Electric Barracuda

Author : Donald P. De Sylva
Publisher :
ISBN 13 :
Total Pages : 200 pages
Book Rating : 4.:/5 (318 download)

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Download or read book Systematics and Life History of the Great Barracuda, Sphyraena Barracuda (Walbaum) written by Donald P. De Sylva and published by . This book was released on 1963 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The great barracuda, Sphyraena barracuda (Walbaum), family Sphyraenidae, is found in all tropical seas, with the exception of the eastern Pacific. The following nominal species are considered as synonyms of barracuda Walbaum, 1972: picuda Bloch and Schneider, 1801; becuna Lacèpéde, 1801; barracuda Shaw, 1804; barracuda Cuvier, 1829; commersoni Cuvier, 1829; dussumieri Cuvier, 1829; agam Rüppell, 1835; affinis Rüppell, 1835; nuageuse Liénard, 1843; picuda Poey, 1866; snodgrassi Jenkins, 1901; and akerstromi Whitley, 1947. S. kadenar Montrouzier, 1857, and microps Marshall, 1953, are probably synonyms. Barracuda were collected off Miami, Florida, from Bimini, Bahamas, and specimens from the Danish Oceanographical Expeditions in the western Atlantic were used. Ontogenetic variation in proportional measurements was determined for 171 specimens from 5.5 to 1111 mm standard length. Keys for identification are presented for barracuda, gauchancho, picudilla, borealis, and sphyraena. Most males mature at two years and all mature by three years. Some females mature at three years, and all mature at four. The spawning season is from April until October off southern Florida. Spawning was not observed but probably occurs in the open ocean. The eggs were not identified from plankton tows. Postlarvae were taken far from shore and near the surface, over depths of 200 to 5200 meters. Age analyses were based upon the scale readings of 555 barracuda, back-calculated lengths from scale measurements, and upon modes in the length-frequency distributions of 2707 specimens from southern Florida. It attains 10 to 12 inches at the end of the first winter, and 18 to 22 inches at the end of its second. It reaches an age of at least 14 years. Maximum length is about 6 feet and a weight of more than 100 pounds. The young barracuda drifts inshore in spring, spends its first summer in shallow nursery areas, and moves offshore to somewhat deeper water in late fall. During the second summer it enters the mangrove habitat or the deeper weed beds. In its third year it enters the coral-reef habitat. The barracuda migrates seasonally along both coasts of Florida. Some individuals may drift out to sea. Young sometimes occur in loose aggregations, but the adults are solitary. Peck order was observed among individuals from 12 to 16 inches long which were confined in a tank. Young feed upon atherinids, gobiids, and clupeids. Tetraodontiform fishes, hemiramphids, and carangids were most commonly taken by the adults. A change from a shallow-water habitat to that of a reef existence is accompanied by a change in food habits. A summary of the 29 attacks reputedly made by barracuda on humans is presented and analyzed. Underwater experiences with barracuda are discussed in relation to factors which are favorable to an attack. Poisoning in humans who have eaten fresh barracuda is due to a toxin in the flesh and not from bacterial poisoning. In the western Atlantic, poisonings have occurred throughout the year. There seems to be no relation between the attainment of maturity or the spawning cycle and the poisonous nature of barracuda flesh. Some 58 per cent of the stomacs of adult barracuda contained fishes which are reputedly toxic, of which 20 per cent were tetraodontiform fishes. Evidence is presented for a food-chain origin of the toxin, and mechanisms are discussed for the transmission of the toxin from planktonic and benthic algae to barracuda by way of intermediate organisms. Variations in hydrographic and meteorological features are believed to results in distinct temporal and spatial variation in the toxicity of barracuda as well as other fishes"--p. 1-2.