WHAT DO THE ANTILLEAN FRESH-WATER FISHES INDICATE?

Cold-water fish are stressed as temperatures rise and oxygen is reduced in Minnesota's lakes
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It may be expected that a considerable proportion of a mainland fish fauna living on land masses (islands) subsequently cut off from a continent will be lowland fishes not particularly well adapted to swift water. If the island were to be partially submerged within a comparatively short geological period, the lowland fish fauna might be entirely annihilated. This would be all the more likely if the original continental connection had been so low as to permit the entrance only of lowland types and the submergence occurred before these lowland fishes had had time to evolve hill-stream types.
Synchiropus splendidus Love this fish, they do well in a Salt Water Setup!
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Several methods may be used to take smallmouths, including fly casting with floating bugs, and trolling or casting with a plug or spinner. The most common and successful method is still-fishing with live bait, such as worms, minnows, hellgrammites and crayfish. Fall brings them back into shallower water, which awakens a drive to eat and put on weight for the winter. Feature Image: The Cisco, a cold-water fish also known as Tullibee or Lake Herring
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In reviewing the distribution of American continental faunas in connection with some recent studies of West Indian fresh-water fishes, I have been struck with the amount of misinformation that passes as sound ichthyological evidence among zoogeographers. Part of this is the fault of the ichthyologists themselves. Papers on fish distribution written by competent ichthyologists and based on modern paleontological and ichthyological data are scarce, and the distributional information in two recent general textbooks on fishes (Kyle, MacFarlane) is scarcely to be relied on. On the other hand, the recent dependable papers that do exist have been neglected by most students of zoogeography. I have come across no modern paper that summarizes the broader geographical aspects of the fresh-water fishes of North and South America, and, in the belief that such may be of some general interest, I shall attempt to supply this want in very brief form. At the same time I shall speak about some of the implications of fresh-water fish distribution in the controversial question of West Indian paleogeography, but, in compliance with my thesis that biogeographical problems cannot be solved on the evidence of one group, I shall not pontify on matters I know I am not competent to settle. There are, of course, exceptional methods by which fishes may be transported. "Rains of fishes" are sufficiently well known and authenticated to make it certain that cyclonic winds, in passing over bodies of water, sometimes pick up small fishes and deposit them at a distance, still alive. It is possible, too, that a fish eagle or gull might drop or disgorge alive a newly caught fish after having carried it over a divide between two distinct river systems. But the frequently made statement that the eggs of fishes are dispersed by adhering to the feet of wading birds in flight should cease to trouble zoogeographers; such a method of transportation is possible, but almost no fish eggs are sufficiently resistant to survive drying in the air more than a very few minutes. The main fact to keep in mind is that fish distribution is much more regular and understandable than it would be if these unusual methods of transportation were of much importance. The importance of fresh-water fishes to students of geographical distribution depends primarily on two facts. Firstly, certain families of fishes possess an ancient physiological inability to survive in salt sea water, which binds them to the land as securely as any known animals. Secondly, on the land, they are inescapably confined to their own particular drainage systems and can migrate from one isolated stream basin to the next only through the slow physiographical change of the land itself (stream capture, etc.). Throughout the world the migrations of fresh-water fishes over extensive continental areas have generally been excessively slower than those of almost any creature that can creep, crawl, walk, or fly, however closely that creature may have been bound by its ecological tolerances. This is exceptionally well illustrated by Central America, where the interpenetration of North and South American faunas has proceeded in many groups practically to the limit of climatic tolerance, but where no truly Neotropical (South American) fresh-water fish has gotten farther north than Texas or New Mexico, and none truly Nearctic (North American) farther south than Nicaragua. The only fresh-water fishes that need especially concern us at present are those of the first two of the categories I have just mentioned. These two categories I shall distinguish as a primary division whose members are very strictly confined to fresh water, and a secondary division whose members are generally restricted to fresh water but occasionally enter the sea voluntarily for short periods. The other groups not specifically placed in divisions grade off into wholly marine forms. Finally, there are a number of species and genera of salt-water families that have taken up more or less permanent residence in fresh water. Most of them return to the sea to spawn.