MODERN FISHES--TELEOSTEI
The lower orders of teleosts retain many characteristics of the
Holostei, and several of their families are known only as fossils in
the Cretaceous and Tertiary rocks. The most primitive survivor of these
ancient forms is the great tarpon of Florida and southward, another
species of which occurs in India--such wide differences in habitats
being an evidence of antiquity in nearly all cases among animals. The
extraordinary mormoids of northern Africa, and the eellike gymnarchus
of Gambia, are other relics of the past, as also are several other
queer African families, the barramundi of Australia, and the arapaima
of the Amazon region. The one last named is the largest fresh-water
fish known, specimens exceeding fifteen feet in length, and weighing
400 pounds, all of which is excellent food. The mother protects her
offspring which, when young, swim in front of her. Several of these
old-fashioned teleosts, like our bowfin and the primitive Dipneusti,
make elaborate nests in which their eggs are deposited, and they and
the fry are carefully guarded by the parent. In this same suborder come
the most familiar and useful game and food fishes--the shad, herring,
trout, salmon, whitefish, smelt, etc.
The shad family is a very large one, numbering about 200 species, most
of which are marine, but a few are "anadromous," that is, they ascend
rivers of fresh water to spawn in the shallows near their sources.
This is the habit of American shad, of which there is only one species
in spite of the many local names in use; and it is regarded by the
fisheries authorities as the most valuable river fish in the country
except the Chinook salmon; but the supply of it would have been
exhausted long ago had it not been for the incessant and energetic
methods of replanting of fry, artificially bred, in all the eastern
rivers, and the transplanting of them to rivers on the Pacific Coast,
the credit for which valuable public service belongs to the United
States Bureau of Fisheries.
The shad is to be found from Florida to Newfoundland. Little is known
of its life in the ocean, but in spring it approaches the coast in
great numbers, and may be had in the St. John's River in Florida in
winter, but it is not numerous until March. It next appears in the
Savannah and Edisto Rivers, and so successively northward, the height
of the run in the Potomac being in April, in the Delaware early in
May, and in the Miramichi River in New Brunswick late in May. The main
body ascends when the water temperature is 56 degrees to 66 degrees.
They come in successive schools, the males preceding the females. They
ascend the rivers, often nearly to their heads, and deposit their eggs
on suitable spawning grounds, pouring out about 30,000 in most cases.
The eggs are very small, semibuoyant, and usually require six to ten
days for hatching, depending, as does the whole operation, on favoring
temperature. After the spawning the shad show hunger, and will often
bite at an angler's fly.
"The herring is beyond question the most important of food fishes in
the Atlantic, if not in the world," declared the late G. Brown Goode,
formerly Assistant U. S. Fish Commissioner. It affords occupation for
immense fleets of boats, and thousands of men, nowhere more numerously
than in the North Sea and along the Norwegian coasts. Professor Huxley
once gave 3,000,000,000 as the number of herring taken annually from
the North Atlantic; but Dr. Goode showed that this was far too low an
estimate, and added that it probably was "no greater than the number
contained in a single shoal if it covers half a dozen square miles, and
shoals of much greater size are on record. And ... at one and the same
time scores of shoals must be scattered through the North Sea and the
North Atlantic, any one of which would go a long way toward supplying
the whole of man's consumption of herring." Herrings are surface
swimmers, and their food consists of the small organisms, chiefly
crustaceous, which have been described as "plankton" in the early pages
of this book. They themselves afford food to every predatory fish,
squid, whale, and bird that frequents their region (mainly north of the
fortieth parallel of latitude), and which has the wit and ability to
seize them. They move here and there in shoals for food, and in spring
migrate to the shallows and rivers of the northern coasts to spawn.
Besides the Atlantic herring, a very similar species throngs in the
North Pacific, and several others live in the Great Lakes and other
waters of this country.
No fishes are better known in America than the salmon, trout, and
whitefish, which are near relatives. Of the salmon there are many kinds
in all the northern parts of the world and in the open ocean. Some
ascend rivers to spawn, and some do not. Our Atlantic salmon, once so
abundant in every river from Connecticut northward, is the same as the
salmon of Europe, and the king of game fish. Now it is at all numerous
only in the Maritime Provinces of Canada, climbing the waterfalls of
those mountain streams to their very springs to deposit its eggs,
whence few individuals survive to return to the ocean. The heaviest
salmon on record is one of eighty-three pounds captured in England in
1821; an American example of forty pounds is considered very large.
The salmon of the North Pacific are of a different genus
(Onchorhynchus) and consist of several species, some Asiatic. On the
American side we have five species, and most of them have been seen in
all the rivers from central California to Alaska, Siberia and Japan;
but the blueback predominates in Fraser River and in the Yukon; the
silver salmon in Puget Sound; the quinnat or Chinook salmon in the
Columbia and Sacramento; while the comparatively worthless dog salmon
is seen everywhere. The quinnat and blueback enter and "run" the
rivers in the spring, and are caught when in prime condition, whereas
the other three run in the fall, and are more usually caught after
deterioration; hence "spring" salmon are best in fact and in trade.
The habits of the salmon in the ocean are not easily studied, but
Jordan, Evermann, and other diligent students have come to certain
conclusions from a great number of facts. They believe that the king
and the silver salmon probably remain not far from the rivers where
they were born. The blueback and dog salmon probably seek deeper
water. It is the prevailing impression that the salmons have some
special instinct which leads them to return to spawn on the same
grounds where they were hatched, but Dr. Jordan says:
"We fail to find any evidence of this. It seems more probable that the
young salmon hatched in any river mostly remain in the ocean within
a radius of twenty, thirty or forty miles of its mouth. These, in
their movements about in the ocean, may come into contact with the
cold waters of their parent river, or perhaps of any other river, at a
considerable distance from shore. In the case of the quinnat and the
blueback, their 'instinct' seems to lead them to ascend these fresh
waters, and in a majority of cases these waters will be those in which
the fishes in question were originally spawned."
As to the fate of the spawning fish, after the eggs and milt have been
voided, and their duty is done, the salmon begin to float downstream
tail foremost. The great majority of them die--certainly all at the
headwaters of the big streams; and it is the opinion of the best
judges that none ever get back from anywhere alive into the ocean
after spawning, but that the race is sustained wholly by the escape of
the young each year. It is supposed that non return from the sea, or
attempt to ascend the rivers until at least three years old.
Trout are in most cases simply small species of salmon, and a great
number of kinds inhabit the ocean, lakes, and rivers of all northern
countries, for none of this great family occur in the tropics or in
the southern hemisphere. Our western trout--the widely distributed
and variable cutthroat, the steel-head of the northwestern coast, the
beautiful rainbow trout of the Coast Ranges, and others are examples.
The common brown "brook" trout of Great Britain belongs here; but
our brook trout, the "speckled beauty" of anglers and poets, is of a
slightly different kind (genus Salvelinus), for it is classed with the
European charrs. The Dolly Varden trout of the Rocky Mountains and the
Sunapee trout are also charrs. The graylings, namaycushes, and smelts
are members of this family, whose final representative among us is the
numerous and very valuable section of whitefish and lake herrings of
the Great Lakes and Canada generally.
No family of fish is of more importance as food for man, not to speak
of the sport many of its members afford, than this; yet, doubtless, it
would have been nearly destroyed by this time had it not been for the
intelligent and patient work of fish culturists and the farsightedness
of governments, both Federal and State, and Canadian, in supporting and
extending economic replenishing of depleted waters. The organization
and breeding habits of the salmon tribe lend themselves to this work.
Passing by some families of deep-sea fishes, of small size and most
bizarre outlines, we come to the suborder that contains the carps,
catfishes and "minnows" of our lakes and streams. Here, the first
to present itself, in the large family Characinidæ, is that fierce
little brute of South American rivers, the "piranha" or "caribe," of
which Col. Theodore Roosevelt had so much to say in describing his
explorations in Brazil in 1913 and 1914. One of his companions was Leo
E. Miller, who has since published another account and increases the
bad reputation of the caribe by what he has to tell of its ferocity:
"In the Orinoco they attain a weight exceeding three pounds, and are
formidable indeed. The natives will not go in bathing except in very
shallow water, and I know of two instances where men were attacked and
severely bitten before they could escape. The fish somewhat resembles a
bass in shape, although the mouth is smaller; the jaws are armed with
triangular, razor-edged teeth; and as they travel in immense shoals
they are capable of easily devouring a man or large animal if caught in
deep water.... Usually they are slow to attack unless their appetite
has been whetted by a taste of blood from a wound; then, however, their
work is done with lightninglike quickness.... To catch them we used a
large hook secured to a long wire leader and baited with any kind of
raw meat, and they always put up a good fight."
A related fish in the Rio La Plata is almost equally dreaded because of
its much greater size and formidable teeth, but it works singly; and
Africa has many similar characinids, whose flesh is good food, though
full of bones. In this order, too, is now classified the family of the
"electric eels" (Gymnotidæ) which are not, however, eels, but merely
long, cylindrical fishes, naked and almost finless. The well-known one
of the Amazon region grows to a length of eight feet and the thickness
of a man's thigh, and is justly feared. It is found only in marshes and
in comparatively shallow parts of rivers, to the annoyance of travelers
who have to ford at such points, beasts of burden being frequently
knocked down by the electric shocks. About four-fifths of the length of
the fish is occupied by the tail, which contains the electric organ.
This consists of two huge masses filled with a jellylike substance,
below the spine, and separated by a narrow median septum. This
apparatus is under the control of the fish, which by it may stun or
kill an enemy or an intended prey, even at a considerable distance.
The family of the cyprinids--the carp, goldfish, chubs, shiners,
loaches, and other "minnows" of this and other countries--contains
about 1,300 species, scattered over the whole world except South
America, Madagascar, and Australasia. All are fresh-water fishes,
feeding on vegetation and small animals; and they vary in size from two
or three inches to a six-foot carp--the original home of which, now the
cosmopolitan giant of the family, was Asia.
Next to these are placed another extensive fresh-water family, that of
the catfishes (Siluridæ). More than 1,000 species, mostly tropical,
have been described; these are grouped in eight subfamilies, among
which there is a wide diversity in shape and habits--in fact, few of
those of foreign lands look at all like the catfishes with which we
are familiar in America. Most of them are sluggish, but some actively
inhabit swift streams. They can exist not only in foul water, but
will live a long time out of this element, and some even make long
migrations overland from river to river. One or more fin rays are sharp
and poisonous in many species, as boys know who handle the little
bullhead incautiously, and an African species is able to administer
a strong electric shock. Its apparatus is not a battery of modified
muscular tissue, as in other electric fishes, but consists of a thick
coat of greasy material surrounding the whole body just beneath the
skin. Another general characteristic is the protection and assiduous
care given to their eggs and young, most species making some sort of a
nest in which the eggs are deposited and the fry kept safe from attack.
The third suborder of teleosts contains eellike fishes of the tropics;
and the fourth contains the true eels and their relatives. Our common
eel is also "common" in most of the temperate countries of the world,
but there are perhaps 150 other species of the family Anguillidæ, a
large proportion of which live altogether in the sea, many of them at
great depths, and showing strange shapes. The generation of the eel
was, until recent years, one of the great mysteries of zoölogy, as
no propagation, or any symptoms of it, ever appear in fresh water.
Finally it was discovered that a queer, almost transparent, compressed
creature, a fraction of an inch long that abounded in the surface
waters of the ocean, and which had been a puzzle to naturalists, who
called it Leptocephalus, was the larva of some sort of eel. This and
other discoveries made it plain that when the eels (of the age of four
or five years) leave the rivers and bays of all countries and coasts
in the autumn, and go out to sea, they do so to spawn, leaving their
eggs on the floor of the ocean, mostly south of Bermuda, according to
J. Schmidt. From them hatch the minute larvæ that, as they grow, rise
to the surface, and when about a year old appear as the silvery young,
called "elvers," that drift on the northward-running currents to the
coasts of Europe and North America, and ascend the streams by millions
in spring. It is not probable that any of the adult eels that go down
to the sea to spawn ever come back; and if any remain in landlocked
waters whence they cannot migrate to the salt water, they do not breed;
but it must be remembered that eels are able to travel a considerable
distance overland, at night, from one piece of water to another, and
so many may finally reach the sea.
The next suborder illustrates the remarkable difference in size and
external appearance that often marks fishes grouped together by
similarity of structure. It includes the muskellunge and all the other
pikes and pickerels, and the tiny shiners and "bait minnows" of our
rivers and brooks, and those of the Old World, one of which is the
smallest fish known; it includes several families of deep-sea fishes,
often of quaint form and with curious appendages; here, too, is the
valuable blackfish of Alaska, the amphibious, phosphorescent little
fish of Indian bays and estuaries which when salted and dried forms the
Oriental delicacy called "Bombay duck"; and here are the blind fishes
of the Mammoth and other American caves. The Heteromi and Cateosteomi
are almost equally miscellaneous assemblages, the most notable members
of the latter being the funny little pipefishes and sea horses that
lurk in the eelgrass near shore, and the males of which carry the
eggs and young about in a pouch on the belly. In the next suborder,
Perceosces, we find more strange denizens of the mid-oceanic depths,
especially the family Chiasmodontidæ, besides some surface ones of
ancient lineage, such as the gar and snakeheads of tropical waters,
the flying fish and the mullets. The Anacanthini is a small group
containing the remarkable pelagic and abyssal macrurids, the fierce
barracudas, and the most valuable single family of food fishes in the
whole list--the cods.
The cod family (Gadidæ) has many species in northern seas and a few
south of the equator. It includes, besides the cods, the haddock, hake,
whiting, coalfish, capelin, ling, and several other market fish of
importance. The cod is a deep-water fish which goes about in great
schools whose movements are not well understood, but in winter they
approach the northern shores of the continent, seeking shallows on
which to spawn, and it is then on the "banks," off New England and
Newfoundland, that the most profitable fisheries are followed. The cod
is extraordinarily prolific, and in addition to this it is propagated
artificially more extensively than any other fish.
Thus we come to the last suborder, Acanthopterygii, or "spiny-finned"
fishes, in which are classified the greater number of really modern
and more or less familiar swimmers in the "briny deep." Among American
members are the sunfishes and black bass, the perches and darters;
the great family (Serranidæ) of sea bass, snappers and West Indian
groupers; the tilefish, which appears and disappears in a puzzling
fashion; the grunting drums and their relatives of the Scienidæ; the
porgies, sheepshead, and other Sparidæ; the brilliantly colored angel
fish of the coral reefs of Bermuda and southward; the surf fishes, so
important in California; the wrasses, parrot fish, and globefishes, or
boxfishes, that inflate their horny hides when alarmed, until they bob
about on the surface like corks.
FISHES WITH PRIMITIVE LUNGS
There remains the fourth subclass--Dipnoi or Dipneusti, the lungfishes.
The reason why these creatures, whose organization is on an antique and
lowly plane, judged by fish standards, have been elevated to subclass
rank is that here the air bladder is modified into a single or double
elongated sac with many cellular spaces, and is connected by a short
tube with the mouth, and thus serves as a lung. The peculiar structure
of the heart, narial openings, and the power of existing for a
considerable period out of water, are extremely amphibianlike, and they
have by various naturalists been regarded as scaly sirens--a sort of
connecting link between the fishes and the amphibians. They are found
fossil in Paleozoic rocks, especially in the Old Red Sandstone of Great
Britain, and also in the Upper Jurassic strata in Colorado.
[Illustration: AN AFRICAN LUNGFISH
(_Protopterus annectens_)]
The surviving species (family Lepidosirenidæ) are widely scattered,
as is characteristic of all these very ancient families. A celebrated
example is the barramundi of Queensland--an elongated, flat-sided fish,
covered, except on the head, with large roundish scales, and having
paired fins that look more like flippers than fins. It becomes four
or five feet long. It lives in still pools in which the water in the
dry season becomes extremely stagnant and overladen with decomposing
vegetable matter; and it is only by rising to the surface occasionally,
and taking air into its lung, that it is enabled to obtain sufficient
oxygen for purposes of respiration. The barramundi does not leave the
water, nor can it live long in the air. It is easily captured, and is
eaten by the blackfellows.
Equatorial Africa possesses three species of the genus Protopterus,
which dwell in marshes, and feed voraciously on young fishes, frogs,
and small animals. The form is somewhat eellike, and the paired fins
are soft, slender appendages of little use, locomotion being effected
by the powerful tail. Like the barramundi this fish rises at intervals
to take a breath of air; its "lungs" are double, while that of the
barramundi is single. In the dry time of summer the protopterus burrows
deeply into the mud of the dried-up marshes, where it curls up with its
head highest and subsists wholly by breathing air until the autumnal
rains bring water enough to enable it to wake up and resume its aquatic
life. A similar eellike species abounds in the swamps, sluggish rivers
and marshes of northern South America, named Lepidosiren, and all its
habits closely resemble those of the African lungfishes.