544 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



The geographical location, near a large mass of land, the size and 

 physical character of the British Islands, is favorable to a large number 

 of different fish, which find many excellent spawning and feeding places 

 and plenty of food of every kind in the tepid sea, the shallow bottom, 

 and the many bays and estuaries. Such a location is particularly favor- 

 able for the Oadidcc, which show a tendency to change genus and species 

 at the expense of the number of individuals. We therefore find near 

 the British Islands a great variety of genera, and the greatest variety 

 of species of Gadidw occurring anywhere in the world, viz, 40 per cent. 



Although I am not prepared to give statistics of the cod fisheries 

 near the British Islands, as the codfish are here mostly eaten fresh and 

 do not get into the market in a preserved state, I know for certain that 

 the different species never occur in such large schools as near the 

 Loffoden Islands, near Finmarken, and near the Banks of Newfoundland. 

 According to Yarrel, there are near the British Islands 9 genera and 32 

 species of Gadidw ; but, according to Dr. Giinther's account, of 1868, 

 there are 10 genera and 23-24 species, out of GO species, found in the 

 whole world. Among these there are many southern varieties of the 

 GadidcB, showing in a very marked manner the influence of the Gulf 

 Stream ; such as Gadus poutassoii^ Motella maculata, Fhycis hlennioides; 

 and still the British Islands are only four degrees farther south than 

 Denmark. 



Toward the western coasts of France and Cantabria the Gadidw almost 

 disappear; only two northern varieties, Gadus callarias and Gadus hiscus, 

 occurring in these waters. This astonishing change can only be ex- 

 plained by the fact that the Aquitanian Sea, which is very deep, has 

 very cold, briny water, which the Gadidw do not like. It is possible 

 that a submarine Arctic stream flows into this submarine cave, driving 

 out all animal life. Such a stream must turn north of the Fucus Bank; 

 for south of Capo Finisterre we find a great change in animal life, and 

 the farther south we get the greater is the variety of species. Already 

 between the Azores and the Portugese coast we meet with entirely 

 new varieties ; still more is this the case near Madeira ami in the western 

 part of the Mediterranean, while these varieties disappear near the South 

 Canary Islands, in the eastern part of the Mediterranean, and in the 

 Black Sea. 



On the coast of Portugal northern and southern varieties are mixed 

 in a very peculiar manner. Tbe genus Gadus has left its genuine rep- 

 resentatives behind, and from the southern region no distinct varieties 

 are found ; consequently, we find there only transition varieties from 

 both regions. There are, nevertheless, in these waters, 3 genera with 

 6 species, viz: Gadus ^ith. 4 species, luscus,pollacMns, 2)outassou, Mer- 

 lucius communis ; Moi^lla, with 2 species, quinqxiecirrata, maculata. 

 Gadus luscus and Motella quitiquecirrata are northern, and Gadus pou- 

 tassou and Motella maculata southern varieties. 



Near the North Canary Islands, especially near Madeira, the south- 



