SIPHONOPHORES OF THE PACIFIC WITH A REVIEW OF THE WORLD DISTRIBUTION BY ANGELES ALVARINO˜ UNIVERSITY OF CALIFORNIA PRESS BERKELEY • LOS ANGELES • LONDON 1971 3 BULLETIN OF THE SCRIPPS INSTITUTION OF OCEANOGRAPHY UNIVERSITY OF CALIFORNIA, SAN DIEGO LA JOLLA, CALIFORNIA ADVISORY EDITORS: G. O. S. ARRHENIUS, C. S. COX, W. W. FAGER, C. H. HAND, TODD NEWBERRY, M. B. SCHAEFER Volume 16 Approved for publication June 19, 1969 Issued October 8, 1971 UNIVERSITY OF CALIFORNIA PRESS BERKELEY AND LOS ANGELES CALIFORNIA UNIVERSITY OF CALIFORNIA PRESS, LTD. LONDON, ENGLAND ISBN: 0-520-09321-6 LIBRARY OF CONGRESS CATALOG CARD NUMBER: 71-627780 CONTRIBUTION FROM THE SCRIPPS INSTITUTION OF OCEANOGRAPHY, NEW SERIES c 1971 BY THE REGENTS OF THE UNIVERSITY OF CALIFORNIA PRINTED IN THE UNITED STATES OF AMERICA CONTENTS Introduction Siphonophores of the Pacific with a Review of the World 1 Distribution Table 1 4 Table 2 6 Acknowledgments 7 Methods 8 List of the Species of Siphonophorae Observed in the Pacific 9 and Adjacent Seas During the Present Studies Distribution in the Pacific 16 Table 3 33 Bathymetric Distribution 267 Table 4 269 References 351 Figures 365 1 INTRODUCTION Most of the published work on Siphonophorae deals with taxonomic descriptions, taxonomic problems and systematic accounts, histology and anatomy and also gives records concerning the distribution of the individual species. Totton’s “Synopsis” (1965) encompassed the anatomy, ontogeny and taxonomy of most of the species of siphonophores. Some data on the distribution of the species, particularly for the Mediterranean and its adjacent seas, appeared in Bigelow and Sears (1937). Garstang (1946) has given a comprehensive account of the morphology, nomenclature and relationships of the Siphonophorae. Data on the development of various species appeared in Haeckel (1869), Metschnikoff (1874), Chun (1882) and Lochmann (1914). Development of Muggiaea atlantica from the egg to the adult form was described by Russel (1938); Agalma elegans, by Totton (1956); Abylopsis tetragona,byC.Carre´ (1967); and Sphaeronectes, by D. Carre´ (1969). Regeneration in siphonophores was reported by Moser (1925). Mackie and Boag (1963) observed that in Nanomia the palpons regenerated. Recently, particular attention has been given to the siphonophores. Mackie (1964) reported on the studies of locomotion in the colonies and Mackie and Boag (1963) on the capture of prey, feeding and digestion and culture of siphonophores. Barham (1966) had considered some siphonophores as sound scatterers because pneumatophores were found with bubbles of carbon monoxide in the physonectes (Pickwell, 1966, 1967). The structure of the pneumatophores had been studied earlier by several workers (Chun, 1897; Bigelow, 1911a; Moser, 1925; Leloup, 1941b). Phosphorescence was observed in several species of siphonophores (reviewed by Boden and Kampa, 1964), but no biochemical studies of this process have been made for this group. No luminiscent organs have been observed in these Coelenterates, so it is probable that any luminiscence was due to contamination by luminescent microorganisms. Parasites in siphonophores were reported by Rose and Cachon (1951) and Totton (1954). ∗ Present address: Bureau of Commercial Fisheries, Fishery-Oceanography Center, La Jolla, California, 92037. 2 Many of the free-swimming Siphonophorae appear to follow the vertical migration of the zooplanktonic organisms on which they feed. The response to light in the Physophorae is shown by the siphosoma region, while the pneumatophore and nectosoma do not present photoreceptive capacity (Mackie, 1964; Mackie and Boag, 1963). Chromatophores occur in the nectophores and pneumatophores (region with no apparent photosensitivity). The nature of the siphosome photoreception is unknown; it could depend on the neurons (Mackie and Boag, 1963). Although the Siphonophorae are not so distinctly restricted to water masses as are most of the Chaetognatha species (reviewed by Alvarino,˜ 1965), it has been observed that some species of siphonophores can be used as indicators of the flow of certain types of waters into a particular region. Russel (1934) observed Muggiaea atlantica at the entrance of the English Channel where it “occurred for an unbroken series of years from 1913 to 1924 (excepting 1915, when none were seen in the collections), but that in 1924 M. kochi first made its appearance and that since that time M. atlantica has disappeared from the area.” Later I studied the plankton of this region and became familiar with the fluctuations in the occurrence of one or other of these species; the presence of M. kochi is an indication of the inflow of water from the south. Moore (1953) has considered that fluctuations in abundance are in part due to “inherent seasonal changes within a given water mass, but in part also to seasonal changes in the water mass present.” He has implied that in the Bermuda region the summer water of northern origin brings into the region species typical of colder regions, while the winter water comes from warmer locations in the south. He also states that in the Florida Current off Miami there is “a fluctuating amount of water of the Gulf of Mexico origin intruding into the main water mass.” He ends his discussion stating: “Although the abundance of several [species] has shown to be different in the Yucatan and Gulf of Mexico waters, none are completely restricted to one mass, and so readily useable as indicator species.” In the California region it has been observed from the monthly 1954 and 1958 California Cooperative Oceanic Fisheries Investigations cruises that Chelophyes appendiculata (a species typical of the temperate regions) is displaced by Ch. contorta (a warm-water species) with an inflow of warm water. A particular pattern of distribution was observed (Alvarino,˜ 1969) for Chelophyes appendiculata, Ch. contorta, Muggiaea atlantica and M. kochi off the Panama Canal in the Caribbean and Pacific regions. The material to be considered here consists of the extensive collections of Scripps Institution of Oceanography in the Pacific and the CalCOFI cruises in the region of the California Current and the Sea of Cortes.´ The material collected in the Pacific extends over a period of fourteen years (table 1). The present work provides the first extensive survey of the distribution of the siphonophores in the Pacific as well as a preliminary account of their bathymetric distribution. Bigelow (1911a) has presented extensive data from the Eastern Tropical Pacific and also from the Northwest Pacific (Bigelow, 1913). Table 2 includes other collections analyzed by the author. The published 3 data on the distribution of the species observed in the Pacific and adjacent seas are compiled in table 3. Table 4 is a compilation of all published data on the bathymetric distribution of the species of Siphonophorae plus the author’s unpublished data. The records of the capture of certain rare species are of special importance. The following are notable: Muggiaea delsmani Totton, 1954; Lensia achilles Totton, 1941; L. ajax Totton, 1941; L. hostile Totton, 1941; Abyla brownia Sears, 1953; Ceratocymba intermedia Sears, 1953; Clausophyes galeata Lens and Riemsdijk, 1908; Sulculeolaria bigelowi (Sears), 1950; Marrus orthocannoides Totton, 1954; Dromalia alexandri Bigelow, 1911. Three newly described species are also included: Vogtia kuruae Alvarino,˜ 1967; Sulculeolaria brintoni Alvarino,˜ 1968; Enneagonum searsae Alvarino,˜ 1968. The isotherms at a depth of 200 m are used for comparison with the distributional ranges of the species because the position of certain 200 m isotherms tends to agree with the limits of the ranges. Temperatures are relatively conservative at and below 200 m, as compared with those in and above the thermocline. It is to be expected, therefore, that general aspects of the ocean climate which existed during the 15-year sampling period are reflected by the distribution of temperature at levels below the thermocline. It is not expected that a particular temperature, perhaps at a particular depth, is associated with a complex of environmental factors that affects or controls the distributional limits of the species. 4 TABLE 1 Collections Studied Expedition/cruise Region surveyed Depths sampled (m) Date NORTHERN HOLIDAY NE Pacific and Gulf of Alaska Various depths; from 118-0 to August-September 1951 227-0 SHELLBACK Tropico-equatorial eastern Pacific Various depths; from 155-0 to May-August 1952 474-0 CAPRICORN Tropico-equatorial South Pacific, 140-0; 400-0; 1000-0 November 1952 with some stations north of the -February 1953 equator TRANSPAC North Pacific Various depths; from 140-0 to July-November 1953 1280-0 and stratified sampling at various depths, from 318-75 and 265-115 to 850-680 and 1175-525 EASTROPIC Galapagos´ Islands Various depths; from 1328-0 to October-December 1955 1583-0 NORPAC NE Pacific (48◦N-20◦N and east 140-0; 280-140; 700-0 July-September 1955 CalCOFI 5508 of 154◦W) NORPAC NE Pacific (157◦W-165◦Wand Various depths; from 100-0 to July-August 1955 POFI north of 34◦N) 141-0 TROLL Tropico-equatorial western 140-0 March-April 1955 Pacific CHINOOK Central North Pacific (Hawaii to Various depths; from 85-0 to July-August 1956 Adak) 130-0 EQUAPAC HORIZON Equatorial western Pacific Various depths; from 140-0; August-September 1956 280-140; 700-0 EQUAPAC STRANGER Equatorial central-western Various depths; from 140-0; August-September 1956 Pacific (175◦W to Hawaii) 280-140; 700-0 DOWNWIND Eastern South Pacific Various depths; from 71-0 to October 1957 -February