XFWC-A 302 1-18 (1969) U.S. Fish Wildi. Serv. Circ. .r' F r!es Sy us No. 4: 4 Pacific rnackerel-1,75(01), 002,03 SYNOPIS OF TH BIOLQ1CAL DATA ON THE PACIF!C MACKEREL Scorn ber japonicus Houttuyn (Northeast Pacific) ITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDUFE SiICE BUREAU OF COMWtERCIAL ISHERIES Circular 302 UNITED STATES DEPARTMENT OF THE INTERIOR U.S. FISH AND WILDLIFE SERVICE BUREAU OF COMMERCIAL FISHERIES y©p © h® a on k©rne ©uw d&) By DAVID KRAMER FAO Species Synopsis No, 40 Circular 30Z Washington, D,C. February 1969 CONTENTS Page Intrtion, i Identity i 1.1Nomenclature 1 1.2Taxonomy i 1.3Morphology 2 2 Distribution, 3 2.1 Total area 3 2,2Differential distribution 5 2.3Determinants of distribution changes 5 2.4Hybridization 5 3 Bionomics and life history 5 3,1Reproduction 5 3,2Preadult phase 7 3,3Adult phase 9 3,4Nutrition and growth 9 3,5Behavior 10 4 Population,,,,,,,..,,,,,,, , ,,,.,,,,,,,,,,,,.........11 4,1Structure 11 4.2Abundance and density (of population) il 4,3Natality and recruitment,,,.,,,,,,,,,,,...,,,..,,, il 4.4Mortality and morbidity,.,,,.,...,,,,,...,..,,.,.,,,, 11 4,5Dynamics of population (as a whole) 11 4.6 The population in the community and the ecosystem 11 5 Fishery 13 5,1Fishingequipment 13 5,2Fishingareas,,,,,,,,..,,,,. 13 5.3Fishingseasons 13 5,4Fishingoperations and results 13 6 Protection and management 13 6.1Regulatory (legislative) measures 13 6.2 Control or alteration of physical features of the environment,,.., 17 6,3 Control or alteration of chemical features of the environment,,.. 17 6,4Control or alteration of the biological features of the environment,. 17 6.5Artificial stocking . 17 Literature cited 17 111 Synopsis of the Biological Data on the Pacific Mackerel, Scomber japonicus Houttuyn (Northeast Pacific) By DAVID KRAMER, Fishery Biologist Bureau of Commercial Fisheries Fishery-Oceanography Center La Jolla, California 92037 ABSTRACT This synopsis attempts to bring together all knowledge extant on the identity (nomenclature,taxonomy, morphology),distribution,bionomics,lifehistory, population, fishery, and protection and management of the Pacific mackerel. INTRODUCTION Pneumatophorusdiego(Ayres)Jordan and Hubbs (1925:221).California, BCF (Bureau of Commercial Fisheries) has assigned the preparation of synopses on var- 1.2 Taxonomy iouseconomically importantspeciesto a numberof its laboratories. Most of these 1.21 Affinities synopses will be published in the U,S, Fish and WildlifeService Circular series,and Phylum Chordata will follow the format presented in Prepara- tion of synopses on the biology of species of Class Teleostomi living aquatic organisms,'T by H. Rosa Jr., Biology Branch,Department of Fisheries, Order Perciformes Food and Agriculture Organization of the United Nations. Family Scombridae i IDENTITY SCOMBER 1iNomenclature Scomber Linnaeus 1.11Valid name Scomber Artedi, in Linnaeus (1758:297) Scomber japonicus Houttuyn, (S. scombrus Linnaeus), Cordylus Gronow (1854:163) (Scomber 1.12 Synonomy scombrus L.). ScomberjaponicusHouttuyn(1782:331), Pneumatophorus Jordan andGilbert(1883: Japan, 593)(as subgenus). Starks(1921:222- 223). Pneumatophorus japonicus (Houttuyn,1782); Starks (1921:222-223), Matsui (1967) separated the mackerels into two genera, Scomber and Rastrelliger, and ScomberdiegoAyres(1856:101),Santa cited differences in 14 characters, chief of Barbara, Calif. which were the presence inScomber of vomer- me and palatine teeth (lacking in Rastrelliger) One synopsis, written by MacGregor, has appeared in and a well-developed anal fin spine (lacking in theU.S. Fish and Wildlife Service Special Scientific adult Rastrelliger), Other differences included: Report--Fisheries series, the hypohyal nearly as long as or longer than epihyal in Scomber, but less than one-third as used are blue mackerel, greenback mackerel, long as the epihyal in Rastrelliger; 12 to 28 striped mackerel, and Americanrnackerel, first dorsal fin interneurals in Scomber, li (rarely 10) in Rastrelliger; the first haemal 1,3 Morphology spine somewhat flattened and bent backward in Scornber but flattened wíththe middle hooked 1,31External morphology and the distal part nearly vertically directed Dorsal IX-I, 9 to 13_IV to VI; anal I-I, 9 to in Rastrelliger, Il-IV to VI; pectoral17 to19; caudal 17; pelvic I,5; first dorsal fin rather high, re- Matsui recognized only three species of ceived entirely into a groove when depressed, mackerels with 31 vertebrae and 5 finlets in widely separated from the much lower second thegenusScomber(including Pneumato- dorsal; scales small, easily lost; two very phorus), These include S, scombrusLiimaeus, small keels on each side of the caudal peduncle, S, japonicus Houttuyn, and S, australasicus Color: dark green to blue above with metallic Cuvier, S, scombrus differs from the others reflections shading into iridescent silvery on in having more heavily ossified bones, in hav- the sides and below; a series of about 30 wavy, ing no swim bladder, and in having the first dark streaks run vertically down the back to haemal spine anterior to the first interhaemal just below the lateral line (fig. 1), bone. He saw no reason forrecognizing Pneumatophorus for the other two species. He Matsui (1967)differentiated three popula- summarized 12 characters for comparison of tions of S, japonicus in the temperate zones of the three species, the most distinguishing of the Pacific Ocean and the west and east Atlantic which, other than the absence of a swim blad- Ocean (table 1). der in scombrus, is the number and arrange- ment of the interneurals under the first dorsal The Pacific mackerel off the coast of North fin--21 to 28 in S, scombrus, 15 to 21 in, America are not known to mix with any of the australasicus, and 12 to 15 in S. japonicus. He other populationsdesignated above. Racìal showed these arrangements by a representa- differences were investigated in this group by tive diagram in his figure 7, Fry and Roedel (1949) in tagging experiments- - Figure 1.--Scomber japonicus (Pneumatophorus diego) Houttuyn (adapted from frontispiece, Fitch, 1951). 1.22 Taxonomic status see 3.51 below--and by Roedel (1952) in a See above, racial study. For the racial study, Roedel examined speci- 1,23 Subspecies mens from six geographic regions: British See above, Columbia, southern California, northern Baja California (Soledad Bay), central Baja Cali- 1.24 Standard common names fornia (Sebastian Vizcaino Bay), the Cape San The name officially sanctioned by the State Lucas region including sections of the Pacific of California -for purposes of keeping records and Gulf coasts of the peninsula, and the Gulf isPacific mackerel, Other names variously of California, 2 Table l.--Difference Between populations of S. japonicus (table7of Matsui,1967) Pacific W Atlantic E Atlantic Pigment pattern on Usually unmarked or Usually clearly marked Usually clearly marked belly only lightly marked by a number of fairly by broken, wavy lines; large spots; some- sometimes by thicker times by broken wavy lines that almost lines; occasionally resemble spotting; unmarked occasionally unmarked Mandibular and Lightly crenulated Strongly crenulated Strongly crenulated premaxillary teeth Scales Smaller than those Larger than those of Similar to W Atlantic of Atlantic Pacific population Gill rakers on 25-29 25-29 29-35 lower 1st arch (on individuals SO ram. SL or greater) Distribution China, Korea, Japan- Massachusetts- Mediterranean; Boninls.; Coast of Venezuela; Argentina Azores-Gulf of Guinea; Calif., Baja Calif., Capetown Gulf of Calif.-Chile Four physical characteristics were selected The natural regionsof the oceans inhabited for detailed study. Three were related to the by thismackerel thusincluded northwest initial position of vertebral structures: the American coastal waters (4,2,4), San Francisco haemal arch, the haemal brace either single waters (4,5.2), California waters (4.6,3), and or paired, and the paired haemal brace; and west Mexican waters (4.6,4). Now, as deter- the fourth to the head length relative to fork mined from populationsof larvae, its range length. may extend only as far north as Point Concep- tion, Calif.,4 south along the coast and into all Statistical analyses gave evidence of five of the Gulf of California (Kramer, 1960), The populations, each region, with the exception of offshore extent of the population is as far as British Columbia and California, being sepa- 200nauticalmiles (370 km.) off northern rable in some degree from adjoining regions. Baja California, and about 200 nautical miles Tag returns, however, demonstrated that a (370 km,) off central Baja California, with the portion of Vizcaino fish eventually reached greatest numbers of larvae concentrated off California waters, The Cape San Lucas ma- upper and central Baja California(fig,2), terial differed radically in all respects from Data from two cruises in 1956 into the Gulf the northern regions and was separable from ofCalifornia by theCa1COFI (California Gulf of California fish except in regard to the Cooperative Oceanic Fisheries Investigations) initial position of the haemal arch. in February (Ahlstrom, 1956) and April (un- published)showed thatthepopulationsof 1,32 Cytomorphology larvae in either of these months exceeded by No data available, far the total population of larvae in 1956 in the entire Ca1COFI area for the whole year of 1,33 Protein specificity surveyson the outer coast. Furthermore, No data available, although the CaICOFI data for the outer coast showed that Pacific mackerel larvae extend 2 DISTRIBUTION