Mackerel

_{-- M a c k e r e l --} _{click on the question number for the answer}
Q 1.
	What is a frigate mackerel?
Q 2.
	What is the difference between a Spanish mackerel and a cero mackerel?
Q 3.
	Why do tunas and bonitos die so quickly when taken from the water?
Q 4.
	What species of fish is correctly called “kingfish?”
Q 5.
	Is the Spanish mackerel related to the northern mackerel?
Q 6.
	What is the red-fin tuna?
Q 7.
	Can a mackerel see itself?
Q 8.
	Is anything being done to ascertain the possibilities of a tuna fishery on the East Coast of the United States?
Q 9.
	I thought that all fish were cold blooded animals but a friend of mine tells me that the tunas are not. Is this true or is he pulling my leg?
Q 10.
	Would you please tell me haw to tell the Spanish, Cero and King mackerel apart?
Q 11.
	While fishing off Miami Beach, Florida, I caught a fish that my guide told me was a blackfin tuna. However, I have caught many of these fish in California where it is known as an albacore. Are these the same fish?
Q 12.
	Some time ago on Pier 5 in Miami I saw a small fish which others said was a tuna. It was less than 10 pounds in weight. I always thought that tuna - at least the ones caught - were very large fish. Do you think this was a tuna?
Q 13.
	How fast can a bluefin tuna swim?
Q 14.
	I have been catching albacore for years on my charter boat allover the Caribbean and Gulf Stream. I now read that the U. S. Government has recently discovered albacore in the Caribbean. Can you please tell me why the government claims to have just recently discovered them?
Q 15.
	I am interested in reading about your snook tagging program, for I have had the opportunity of watching the California Department of Fish and Game tag albacore. I would be glad to help you tag snook for I catch and release great many of them during the year. Would you know if any of the California tagged albacore were ever recaptured?
Q 16.
	Is it correct to consider the Spanish mackerel as a scaly fish?
Q 17.
	Does the bluefin tuna spawn off south Florida?
Q 18.
	Is the so-called “northern” or “common” mackerel ever found in Florida waters?
Q 19.
	At Batabano, Cuba, I notice that tuna schooners have a pipe arrangement on the stern which has small holes through which water is pumped under pressure, forming a spray in the wake of the ship as it trolls. How does this arrangement work and what is its value? Also, has this device been used when trolling for other fish?
Q 20.
	What is the range of the Spanish mackerel?
Q 21.
	I notice some canned tuna is marked “white meat” and some is marked “light meat”. Are these different?
Q 22.
	What kind of gear is used in the Spanish mackerel fishery in the Gulf of Mexico?
Q 23.
	Is the kingfish fishery seasonal? If it is, when are the kingfishes in the Miami areas?
Q 24.
	Do tuna fish have scales? I have seen albacore which seem to have very fine scales but am interested in the tuna that is used for canning purposes.
Q 25.
	While cleaning a 30-pound wahoo caught off Ocean City, Maryland, two live objects were taken from the stomach cavity of the fish. They were a dark slate gray in color with an elongated neck, yellowish in color, pear shaped, and about the size o a plum, with apparently no hard parts. They were both alive and showed no signs of having been attacked by the fish’s stomach. Can you tell me if they were some form of parasite or something the fish had been feeding on?
Q 26.
	The meat of a fresh-caught blackfin tuna usually is pink and firm. Lately several have been caught with the meat a milky pink, and not firm. Is this a seasonal change or would you say the tuna are unhealthy?
Q 27.
	How many types of tuna are there?
Q 28.
	Are the Spanish mackerel and the Sierra of the Pacifis the same species?
Q 29.
	In California the albacore is called "Mystery Fish." No eggs have been found in any fish caught here, no doubt because the mating season is over when they are migrating in this area. It was said that no one knew the males from the females, or if they laid eggs or gave birth to young. Experts assured me ten years ago that the only available literature on the subject was in Danish, Italian or Japanese. Is there now any available information in English?
Q 30.
	What is the fish commonly called oilfish and where is it found?
Q 31.
	I was told by a fishing guide at Palm Beach that kingfish have been known to jump 30 to 40 feet clear of the water. Is this true or false?
Q 32.
	During the last week in May I caught a ten-pound kingfish with its belly chock full of milt on the reef about three miles north of the wreck buoy off Jupiter Island. Do kings spawn around this reef in late spring?
Q 33.
	I have used the terms “False Albacore” and “Little Tuna” for the fish commonly known along the Atlantic as the Bonito, and my friends have criticized me for it. Are these terms correct, or not?
Q 34.
	In over forty years of fishing, I have only captured one wahoo with roe, and know very little about them. Where and when do they spawn, and what are the worm-like things in their stomachs when they are cut open?
Q 35.
	We run a sport fishing boat in Cape May, New Jersey. Last summer, there were hordes of bluefin tuna off our coast, but pickings were lean for sport fishermen. At the same time, hundreds of tons were being taken by sixteen tuna clippers from the Pacific coast. They spotted schools of tuna by plane, then closed in and made a set regardless of the small boats. All the sportfishermen in New Jersey cannot catch as many tuna in a season as one of these boats catches in one day. They also catch thousands of pounds of bluefish and other schooling fishes. Isn't there a grave danger that the tuna will be fished out by these methods?
Q 36.
	Our fishing club ran a tournament, with a prize for the largest tuna. The only fish caught was skipjack tuna (Kalsuwonus pelamis). In your opinion, should the skipjack have qualified as a winning tuna?
Q 37.
	How high can a kingfish jump?
Q 38.
	Would you please tell me what the small yellow spots are that see on some of the Pacific albacore (Thunnus germo) that I catch. The spots are rather dull now, but when first caught they are bright yellow. It would seem that approximately 16 to 18 fish out of 100 have the spots, and they are almost always under the pectoral fin or on the small of the tail, top or bottom near the caudal fin. The tuna that are spotted seem to average 6 or 8 spots to a side.
Q 39.
	For years I have enjoyed fishing for Boston mackerel in the Atlantic Ocean. I have always accepted that when you hook them and bring them into the boat, they shed their scales-unlike any other fish I have caught. A fishing friend from the midwest would not believe me when I told of this, so could you settle the argument for me: don't mackerel shed their scales when caught?
Q 40.
	Is there any significant difference between the Atlantic bluefin tuna and the southern bluefin tuna of the Pacific and Indian Oceans? Also, what are the significant differences between the bluefin tuna and the bigeye tuna?
Q 41.
	On page 162 of C. P. Idyll's The Sea Against Hunger, he speaks of “…the 50-mile baited lines of the Japanese tuna fleets.” Could that possibly mean a 50-mile long line, or does it refer to the combined total of lines in the fleet?
Q 42.
	What are the differences between the Atlantic bigeye tuna and the Allison or yellowfin tuna?
Q 43.
	On a fishing trip off Cape Hatteras, North Carolina, I landed a 30-pound wahoo that had two reddish, globular specimens fastened by a sucker-type mouth to the wall of its stomach. The specimens measured about 3 by 1.5 centimeters and resembled some sort of leech. Can you identify them?
Q 44.
	Are there any species of tunas that may be captured without endangering dolphins?
Q 45.
	During summer months, we catch a considerable amount of bonito off Jupiter, Bobe Sound, and Stuart, Florida. Is there any way to utilize this fish other than for bait?
Q 46.
	Is the albacore found in the Atlantic Ocean? If so, what is its migration pattern?
Q 47.
	What is the status of the bluefin tuna ranching project discussed in the May-June 1977 issue of Sea Frontiers? Also, has anyone succeeded in rearing the bluefin from the egg?
Q 48.
	Has the death of dolphins associated with tuna fishing in the eastern Pacific Ocean declined?
Q 49.
	Is it true that bluefin tuna fishing in the Western Atlantic is being severely restricted?
Q 50.
	A crew member on my boat was a bit careless when boating a wahoo, and the fish bit the calf of his leg. At the hospital where the wound was sutured, the doctor asked for the head of the wahoo so that it could be checked for rabies. Do fishes get rabies?
Q 51.
	I have read that homing pigeons have a substance in their heads that allows them to detect the earth's magnetic field and navigate by it. Do any aquatic organisms have this material?
Q 52.
	I found an object resembling a round glassy marble about 1/2 inch in diameter in a can of tuna cat food. Can you tell me what it is?
Q 53.
	In a restaurant at St. John, U.S. Virgin Islands, I was served escolar. What kind of fish is it?
Q 54.
	In light of all the new interest in eating fish oil to aid in lowering cholesterol, is it better to buy tuna fish packed in oil or in water?
Q 55.
	I know that tuna fishermen set their nets around herds of dolphins and catch tuna swimming under these mammals. I also know that fishermen on U. S. boats are trying to reduce the dolphin incidental catch that can occur in this situation. But, has anyone figured out why the dolphins and tuna are found together in the first place?
Q 56.
	In outward appearance, the false albacore and bonito seem to resemble each other. How can I tell the two fishes apart?
Q 57.
	I have heard that certain oily fishes cause diarrhea. Which fishes are they?


_{-- a n s w e r s a b o u t t h e M a c k e r e l --}
	Q&A 1.	What is a frigate mackerel?
	This fish, Auxis rochei, is a swiftly-swimming fish of the tropical Atlantic ranging occasionally northward to Cape Cod. Allied to the bonito and tunny, the frigate mackerel is reported to travel in large schools, but is not frequently seen. In shape this fish is remarkably torpedo-shaped and rounded, with a rather small tail fin. It may be told from the true mackerels by its stout form and from the bonitos by the fact that the two dorsal fins are well separated with an area of smooth skin in between.
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	Q&A 2.	What is the difference between a Spanish mackerel and a cero mackerel?
	Although both of these excellent food fishes are somewhat similar in appearance, they may be distinguished readily as follows: The spanish mackerel, Scomberomorus maoulatus, reaches a length of about 3 feet and is marked on the sides with a number of small, brownish-yellow spots. The cero or painted mackerel, Scomberomorus regalis, is somewhat more slender, reaching a length of 6 feet, and tends to keep more offshore. In this fish the lateral spots are somewhat smaller and tend to unite in a continuous band along the side. Neither of these fish is closely related to the common, or northern mackerel, Scomber scombrus.
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	Q&A 3.	Why do tunas and bonitos die so quickly when taken from the water?
	The reason for this is the normally high oxygen requirements of these fish, which causes then to expire much more quickly than other fishes after they have been removed from the water. The tunas and bonitos (Suborder Scombroidei) are known for having very oily flesh and in most cases a highly developed system of blood vessels in the flesh next to the skin. These fishes may be considered to be the only "warm blooded" fishes, as their high metabolism results in the interior of the body normally being several degrees higher in temperature than the surrounding water.
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	Q&A 4.	What species of fish is correctly called “kingfish?”
	Two species of Atlantic coast fishes are commonly known as kingfish, though they are not in any way related. The northern kingfish, Menticirrhus saxatilis, is a member of the drumfish family and is closely related to the whiting. Although it sometimes is found in Florida, it is common only north of the Chesapeake Bay region. On the sandy shores where it is found it swims close to the bottom and is remarkable in lacking the swim bladder found in most other fishes. It feeds on shrimps, crabs, squids, worms, and young fish. The other kingfish, Scombermorus cavalla, is a member of the mackerel group and is more correctly called the king mackerel. This species grows to a length of five feet and a weight of 100 pounds and is considered to be a prime food fish. Its delicately flavored and richly textured flesh is most commonly sold in the form of kingfish steaks.
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	Q&A 5.	Is the Spanish mackerel related to the northern mackerel?
	Yes, but not closely. The northern mackerel, Scomber scombrus, reaches about a foot in length and feeds on very small crustaceans in the sea, which it strains from the water by means of its sieve-like gill rakers. The Spanish mackerel, Scomberomorus maculatus, is larger and carnivorous, feeding largely on smaller fishes. This species is considered to be one of the best eating of all food fishes.
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	Q&A 6.	What is the red-fin tuna?
	This rare and remarkable oceanic fish is not a tuna at all, but an entirely different type of fish. More properly known as the opah or moonfish, the red-fin "tuna," Lampris luna, reaches a length of 6 feet, and is rounded and bulky in shape. The body is a lustrous silver marked with strawberry-colored spots and the fins are bright red. Not often captured, this fish is noted for its rich and delicate oily flesh. It is considered to be one of the best of food-fishes.
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	Q&A 7.	Can a mackerel see itself?
	Because of the position of its eyes and the rigid form of its streamlined body, the mackerel can either see or touch itself, as many other fishes can. Mackere1s and related fishes such as tunas and bonitos (family Scombridae) do not pump water through their gills as more sluggish fishes do, but rely instead on their forward momentum to circulate water past their gill membranes. That is why most of these fishes will quickly die when placed in a smal1 tank where their movements are restricted.
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	Q&A 8.	Is anything being done to ascertain the possibilities of a tuna fishery on the East Coast of the United States?
	At present, the Fish and Wildlife Service of the federal government is doing exploratory work on the tuna, and this Laboratory is engaged in biological research on these species. Recently, the Fish and Wildlife Service vessel Oregon caught 28 yellow fin tuna, (Thunnus macropterus), in eleven sets of 300 hooks each. The smallest of these weighed 73pounds, the largest 189 pounds, with the average weight close to 100 pounds for the 28 tuna. Eight black fin tuna, (Thunnus atlanticus), averaging five to six pounds each were caught during this cruise. Surface fishing was eliminated when it was found that the best results were obtained at about 20 fathoms. However, the yellow fins were taken at various depths from the continental shelf shoreward. A major problem encountered in this hook and line fishery is that of the sharks. It was found that when the lines were brought aboard, the baits that were knocked off the empty hooks into the water acted as a chum for sharks. This, of course, resulted in the mass feeding of sharks on the hooked tuna. One member of the expedition "chummed" the sharks to the surface at the stern of the boat where he shot them. A considerable amount of exploratory fishery has been done on bluefin tuna, (Tlnmmus thynnus), off the New England coast. There seems to be a reasonable hope that a substantial tuna fishery may be developed on the East Coast, but there is no likelihood that it will approach the size of the Pacific fishery.
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	Q&A 9.	I thought that all fish were cold blooded animals but a friend of mine tells me that the tunas are not. Is this true or is he pulling my leg? San Diego, California
	In general fish have a body temperature of about one half a degree Fahrenheit above that of the surrounding water. However, it is true that some of the fishes of the tuna family, Scrombridae, maintain a body temperature several degrees above their environment. In studying the Pacific albacore, scientists found that the body temperature was 4° F. above that of the water, and that it then rose as high as 10° F. within ten minutes after capture. The rise in body temperature after capture is unexplained as yet.
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	Q&A 10.	Would you please tell me haw to tell the Spanish, Cero and King mackerel apart? Homestead, Florida
	The king mackerel, Scomberomorus cavalla, can be identified by looking under the gill cover and inspecting the gill rakers on the lower part of the first gill arch. In this species, there are 7 or 8 on the lower limb. Usually there is no coloration to the body other than the silver color, except in young specimens. The spinous dorsal (top) fin has no black on its anterior half (except in the young). This species attains the largest size of the three species of mackerel which you mention, reaching a weight of 100 pounds and over 5 feet in length. The Spanish mackerel, Scomberomorus maculatus, has a higher number of gill rakers on the lower part of the first gill arch, the number being 10 or 11. The sides of the body are covered with oval, golden spots but there are no longitudinal stripes on the body. The spinous dorsal fin is black anteriorly, The Spanish mackerel, Scomberomorus maculates, reaches a weight of 10 pounds or more but averages about 2 pounds. The cero or painted mackerel, Scomberomorus regalis, has 12-13 gill rakers on the lower limb of the first arch. The sides of the body have both the golden spots and the longitudinal stripes. As in the Spanish mackerel, the spinous dorsal fin is black anteriorly. The cero attains a weight of 35 pounds but usually averages 2-5 pounds. In identifying these species, it is important to remember that one character will not definitely identify a fish but that a combination of all these characters must be used.
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	Q&A 11.	While fishing off Miami Beach, Florida, I caught a fish that my guide told me was a blackfin tuna. However, I have caught many of these fish in California where it is known as an albacore. Are these the same fish? Indianapolis, Indiana
	While the blackfin tuna is sometimes erroneously called the false albacore or albacore tuna, it is distinct from the true albacore of the Pacific. Your guide was probably correct in stating that it was a blackfin tuna. The albacore (Thunnus alalunga) is found in the Pacific and eastern Atlantic and Mediterranean Sea, but as far as is known there are no authenticated records of this fish from the western North Atlantic. The albacore that you have seen in California is distinguished from the Atlantic blackfin tuna (Thunnus atlanticus) by the long pectoral (side) fins which extend back past the second dorsal (back) fin. The albacore attains a larger size than does the blackfin tuna, the record from California slightly over 65 pounds, and the average weight less than 40 pounds. The blackfin tuna can be separated from the albacore by its shorter pectoral fin, which extends only to the second dorsal fin. The blackfin tuna averages under 12 pounds and the maximum weight recorded is just over 20 pounds.
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	Q&A 12.	Some time ago on Pier 5 in Miami I saw a small fish which others said was a tuna. It was less than 10 pounds in weight. I always thought that tuna - at least the ones caught - were very large fish. Do you think this was a tuna? Elizabeth, New Jersey
	On some days many small tuna are landed at Pier 5. If the tuna you saw had four black stripes on a white belly, it was an oceanic bonito, Katsuwonus pelamis. If it had a vermiculate pattern of black on its back, it was a little tuna, Euthypnus alletteratus. If it was solid colored it was probably a blackfin tuna, Thunnus atlanticus, or a bluefin tuna, Thunnus thynnus, The bluefin tunas and yellowfin tunas, Thunnus albacares, grow to be very large (several hundred pounds) whereas the blackfin and little tunas and the oceanic bonito remain small (average under 50 pounds). Small specimens are frequently caught by anglers in Florida waters.
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	Q&A 13.	How fast can a bluefin tuna swim? Macon, Georgia
	It is not really known. In 1938 a man equipped his reel with a speedometer and went to Nova Scotia to obtain information about the speed of this tuna. He found out that the speedometer showed 45 miles per hour when the tuna waas hooked and frightened. This may be open to question. We usually fly over the Bahama waters around noon. The schools can be clearly seen from an altitude of 500 feet, and in the early part of the season it is possible to pick out a solid school, which could not be confused with anything else and follow it from around Orange Bay all the way up to Great Isaac. Timing about a 12 or 15 mile run, the average speed came to about 3.3 or 3.5 knots. Sometimes we have timed them to 4 or 5 knots; sometimes much slower. The bursts of speed which people sometimes observe might be caused by frightening the fish. Judging from the time it takes the tuna to get from the Bahamas to Nova Scotia waters, which is about 16 days, the rate again comes to about 3.5 miles per hour.
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	Q&A 14.	I have been catching albacore for years on my charter boat allover the Caribbean and Gulf Stream. I now read that the U. S. Government has recently discovered albacore in the Caribbean. Can you please tell me why the government claims to have just recently discovered them? Miami, Florida
	The fish which you have been catching is most likely the blackfin tuna (Thunnus atlanticus) which is common in parts of the Caribbean and Gulf Stream, and which is often referred to, erroneously, as "albacore tuna" because of the rather long pectoral (side) fins. The government report is referring to the true albacore (Thunnus alalunga). This species can be distinguished from the blackfin tuna by its extremely long pectoral fins which reach back past the second dorsal (back) fin, while in the blackfin tuna the fins reach only as far as the beginning of the second dorsal fin. This true albacore was previously known to inhabit the Mediterranean Sea, the eastern part of the Atlantic Ocean and the Pacific Ocean. Although there were no official records of this species, it has long been suspected to exist in some parts of the western North Atlantic including the Caribbean, and the recent government exploration has confirmed the presence of this species in this area.
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	Q&A 15.	I am interested in reading about your snook tagging program, for I have had the opportunity of watching the California Department of Fish and Game tag albacore. I would be glad to help you tag snook for I catch and release great many of them during the year. Would you know if any of the California tagged albacore were ever recaptured? Naranja, Florida
	The albacore, Thunnus alalunga, which suddenly appears off the southern California coast in mid-July and disappears again in September, may be making a round trip across the Pacific Ocean during the period it is gone from California shores. This possibility came to light recently with the recovery off California of a tagged albacore. This fish was recovered in almost the same spot it was tagged 111/2 months earlier. Previously, four California-tagged albacore had been recovered by Japanese fishermen – two off Japan and two in Mid-Pacific. One of those fish had been tagged at the same time and place as the one just recovered off California, and had been at sea six months - just half the time it took the California recovery to get back to the original tagging spot.
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	Q&A 16.	Is it correct to consider the Spanish mackerel as a scaly fish? Miami, Florida
	Yes, the Spanish mackerel has scales. These scales which only partly cover this species, are so small however that they are frequently overlooked.
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	Q&A 17.	Does the bluefin tuna spawn off south Florida? Tampa, Florida
	The occurrence of recently spawning fish and eggs and larvae believed to be those of the bluefin tuna suggest that these fish spawn in the Straits of Florida during May and early June. The main spawning area appears to be on the outer margin of the Florida current between Riding Rocks and Bimini in the Bahamas. The spawning habits of the smaller tuna in the area are at present unknown. The evidence suggests that the American and European tuna represent independent units inasmuch as the spawning time overlaps and the areas of spawning are about 4.000 miles apart.
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	Q&A 18.	Is the so-called “northern” or “common” mackerel ever found in Florida waters? Rye, New York
	The normal range of the common mackerel on the Atlantic coast of North America stretches from the Gulf of St. Lawrence south to Cape Lookout, North Carolina. In 1889, Capt. John W. Emmons, of the schooner Bell of the Bay, while on a winter cruise off Cape Canaveral, Florida, sighted several schools of mackerel about 20 miles southeast of the cape. The captain was confident that these were the so-called “northern” or “common” mackerel, but the record must be regarded as doubtful.
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	Q&A 19.	At Batabano, Cuba, I notice that tuna schooners have a pipe arrangement on the stern which has small holes through which water is pumped under pressure, forming a spray in the wake of the ship as it trolls. How does this arrangement work and what is its value? Also, has this device been used when trolling for other fish? Middletown, Delaware
	This spray system was developed by the Japanese. It consists of a power-driven pump which supplies a constant flow of sea water to a number, of spray outlets, situated at 3 to 4 foot intervals along the walk from which the fishing is done. In Japan, a 125 gross-ton vessel will have one or two centrifugal pumps with 4 to 5 inch intakes. These deliver water into one or two header pipes, depending on whether fishing is done from one or both sides of the ship. A distributing pipe is laid along the fishing walk. The water pressure is low, and a gentle spray falls between 6 and 18 feet from the hull of the vessel, forming a ruffled band which will be from 4 to 8 feet wide. It is assumed that the ruffling of the surface water hides the vessel and the fishermen from the fish. Also, the tunas demonstrate a "feeding frenzy" which, may be heightened by the spray system. Although the actual value of the method is difficult to determine, its commercial use where pole and line fishing for tuna takes place (Japan, Hawaii, Eastern Pacific Ocean, and Cuba) shows clearly that fisherman are thoroughly convinced that it is useful. We know of no species of fish other than tuna on which this method is used.
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	Q&A 20.	What is the range of the Spanish mackerel? Wilmington, Delaware
	In the Western Atlantic, the Spanish mackerel, Scomberomorus maculatus (Mitchill), is distributed from Cape Ann, Massachusetts, southward to Brazil, It occurs in the northern portion of its range as a spring and summer visitor and in Florida waters is most common from September through about March, Although the average fish is from one to three pounds, it has been known to reach a weight of 25 pounds. The species is also widely distributed in tropical waters in the Eastern Atlantic. A closely related species occurs in the Eastern Pacific.
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	Q&A 21.	I notice some canned tuna is marked “white meat” and some is marked “light meat”. Are these different?
	The white meat tuna is a higher grade and costs more than the other. Only albacore or longfin tuna (Germo alalunga) may be called "white meat" tuna, according to Food and Drug Administration laws. Bluefin tuna (Thunnus thynnus), skipjack (Katsuwonus pelamis), yellowfin tuna (Neothunnus macropterus), and little tuna or false albacore (Euthunnus alleteratus) are all packed as "light meat" tuna. The canned flesh of these species is slight1y darker than that of albacore and sometimes has a somewhat stronger taste.
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	Q&A 22.	What kind of gear is used in the Spanish mackerel fishery in the Gulf of Mexico? Veracruz, Mexico
	The fishermen in Florida use gill nets in the Spanish mackerel fishery. The nets range from 250 yards to 900 yards in length and have an inside stretched mesh from three inches to three and three-fourth inches. They range in depth from 60 to 200 meshes. The boats used in this fishery range from 20 feet to 45 feet and are powered by high-speed engines. During the 1920's, both purse seines and gill nets were used. Although purse seining is an effective method of fishing for Spanish mackerel, the gill net possesses several advantages. The boats used in the gill net industry are smaller than purse seine boats; the crew on a seine boat usually consists of about fifteen men while the gill net boat requires only two or three men. These result in a decrease in the costs of operation in the gill net industry.
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	Q&A 23.	Is the kingfish fishery seasonal? If it is, when are the kingfishes in the Miami areas? Fort Benning, Georgia
	The kingfish fishery is definitely a seasonal fishery. It begins in the latter part of October or in early November, depending upon the temperature, and extends into the spring, usually until around April.
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	Q&A 24.	Do tuna fish have scales? I have seen albacore which seem to have very fine scales but am interested in the tuna that is used for canning purposes. Modesto, California
	All of the tunas have scales on their bodies. Over the general surface of the tunas the scales are extremely minute and may sometimes appear to be lacking entirely. In the section around the head, on the cheeks and in a triangular area on each side of the body just posterior to the head, however, there is fairly prominent scaling. The albacore, bonito, and several others belong to the general group of the tunas, and share these characteristics to a certain extent.
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	Q&A 25.	While cleaning a 30-pound wahoo caught off Ocean City, Maryland, two live objects were taken from the stomach cavity of the fish. They were a dark slate gray in color with an elongated neck, yellowish in color, pear shaped, and about the size o a plum, with apparently no hard parts. They were both alive and showed no signs of having been attacked by the fish’s stomach. Can you tell me if they were some form of parasite or something the fish had been feeding on? Trenton, New Jersey
	The objects were internal parasites and are commonly called flukes or trematodes. Certain trematodes are common in the intestinal tract of large fishes and some of the flukes can attain fairly good size. In life, of course, they are not injured by the digestive juices of the host. They in no way impair the fpps qualities of the host.
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	Q&A 26.	The meat of a fresh-caught blackfin tuna usually is pink and firm. Lately several have been caught with the meat a milky pink, and not firm. Is this a seasonal change or would you say the tuna are unhealthy? Riviera Beach, Florida
	With the information received it is not possible to give the reason in your particular instance. However, there are a number of reports of discoloration in tuna meat, causing an unsightly appearance in the canned product. Research at the University of Washington gives as a possible reason an unbalance of pigments in the flesh and the oxidative action of the air. It is not thought that the tuna are unhealthy. The condition is one that comes and goes.
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	Q&A 27.	How many types of tuna are there? New South Wales, Australia
	Until recently most groups of fishes have been studied on a regional basis. As a result, many widespread species were named separately in different regions. This resulted partly from a lack of proper liaison between biologists and partly from lack of adequate libraries, collections and other facilities in regions where science has flourished only recently. As a result, there are many more species of tunas listed than actually occur in nature. In addition, this group is complicated by considerable changes that take place with the growth of certain species, so that the young and the adults were named separately. It is now felt certain that the yellowfin tuna, the big-eye tuna, the albacore and the skipjack tuna are world-wide species. In addition, it is likely, although less certain, that the bluefin tuna is a single world-wide species, excluding one very peculiar form that occurs in the Australasian region. It apparently has no counterpart in the Atlantic, nor does the blackfin tuna seem to have a counterpart in the Pacific. For further information, contact the Inter-American Tropical Tuna Commission, La Jolla, California.
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	Q&A 28.	Are the Spanish mackerel and the Sierra of the Pacifis the same species? West Palm Beach, Florida
	The two species are quite distinct even though they have a superficial resemblance. The Spanish mackerel (Scomberomorus maculates) is restricted to the Atlantic, while the Sierra mackerel (Scomberomorus sierra) is a Pacific species.
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	Q&A 29.	In California the albacore is called "Mystery Fish." No eggs have been found in any fish caught here, no doubt because the mating season is over when they are migrating in this area. It was said that no one knew the males from the females, or if they laid eggs or gave birth to young. Experts assured me ten years ago that the only available literature on the subject was in Danish, Italian or Japanese. Is there now any available information in English? Balboa Island, California
	A very considerable amount of information has been built up on tunas and allied species during the past ten years. In addition, many of the earlier reports in Japanese have been translated and are now readily available. The Japanese people are highly dependent upon resources of the sea and it is understandable that they have contributed a great deal of our knowledge on tunas. It has been determined that there are relatively few species of these fishes and that most occur on a worldwide basis. It is not usually possible to distinguish the sex in these fishes by their external appearance. All are egg layers and all broadcast their eggs in the open sea in enormous quantities. The larval stages of most tunas are at least known if not described in detail. A list of publications in connection with tunas is avai1able either from the Government Printing Office or from the U. S. Fish and Wildlife Service, Washington, D. C. Most of these publications can be purchased or can be obtained by writing to your Congressman. A branch of the U.S. Fish and Wildlife Service, in Hawaii, has studied these fishes in the mid-Pacific area on an intensive basis. In addition, the Inter-American Tropical Tuna Commission, which operates out of La Jolla, Calif., and other West Coast cities, has conducted thorough studies for a number of years. It is suggested that you visit the headquarters of the Inter-American Tuna Commission at La Jolla, which is not far from Balboa Beach.
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	Q&A 30.	What is the fish commonly called oilfish and where is it found? Rarotonga, Cook Islands
	The oilfish, Ruvettus pretiosus, is found around the world in low latitudes, for the most part not extending far beyond the tropics. Almost everywhere it is scarce, only an occasional individual being caught on a deep rig or on a flagline set. Indications are that the only area where they are found in numbers and are exploited is in the Philippines-Polynesia region. Little is known of its biology. Ruvettus is rarely taken around Hawaii; otherwise it might be used there. Both this species and Promathichthys prometheus belong to an essentially world-wide, oceanic group, the snake mackerels. It is suggested that you contact Dr. Innocencio Ronquillo, Fisheries Research Division, Bureau of Fisheries, Department of Agriculture and Natural Resources, Diliman, Rizal, Philippine Republic, for more detailed information.
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	Q&A 31.	I was told by a fishing guide at Palm Beach that kingfish have been known to jump 30 to 40 feet clear of the water. Is this true or false? Tampa, Florida
	Many estimates concerning fishes at sea, their speed, jumps and in the case of flying fishes their glides, are exaggerated. Partly this is due to a lack of perspective at sea, or of a lack of nearby and familiar objects that could form a background for estimate. Thirty or forty feet is higher than most Florida homes, actually the height of a good-sized tree. No kingfish (king mackerel) could leap that high. A better basis of est1mate is terms of body lengths of the fish. Some fishes, notably the tarpon, can clear twice their length, reaching 10 to 12 feet into the air. This is a tremendous leap and few fishes can do it. Sometimes a sea will fall away from a jumping fish and make it appear to have leaped higher than it actually did. LEAPING KINGFISH Dr. Gilbert Voss, associate professor of marine biology at the University of Miami Institute of Marine Science, disagrees with the answer to a Sea Secrets question in the September issue. Dr. Voss writes: "The reply stated that no kingfish could leap 30-40 feet into the air and attempted to explain this statement by referral back to heights of jump based on body length, giving the tarpon as an example. "However, in the jumping of tarpon we are dealing with tail thrust torque alone, while in kingfish both thrust and momentum must be considered. The tarpon's tail is broad and deep for power on short runs; the kingfish tail, narrow and crescent-shaped, allows sustained high speed. Charterboatmen know that kingfish make spectacular jumps when after a fast-moving outrigger bait, probably from a deep swimming position, as the fish rises almost completely vertical into the air. According to Lane's speed tables the wahoo, a near relative, can travel at 31 m.p.h. Under the excitement of the chase a kingfish can probably do as well or better. I have seen any number of kingfish leap, in a calm sea with no wave drop off, far above my head while standing on the flying bridge of a charterboat, a total height of at least fifteen feet. On more than one occasion I have seen them jump as high as the tip of the outrigger in fishing position, approximately 35 feet."
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	Q&A 32.	During the last week in May I caught a ten-pound kingfish with its belly chock full of milt on the reef about three miles north of the wreck buoy off Jupiter Island. Do kings spawn around this reef in late spring? Stuart, Florida
	The king mackerel – which is the preferred name for the fish that is often called the kingfish – probably spawns through much of the warm part of the year, undoubtedly offshore and quite possibly along the outer reek. The young king mackerel enter the bays and are commonly caught by bridge fishermen until they are about one and a half feet in length, At this time they closely resemble the Spanish mackerel and are seldom distinguished by the fishermen.
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	Q&A 33.	I have used the terms “False Albacore” and “Little Tuna” for the fish commonly known along the Atlantic as the Bonito, and my friends have criticized me for it. Are these terms correct, or not? Palm Beach, Florida
	Yes, these terms are correct. “False Albacore” is used by some for the reason that the fish, the scientific name of which is Euthynnus alletteratus, is not an albacore. However, leading ichthyologists are leaning toward the preferred name of “Little Tuna,” which is being used with increasing frequency.
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	Q&A 34.	In over forty years of fishing, I have only captured one wahoo with roe, and know very little about them. Where and when do they spawn, and what are the worm-like things in their stomachs when they are cut open? Harbour Island, Bahamas
	Research has and is being done concerning this fish, but results are still incomplete. It is believed that the wahoo spawns from about April to November, as is evidenced by ripening eggs found in captured fishes, although no spawning has been observed in the field. It is strange that you have not seen more females with ripened roe in your waters, for they are not uncommon on the western side of the Florida Straits. The number of eggs produced by this species is large, some females having been taken in the Pacific containing more than six million eggs; however only a fraction of these survive to adulthood. From the size of small wahoo taken by fishermen in Florida waters, it is judged that they were spawned during the summer months. The worms in the stomach are trematodes of the genus Hirudinella, which are commonly found in the posterior end of the stomachs of wahoo. Generally there are two trematodes, but wahoo have been taken with as many as seventeen. In the waters around Hawaii, 98% of the wahoo examined by scientists have been infected by these organisms. Apparently the parasites have no effect on the taste of the fish.
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	Q&A 35.	We run a sport fishing boat in Cape May, New Jersey. Last summer, there were hordes of bluefin tuna off our coast, but pickings were lean for sport fishermen. At the same time, hundreds of tons were being taken by sixteen tuna clippers from the Pacific coast. They spotted schools of tuna by plane, then closed in and made a set regardless of the small boats. All the sportfishermen in New Jersey cannot catch as many tuna in a season as one of these boats catches in one day. They also catch thousands of pounds of bluefish and other schooling fishes. Isn't there a grave danger that the tuna will be fished out by these methods? Cape May, New Jersey
	There is no doubt that certain species of marine fishes have been overfished, but this does not apply to the bluefin tuna stocks of the Atlantic. The fishery is a small one, and the bluefin can certainly withstand far heavier exploitation. The fact that a few commercial boats take far more fish than the anglers means nothing in respect to whether overfishing is taking place. What counts is how many fish are being taken by all methods in relation to the quantity left in the stock to maintain the population. It is irksome to the angler to be unable to hook fish while the commercial boats are maiking good catches, but this simply means that the fish are not attracted to bait at that time. The fact that the clippers are making good catches suggests that there is a plentiful supply of tuna, not otherwise. As long as catches are good, the tuna are in no danger. It would be wise, however, for you to urge your state fish commission to investigate the bluefin tuna and other species you feel are threatened by overfishing. Research while the species is plentiful may prove to be extremely valuable if, in future years, the stock were to be threatened by extinction.
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	Q&A 36.	How high can a kingfish jump? West Palm Beach, Florida
	The kingfish, or king mackerel, sometimes leaps as it strikes at outrigger baits skipping on the surface. It comes up under the bait at high speed and its momentum takes it clear of the water to estimated heights of up to 25 or 30 feet. When hooked, the kingfish rarely breaks the surface.
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	Q&A 37.	Our fishing club ran a tournament, with a prize for the largest tuna. The only fish caught was skipjack tuna (Kalsuwonus pelamis). In your opinion, should the skipjack have qualified as a winning tuna? Valley Stream, New York
	It is the general consensus among marine biologists that the skipjack tuna is a true tuna. The Food and Drug Administration, in preparing proper labels for canned fish, concluded also that skipjack are tuna. To avoid confusion in future tournaments, you should list specifically those species that you intend to include under your general listing of "tuna."
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	Q&A 38.	Would you please tell me what the small yellow spots are that see on some of the Pacific albacore (Thunnus germo) that I catch. The spots are rather dull now, but when first caught they are bright yellow. It would seem that approximately 16 to 18 fish out of 100 have the spots, and they are almost always under the pectoral fin or on the small of the tail, top or bottom near the caudal fin. The tuna that are spotted seem to average 6 or 8 spots to a side. Astoria, Oregon
	Digenetic trematodes are known to occur on the scales and skin of fish and produce cysts that appear similar to the spots you observed on the albacore. These trematodes occur as both the larvae and the adult in the Pacific albacore.
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	Q&A 39.	For years I have enjoyed fishing for Boston mackerel in the Atlantic Ocean. I have always accepted that when you hook them and bring them into the boat, they shed their scales-unlike any other fish I have caught. A fishing friend from the midwest would not believe me when I told of this, so could you settle the argument for me: don't mackerel shed their scales when caught? Elkins Park, Pennsylvania
	Regrettably, there is so much variability in common names that it is impossible to determine the species to which you refer. The Atlantic mackerel, Scomber scombrus, and most other mackerels have very small scales, so small that their skin is velvety to the touch. These scales would not be shed as you describe. The herrings, on the other hand, have deciduous scales, which are shed when the fish is caught. It is possible that your "Boston mackerel" is a species of herring.
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	Q&A 40.	Is there any significant difference between the Atlantic bluefin tuna and the southern bluefin tuna of the Pacific and Indian Oceans? Also, what are the significant differences between the bluefin tuna and the bigeye tuna? Trenton, New Jersey
	The most recent scientific review of the bluefin tunas refers all of the nominal types to the single species Thunnus thynnus, with the single exception of the southern bluefin tuna, Thunnus maccoyi. This species is similar to the bluefin tuna and differs principally in the color of the fleshy caudal keels (yellow in maccoyi; dark in thynnus). The other features that exhibit differences concern the internal anatomy. The only real reason for continuing these two as species on the basis of such minor difference is that both species seem to occur together in the southeastern Pacific and the eastern Indian Ocean. Until the biology is better worked out, this allocation should be considered tentative. The bluefin tuna and the bigeye tuna are very different; the bigeye actually being more closely related to the blackfin tuna of the western Atlantic. The principal characters of the bigeye tuna are: gill rakers 23 to 31, pectoral fin of intermediate length (22 to 31 per cent of forklength), and yellow finlets. Further information can be obtained by reference to "Comparative Anatomy and Systematics of the Tunas, Genus Thunnus" by R. H. Gibbs, Jr. and B. B. Collette. In: Fishery Bulletin, 66(1): 65-130, published by the Bureau of Commercial Fisheries; now called National Marine Fisheries Service.
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	Q&A 41.	On page 162 of C. P. Idyll's The Sea Against Hunger, he speaks of “…the 50-mile baited lines of the Japanese tuna fleets.” Could that possibly mean a 50-mile long line, or does it refer to the combined total of lines in the fleet? Marco Island, Florida
	Although it may seem incredible, it is true that a single large tuna vessel will fish as much as 50 miles of longline gear.
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	Q&A 42.	What are the differences between the Atlantic bigeye tuna and the Allison or yellowfin tuna? New York, New York
	The bigeye tuna,Thunnus obesus, and the yellow fin tuna, T. albacares, are similar in many characters. The true diagnostic characters of the species deal with the liver, circulatory system, and shape of the vertebrae. Morphometric characters, such as the height and length of the fins and body depth, are also used but they are less reliable since they may vary with the age and size of the specimen. Generally, it can be said, however, that in large specimens (over 80 pounds) of yellowfin tuna the second dorsal and anal fins are relatively longer, the relative distance from the snout to the second dorsal is lower, and the diameter of the orbit (bony socket of the eye) is less than in the bigeye tuna. Although Pacific populations of the bigeye have relatively longer pectoral fins than the yellowfin, Atlantic populations are similar to the yellowfin in this character. Qualitatively, the bigeye is "chunkiest" in the ventral surface just beneath the first dorsal fin, while the yellowfin carries its weight farther aft. Coloration may also vary in both species, but generally the yellowfin has a much brighter lateral band than the bigeye. In addition, the black margin on the dorsal and anal finlets is much narrower on the yellowfin than on the bigeye tuna.
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	Q&A 43.	On a fishing trip off Cape Hatteras, North Carolina, I landed a 30-pound wahoo that had two reddish, globular specimens fastened by a sucker-type mouth to the wall of its stomach. The specimens measured about 3 by 1.5 centimeters and resembled some sort of leech. Can you identify them? Selbyville, Delaware
	The specimens you describe are giant digenetic trematodes, or flukes, of the genus Hirudinella and, in all probability, are H. ventricosa. Hirudinella infest wahoo and sometimes large dolphins and, as you have observed, are usually found in pairs, although in larger fishes, four individuals often occur. The worms are hermaphroditic (have both male and female sex organs) and, like other flukes, have a complicated life cycle that includes other host species, often a snail. The cycle of H. ventricosa is still unknown. Although it is wise to remove any obvious worms or foreign organisms, it is generally conceded that thorough cooking of the flesh of fishes will render the parasites harmless to man (see “Are Infected Fish Harmful?" Sea Frontiers, Vol. 10, No.5, Christmas, 1964).
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	Q&A 44.	Are there any species of tunas that may be captured without endangering dolphins? Madison, Wisconsin
	The albacore tuna, Thunnus alalunga, is not harvested in seines, but with longlines. Although this method is not as productive as seining, it does not destroy dolphins. Due to the harvesting method, the price of albacore is higher than other types of tunas. Many people consider the flavor of albacore to be superior to that of other tunas and are, therefore, willing to pay the higher price, a price which also buys for many purchasers the comforting realization that no dolphins died during the harvest of their purchase.
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	Q&A 45.	During summer months, we catch a considerable amount of bonito off Jupiter, Bobe Sound, and Stuart, Florida. Is there any way to utilize this fish other than for bait? Robe Sound, Florida
	The fish you refer to as the bonito is probably the little tunny (Euthynnus alletteratus). The flesh of this fish can be eaten but, since it is very rich and bloody, spoilage can occur rapidly. One way to prevent this is to fillet the fish, bleed and wash it in clean freshwater, and then refrigerate or cook it immediately or marinate it in milk overnight in a refrigerator.
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	Q&A 46.	Is the albacore found in the Atlantic Ocean? If so, what is its migration pattern? Santa Ana, California
	There are sizable populations of albacore, or long-finned tuna (Thunnus alalunga), in both the Atlantic and Pacific oceans. The average catch of albacore in the Atlantic over the past ten years has been about 75,000 metric tons. There appear to be separate populations in the North and South Atlantic oceans with little mixing or interchange between the two groups. The North Atlantic group appears to migrate from the summer spawning area in the western North Atlantic to the Bay of Biscay in winter. Some of these fish also spend the winter in the Caribbean Sea. In the South Atlantic, the major summer concentration is off the coast of Brazil, while in winter two separate concentrations appear off the coasts of Uruguay and Argentina in the western South Atlantic and off the coast of South Africa. The group off South Africa, however, may be fish from the Indian Ocean that seasonally migrate around the tip of Africa. Further information on this species and its movements is given in "Proposed Migrations of Albacore, Thunnus alalunga, in the Atlantic Ocean" by G.L. Beardsley, Jr., published in Transactions of the American Fisheries Society, 98(4): 589-598 (1969).
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	Q&A 47.	What is the status of the bluefin tuna ranching project discussed in the May-June 1977 issue of Sea Frontiers? Also, has anyone succeeded in rearing the bluefin from the egg? Kokomo, Indiana
	Fewer bluefin tuna (Thunnus thynnus) were ranched in the pens of Janel Fisheries Ltd. (Nova Scotia) in the 1979 season than in previous years. The project relies on the fact that Atlantic bluefins move inshore in early summer to feed on forage fishes. There they are captured by northeast fishermen, who sell them to Janel Fisheries for fattening in holding pens and subsequent sale to the Japanese market. By fall 1979, however, only 58 T. thynnus had been taken for impoundment, possibly due to lowered stocks of this species or a reduced availability of forage fishes in the area. Researchers at Kinki University Fishery Experimental Laboratory, Wakayama, Japan have succeeded in hatching T. thynnus from ripe eggs obtained from bluefins captured and reared in holding pens. The eggs were hatched in tanks with water temperatures of 71.6° to 75.2°F, and the larvae grew 4 millimeters in the first four days. The Japanese are now attempting to develop methods to rear this species to postlarval stages.
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	Q&A 48.	Has the death of dolphins associated with tuna fishing in the eastern Pacific Ocean declined? Santa Fe, New Mexico
	The dolphins killed when they became entangled in tuna nets and drowned in 1978 and 1979 numbered about 18,500 and 17,000 respectively. Although the total for 1980 is not available as this issue goes to press, early figures indicate that it will be lower than 17,000. The U.S. Department of Commerce has set a 20,500 per-year limit on the number of dolphins that may be killed incidentally in nets set for yellowfin tuna during the next five years. This quota is based on scientific findings that indicate that taking this number of animals will not deplete the stocks.
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	Q&A 49.	Is it true that bluefin tuna fishing in the Western Atlantic is being severely restricted? Westbrook, Connecticut
	Yes. Increasing concern over declining stocks of bluefin tuna has led the member nations of the International Commission for the Conservation of Atlantic Tunas (ICCAT) to recommend that the 1982 catch of bluefin tuna in the Western Atlantic be as near zero as possible. Due to overfishing during the last 20 years, the number of medium and giant bluefin tuna has already been reduced about 70 percent. Since a certain amount of fishing is necessary for stock assessment and allowance must be made for a bycatch of blue fin by other fisheries, the 1982 and 1983 quotas for the Western Atlantic will be set at 1,160 metric tons, a significant decrease from the 1980 catch of 6,646 metric tons. The quota has been subdivided so that V.S. fishermen may take 605 metric tons; the Japanese, 305 metric tons; and the Canadians, 250 metric tons. The Japanese allotment represents only 6 percent of their 1980 catch. U.S. commercial swordfishermen who occasionally take bluefin on their longlines will be restricted to an incidental catch of two bluefin per trip. In the Gulf of Mexico, Japanese longliners who had previously caught 8,000 to 10,000 bluefin each year have voluntarily agreed to cease fishing there for now. The ICCAT will meet again in 1983 to reassess the impact of these measures; however, it is feared that it may take years of careful management to undo the damage already done.
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	Q&A 50.	A crew member on my boat was a bit careless when boating a wahoo, and the fish bit the calf of his leg. At the hospital where the wound was sutured, the doctor asked for the head of the wahoo so that it could be checked for rabies. Do fishes get rabies? Lighthouse Point, Florida
	No. Only warm-blooded animals are susceptible to infection with rabies virus, and the susceptibility varies widely from species to species. According to "Rabies," Scientific American, January 1980, skunks, opossums, and fowl are relatively resistant, but foxes, cats, and cattle are highly susceptible. Human beings and dogs occupy an intermediate position.
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	Q&A 51.	I have read that homing pigeons have a substance in their heads that allows them to detect the earth's magnetic field and navigate by it. Do any aquatic organisms have this material? Fort Worth, Texas
	The green turtle, common Pacific dolphin, and Cuvier's beaked whale, as well as some bacteria, algae, chitons, and tunas, have been found to possess quantities of magnetite in their bodies. The iron-rich particles act like tiny compass needles, orienting to magnetic field lines. Certain aquatic bacteria and algae with magnetite tend to maintain a particular geographic heading. If the magnetic field is artificially altered, they change their direction of motion accordingly. Northern hemisphere bacteria orient toward the north, while southern hemisphere bacteria typically orient toward the south. Such behavior ensures that, at either location, the bacteria move down into the sediment. Magnetite in yellowfin tuna occurs in tissues in the snout. Through conditioning experiments at the National Marine Fisheries Service, Honolulu, four yellowfins have been trained to distinguish the natural magnetic field in Hawaii from a stronger one. Their ability to use magnetic fields in their extensive migrations, however, has not been proven. Likewise, the importance of magnetite to sea turtles and marine mammals can only be speculated at this stage.