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Smithsonian National Museum of Natural History

Department ofVertebrate Zoology

Division of Fishes

Spencer F. Baird
Spencer F. Baird circa 1875
© Smithsonian Institution

The following interview with Theodore Gill was conducted by a Washington Post reporter in August 1889. Within the previous decade, a great deal of information about marine life in the depths of the oceans had become available due to explorations on specially equipped ships. It was an exciting time for both naturalists and interested laymen. The text of the interview with Gill is being reproduced here from Washington Post, 11 August 1889.


Some of Them Live 18,000 Feet below the Surface


Strange Creatures with Phosphorescent Eyes and Luminous Appendages to Attract Their Prey – The Champion Swallower of the Ocean Described

"There are strange-looking creatures at the bottom of the sea," said Prof. Theodore Gill, of the Smithsonian Institution, to a Post reporter a few days ago. Professor Gill is one of the highest authorities on fishes in the United States, and in his little den up the tower of the gothic pile built with Mr. Smithson's money he has lots of books and pictures relating to all manner of creatures which inhabit the deep.

Black Swallower
Black Swallower
Plate 74, Oceanic Ichthyology by G.B. Goode and T.H. Bean

"Our knowledge of deep-sea fishes is quite recent," continued Professor Gill. "Indeed, a quarter of a century ago some maintained that life to any extent did not exist at great depths; that it could not exist, in fact, because the sunlight could not penetrate so far beneath the surface. From time to time, however, strange and unfamiliar forms of fishes were found by accident, either floating on the surface or caught by fishermen. These forms bore every impress of coming from great depths and naturalists had the suspicion forced upon them that they had not by any means explored the domain of the sea. These new-found fishes had loose, flaccid structures; their bones were fibrous and so soft as to be easily penetrated by a needle, and their eyes were large. Experiments in deep-sea dredging were begun by a number of gentlemen at their own expense, and the result showed that the ocean was literally alive with fish. Finally the Challenger expedition was sent out, and it has taken thirty large volumes to recount all its discoveries."

"How deep are fish found in the sea?"

"They have been brought up from the depth of 2,900 fathoms, or nearly 18,000 feet below the surface. At that depth the pressure of the water is nearly three tons to the square inch. The difference between this pressure and that at the surface leads to many curious results. For instance, in the Madeiras, the fishermen catch with a hook and line a fish known as the cherne, which lives about 1,200 feet below the surface. When the fish is brought to the top it is nearly dead, and looks as if it had a cataleptic spasm. Its eyes are forced from their sockets and look so peculiar that when a person has prominent eyes the fishermen say he has 'eyes like a cherne.' Sometimes, from this same cause of difference in pressure, it rises faster as it approaches the surface than the line can be hauled in, and then it bobs up out of the water for some distance, just like a cork or bladder. Very frequently, fishes which are brought up in dredges or trawls from greater depths burst in pieces before they can be examined."

"Are fishes specially equipped for living in such deep water?"

"Certainly. In the first place they have as a general rule, large eyes. We can hardly imagine that there is any light at 10,000 or 15,000 feet below the surface and yet there must be some, or else the fishes would be blind. Cave fishes, which exist in total, absolute darkness, have no eyes at all, and I am certain that it would be the same case with deep-sea fishes if the same conditions existed. Of course, if a man could descend to such a depth he would see nothing, but I am convinced that there is a diffused light sufficient to enable the fishes to see. In order, however, to more fully equip the fishes, nature has provided them with phosphorescent spots like eyes."

"What are they for?"

"I can hardly tell you. All I know is that these eyes are ranged along both sides of the fish, and are perfect lenses. They either illumine the path of the fish through the abyssal depths, or else they serve to attract prey. I incline to the latter belief. There is no vegetable life in the region inhabited by these fishes, and they are carnivorous. They feed upon each other, and I have no doubt, also, but that a vast quantity of animal matter starts at the surface of the ocean and sinks steadily downward, like a constant rain, until it is devoured by these deep-sea fishes."

"Are the deep waters of tropics more populous than those elsewhere?"

"So far as the great depths are concerned, there is no indication at present that such is the case. The fishes of the deep sea are not subject to those of laws of distribution which regulate those of the shallow waters. Now in the shallow waters we have them divided or distributed into distinct zones–the tropical, temperate, north or south temperate, and arctic or antarctic. But in the deep seas the climate which determines on the surface the distribution of fishes is so nearly uniform that the same forms may be found all over the great depths. Another interesting thing is that fishes that are found at these great depths in the tropics may be found near the surface in the arctic or antarctic. A fish so rarely found in Scandinavian waters that nobody gave it an English name has been discovered in large quantities about 12,000 feet below the surface further south, fifty different species being now recognized."

"Would this not indicate that fish travel for great distances under the sea?"

"Well, it shows at least that they all sprang from a common center, and then, you know, they have had ages and ages in which to disperse themselves all over the globe."

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