F Pi/Si 14 FAO Fisheries iio. 114 SAST - Scallops - 3,16(08) SYNOPSIS OF BIOLOGICAL DATA ON SCALLOPS Ch/aniys (Aequipecten) opercularis (Linnaeus) Argopcten frradins (L n Argopecten gibbus (Leis) FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS FAO Fisheries Synopsis No. 114 FIRS/S114 (Distribution restricted) SAST - Scallops - 3,16(08) SYNOPSIS OF BIOLOGICAL DATA ON SCALLOPS (Chlamys (AeQuipecten) opercularis (Linnaeus) Aropec ten irradians (Lamarck) Argopecten gibbus (Linnaeus)) Prepared by M.J. Broom Marine Resources Research Unit Portsmouth Polytechnic Portsmouth England FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, December 1976 ii 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 of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. M-42 IS 92-.5-1OO213-4 The copyright in this book is vested in the Food and Agriculture Orga- nization of the United Nations. The book may not be reproduced, in whole or in part, by any method or process, without written permission from the copyright holder.Applications for such permission, with a statement of the purpose and extent of the reproduction desired, 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 PREPARATION OF THIS SYNOPSIS This synopsis is concerned with the biology and exploitation of three species of pectinid mollusc in the North Atlantic. The inclusion of the three species in the same synopsis is justified by their close similarity, not only in biological but also in economic and industrial terms, and by the rela-- tively small amount of data available on them. The author wishes tò acknowledge the advice and information received from Mr. G. Pickett (Fisheries Laboratory, Buruham-on-Crouch) and Dr. J. Mason (Fisheries Laboratory, Aberdeen).The author would also like to thank Mr. M. Castagna of the Virginia Institute of Marine Science, and Dr. H. Porter of the Institute of Marine Sciences, University of North Carolina, for sending me shells of A. irradians and A. gibbus respectively. Distribution: Bibliographic entry: FAO Department of Fisheries Broom, M.J. (1976) FAO Regional Fisheries Officer FAO Fish.Synop., (114):44 p. Regional Fisheries Councils and Commissions Synopsis of biologicaldata on scallops Selector SN (Chlainys (Aequipecten).operculs -is (Lipus) Author Argopected irradians rck), Argonecce' gibbus (Linnaeus)) Synopsis. Biological data, Marine mo1iusks Taxonomy. Morphology (organisms). Keys. Geographical distribution. Hybridization. Sexual reproduction. Life cycle. Development (biological). Autecology. Population charac- teristics. Shellfish fisheries. Fishing gear. Fishing grounds. Fishery Fegulations. Mollusk culture. Pectinjclae. Chlamys (Aequipec ten) opercularis. Argopecten irradians. Argopecten gibbus. ARE,Europe. MED. ASE,Norocco. ASW,Mexico Gulf. ASW,USA. AN W , U SA FIRS/S114 Scallops V CONTENTS Page 1 IDENTITY 1.1 Nomenclature 1.11 Valid manies 1 1,12 Objective synonymy 1 2 Taxonomy 1 1,21 Affinities 1 1,22 Taxonomic status 5 1.23 Subspecies 5 1,24 Standard Common mames,vernacular names 5 1.3 Morphology 5 1.31 External morphology 5 132 Cytomorphology 7 1.33 Protein specificity* 2 DISTRIBUTION 7 2,1 Total area 7 2,2 Differential distribution 7 2,21 Spawn, larvae and juveniles 7 2,22 Adults* 2.3 Determinants of distribution changes 8 2.4 Hybridization* 3 BIONOMICS AND LIFE HISTORY 8 3.1 Reproduction 8 3.11 Sexuality 8 3,12 Maturity 8 3.13 Mating* 3,14 Fertilization 8 3.15Gonads 8 3.16 Spawning 9 3,17 Spawn 11 3.2 Preadult phase 11 3.21 nbryonic phase 11 3,22 Larval phase 11 3.23Adolescent phase 13 3,3Adult phase 13 3.31 Longevity 13 3,32Hardiness 13 3,33 Competitors 14 3,34 Predators 14 3,35 Parasites, diseases, injuries and abnormalities 14 FIBS 511 S callo.s Page 3.4Nutrition and rowth 16 3.41 Feeding 16 3,42Food 16 3,43Growth rate 17 3,44Metabolism 19 3,5 Behaviour 20 3.51 Migrations and local movements 21 3.52 Schooling 20 3.53 Responses to stimuli 20 4 POPULATION 21 4.1 Structure 21 4,11 Sex_ra±io* 4,12Age composition 21 4,13Size composition 22 4,2 Abundance and density (of population) 30 4,21 Average abundance 30 4,22 Changes in abundance 30 4.23 Average density 30 4.24Changes in density 4.3 Natalit and recruitment 31 4,31 Reproduction rates* 4,32Factors affecting reproduction* 4033 Recruitment 31 4,4 I4ortalit and morbidit 31 4,41 Mortality rates 31 4,42 Factors causing or affecting mortality 31 4,43 Factors affecting morbidity* 4,44 Relation of morbidity to mortality rates* 4.5 ics of as a whole 4,6The o.ulation in the communit and the ecos stem 32 33 5 EXPLOITATION 5.1 Fishing e.ui.ment 33 5,11 Gears 33 5,12 Boats 34 5,2Fishinareas 5,21 General geographic distribution 34 5,22Geographic ranges 34 5.23Depth ranges 34 5,24Conditions of the grounds 36 F158 S114 Scallo.s vii Page 5,3Fishing seasons 36 5.31 General pattern of seasons 36 5.32 Batee of beginning, peak and. end. of season 36 5,33 Variation in dates or duration of season* 5.4Fishing operations and results 36 5.41 Effort and intensity 36 5.42Seleotivity 37 5,43 Catohes 37 6 PROTECTION AND MAFAGENT 38 6.1 Regulatory (legislative) measures 38 6,11 Limitation or reduction of total oatoh 38 6,12 Proteotion of portions of populations 38 6,2 Control or alteration of physical features of the environment* 6,3 Control or alteration of chemical features of the environment* 6,4Control or alteration of bioloical features of the environment* 6.5Artificial stooking* 7 POND FISH CULTUBE* 8 REFERENCES * As no information was available to the author, these items have been omitted from the text FIRS 5114Scallo.s 1 IDEMTITY 1.2 Taxonor 101 Nomenclature 1,21 .Aífinities 1011 Valid name Suprageneric The following are the valid nanee of each The classification here adopted for groups of the three species: doy to "order" is that used by Morton and Yonge(1964). "Superfamily" and "family" are Chlamys Aeciiiecten opercularis (Linnaeus)0 those used by Meere(1969),thus: The author has been unable to trace the original publication of the combinations opercularis. Phylum Mollusca However, Aequipecten was first suggested as a Class Bivalvia new subgenus of Pecten opercularis (an earlier, Subclass Lamellibranchiata invalid nane for opercularis) by Order Anisomyaria Fischer, P0H.,1886,Manuel de conchyliologie, Superfamily Pectinacea Paris, 1 369 p. (For further discussion of the Family Pectinidae confused situation relating to the nomenclature of this species see Section121). Generic Argopecten irradians (Lamarck) Waller, T.R., To quote Waller (1969, p. 36): "... broad 1969,The evolution of the Argopecten gibbus usage of the name Chlaqys has lead to a world- stock (Moliusca: Bivalvia), with emphasis on wide genus containing a tremendous amount of the Tertiary and Quaternary species of eastern morphological variation, a profusion of subgeneric North America0 Paieontol0Soc.Mem0,(3):125 p. names, and a cumbersome nomenclature involving Also J.Paieontol7 Supiloto No05). and species_groups.11 Argopectengibbus (Linnaeus) Wailer, T.R., As a result of this some authors use the 1969,Ibid. name Chlam s as the generic name, qualifying species descriptions with the use of subgenera, 1.12 Objective synonony as in Chlamys (Aequipecten) opercularis, while others use the term Chlamys as a group description - Original invalid names and elevate the various subgenera to full generic rank, It is not the task of the present author C. Rlaris was first named as to argue for, or against, the use of Aequi.ecten Ostrea opercularis by Linnaeus(1758). in a full generic sense in the case of Chlamys (uipecten) opercularis. Instead an attempt A. irradians was first named as Pecten is made to clarify the distinctions between irradians by Lamarck(1819). species bearing the name Ohlamys in the group (or generic) sense, the name Chiamys in the A. gibbun was first named as Ostrea gibba generic (or subgeneric) sense and the nane by Limiaeus(1758). Aequipecten in the generic (or subgeneric) sense. Junior objective synonyms The term Chla s was first proposed by RSding, P.F. 179 Mueuni Bol4enianuxn (2):p.161 No information on the junior objective with Pecten islandicusiJ (Miiller) as the type synonomy of C, opercularis was available to the species by subsequent designation (Herrmannsen, author. 1847). The following description of the Chlainys group was provided by Moore(1969)who used A, irradians RSding's original term as a group description Aequipecten irradians irradians (Lamarck) to be further divided into genera: Clarke(1965, p. 1763 "Higher than long or rounded, commonly A, gibbus somewhat oblique; L V usually more convex but n Aeguipecten ibbus (Licnaeus) Dodge(1952, in some species valves nearly equally convex; p. 182) auricles clearly delimited, usually large; byssal Aequipecten (Plagcctenium) (L.) notch large; ctenoliurn usually present; sculpture Abbot(1954, p, 363) of radial (usually stronger) and concentric a Aequipecten Ar:osecten (L.) Warmke elements, with scalelike spines commonly developed and Abbot(1961, p. 170 at their junctions, especially on L V but some These are the originally published combinations of generic and trivial names; they are not necessarily valid at the present time 2 FIRS 5114 Scallo.s shells nearly smooth; interspaces of many forms The type specimen of A. gibbus is a single with intercalaries in adult; margin usually valve in the collection of the Linnean Society scalloped; cardinal orlira variable in number of London, 10th edition specimen No.