THE BLUEFISH: MARAUDER OF THE SEAS
On the night of August 13, 1964 Robert Wicklund and Stuart Wilk, diver-biologists with the U.S. Marine Gamefish Laboratory at Sandy Hook, N.J., were 35 feet below the surface of the Atlantic 10 miles east southeast of Monmouth Beach. Equipped with scuba apparatus, both men were observing fish life from a protective diving cage attached by cable to the research vessel Challenger above them. Four floodlights mounted on the cage lit up the depths, and as the cage slowly drifted with the Challenger, Wicklund and Wilk began to notice round herring feeding on plankton. At first there were several hundred of the cigar-shaped, seven-inch fish, then there were thousands. Soon the cage was in the middle of a vast school numbering into the millions. Suddenly both men were startled by a tremendous roar in the water. The millions of herring had panicked, and their fright was such that many of them rushed through the bars of the cage and beat upon the bodies of the divers. At one point the cage was so thick with herring that Wicklund could not see Wilk only four feet away.
A school of bluefish had caused the panic. The bluefish, each about 15 inches long, had knifed into the middle of the herring and were feeding ravenously on them. For fully 15 minutes the roar set up by the millions of fleeing fish continued, and when the massacre was over and the divers were back aboard the Challenger hundreds of herring littered the bottom of the cage. A camera that Wicklund had tried to use to take photographs of the event was clogged with fish. "It was a thrilling and amazing experience," Wicklund recalled recently. "It was almost frightening in the beginning. The whole thing was eerie and exciting."
Of all the game fishes in the ocean none has a more murderous reputation than the bluefish. Marauding blues, from snapper size of less than 10 inches to lunkers three feet long, periodically range the Atlantic and Gulf coasts of the U.S. In the summer months the northeast coast from Cape May to Cape Cod is one of the world's great fishing grounds for blues, which throng there by the millions. Only last summer—a banner bluefish season off Long Island—a commercial-fishing-boat captain, searching for menhaden, reported that he had passed through a 30-mile-wide school of blues at sea. The holds of his boat were empty; the blues had ravaged every menhaden in sight. Even normally sober government reports testify to the savagery of blues. No less formidable a Victorian figure than Professor Spencer Fullerton Baird (whiskers, frock coat), the first head of the old U.S. Commission of Fish and Fisheries, cast aside academic caution to denounce the blue, in Sunday-supplement terms, as "an animated chopping machine." In 1871 Professor Baird wrote, "Going in large schools, in pursuit of fish not much inferior to themselves in size, they move along like a pack of hungry wolves, destroying everything before them. Their trail is marked by fragments of fish and by the stain of blood in the sea, as where the fish is too large to be swallowed entire, the hinder portion will be bitten off and the anterior part allowed to float away or sink." The professor estimated that in the four summer months off the southern New England coast bluefish destroyed the incredible number of twelve hundred million millions offish.
Later writers have thought Professor Baird's toll perhaps exaggerated, but none has kind words to say for the blue. In Fishes of the Gulf of Maine, published in 1953, Henry B. Bigelow and William C. Schroeder brand bluefish as "sea pirates" and call the species "perhaps the most ferocious and bloodthirsty fish in the sea, leaving in its wake a trail of dead and mangled mackerel, menhaden, herring, alewives and other species on which it preys."
To commercial fishermen blues are a curse. They cannot be caught in most nets, because they can chew through them. One old name for them, tailors, is said to come from their ability to cut their way free. Anglers account for the vast bulk of blues taken annually, a staggering 50 million pounds. When blues are present, they are there in numbers. A school can be found by seeing fish break water. Excited gulls and terns, eager to feed on the remnants left behind by rampaging blues, are another sign. When blues are feeding, the birds wheel and dip but rarely dive into the water as they do on a school of striped bass. According to Henry Lyman, author of Bluefishing and publisher of The Salt Water Sportsman, bluefish and killer whales are the only species in the sea that keep birds from diving. Some veteran anglers can locate bluefish by smell. Various fishes, such as the round herring and menhaden, feed on an odorous plankton, and bluefish, in turn, arrive to feed on them. James R. Bartholomew of the Farlow Herbarium at Harvard likened the telltale odor to "a cross between a pea-soup fog on the Grand Banks and a crate of honeydew melons."
Bluefish are delicious to eat, and they can be caught on lures ranging from streamers to plugs. Wire leaders are ordinarily employed because of the fish's sharp teeth. Lyman has written of a 12-pound blue that bit a solid metal one-pound lure in half. The story is authentic, for the fish was caught a few days later with half the lure in its stomach. There is no fish gamer than the blue. Even when boated, blues keep up the battle, and removing a lure sometimes takes doing. The father of Edward Migdalski, the Yale ichthyologist, lost the forepart of his right index finger to a two-pound blue.
The bluefish bears the scientific name Pomatomus saltatrix. Pomatomus is a combination of two Greek words, poma (cover) and tomos (cut), which perhaps refer to the indentation on the gill cover, and the Latin saltatrix is a tribute to the blue's gameness, meaning "one who leaps." The bluefish is the only member of the Pomatomidae family. In fishes, this family stands between the Serranidae, which includes the striped bass, and the Carangidae, the jacks.
Blues are found all over the world. They are off the east coast of South America, off southern Africa and Madagascar, the Malay Peninsula and southern Australia. They are also found in the Black Sea and the Mediterranean and off the Azores and northwest Africa between Agadir and Dakar. Reports have long had it that the biggest blues in the world, supposedly up to 45 pounds, are off the Moroccan coast, but Emile Postel, a biologist with the French Office of Scientific and Technical Research of the Deep Sea, says the largest he has seen there weighed 15½ pounds. The present world record on rod and reel is a 24-pound 3-ounce blue caught off the Azores in 1953. Before that the rod-and-reel record was a 20-pounder landed off Montauk, N.Y. in 1951. The alltime whopper, taken on a handline, was a 27-pound blue caught near Nantucket back in 1903.
As fascinating and desirable—either as game fish or food—as bluefish are, it is surprising that until recently next to nothing was known of their life history. They hit the northeast coast in the summer, they were caught, then they disappeared and that was that until the next summer. Now, however, as the result of research under way at the U.S. Marine Game Fish Laboratory at Sandy Hook (SI, March 9, 1964) and also at the University of Connecticut Marine Research Laboratory at Noank, some of the mysteries surrounding the bluefish are being solved. The most extensive work is being done, on the usual meager budget, at Sandy Hook, and there perhaps the most spectacular research is being done by Bori L. Olla, an animal behaviorist.
Bluefish are usually difficult to keep in captivity, but last year Olla was able to keep and observe eight blues in a 32,000-gallon filtered-seawater aquarium in the basement of the lab. The aquarium, built of concrete, is 35 feet long, 15 feet wide and 10 feet deep. The sides are fitted with six viewing windows, and special overhead fluorescent lights enable Olla to approximate dawn, daylight, dusk and moonlight.
Olla's fish were captured off Palm Beach in March 1964, anesthetized and flown to Sandy Hook. When they revived, the lights had been arranged to simulate Florida daylight. Originally there were 10 fish, each about a pound and a half, but two of them succumbed to a fungus infection. The remaining eight have been healthy and have gained a pound each. Shortly after the fish arrived, Olla and several assistants began a round-the-clock observation program. The scientists were curious to see if the fish, like many birds and mammals, had an internal rhythm or pattern of activity related to light. He found that bluefish are never really at rest—a fact that may account for their scrappiness. Olla was able to measure their rate of activity by noting the time it took the fish to swim between two broad lines marked in the tank. When the blues were active they covered the 12-foot course in as little as nine and a half seconds; when they were "resting" they took up to 16 seconds to swim the distance. Olla and his team found that bluefish are diurnal, that is, they are most active during daylight hours. The daily pattern of activity is almost always the same. The blues are slow-moving at night, but shortly before dawn there is an increase in swimming speed, which reaches a peak between the hours of 11 a.m. and 2 p.m. After that the rate starts to slow, though there is sometimes a sudden rise at twilight. Olla's findings are of such significance (they might even have relevance to the workings of man's biological clock in outer space) that he delivered a paper on the subject before the American Association for the Advancement of Science.
Olla has found that bluefish have keen eyesight in good light. "We're positive that these bluefish can see a bait or lure in the air before it hits the water," Olla says. "We've thrown baitfish to the other end of the tank, and the blues follow them at tremendous speeds and grab them as they hit."
Olla notes that when blues feed they flash their two pelvic fins, usually held tight against their sides. "I'm not sure, but it might be a signaling device to the rest of the school to keep them all in a state of excitement," he says. "If fish on an edge of the school come across food, their flashing fins would let the others know where the food is. But this is just conjecture."
The eight blues at Sandy Hook normally travel in a school. The school disperses when the fish are feeding and, after having fed, it regroups again. When frightened, the fish dive for the bottom and go into a pod, a very compact school in which their bodies press against one another. Frightened blues in a pod swim actively and refuse to feed. Blues can be frightened by unusual sounds or disturbances in the water. A blue's heart normally beats about 60 to 70 times a minute but, unlike mammals, its heart slows when it is frightened. By testing heart deceleration with a sensitive electrocardiograph, Olla was able to note the blues' responses to sounds, and he found that they can hear sounds ranging from less than 100 to 3,100 cycles per second. This range is nowhere near as extensive as man's, but in practical terms it means that, while they are not able to hear voices above water, they can detect the slap of an oar or the plop of an anchor. Moreover, blues also can detect water movements through their lateral lines, a sort of sixth sense that fish possess. The lateral lines are a row of receptors along each side. "If you started kicking in the water," Olla says, "a bluefish 50 feet away might not hear it, but he would get the message through the lateral line."
There is no external way of determining the sex of bluefish, but Olla thinks it likely that he has both males and females. The fish are so acclimated that he is cautiously hopeful they may attempt to spawn this year. So little is known of bluefish spawning that biologists have even been hard put to identify bluefish eggs and larvae. In an attempt to remedy this, John R. Clark and David G. Deuel succeeded in July 1964 in artificially fertilizing bluefish eggs with sperm taken from ripe fish. Bluefish eggs had been artificially fertilized on two previous occasions, most recently by a Russian biologist, but the drawings showing eggs and larvae were not adequate for identifying samples taken at sea. At Sandy Hook the eggs took 46 to 48 hours to hatch in beakers of seawater, and Clark and Deuel succeeded in keeping one larval blue alive for a record seven days. At regular intervals specimens of eggs and larvae were preserved, and drawings made of them will be of great value in identifying spawn at sea. A bluefish egg is quite small, about the size of this letter o. At the University of Connecticut marine lab Dr. William A. Lund Jr. also has been working on the early life history of bluefish. Lund is of the opinion that bluefish spawn close to shore in his area, and Clark feels this is also true along the Jersey coast, where there apparently are two spawning periods, one in May, the other in July. "It is vital for us to know the eggs and larvae and their whereabouts and the forces at work," Clark says. "We would like to know about possible mortality from polluted water or warm water. If there are discrete stocks, subject to different conditions in different places, we want to know about them. Spawning may be affected by a cold spring. There may be predators at work in July. It is an accepted thing in fishery management that you're going toward some practical goal. Perhaps some day all the wetlands will be destroyed and the spawning and nursery grounds gone. Some day we may need hatcheries for marine fish."
The migrations of bluefish up and down the coast also are being studied at Sandy Hook. The biologists are trying to find out why bluefish frequent certain waters. Last summer, for instance, bluefish, from two inches to six pounds, swarmed up the Hudson River as far as Peekskill, N.Y., almost 50 miles from the harbor mouth. Snapper blues were seined out of brackish water at Croton with pumpkinseed sunfish. What is it that attracts them? Are they just roaming, or are they following the baitfish up the river? Where do they go from the river, Long Island Sound or the Jersey coast?
To find out about the comings and goings of bluefish, Clark began tagging them in 1962. Deuel has continued the work. So far they have tagged 14,000, and the lab has received 850 returns. At first Clark used rod and reel and, although this was fun, it was too slow. Deuel now catches blues in a strong monofilament net, and he can tag about 30 in an hour. To his surprise, he has taken about 60% of the netted fish close to the bottom. Larger blues, those five pounds or over, are, for some reason, rarely caught in the net. Lund, up in Connecticut, has had the same experience. Lund has gone after the larger blues by trolling handlines, and he has caught them up to 15 pounds. He catches the big ones in The Race, a celebrated fishing ground near the mouth of Long Island Sound.
Lionel A. Walford, director of the Sandy Hook lab, theorizes that the blues found off Delaware Bay in May probably belong to a population that stays in the northeast the year round and does not migrate to Florida as previously thought. "There may be one population, if not two, that remains in northern waters the year round," Walford says. Deep-sea trawls have taken bluefish over the Hudson gorge in midwinter, and a biologist in North Carolina has informed Walford that swordfish caught 50 miles offshore in February had bluefish in their stomachs. "According to temperature charts, there is a band of 50° to 55° water extending along the edge of most of the continental shelf from southern New England down. A small population of cold-tolerant blues could winter in this band. Another population, probably the principal one that summers off the New Jersey and New York coasts, seems to be associated with 59° to 64° water. This temperature range extends all winter long in a narrow band from just south of Cape Hatteras to northern Florida. We think that many blues can be found in this band during winter. The opinion of the scientists at Sandy Hook is that although bluefish wintering in Florida are feeding and maturing sexually, their principal spawning occurs as they journey northward. The northward migration is not triggered by temperature alone, because the fish leave before the water temperature changes. After spawning, the eggs drift and the parent fish continue north, eventually joining the northern stock. The offspring summer in estuarine areas of North Carolina. That winter they go out on the shelf and return again to North Carolina the following summer. By the second winter they are ready to go to Florida.
"There are several local populations on the coast. One of these is primarily northern and cold-tolerant, and there is another warm-water stock which summers in Chesapeake and North Carolina waters and then travels to southern Florida and perhaps northern Cuba. Judging from tag returns, a member of this warm-water population will sally forth into New Jersey or Long Island waters," Walford says. Bluefish are not as numerous along the Gulf Coast as they are on the East Coast, and the populations do not mix very much. For some reason that biologists have not been able to fathom, the fish in the Gulf of Mexico tend to stay on one side or the other of the Mississippi River. Walford does not rule out the possibility, however slim, that some of the blues on the East Coast, particularly the bigger fish which prefer the off-shore areas, migrate across the Atlantic to the Azores or North Africa. "This is a possibility we must test," he says. "I think enough of this possibility to have our tags printed in French and Spanish as well as English."
Last year was a poor one for blues off Jersey but, according to forecasts filed with the Atlantic States Marine Fisheries Commission by state biologists, the waters from Montauk to Cape Cod should again teem with blues. Walford hopes that any anglers who catch tagged fish or note any unusual occurrences will report their findings to the laboratory. Information of this nature will help disclose the life history of the blue. Walford says, "It's as though we were looking at a very fuzzy picture that is starting to come into focus."
ILLUSTRATION
JACK KUNZ