Popular Science Monthly/Volume 55/September 1899/West Indian Poisonous Fishes

WEST INDIAN POISONOUS FISHES.
By JAMES MACDONALD ROGERS, F. R. C. S.,

STAFF SURGEON, R. N.

AT a time when so much attention is being paid to the West Indian Islands as regards their politics, social condition, and natural history it may not be out of place to briefly consider the subject of the poisonous fishes to be found in the neighboring seas. Considering the number of unwholesome fish abounding in these waters and the numerous cases of illness caused by them, I was surprised on investigation to find that so little appeared to be known or written on the subject. During my three-years' cruise in the West Indies the study of those fishes reputed to be poisonous was forced upon me by reason of the numerous cases of illness among the sailors of my own ship. When it is asserted that there are no less than sixty varieties of noxious fishes to be found in Cuban waters alone, it seems desirable that those who are about to settle in these parts should have some general idea as to what fish to choose and what to avoid.

Colored fishermen are not too particular about hawking unwholesome fish in the streets, even when its sale is forbidden in the market, and numerous cases have come under my notice where the unwary purchaser has paid the penalty by a sharp and painful illness. One of the great delights of our sailors is to land on some sandy beach, provided with a large seining net, in order to catch fish, the consumption of which varies the monotony of salt beef and pork. On examining the hauls they made I invariably found some unwholesome specimens, which I advised them to reject, and by so doing every time they went seining had no more cases of fish poisoning on board.

In tropical seas some fish are found to be always poisonous wherever and whenever caught, but there are numerous instances where wholesome fish become noxious when found in certain localities, especially on coral reefs and shoals. Fish when feeding on decomposing coral polyps, medusæ, and poisonous mollusks found on these reefs often become noxious, as the following instance will prove: Midway between Cuba, Hayti, and Jamaica lie the extensive reefs and shoals of the Formigas, which are several miles in extent and covered by a small depth of water. These shoals present a concentration of all the incidents to be found in West Indian fringing shore reefs. Arborescent corals and spreading millepores stretch on walls and ledges, interspersed with huge meandrinas and brain-stones, among which lodge a profusion of Holothurias, starfishes, and a variety of sponges. This great mass of reefs, called from their clustering swarm the Ants' Xest, or the Formigas, abound with all sorts of fishes. As you approach the great submarine plateau, the odor of the slime and of the spermatic substances that find a resting place in the crevices and shallow pools spread through it is very remarkable—the pleasant blandness of the sea breeze suddenly changing to the nauseating smell of a fish market. Those who have waded on tropical shore reefs know not only the strong scent given out by the polyps that build there, but feel how sensibly the hands are affected, and how the skin of the thighs is susceptible of a stinging irritation from the slightest contact with the slime of corals. It has been found by invariable experience that all the fishes taken on the Formigas are pernicious; that the barracudas especially are always poisonous. Similar stretches of shoals among the Bahamas produce fishes deleterious as food.

The low-spreading ledges and banks of the Virgin Islands, called the Anegadas, or the Drowned Islands, afford a similar unfavorable ground for fishing. In this way we may account for the remark of Dr. Grainger that fishes are poisonous at one end of St. Christopher while they are harmless at another. We get over, by these several incidents of those fishing grounds, the adventitious occurrence of poisonous among wholesome fishes, which become deleterious from the food on which they subsist at certain seasons on certain banks and coasts.

Again, in the tropics wholesome fish soon become virulently poisonous if kept too long, as the fierce heat favors rapid decomposition. In this short article I have only space for a description of the most common and injurious fishes met with in the West Indies. One of the commonest fish in these seas is the barracuda (Sphyræna barracuda), which can be easily recognized by its elongated body, covered with cycloid scales. The color is dark olive-green on the back, fading to a lighter green on the sides, while its under surface is silvery white. The mouth is wide and curved, with long and sharp teeth. These fishes are large and voracious, often attaining the length of six feet; and as they are usually found close inshore, amid the heaviest surf, they are as much feared by fishermen and bathers as the shark. Indeed, they are more to be feared, for the shark as a rule is timid, and unless extremely hungry is cautious in its voracity. The barracuda, on the contrary, is very bold. The shark flees from a splashing in the water, but the barracuda goes there to see what he may find, as he is only attracted by live bait. The wounds inflicted by the barracuda are exceedingly severe and sometimes fatal.

When young this fish is generally used as food, but having attained a certain size the flesh becomes exceedingly noxious, at least at certain seasons of the year. This change is said to be due to the poisonous fish on which they feed. When caught on certain banks, as the Formigas, their flesh is always extremely unwholesome, and, as Kingsley says, they have this advantage, that while they can always eat you, you can not often eat them with impunity. The Cubans, as a rule, will not touch this fish, and at Santa Cruz it is the custom never to eat it till the next day, and then not till after salting it; but that is apparently no safeguard, as four persons living in Kingston, Jamaica, suffered severely after eating "corned barracuda."

It is stated that when unwholesome, its teeth will be found of a blackened color at the base, and on inserting a silver coin into its flesh this will also turn black. The poisonous symptoms caused by this fish are peculiar, and were strongly marked in the case of a friend of mine who was a solicitor living in Barbados. He and several others who had partaken of the same fish suffered from severe gastro-intestinal disorder, with intense nausea and vomiting. His face swelled up and became tubercular like a leper; afterward, general muscular tremblings and acute pain about the body, particularly in the joints of his hands and arms, came on. The nails of his feet and hands became black and fell off without any pain, and his hair also fell out. For years after he suffered from debility and tubercular skin eruptions. Death sometimes follows, but those who do not die suffer for a long time from its effects, which in some cases last for twenty-five years.

The "yellow-tailed sprat" (Clupea thrissa) is common in the West Indies, and may be recognized by having its last dorsal ray prolonged into a filament. A black spot behind the gill cover is said to distinguish it from a somewhat similar fish, the "red-eared pilchard," which has a yellow spot behind its gill cover. Schomburgk gives testimony to the poisonous properties of the "yellow-tailed sprat" when found at certain periods of the year among the Leeward and Virgin Islands.

The eating of this poisonous "sprat" is said to be followed by most violent symptoms and rapid death. The common saying in the West Indies—that if you begin at the head you never have time to finish the tail—is almost literally true.

The eating of the roe of this "sprat" caused in Japan, in the year 1884, twenty-three deaths. The victims suffered from severe inflammation of the mouth and throat, strong abdominal pain, formication in the arms and legs, disorders of vision, paralysis, convulsions, and loss of consciousness. Nausea, vomiting, and diarrhœa often occurred. Death followed in some cases in a quarter of an hour, but mostly in from two to three hours.

Lacroix describes a case of poisoning through eating the "sprat" which occurred on board a French man-of-war. Out of a crew of fifty men, thirty were dangerously ill and five died. The men experienced strong muscular cramps in the arms and legs, nausea, vomiting, and diarrhœa. Afterward congestion of the brain, delirium, and coma supervened.

Most of the cases of fish poisoning which I have met with in the West Indies have been due to eating various kinds of "snappers," especially the "gray snapper." The tropical species are very numerous and difficult to differentiate, owing to their frequent change of color according to age and surroundings. In 1897, at St. Georges, Grenada, twelve persons who partook of a large gray snapper were attacked with severe symptoms of fish poisoning. A few hours after the meal all these were suffering from pain and fullness in the stomach, followed by persistent vomiting, severe cramps, watery evacuations, weak, thready pulse, and labored respirations. One of the victims was examined by me four months afterward, and he stated that, owing to intense weakness, he had been forced to keep his bed for several months, during which period he suffered from various nervous disorders. He had shooting pains and tingling of the limbs, dimness of vision, and quick, thready pulse.

In 1893 seventeen persons living in Bridgetown, Barbados, were attacked by similar symptoms to those mentioned above. All these had eaten of a fish which had been hawked about by a fisherman, and which was subsequently identified as a "gray snapper," though sold under a more innocent name,

A Spanish naval surgeon, Don Anton Jurado, while serving on board the gunboat Magallanes bad an opportunity of proving Poey's statement that the fishes caught on the coast of Cuba are often very poisonous. No less than twenty-seven of the officers and men were taken ill, most of them with gastro-intestinal disturbance of a more or less severe nature; the others suffered from nervous symptoms.

The horse mackerel, green cavalla, and the jack are often found most unwholesome when caught in West Indian waters.

In Barbados a whole family were seized with symptoms simulating cholera from eating "green cavalla."

The editor of The Barbadian writes: ""We think it right to caution people against the fish called 'green cavalla' from being purchased by their cooks. Some years ago we know that several individuals were extremely ill from eating this fish, which is frequently very poisonous. The night before last a whole family in Bridgetown, except the master, who fortunately had dined out, were seized with violent cholera after having partaken of cavalla."

The "jack" (Caran plumieri) is found to be poisonous in some seasons of the year, and it is said that at such times two small red lumps appear in its gills. When they are suspected of being in a poisonous condition an experiment is tried upon a duck by giving her one of them to swallow, and if at that season it is poisonous the duck dies in about two hours. The "rock hind," or "smoky hind," after attaining a certain size becomes most unwholesome, and often infested with parasites. Numerous instances of severe symptoms attacking persons after eating this fish are recorded.

Toadfish, or Tetrodons, are occasionally met with, and are to be avoided as being extremely poisonous, especially if the roe or liver be eaten. A family of coolies in Trinidad, in spite of being warned, ate one of these fishes, with a fatal result. The symptoms were blunted sensibility, trembling, general muscular weakness, difficulty of breathing, vomiting of blood, convulsions, and death.

The Diodonts, "trunkfishes," are not nearly so poisonous as the Telrodonts, but they are found to be very noxious at certain times or in certain localities, more especially if the gall bladder, liver, and intestines are not removed before cooking. It is reported that those persons who had eaten them suffered from loss of sensibility, cold sweat over the whole body, and stiffened limbs. Death followed in some cases.

The "prickly bottle fish" (Diodon orbicularis), met with in the Gulf of Mexico, is said to be injurious when eaten.

The Ostracion triqueter, called in the West Indies "fair maid," "plate fish," "trunkfish," is often eaten with no ill effects by the negroes, who, after cleaning it, bake it in its hard shell-like covering. There is, however, a gelatinous matter near the tail which is called "the jelly," and a similar substance is found near the head. When only part of this jelly has been eaten its effects are a peculiar vertigo, nausea, vomiting, pains all over the body, more especially in the limbs. The feeling of vertigo is similar to that of intoxication, hence the fish has been called "drunken fish."

The "filefishes," or "trigger fishes," when found in the tropics, where they feed on coral polypi, have the reputation of being most unwholesome.

In the West Indies "sea eels," or murenas, are only eaten by the negroes. The blood of eels is said by Mosso to contain a poison like that of vipers. It is related that a man drank some eel's blood mixed with wine, and was in consequence seized with severe diarrhœa, disturbance of vision, foaming at the mouth, and stertorous breathing. He ultimately recovered after vigorous treatment.

Dr. Gordon, of Montego Bay, Jamaica, records a case of death from eating the flesh and liver of a species of coast conger (Gymnothorax restratus). In spite of treatment, the man died after a lingering illness.

Space will not permit me to dwell in this article on the remaining noxious fishes, but it is to be hoped that enough has been written to teach people to be cautious in their selection of fish when in the West Indies.