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SYNOPSIS of BIOLOGICAL DATA on the SCHOOL SHARK Galeorhinus Australis (Macleay 1881)

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SYNOPSIS of BIOLOGICAL DATA on the SCHOOL SHARK Galeorhinus Australis (Macleay 1881) FAO Fisheries Synopsis No. 139 FHVS139 (Distribution restricted) SAST - School shark - 1,O8(O4)O1LO S:OPSIS 0F BIOLOGICAL EATA )N THE SCHOOL SHARK Galeorhinus australis (Macleay 1881]) F 'O FOOD AND AGRICULTURE ORGANIZATION OF E UNITED NATIONS FAO Fisheries Synopsis No. 139 FIR/S139 (Distributíon restricted) SAST - School shark - 1,08(04)011,04 SYNOPSIS OF BIOLOGICAL DATA ON THE SCHOOL SHARK Galeorhinus australis (Macleay 1881) Prepared by A.M. Olsen* 11 Orchard Grove Newton, S.A. 5074 Australia FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome 1984 The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization oftheUnited Nationsconcerning thelegal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. M-43 ISBN 92-5-1 02085-X Allrightsreserved. No part ofthispublicationmay be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic,mechanical, photocopyingor otherwise, withouttheprior permíssion of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy. © FAO 1984 FIR/5l39 School shark PREPARATION OF THIS SYNOPSIS The authors original studies on school shark were carried out while being a Senior Research Scientist with the CSIRO, Division of Fisheries and Oceanography, Cronulla, New South Wales, and continued during his service as Director of the Department of Fisheries and Fauna Conservation, South Australia. The CSIRO Editorial and Publishing Service kindly granted permission to reproduce from the Australian Journal of Marine and Freshwater Research, Volume 5(3), 1954, synopsis Figures 2-6, 8, 14-22, from Volume 10(2), 1959, synopsis Figure 23, and from Volume 30, 1979, synopsis Figures 7 and 24. Very recently, the scientific name of the school shark has been found tobe Galeorhinus galeus, and this name will be used in the forthcoming FAO species catalogue, Sharks of the World (FAO Fish. Syn. 125, Vol. 4). Unfortunately, it was too late to include the new name in this publication. * Formerly Senior Research Scientist of the CSIRO, Division of Fisheries and Oceanography, Cronulla, N.S.W., Australia ABSTRACT This synopsis consolidates all the available published data on the biology, growth, migration and population dynamics of an elasmobranch species which has been exploited for food for nearly 60 years in southeastern Australian waters. This shark species is also fished commercially in New Zealand. Tagging results show that there is an homogeneous stock of low fecundity, slow maturing and longlived school sharks which can live to, at least, 53 years of age in southeastern Australian waters. Adult school sharks accumulate naturally occurring mercury in their flesh in excess of legal maximum concentrations. There is no uniform management strategy by the five fisheries authorities for the widely ranging stock of school sharks in southeastern Australian waters. Distribution: For bibliographic purposes this document should be cited as follows: Author FAO Fisheries Department Olsen, A.M., Synopsis of biological data on the FAO Regional Fisheries Officers 1984 school shark, Galeorhinus australis Regional Fisheries Councils and Commissions (Macleay 1881). FAO Fish.Synop., Selector SM (139):42 p. FIR/S139 School shark iii CONTENTS Page IDENTITY 1.1 Nomenclature i 1.1.1 Valid name i 1.1.2 Objective synonymy i 1.2 Taxonomy 1.2.1 Affinities i 1.2.2 Taxonomic statua 3 1.2.3 Subspecies 4 1.2.4Standard and vernacular names 4 1.3 Morphology 4 1.3.1 Ekternal morphology 4 1.3.2 Cytomorphology 4 1.3.3 Protein specificity 4 DISTRIBUTION 4 2.1 Total Area 4 2.2 Differential Distribution 4 2.2.1 Juveniles - southeastern Australian waters 4 2.2.2 Adults - southeastern Australian waters 4 2.3 Determinants of Distribution Changes 5 2.3.1 Effects of ecological determinants 5 2.3.2 Behavioural determinants 6 2.4 Hybridization 6 2.4.1 Hybrids 6 3. BIONOMICS AND LIFE HISTORY 6 3.1 Reproduction 6 3.1.1 Sexuality 6 3.1.2 Maturity 6 3.1.3 Mating 6 3.1.4Fertilization 6 3.1.5 Gonads 7 3.1.6 Breeding (nativity) 7 3.1.7 Spawn (ova and spermatozoa) 8 3.2 PreAdult Phase 8 3.2.1 Embryonic phase 8 3.2.2 Juvenile phase 9 3.2.3 Adolescent phase 10 3.3 Adult Phase 10 3.3.1 Longevity 10 3.3.2 Hardiness 10 3.3.3 Competitors 10 3.3.4Predators 11 3.3.5 Parasites, diseases, injuries and abnormalities il 3.4Nutrition 12 3.4.1 Feeding 12 3.4.2 Food 12 .3.4.3 Growth rate 12 3.4.4Metabolism 15 iv FIR/Sl39 School shark Page 3.5 Behaviour 15 3.5.1 Migrations and local movements 15 3.5.2 Schooling 15 3.5.3 Responses to stimuli 18 4. POPULATION 20 4.1 Structure 20 4.1.1 Sex ratio 20 4.1.2 Age composition 20 4.1.3 Size composition 20 4.2 Abundance and Density of Population 27 4.2.1 Average abundance 27 4.2.2 Changes in abundance 27 4.2.3 Average density 27 4.2.4Change in density 28 4.3 Natality and Recruitment 28 4.3.1 Reproduction rates 28 4.3.2 Factors affecting reproduction 28 4.4 Mortality and Morbidity 28 4.4.1 Mortality rates 28 4.4.2 Factors causing or affecting mortality 29 4.4.3 Dynamics of population as s whole 30 4.5 The Population in the Community and Ecosystem 30 EXPLOITATION 30 5.1 Fishing Equipment 30 5.1.1 Present gear (summarized from Hughes, 1971, 1981) 30 5.2 Fishing Areas 32 5.2.1 General geographic distribution 32 5.2.2Geographic range 32 5.2.3 Depth ranges 32 5.3 Fishing Seasons 32 5.3.1 General pattern of season(s) 32 5.3.2 Dates of beginning, peak and end of season(s) 32 5.4 Fishing Operations and Results 32 5.4.1 Effort and intensity 32 5.4.2 Selectivity 32 5.4.3 Catches - southeastern Australia 32 PRODUCTION AND MANAGEMENT 37 6.1 Regulatory (Legislative) Measures 37 6.1.1 Limitation or reduction of total catch 37 6.1.2 Protection of portions of populations of school sharks 37 7. MISCELLANEOUS 39 7.1 Metallic Element Concentrations 39 7.2 Vitamin A Potency of School Shark Liver Oil (International Units/gm Oil) 39 8. REFERENCES 40 FIR/S139 School shark i 1. IDENTITY - Specific (Figure 1) 1.1 Nomenclatura McCulloch, A.R., Proc.Linn.Soc.N.S.W., 46(4), 1921, 457-72, pl. 37, Figures 5-7. Typespecimen 1.1.1 Valid name UANM No. 39972, Australian Museum. Total length 1 420 mm. Head and body skinned out. Type local- Galeorhinus australia (Macleay)*. Proc. ity: Port Jackson, N.S.W. (Macleay, w., 1881). Linn.Soc.N.S.W., 6(2), 1881, 354-5. - Diagnosis 1.1.2 Objective synonymy Galeorhinus australia: description compound- Galeus australis Macleay, 1881. ed from Fowler, H.W., Bull.U.S.Nat.Mus., 100(13), 1941, 188-90 and McCulloch, A.R., Proc.Linn.Soc. 1.2 Taxonomy N.S.W., 46(4), 1921, 457-72, pl. 37, Figures 5-7. 1.2.1 Affinities Body: Moderately long, slender. - Suprageneric Head: About 5.5 in total length. Phylum Vertebrata Snout: Rather attenuate, obtusely pointed Subphylum Craniata and depressed, translucent at tip; preoral length Superclass Gnathostomata 2.4 in length of head ro first gill opening. Lat- Class Elasmobranchii eral edges anterior to the nostrils are moderate- Subclass Selachii ly sharp. Order Lamniformes Suborder Scyliorhinoidei Nostrils: Much nearer upper lip than end of Family Carcharhinidae snout, space between 1.44 in distance from tip of snout; anterior margin of each has a small lobule - Generic projecting backward. Internarial 1.3 in dentary width; front nasal valve with two short points. Genus Galeorhinus Blainville, 1816. Bull. Soc.Philom., Paris, 8:121. Mouth: Crescentic, anterior margin of mouth in advance of eye; width of mouth equal to dis- Genotype Squalus galeus (Linnaeus), 1758:234. tance from end of snout. A longer upper and a shorter lower labial fold present at each angle. The generic concept adopted here is com- Dentary width 2.75 in head length. pounded from Fowler, H.W.(1941) and Compagno, L.J.V. (1970). Eye: External nictitating membrane present in juveniles, internal in adults and subadults. Body moderately long, slender, body cavity Eye length about 3 in distance from end of snout; about 1/2 total length. akin above eye forms an imperfect fold. Head moderate, over 1/5 of total length in Spiracle: A small slit located about 0.5 adults, snout obtuse, depressed. Eyes low on eye length behind eye. sides of head, orbit almost twice as long as high, with nictitating membrane present, inter- Gill openings: Equidistant, subequal, fourth nal in adults and subadults. Mouth wide, cres- widest and equal to eye length, fifth is smallest, centic, with short labial fold on each jaw. Nos- both openings located above and behind insertion trils, small and separated, are closer to mouth of pectoral base. than snout tip. Teeth alike in two jaws, tri- angular, outwardly inclined, notched with serra- Teeth: About three series of functional tions on outer edges. teeth in upper jaw, teeth are smallest anteriorly and largest laterally. Centre cusp of each lat- Last gill opening above pectoral.Spiracle eral tooth is oblique, there is a sharper angle small, behind eye.
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