Skip to main content
Open Access Publications from the University of California
Cover page of Taxonomy and distribution of the marine calanoid copepod family Euchaetidae

Taxonomy and distribution of the marine calanoid copepod family Euchaetidae


The marine calanoid copepod family Euchaetidae and its two genera, Euchaeta and Paraeuchaeta, are redefined. Fourteen species of Euchaeta and 61 species of Paraeuchaeta, including 13 new species, are described and their geographic ranges defined from specimens found in midwater trawl and plankton net samples collected throughout the Atlantic, Pacific, and Indian oceans. The species of Euchaeta are classified into three species groups - marina, concinna, and acuta groups - and an independent species, E spinosa; those of Paraeuchaeta were classified into six species groups malayensis, pavlovskii, norvegica, glacialis, hebes, and antarctica groups - and three independent species - P. biloba, P. bisinuata, and P. grandiremis. Each of the nine species groups is defined with detailed descriptions of its representative species and each of the four independent species that could not be grouped is also described in detail. Phylogenetic relationships among the species groups and independent species are discussed. Keys are presented for identification of the species groups in each genus and the species in each species group containing three or more species. The geographic distribution of the species groups and common species is discussed.

Cover page of Annual Cycles of Diving Behavior and Ecology of the Weddell Seal

Annual Cycles of Diving Behavior and Ecology of the Weddell Seal


Annual diving patterns in pinnipeds are difficult to study because most seals and sea lions are at sea and inaccessible for a large portion of the year. Consequently, until recently, most studies of pinniped biology were concerned with the onshore behavior of species that breed in accessible sites. Of all the species studied, however, the Weddell seal (Leptonychotes weddellii) presents a remarkable exception to the generally incomplete view of the natural history of marine mammals. The south polar, fast ice environment of Weddell seals provides an unparalleled opportunity for diving studies. Because Weddell seals regularly haul out onto the sea ice surface, investigators can approach the seals whenever sea ice is present. As a result, it is possible to study adult males, females, and sub-adults at different times in their life cycles and examine their breeding success and population movements. We present information collected during six field seasons, including a full year study in 1981. The goal of this project was to examine how behavioral responses to diving in the Weddell seal vary with season and location. In order to correlate diving behavior with seasonal or geographical variations, it is necessary to discuss the seals' environment. This includes not only the physical environment above and below the sea surface, but also how the seals may navigate and hunt under those conditions and what prey would be available. The following sections describe the study sites and examine the navigation abilities and feeding habits of the seals. By reviewing this information first, the reader will have a better understanding of some of the factors that may influence the diving patterns that are reported later.

Cover page of A systematic revision of the deep-sea subfamily Lipomerinae of the Isopod Crustacean family Munnopsidae

A systematic revision of the deep-sea subfamily Lipomerinae of the Isopod Crustacean family Munnopsidae


The fully natatory families of the janiroidean Asellota, the munnopsids sensu lato, include a group of genera that blurs the distinction between the Ilyarachnidae and the Eurycopidae. This work determines the interrelationships of the ilyarachnid-like eurycopids, and shows that they are a monophyletic group. In so doing, the family-level systematics of the munnopsids is revised. The ilyarachnid-like eurycopids are assigned to a newly constituted subfamily, the Lipomerinae, and five genera are described, four of which are new. A diagnosis of the subfamily Lipomerinae with a key to the superspecific taxa is included in the taxonomic part. One species in each superspecific taxon is fully described. Coperonus n. gen. is a primarily Southern Hemisphere group with several species in the south Atlantic and around the Antarctic continent. The most ilyarachnid-like genus is Hapsidohedra n. gen., which may have a cosmopolitan distribution. Lionectes n. gen. is found in Antarctic waters. The pan-Atlantic genus Lipomera Tattersall is further divided into three new subgenera. One of these subgenera, L. (Tetracope) n. subgen., has a coiled gut, a rare occurrence among Crustacea. The cosmopolitan Mimocopelates n. represented by a North Atlantic species group based on the species M. longipes n. sp.,and an equatorial species M. anchibraziliensis n. sp. Character analyses of most munnopsid genera present the characters that reveal relationships between taxa. The character states were assigned evolutionary polarities by comparison with characters in a presumed munnopsid sister group, the Acanthaspidiidae, and other janiroidean families. Computerized phylogenetic analyses produced cladograms that were not fully resolved, but had significantly lower homoplasy values than a tree based on previous classifications. The Lipomerinae were the most significantly monophyletic group of the munnopsid taxa, and a consensus tree of all possible cladograms confirmed the monophyly of the Lipomerinae. Because the previous classifications of the families were not consistent with the most parsimonious cladograms, the following proposals are made: all munnopsid families should be placed into one large family, the Munnopsidae; the Ilyarachnidae and the Munnopsidae sensu stricto should be demoted to subfamilial status; and the current subfamilies of the Eurycopidae should be retained. This new classification recognizes the monophyly of the Lipomerinae within the Munnopsidae. Alternatives to this classification are discussed. Supporting the text are appendices illustrating and defining morphological terms.

Cover page of Review of the Deep-Sea Fish Family Platytroctidae (Pisces: Salmoniformes)

Review of the Deep-Sea Fish Family Platytroctidae (Pisces: Salmoniformes)


The salmoniform fish family Platytroctidae (Searsidae) was last revised by Parr (1960) and then included 17 species in 12 genera. Since Parr's revision, 20 nominal species and 2 genera have been introduced. This rapid increase in new taxa, a number of which are poorly diagnosed and described, has left the taxonomy in an unsatisfactory condition. As a result of our study, 5 species and 2 genera are synonymized. We recognize 37 species (5 new) in 13 genera (1 new). A key to the family is presented and each genus is diagnosed and described, with a synopsis for each species. Besides the sac beneath the cleithrum that contains luminous fluid (shoulder organ), platytroctids are clearly set apart from other alepocephaloids by a number of synapomorphies including the presence of a subcutaneous canal system, a unique arrangement of the anterior predorsal spines, and the configuration of the caudal skeletal complex. Intrafamilial relationships were determined by use of a number of characters, including nature of photophores, presence or absence of a cleithral spine, fin position, shape and configuration of supraorbital and infraorbitals, path of cephalic lateral line canals, and dentition and jaw structure. Subfamilies are not recognized, but lines of relationship between the genera may be discerned. The deeper-living genera (bathypelagic) form a natural group and are regarded as the more advanced. They differ from the shallower-living (mesopelagic) genera in having a spinous cleithral symphysis, and are more compressed, with considerable nonmuscular tissue along the dorsal margin of the body. The platytroctids and alepocephalids are viewed as having had a common ancestor, which perhaps was closest to the Bathyprionidae among living forms. The course of platytroctid evolution is viewed as involving movement from mesopelagic to bathypelagic depths, with many of the morphological changes being reductional. Persparsia is regarded as the most primitive and generalized genus. Most platytroctid distributions are in the form of relatively narrow bands along the highly productive equatorial waters and the western side of continents. More oceanic records are primarily in areas of high-relief bottom, such as ridges and fracture zones, and near oceanic islands. Records of the generalized genera Persparsia and Paraholtbyrnia are from areas where temperatures at mesopelagic depths are relatively high -- up to 12 deg C. However, the remaining mesopelagic genera are mostly distributed meridionally in colder waters of the eastern boundaries of the Atlantic and Pacific. They tend to be rare toward the tropics. The more advanced genera predominate at low latitudes. The generalized eastern boundary forms are typically provincial in distribution. In contrast, four of the more advanced equatorial forms are circumglobal. However, none of them extends south of 24 deg S, and two, Platytroctes apus and Searsia koefoedi, have never been taken in the South Atlantic. Both species show geographic variation, with the eastern Pacific and Atlantic populations more similar to each other than to the Indo-Pacific population. From this and other evidence, we suggest that the former Panama seaway may have provided a passage for deep-water as well as shallow-water fishes.

Cover page of Variation of spotted and spinner porpoise (genus Stenella) in the Eastern Pacific and Hawaii

Variation of spotted and spinner porpoise (genus Stenella) in the Eastern Pacific and Hawaii


Spotted and spinner porpoise occur in coastal and offshore tropical waters of the eastern and central Pacific, as well as elsewhere in world tropical waters. They are important in the tropical yellowfin tuna fishery as indicators and aggregators of tuna. In the eastern Pacific, the range of both is a triangle with the base the coastline from Cabo San Lucas, Mexico to Columbia, and the apex extending seaward to about 10°N latitude, 145°W longitude. Variation owing to ontogeny, sexual dimorphism, individual variation, and geographical differentiation in coloration, external size and shape, and skeleton are described in qualitative and quantitative terms, and three geographical races of the spotted porpoise, Stenella attenuata (Gray, 1846), and four of the spinner porpoise, S. longirostris (Schlegel, 1841), (nomenclature is provisional) are defined.

Cover page of Siphonophores of the Pacific with a Review of the World Distribution

Siphonophores of the Pacific with a Review of the World Distribution


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. Although the Siphonophorae are not so distinctly restricted to water masses as are most of the Chaetognatha species, 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 Muggiaea kochi first made its appearance and that since that time Muggiaea 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 Muggiaea 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 Chelophyes contorta (a warm-water species) with an inflow of warm water. A particular pattern of distribution was observed for Chelophyes appendiculata, Chelophyes contorta, Muggiaea atlantica and Muggiaea 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 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; Lensia ajax Totton, 1941; Lensia 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 meters are used for comparison with the distributional ranges of the species because the position of certain 200 meter isotherms tends to agree with the limits of the ranges. Temperatures are relatively conservative at and below 200 meters, 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.

Cover page of Systematics, Variation, Distribution, And Biology Of Rockfishes Of The Subgenus Sebastomus (Pisces, Scorpaenidae, Sebastes)

Systematics, Variation, Distribution, And Biology Of Rockfishes Of The Subgenus Sebastomus (Pisces, Scorpaenidae, Sebastes)


Following Matsubara, Sebastodes is synonymized with Sebastes.

The form known as S. helvomaculatits found in southern California is distinguished from that species and described as S. simulator, n. sp. S. rhodochloris (Jordan and Gilbert) is synonymized with S. helvomaculatus Ayres, and the form called S. rhodochloris by Phillips is described as S. ensifer, n. sp. S. eos of authors is a complex and a new species, S. rosenblatti, is described. In addition, three other new species, S. noting, S. lentiginossus and S. exsul, are described. Full description is given to each of the seven remaining species of the subgenus Sebastomus. Forms occurring in the southern hemisphere are all referred to as S. capensis. On the basis of similarities in meristics, body configuration, and color patterns, relationships among species of Sebastomus are discussed.

Meristic numbers in species of Sebastomus are found to be constant ontogenetically and geographically. Vertebral counts tend to be higher in northern species of Sebastes than in southern ones. Variability of meristic numbers is discussed, using the coefficient of variation as a criterion.

Allometry and its significance in taxonomy is discussed. Morphometric characters in speciea of Sebastomus are found to vary geographically. Both slopes and intercepts of the allometric regressions are equally susceptible to variation. There seems to be a correlation between growth rate and body form within a population.

Distributional data for all eastern North Pacific species of Sebastes are presented, with 34 new range records. Species of Sebastes are concentrated in the area from 34 to 38°N. As many as 50 species may occur in the same latitudinal range. There seems to have been a barrier near the latitude of San Francisco. A hypothesis involving differentiation following crossing of this barrier can explain the observed pattern of species distribution.

Growth of Sebastes umbrosus is studied in detail, using otoliths for age determination. Growth data back-calculated from otolith measurements are compared with those from average lengths of age groups and the discrepancy is discussed. This species can attain an age of 17 but mortality seems to increase after age 7. A Bertalanffy curve describes growth of this species well. Lee's Phenomenon is demonstrated and is explained as result of size-dependent mortality. No compensatory growth is detected and there is no correlation between early and subsequent growth. Fish that grew fast in early years, however, continue to be larger. There is no difference in growth rate between sexes. Individuals from Tanner Bank seem to grow more slowly than those from La Jolla.

Growth data of S. rosaoeus, S. ensifer, S. chlorostictus, and S. dallii are also presented, and, along with those of S. umbrosus are compared with those of other species of Sebastes.

Individuals of small species of Sebastomus such as umbrosus and ensifer may reach sexual maturity at age 3, whereas those of large species such as constellatus, chlorostictus, and rosenblatti generally do not mature until 10 years old or older. Species of Sebastomus spawn from February to July. Young of the year have been found to settle to the bottom starting from October.

Cover page of The Ecology of the Plankton Off La Jolla, California, in the Period April Through September, 1967

The Ecology of the Plankton Off La Jolla, California, in the Period April Through September, 1967


General Introduction, Hydrography, and Chemistry, by J. D. H. Strickland, Lucia Solorzano, and R. W. Eppley.

Vitamin B12, Thiamine, and Biotin, by A. F. Carlucci

Estimates of Phytoplankton Crop Size, Growth Rate, and Primary Production, by R. W. Eppley, F. M. H. Reid, and J. D. H. Strickland

Relationships of Phytoplankton Species Distribution to the Depth Distribution of Nitrate, by R. W. Eppley

Phytoplankton Taxonomy and Standing Crop, by F. M. H. Reid, E. Fuglister, and J. B. Jordan

Numerical Abundance and Estimated Biomass of Microzooplankton by J. R. Beers and G. L. Stewart

Production of the Planktonic Copepod, Calanus helgolandicus by M. M. Mullin and E. R. Brooks

Cover page of The Desmosomatidae (Isopoda, Asellota) Of The Gay Head-Bermuda Transect

The Desmosomatidae (Isopoda, Asellota) Of The Gay Head-Bermuda Transect


This study treats asellote isopods of the family Desmosomatidae from benthic samples taken>on, or in the vicinity of, a transect between Woods Hole, Massachusetts, and the islands of Bermuda. Samples came from a depth range of 20-5,100 meters and represent the continental shelf, slope, and rise, the abyssal plain beneath the Sargasso Sea, and the Bermuda Rise.

Thirty-nine species have been found in this region, and all but ten of them are new. Nearly the full range of morphologies known to exist in the family is represented. Study of this material revealed the necessity for a complete revision of the family. Fifteen genera belonging to two subfamilies are recognized. This classification reflects a basic evolutionary pattern within the family. The Desmosomatinae n. subf. includes the most primitive genera and those genera in which the first pereopod has become reduced and attenuated. The Eugerdellatinae n. subf. contains genera whose first pereopod has become robust and raptorial or chelate.

The large number of individuals in single species from some of the samples has allowed close examination of development, sexual dimorphism, and individual variation. Eugerda tetarta n. sp. is described in detail from these points of view. In the female there are three manca and three juvenile stages. These are followed by two or three cycles of reproductive maturity in which each brooding stage is preceded by a preparatory one. Molting into the preparatory stage is accompanied by growth, but none is exhibited as the animal achieves brooding condition.

Males are first distinguishable at the third manca stage. This stage is followed by two juvenile and one preparatory stage in which the male looks like the female except for the usual differences in the second antenna and pleopods I and II. Profound metamorphosis accompanies the ecdysis into the copulatory stage, and as a result the mature male bears little resemblance to the female. The adaptive meaning of these changes is discussed.

Analysis of several specimens from one station reveals little individual variation. Differences in the shape of body and limb segments are usually too subtle to be detected in visual inspection. Variation in setal count is slight and tends to be allometric.

Our knowledge of geographic distribution must be regarded as fragmentary because adequate samples are lacking from most oceans. Present information indicates that nearly all the genera are cosmopolitan or will prove to be so. Species, on the other hand, have limited distributions. Only seven have been found in more than one ocean or sea. The limited distribution of species is undoubtedly related to the absence of dispersive stages in development.

The Desmosomatidae is primarily a cold-water group. Typically its members occur in shallow water only at high latitudes. In those rare cases where species have been found in shallow warm water, the annual range of temperature change is slight. On the transect, the distribution of desmosomatids in water shoaler than 200 meters is limited to the outer portion of the shelf, thus avoiding the main effects of the pronounced temperature fluctuations along this part of the coast. All species show some degree of zonation with depth. Only two display depth ranges extending beyond 2,500 meters. A few species exhibit polar emergence.

All species found on the transect are fully described and illustrated. The descriptions of previously known species are based on transect material, not on the original types.