussaal, Anguilla vulgaris Turt

423
E.
Der Flussaal, Anguilla vulgaris Turt. Handbuch der
Binnenfischerei Mitteleuropas. III. E. Schweizerbart'sche Verlagsbuchhandlung (Erwin Nagele). Stuttgart 1930.
EHRENBAUM.
The present paper, which has appeared as a reprint from the large
work "Handbuch der Binnenfischerei Mitteleuropas", is dedicated to the
Danish biologist, Professor JOHS. SCHMIDT, "the keenwitted and successful
investigator of the life-history of the eel".
It may be said at once that this paper is clear, compact and up-to-date
and gives, so far as is possible in the limited space, a comprehensive account
of the biology, the economic value and the practical fishery of the european
eel. As the whole paper covers only about 60 pages with numerous illustrations, it has naturally been impossible to give a more detailed view
of all the different questions in connection with the life-history and the
economic importance of this fish, but looking through the paper, the reader
will be surprised at the number of details to be met with.
One of the most interesting sections of the paper is that which deals
with the propagation and the young stages of the eel, and here we find
a short review of all the important investigations of Professor SCHMIDT.
In the most clear and attractive manner a description is given of the different expeditions with a short statement of the results which were obtained on the various cruises in the Atlantic. Furthermore, the author
mentions the few points regarding the breeding of the eel which are still
open to question. In the other sections relating to biology, we find a discussion of all the most important points of interest, as migration, food, growth,
enemies and diseases of this fish, together with a description of the differences in the appearance and development of the sexual organs.
The paper is concluded with chapters on the economic value of the
eel fishery, and on the fishing gear and methods of fishing. Here the author
gives a particularly interesting account of the importance of and the
practical details relating to the transplantation of elvers from Atlantic
coastal waters to the continental countries of Europe.
Naturally the present paper essentially comprises a summary of previously published observations, but it gives in the most excellent manner
a survey of our knowledge of the eel. The style is simple and agreeable,
so that not only scientists but also readers who may have only the slightest
interest in biology will be able to read it with advantage. P. JESPERSEN.
C. F.
HICKLING. A contribution towards the life-history of the Spur-dog.
Journal of the Marine Biol. Association. N. S., Vol. XVI, No. 2.
Plymouth 1930.
Die zahlreichen Untersuchungsfahrten, welche der Verfasser im Auftrage der englischen Fischereibehorde in den letzten Jahren zum Studium
des Seehechts (Merluccius) unternommen hat, gaben ihm Gelegenheit, auch
andere Fangobjekte in den Kreis seiner Forschungen zu ziehen, und die
oben genannte Veroffentlichung gibt davon bezuglich des Dornhais (Acanthias vulgaris Risso) interessante Kunde, die die fruher in der gleichen
Zeitschrift (Vol. XII, p. 468) veroffentlichten aufschlussreichen Mittei-
424
lungen von E. FORD vorteilhaft erganzt. (Dr. J. R. NORMAN macht darauf aufmerksam, dass die richtige Benennung dieses Fisches ist Squalus
acanthias L. Journal du Conseil 1930, p. 261).
Die ungewohnlich grossen Tiefen, in denen die Untersuchungen iiber
den Seehecht zum Teil vorgenommen wurden, gaben Gelegenheit, das Verhalten des Dornhais in diesen Regionen kennen zu lernen, wo er bisweilen
(z. B. im Gebiet der Faeroe-Shetland-Rinne) neben dem Kohlflsch als einziger Nutzflsch angetroffen wurde. Die in der Tiefe gefangenen Dornhaie
waren durchweg grosser als in den flacheren Gebieten, und zwar wurden
die mannlichen Fische in flacherem Wasser angetroffen als die Weibchen
gleicher Grosse. Aber die grossen trachtigen Weibchen machten insofern
eine Ausnahme, als sie meist auf der Wanderung in flacheres Wasser beobachtet wurden.
Nach Ausweis des Leber- und Fleisch-Gewichtes waren die Dornhaie
des tieferen Wassers meist in besserem Ernahrungszustand, doch ist das
wohl nicht als feste Regel anzusehen.
Das Lebergewicht nimmt in beiden Geschlechtern mit der Lange zu,
ist aber beim Weibchen gewohnlich hoher. Trachtige Weibchen biissen
ihren Ernahrungszustand ein bei der Wanderung auf flacheres Wasser.
Verfasser vertritt die Ansicht, dass der bessere Ernahrungszustand in
tieferem Wasser der giinstigen Einwirkung des hoheren Druckes auf den
Stoffwechsel zuzuschreiben ist, da derselbe dem Aufbau von Reservestoffen
giinstiger sei als dem Abbau. Der erhohte Stoffwechsel in der Zeit der
Geschlechtsreife veranlasse daher die grosseren Fische tieferes Wasser aufzusuchen, und zwar die aufbauenden Weibchen in starkerem Masse als
die Mannchen.
EH.
H. S.
DAVIS. Care and Diseases of Trout. U. S. Department of Commerce,
Bureau of Fisheries, Document No. 1061. Washington, 1929.
This report has as its subject trout breeding in the United States of
America, where trout farms are conducted by the government as well as
by private persons.
The increasing demand for large trout for stocking purposes has added
to the problems of the breeder, who has now to keep fish growing and in
health until they are large enough to satisfy the demands of the customer.
Mr. DAVIS deals with the methods by which this can be successfully done.
Salvelinus fontinalis is the trout to which reference is chiefly made.
The first section of the paper is on the care of flngerling trout. It is
the aim of the breeder to reproduce natural conditions as far as possible,
and the methods of doing so are discussed in detail. Out-of-door raceways
are recommended as the best means of holding fry as soon as they begin
to feed. The next section deals with the care of raceways and ponds.
As regards the food best suited to the requirements of trout, a mixture
of beef heart and liver is recommended as the best diet for young fish,
while older fish thrive well on fresh meat combined with dried animal products (fish meal etc.). Dried vegetable products (cereals and beans), when
well cooked, may be used. A certain proportion of fresh meat is essential
for health. These observations are founded on the results of feeding ex-