Marine Housekeeping

by RALPH NADING HILL

1

THE chief problem of the biological staff of the Marine Studios during its first years of operation was to find by trial and error which of the more interesting and spectacular marine forms would live in the oceanarium and which would not. Feeding was one of the main factors to contend with, and another was temperament. The collecting staff has never brought in a live tuna. Spirited sailfish have always failed to survive capture because of the exhausting battle they put up when hooked.

As the result of a continuing personality clash between the porpoises and California sea lions, the aquarists concluded that the latter would have to go. Arriving from New York aboard the Florida East Coast Railway prior to the opening of the Marine Studios, the sea lions had joined the original porpoises, mother and calf, in the circular tank. Much to the misery of the mother porpoise, the sea lions, which are equally good swimmers, took almost perverse pleasure in pursuing her cub. The tables were turned, however, by two large bull porpoises subsequently brought in. Rutting the sea lions away from the feeding table and outdistancing them for thrown scraps of fish, they made life so frustrating that the sea lions dejectedly withdrew to the side of the tank. They did not recover their spirits until they were removed to a canal cage. Here one of them named Hutch caused the aquarists more trouble than all the other specimens combined.

Hutch was a rather accomplished performer who seemed quite conscious of his talents in entertaining visitors with a variety of tricks. Growing tired of over two years’ confinement, he escaped in October, 1940, and made his way leisurely down the Florida coast toward Key West. Near Oak Hill he overtook a fishing boat. To the astonishment of its crew, he climbed aboard and before their eyes devoured a whole mess of freshly caught mullet. This made him groggy. Easily lassoed, he was taken ashore. Here he found himself the center of attraction and gave his identity away by doing some of his old tricks. Soon he was again back in his bayou pool at Marineland.

Five months later he escaped again. Nine days after his disappearance, news reached Marineland that he was in Miami, 300 miles away. Incredible as it may seem, he had swum the whole Florida coast via the Inland Waterway—a fact explaining alarmed reports of an undulating sea monster from various places on his itinerary. He chose as a home the area on the Miami waterfront where the charter boat captains tie up their craft. He had discovered that the boats returned every evening with fish and that the skippers were not niggardly about sharing them. The skippers in turn had learned that Hutch, by drawing crowds to the pier to watch him eat fish they had just caught, was the best possible advertising agent for their business. They would have no part in helping to capture him and return him to the Marine Studios.

Early on the morning of March 23 a Marine Studios truck containing a double-sectioned cage arrived on the Miami waterfront. The charter captains were distraught as they watched the keepers place the cage on the low float of the dockmasler’s office, for in one section, barking irresistibly, was Butch’s mate, Fanny. Butch stuck his head out from under Pier 5. Swimming over to the float, he thrust his head through the door of the unoccupied cage. He was about to enter when the frantic charter captains appeared in the sterns of their boats with armloads of fish, shouting: “Hutch! Don’t go in there!” They quickly surrounded him with a ring of floating fish. Butch hesitated for a moment and then, casting an almost guilty glance at Fanny, plunged back into the water. The Marine Studios keepers realized now that they were undone, for they were well aware of Butch’s enormous appetite. Gobbling fish as long as he was able to swallow, he heavily made his way under the Waterfront Restaurant Pier and went to sleep. Nothing would bring him out again. Not even Fanny. “It looks hopeless today,” admitted his keepers. “We’ll try again at dawn tomorrow.”

But hostilities could not be renewed until Butch recovered his appetite. The weary keepers of the Marine Studios at last succeeded in recapturing him with Fanny’s help. But the management and biological staff had had enough. Both animals were shortly sold. Porpoises, sharks, rays — yes. Sea lions? No.

2

WHEN it was decided to reopen the Marine Studios after the war, it had to be restocked, and the directors engaged Captain William B. Gray to conduct what was undoubtedly the most ambitious expedition of its kind in history. Gray, one of America’s foremost game fishermen, well understood the difference between merely catching fish and catching them so that they would live in captivity. In an aquarium of his own in Palm Beach he had long maintained a number of rare specimens. The holder of several records, he had helped establish the International Tuna Tournament in Nova Scotia and had cruised the Central and South Pacific with the William K. Vanderbilt Expedition in the successful quest for new species of fish.

Gray’s Marine Studios task force consisted of a 36-foot cruiser, the Beau Gregory, together with several smaller power boats. Since captured fish had to be quickly brought in and transferred to the oceanarium, Gray’s expedition was not just one long marine safari, but a series of shorter ones. In six months he caught literally thousands of fish for the oceanarium, certainly a record from the standpoint both of quantity and of variety. The gigantic haul included a number of jew fish, none weighing under 100 pounds, five hard-won sailfish (which failed, as usual, to survive in the tanks), eight 6-foot barracuda, two tarpon, a dozen moray eels, sea turtles weighing up to 200 pounds, three tiger sharks all over 12 feet in length, a sawfish, a 2200-pound manta ray, and six porpoises. Also octopuses, sea horses, and hundreds of other pounds of assorted tropical fish from the Caribbean.

Gray had enough experiences of the kind that are found in sporting magazines to fill several issues. The giant manta fought for sev en long hours before he could be hauled near enough to be anesthetized. In the capture of the large sawfish Gray, after reeling him in to within a few feet of the Beau Gregory, entrusted his pole to a crew member. Then he seized a coil of hemp rope and made a lasso, which, when the sawfish was brought alongside, he dropped over the 5-foot saw. The sawfish lunged off as if this were his first run, and it was all Gray could do to hold on. When at last he tamed the creature he realized that he had nothing to put him in to take him back to Marineland 150 miles away. He had some seagoing trailers, but they were not big enough. While considering what to do, he tied the sawfish to some offshore pilings and continued fishing.

There was, it seemed, only one solution, and this required going ashore. Buying the hull of an old boat and riddling it with holes, he towed it out to sea, tied the sawfish in it so that it would not beat itself to pieces, boarded over the top, and started off on the long haul to the Studios. A storm overturned the old hull on route and the sawfish, for perhaps the first time in the history of his species, spent an hour upside down while the crew labored to right the boat. To prevent this peculiar accident from recurring, two empty oil drums were fastened to each side of the boat for the remainder of the journey. The sawfish arrived in good condition, but since his saw made him just too long to fit into any of the transfer tanks, a major engineering effort was required to move him from the Inland Waterway landing to the oceanarium. An amphibious vehicle had to be rigged up to carry him across the highway to the foot of the tanks. Here he was hoisted up and lowered into the flume by means of the usual boom, block, and tackle.

Gray had rather good luck capturing sharks, but the drugged sharks, once deposited in the tanks, would lie in a corner and die of suffocation. Swimming greatly facilitates the breathing of all pelagic sharks, for it forces water across their gills from the moment they are born to the moment they die. If they arc anesthetized they of course cannot swim; and without swimming, breathing is difficult. For this reason many of the early sharks died of suffocation in confining live wells. This difficulty w as corrected by direct ing a stream of water t hrough the well, the theory being that if the shark could not pass through the water, the water could pass through the shark.

To augment the shark’s recovery, Curator Arthur McBride evolved a system which is amiably called “walking the shark.”As soon as one of Captain Gray’s sharks was lowered into the flume of the oceanarium, two divers, one on each side, would grasp the shark around the middle and literally walk him back and forth, like a New Year’s Eve victim, until the oxygen from the water flowing across his gills had sufficient ly restored his metabolic processes to permit him to fend for himself.

Because he is busy surving, the shark is neither fearful nor hungry, so the diver is in no danger. Even under ordinary conditions, w hen he is making his daily circuits of the tanks with his feeding basket, the diver is relatively safe.

Part of the fascination of diving, whether in the oceanarium or in the sea itself, is the otherworldliness of it, a feeling imparted by the pressure of the cold water, the drumming of the air pump in the diver’s helmet, the clumsy lightness of his body, and the strange floating world outside his helmet. A diver entering the Studios tanks is quickly surrounded by porpoises, rays, and jewfish looking for food, and he soon gels to know and enjoy the peculiarities of all the creatures in his marine barnyard. From his vantage point in the center of the circular oceanarium the many portholes look like tiers of prison cells.

It seems almost inconceivable to the public that the carnivores do not immediately devour the other fish within the confined quarters of the two tanks. One reason seems to be that they are well fed. At intervals throughout the day, divers descend into the circular and the rectangular tank with wire baskets full of the food most cherished by the various species. Fish soon become accustomed to eating this way, with the result that chasing live fish and devouring them actually becomes annatural.

But there is another, and perhaps equally important, explanation. When a new fish enters the tank he is as scared as any other animal in new surroundings and shows it by darting about nervously. When he does so he is almost certain to be chased by the barracuda, jacks, tarpon, and other large carnivores — and perhaps eaten. Enjoyment of the chase is found everywhere throughout the animal kingdom and seems to be a strictly psychological phenomenon. A dog chases a scared cat; a cat chases a scared dog. A new boy in a gang is hazed. However, if the new fish is able to survive the first few days and behave normally by acclimating himself to his strange surroundings—lo, he is no longer chased. When two or three hundred fingerling mullet were put into the circular tank their chances were considered very slim, since they are a favorite food. Many were pursued and eaten at the outset, but there remain today several dozen very much larger mullet with a life expectancy that improves annually with their size.

At the Marine Studios the curious phenomenon of adaptation to strange surroundings may be observed not only in the rectangular but in the circular oceanarium, where to amuse themselves the porpoises chase new red snappers, grunts, and triggerfish around the tank, even toss them out of the water and sometimes eat them. After a few days the novelty wears off and the newcomers are ignored. How the porpoise, or indeed any other species, is able to tell the new residents from the old, unless it is because of their slightly different behavior pattern, is not known. A porpoise was once observed passing by one old-resident sheepshead to pursue a newcomer almost exactly the same size only a few feet away.

It should not be implied that old residents are never eaten, for they are occasionally. A giant grouper was photographed swallowing a sting ray, a favorite food in the sea. So big was the ray that for two days his tail stuck out of the grouper’s mouth. In the light of the moon, barracuda have been seen attacking mullet with a single savage thrust and severing their bodies neatly from their heads, which sink lifelessly to the bottom of the tank. Sharks have been seen doing the same. On several occasions porpoises have ganged up on and killed tigers in the circular tank while ignoring other kinds of sharks. They had their reasons for doing so. In the stomach of a 12-foot tiger shark which failed to survive capture, McBride found the greater part of the skeleton of a bottle-nosed dolphin. However, if cannibalism were not unusual in the tanks the whole idea of the oceanarium would be unworkable. To pay for a continuing large-scale replacement of casualties would be ruinous.

3

THE only segregation of species is that made necessary by the physical structure of the Marine Studios with its two tanks, circular and rectangular. The porpoises, because of their size and number and because they are active animals requiring ample swimming space, now share the circular tank with only a few other species — groupers, loggerhead turtles, and a variety of small reef fish. The reef fish stay close to protective niches in the rock at the bottom of the tank, the groupers congregate near the windows like the stag fine at a dance, and the portly turtles navigate about with supreme indifference toward the porpoises with their trail of waves and bubbles. If the porpoises try to turn them over, butt them about, or otherwise worry them with their games, the turtles have only to retire to the bottom of the tank for a while.

Because the turtle is one of the most durable of animals, surviving almost unchanged from the armor-plated reptiles from which he sprang two hundred million years ago, the question of his life span is a fascinating one to ichthyologists. It is possible that land turtles, another group entirely, may live much longer, alt hough again probably not as long as is commonly thought. While the scales of many fish, like the rings in tree trunks, closely indicate their ages, what of the age of the scaleless porpoise, the whale, and the shark? There is no exact knowledge. The moray eel is reported to have reached the age of fifty-five, the fresh-water catfish sixty, and the lowly sea anemone, surprisingly enough, one hundred.

The age which the giant grouper or jewfish can attain is not known, but observation at the Marine Studios has at least added this much to the store of knowledge of this species: that just as it is possible for a human being to die of obesity, so may a 500pound, eighteen-year-old jewfish. Ever since the deceased specimen in question had been placed in the tanks two years previously, he had made himself obnoxious by parking directly in front of the window most cherished by photographers for obtaining pictures of life in the circular oceanarium. Early on an April morning in 1949, Drayton Capo, the night pumpman, heard a great commotion in the tank and upon investigating found the jewfish crashing into the walls of the tank and caroming around at an astonishing speed. To the amazement of Capo, not to mention the porpoises, the usually torpid fish kept this up for some time until, at the end of his last strange pirouette, he died. An autopsy performed the same day revealed a liver so riddled with fat that it could not possibly function. Death was pronounced as due to overeating and lack of exercise. The fish had gained 50 pounds in two years, which brought his weight to within a mere 51 pounds of the largest specimen ever brought in on rod and reel — 551 pounds.

The Marine Studios giant jewfish had been brought up from very deep water in a commercial fishermen’s net. The jewfish, although edible, is not a delicacy. Deciding that their ugly prize would be far more useful as an exhibit, the fishermen had hailed a Marine Studios collecting barge, which took him ashore.

While apparently in good condition when placed in the circular tank, the great fish could neither right himself nor submerge, and started swimming around the surface on his back. Apparently he was having trouble with his swim bladder, for it had expanded enormously during his sudden withdrawal to the surface in the net, and now would not deflate. Curator McBride therefore procured the largest syringe in his laboratory and, taking a station on a platform overhanging the surface of the water at the side of the tank, waited until the jewfish swam within reach of his needle. When he did, McBride thrust it into his side. Lunging away from the platform, the grouper started off on a dizzy marathon of the tank, the broken needle still protruding. But the operation was successful. The massive fish sank below the surface and soon righted himself. Long before the needle worked loose he recovered the enormous appetite which spelled his end two years later.

In his slovenly eating habits and disdain for exercise he proved no different from other groupers. They do not seem to exert themselves in the pursuit of food even in the ocean. Instead they are accustomed to hover in one place, and when a fish swims by they open their mouths and in a split second the prey disappears, like a coin cylinder in a pneumatic tube.

The jewfish that swallowed the sting ray at the Marine Studios had not been seen eating for a month until the day shocked spectators saw him “inhale” the 50-pound ray, which had swum too close. In one gulp he swallowed all except the tail! On another occasion, when a whip ray was having young, the jewfish stationed himself nearby and ate the young as fast as they were born. When Kbibdella infested the South Florida coast and gained entrance to the oceanarium it temporarily blinded one jewfish. Until his sight was restored with applications of Silvol solution to his eyes, he was fed by merely waving a fish in front of his nose. The diver who fed him once came a little too close. Before he knew it, most of his arm had disappeared into the creature’s mouth. When he landed a heavy blow on the head of the grouper the fish opend its huge jaws and released the arm unharmed.

A tame cormorant, one of a group brought to the Studios as a pet, while diving for scraps of fish one day, also came too close to the blind fish. Spectators were appalled to see the bird disappear in the maw of the grouper. In the second or two before he could be swallowed, however, the bird so pecked and jabbed at the interior of the grouper’s mouth that the surprised fish disgorged him intact. To the amusement of observers the cormorant popped up to the surface like a cork, apparently none the worse for his experience.

4

UPON viewing ihe thousands of specimens in the rectangular tank, fishermen are somewhat saddened to think what lovely sport some of them would make on the end of a line. From time to time there has actually been some fishing in the rectangular tank, but purely for scientific or emergency reasons. On one occasion Curator McBride wanted to remove eight sheepshead. Fishing for them, he decided, would not only accomplish this more quickly than trying to net them, but perhaps add something to the general knowledge of how fish bite—and how they manage to steal the bait.

Spectators crowded the portholes as lucky members of the staff dangled fiddler crabs before the sheepshead in full view early one morning. By late afternoon four of the eight had been caught but four more, filled with fiddler crabs, were still at large. The technique of the surviving sheepshead was to approach the bait, examine it warily, then bite off the claws and feelers without exerting more than the slightest tug on the line. Having accomplished this, they would again approach and, without as much as touching the hook, remove the crab, so that when the fishermen raised their lines, all they had was a bare hook. The staff was at length reduced to the exasperating task of netting the four from the midst of thousands of other fish.

Of the great number of sharks that have lived in the rectangular tank, a few have been cannibals and hence have had to be withdrawn and carted away for fertilizer. Circling the tank slowly with their convoy of pilot fish, the vast majority appear almost oblivious to the galaxy of creatures within fin’s length. They seem perfectly contented with what they are feel and ordinarily cause no more concern to the divers than the tiny angelfish. There is always the exception, of course, which for unknown reasons goes on a rampage. A lemon shark went for weeks without eating anything, then suddenly devoured a sting ray and a spotted whip ray 5 feet long—but not before both rays had succeeded in sticking their poisonous barbs into his head.

The hard-shelled sea turtle is one of the few creatures that are more or less invulnerable to the shark, and in this connection Douglas Burden has reported a most remarkable circumstance, He was watching attendants feed a very large tiger shark, which was done by suspending half a tarpon, weighing perhaps 40 pounds, on the end of a wire. For a few minutes the shark cruised about, as was his custom, in a series of figure eights. Viewing his prospective meal from every angle, he at length turned and started for it in a beeline, opening his mouth wide as far away as fifteen feet.

At this point a big green turtle swam leisurely into the shark’s path, completely unaware of the impending danger. He did not discover his error until the shark was a scant three feet away, and it was then too late to paddle to safety. With a deft and astonishingly fast motion he flipped himself up on his side, presenting his broad carapace to the cavernous mouth of the shark. When it snapped shut the spike-like teeth merely grazed the surface of the shell. The turtle then righted himself and with powerful strokes of his flippers left the vicinity. As for the shark, he made a new series of maneuvers and then swallowed his intended meal with one gulp. The feeding habits of resident sharks at the Marine Studios have disproved the old saw about a shark having to turn on his side to eat. He swallows his prey quite like any other fish.

Of the very few exceptions to the statement that sharks live peaceably on the food given them, perhaps the most notable was the case of the “deranged “ sand tiger, whose eyes one morning started rolling about, He suddenly began to attack everything in his path. Advancing upon a sea turtle, he opened his mouth wide and closed it on the shell of the turtle with a crunch that sounded in the water, according to a diver, like hail on a tin roof. The shark broke off some of his front teeth in this unsuccessful assault, then proceeded to pursue other specimens in the tank. With his eyes still shifting about wildly he approached within six inches of the diver, who fended him off with his wire feeding basket and hastily made for the ladder leading out of the tank. Since neither he nor the other divers were anxious to go down again, the aquarist decided that the shark must go. Grappling hooks were secured; and as the fascinated public stood by, the aquarist, with the aid of the divers, lowered the hooks and waited for the “deranged” shark to pass over them on his next tour around the tank. When he did they quickly pulled up their stout line and managed to sink the hooks into his soft underbelly.

A fearful struggle ensued as the shark, with powerful lashes of his tail, tried to free himself. With a lunge he suddenly got away. As he took off on repeated circuits of the tank, he was swimming so much faster that it was much more difficult to hook him. At last they succeeded, however. Dragging him toward the gate to the flume, they managed to pull him through and to attach their line to the cable of the hoist. So great were the shark’s struggles that it was some time before they could draw him out of the water with the winch and lower him into a truck waiting below the outside wall of the flume.

An interesting sidelight to the departure of the troublesome shark was the failure of two remoras fastened to his head and body to disengage themselves when he was hauled out of the water. Loyal to the last, like officers of a sinking ship, they accompanied their host to the boneyard, although they might easily have fastened themselves to one of the other sharks in the tank.

Unlike the lamprey, which sucks the blood of its host, the shark remora uses his adhesive disc only as a means of transportation. When the shark attacks his prey the remora loosens his grip and swims forward to pick up scraps of food resulting from the fray, then hurries back to reattach himself and ride forth to his next meal. A single shark may carry three or four remoras one to two feet long without discomfort or annoyance since his passengers are streamlined and offer little resistance. If the adhesive disc, whose interior structure resembles the slats in a Venetian blind, remains in one location long enough, however, it may affect the skin of the shark or the tarpon, to which they also attach themselves. So great is the adhesive power of the discs that they have occasionally been employed in catching turtles. This is done by tying a line to the remora’s tail and releasing him in the water in the vicinity of the turtle. The peculiar fish will quickly orient himself and with no delay swim to the turtle. So powerful is his hold upon the shell that the line attached to the remora’s tail may be drawn in slowly, bringing both remora and turtle to the boat.

This affinity of one marine creature for another dissimilar in every way is one of the most intriguing phenomena of the sea. In small tropical aquariums set into the walls in the corridor a number of these relationships may be seen. In the same tanks containing tiny sea horses are small red sponges that seem to have legs. Close examination reveals that the legs belong to small crabs which carry the sponge around on their backs and in so doing greatly diminish their chances of being seen and eaten. The traveling sponge is at the same time far less likely than a stationary one to be covered with sand.

Another species of crab, the hermit, improves his natural defenses by carrying sea anemones around on his shell. The migrating anemone has a far greater opportunity lo satisfy its appetite than one which must wait in one place to trap an errant fish. In return for providing the anemone with a more fruitful hunting ground, the crab may exact a fee by appropriating and eating some of the prey trapped by his consort and at the same time gain security from enemies such as the octopus through the anemone’s stinging tentacles. Lumbering about with the added protection of a conch or whelk shell on his back, the hermit is one of the more familiar examples of “cohabitation. “The Marine Studios collecting staff brought in one crab whose borrowed shell also sustained five sea anemones, two slipper shells, eight small barnacles, a dozen tube worms, a large flatworm, and a pink porcelain crab.

Perhaps the strangest relationship of all is enjoyed by the sea slug and small members of the anemone family. The sea slug or nudibranch, a snail that has no shell, can without difficulty swallow stinging cells like those with which the anemone kills its prey. The cells are not digested but in some manner migrate out to the surface of the nudibranch, where with the slightest stimulus they may be set off to poison predators. How the sea slug manages this feat of acquired protection is a mystery no less remarkable than how the eel finds his way thousands of miles to spawn in the deep Sargasso Sea, or the salmon his tortuous route to the tiny stream where he was born. Someday the myriad forms in the sea may be understood as thoroughly as life on the land. Meanwhile it is refreshing to think that there arc many natural mysteries for which an increasingly scientific world has no explanation whatever.