It is reported that, for the first time, Prochloron cells were found associated with an animal other than a colonial ascidian-namely, a synaptid holothurian, Snaptula lamperti. This occurance brings into question the supposedly obligate nature of the association of this problematic algae with didemnids and their allies.
Seventeen species of Eunicidae belonging to the genera Eunice and Palola were found on the eastern Brazilian Coast. Among them are two new species: Eunice marcusi and Palola brasiliensis. The coast line is dominated by calcareous bottoms and its fauna is one of the poorest known in the western Atlantic.
During the MD/08 Benthos Expedition (from 7 March to 26 April 1976) about 7,000 polychaetous annelids were collected from 70 stations from Marion, Prince Edward Islands and Crozet Islands. A cluster analysis was used to define benthic polychaete taxocoenoses with a matrix data of 77 species and 55 samples. Six polychaete assemblages were found in which two were original: an assemblage occurring in shallow water and black sand with Pseudonereis anomala, Leitoscoloplos fragilis and Travisia kerguelensis and a second group in deeper water and hard bottom with Polyeunoa laevis the dominant species. These polychaete assemblages occurred on the continental shelves of Marion, Prince Edward and Crozet Islands, and were discussed in relation to their biogeography and compared with the fauna of South Africa and the Kerguelen Islands.
Study of seven species of the genus Munida in the western Atlantic has revealed six species of bopyrid isopod parasites, all of which were undescribed. Bonnieria americana, n. sp., infests Munida microphthalma A. Milne Edwards; Anuropodione carolinensis, n. sp., infests Munida iris iris A. Milne Edwards; Anuropodione megacephalon, n. sp., infests Munida pusilla Benedict; Balanopleon tortuganus, n. gen., n. sp., infests Munida simplex Benedict; Aporobopyrina anomala, n. sp., infests Munida valida Smith; and Pleurocryptella fimbriata, n. sp., infests Munida constricta A. Milne Edwards and M. miles A. Milne Edwards. In addition, a pair of bopyrids was found infesting a specimen of Munida irrasa A. Milne Edwards, but, since the female appears to be damaged and the male immature, these are not described or named.
The Research Vessel John Elliot Pillsbury of the University of Miami obtained a small collection of porcellanid crabs during five cruises over a 3-year period from 1968 to 1971 throughout the Caribbean Sea below 20°N latitude. The material consisted of 195 specimens divided into 7 genera and 13 species, all of well known littoral or sublittoral forms. While no new species were recorded, several gaps in distributional and ecological knowledge were filled, and a range extension is reported for Petrolisthes cessacii (A. Milne Edwards, 1878) previously known only from a small area on the western coast of Africa, and a single published record from Brazil.
An enumeration is given of the 18 known Atlantic species of Nephropidean lobsters. Special attention is devoted to the family group taxonomy, and to the morphology of the carapace. Keys are provided to all species. One subfamily, two genera and three species are described as new. The geographic distribution of each species is discussed, and all available information on the biology of the tropical forms is brought together. The species are provided with descriptions and figures or with references to such descriptions and figures published elsewhere.
Schultz and collaborators (1953-1966) listed 543 species of fishes from the Marshall Islands (Gobiidae omitted). Eighty-six new records and new species of fishes have been recorded since their series of bulletins appeared. In the present paper the following 106 new records or valid early records overlooked by Schultz and collaborators are reported from the Marshalls, principally Enewetak and Kwajalein: the hexanchid Hexanchus griseus; the albulid Albula glossodonta; the muraenid Uropterygius kamar; the congrids Heteroconger hassi and Poeciloconger fasciatus (also here recorded from the Hawaiian Islands); the ophichthid Apterichtus klazingai; the antennariids Antennarius analis, A. pictus, A. randalli, and Antennatus tuberosus; the isonid Iso hawaiiensis; the anomalopid Photoblepharon palpebratus; the holocentrids Myripristis adustus, M. vittatus, Sargocentron caudimaculatum, S. melanospilos and S. praslin; the syngnathid Syngnathoides biaculeatus; the scorpaenids Dendrochirus zebra, Parascorpaena mcadamsi, and Scorpaenodes hirsutus; the pegasid Eurypegasus draconis; the serranids Anthias pleurotaenia, Cephalopholis analis, C. sonnerati (C. purpureus is a junior synonym), Epinephelus caeruleopunctatus, Gracila albomarginata, Plectranthias winniensis and Plectropomus oligacanthus; the grammistid Pogonoperca punctata; the plesiopid Calloplesiops altivelis; the cirrhitid Oxycirrhites typus; the apogonids Apogon doryssa and Apogonichthys perdix (A. waikiki is a junior synonym); the malacanthids Hoplolatilus cuniculus, Malacanthus brevirostris and M. latovittatus; the carangids Alectis ciliaris, Carangoides plagiotaenia and Trachinotus blochii; the lutjanid Lutjanus semicinctus; the caesionid Caesio caerulaurea; the haemulids Plectorhynchus obscurus and P. picus; the lethrinid Lethrinus ramak; the nemipterid Pentapodus caninus; the mullids Mulloides pflugeri, Parupeneus barberinoides, P. blfasciatus (P. trifasciatus is a junior synonym; the species in the Pacific that has been named trifasciatus should be identified as P. moana), P. heptacanthus and Upeneus taeniopterus; the kyphosid Kyphosus vaigiensis; the chaetodontids Chaetodon tinkeri and Heniochus varius; the pomacanthids Centropyge bicolor, C. loriculus, C. multifasciatus, Genicanthus bellus and G. watanabei (G. vermiculatus is a junior synonym); the pomacentrids Amblyglyphidodon leucogaster, Chromis atripes, C. elerae, C. vanderbilti, Chrysiptera caeruleolineata and Lepidozygus tapeinosoma; the labrids Anampses melanurus, A. meleagrides, Bodianus anthioides, B. axillaris, B. diana, B. loxozonus, Cheilinus bimaculatus, C. orientalis, Cheilio inermis, Cirrhilabrus exquisitus, Cymolutes torquatus, Halichoeres richmondi, Pseudocoris yamashiroi, Pseudodax moluccanus, Pseudojuloides cerasinus and Xyrichtys pavo; the scarids Calotomus spinidens, Scarus atropectoralis, S. dimidiatus, S. Jorsteni (the S. tricolor of Randall and Choat, 1980), S. frenatus, S. ghobban, S. niger and S. oviceps; the blenniids Entomacrodus caudofasciatus and Plagiotremus rhinorhynchos; the callionymid Synchiropus ocellatus; the acanthurids Acanthurus maculiceps, Ctenochaetus binotatus (C. oculocoeruleus is a synonym), C. hawaiiensis, C. marginatus (C. cyanoguttatus is a junior synonym), C. strigosus and Naso tuberosus; the siganid Siganus puellus; the balistid Xanthichthys caeruleolineatus; the monacanthid Cantherhines fronticinctus; the tetraodontids Canthigaster bennetti, C. coronata, C. epilampra and C. valentini; and the diodontid Diodon liturosus. Seventy of these records are represented by specimens in museums (mainly the Bishop Museum, Honolulu), 30 are based on photographs (two from a submarine and the rest by divers), one from a figure in Hiyama (1943), and five on sight records.
The 107-year growth history of a massive coral Solenastrea bournoni from Aorida Bay was reconstructed with x-ray imagery from a single 4-in.-diameter (10 cm) core that penetrated the exact epicenter of the 95.3-cm-high colony. The growth record core was collected in October 1986, and another “proof” core was drilled 1 year later to verify annual density banding in this species. Growth increments totalled 952.9 mm, averaging 8.9 mm/yr over the life of the coral. To our knowledge, this is the first time that growth rate of S. bournoni has been determined. Growth rate trends in the Aorida Bay coral were compared to those in a Montastraea annularis of similar age from Hen and Chickens, a nearby patch reef on the Atlantic Ocean side of the Florida Keys. Both corals were rated as potential indicators of natural and man-induced perturbations by comparing their growth rates in years of severe environmental stress to each coral's long-term growth rate average. It was concluded that growth rate, at least in these specimens, is a questionable indicator of past hurricanes and freezes. There does appear to be, however, a possible cause-and-effect relationship between major man-induced environmental perturbations and a prolonged reduction in growth rate in each coral's growth record.
Six new species of hermit crabs of the genus Paguristes are described in detail and fully illustrated. Indications of intraspecific variation are given and distinguishing morphological characters are discussed.
Several thousands of pycnogonid specimens from 451 stations or samples, belonging to 76 species in 7 families are recorded. Of these, 23 represent new species or subspecies; moreover 1 new genus and 1 new subgenus are described. The samples studied came from the entire tropical belt of the Atlanto-East Pacific region, but mostly from the Caribbean and adjacent regions. Both shallow-water and deep-sea material is treated.
Egea inermis Joubin, 1933, is fully redescribed and illustrated from the postlarval to near mature form based on a reexamination of the type material and fifty-eight newly reported specimens collected in the Atlantic by the Danish research ship DANA and other vessels. Phasmatopsis lucifer G. Voss, 1963, is placed into synonymy. Known geographic and vertical distribution are given. The validity of the genus is reaffirmed, and the relationship of Egea inermis to a small group of nominal species of taoniids which, in part, have been identified to the genus Phasmatopsis de Rochebrune, 1884, by Clarke (1962) is discussed. It is shown that the genus Phasmatopsis cannot be used and that further study is necessary to clarify the existing interrelationship of the group.
A series of laboratory feeding experiments determined rates of predation by 11 species of common zooplanktonic predators upon embryonic and larval stages of the Pacific Sand Dollar, Dendraster excentricus (Eschscholtz). Rate of predation by the predator species was not constant upon the prey stages, and four patterns of predation emerged: (1) Three crustacean and two hydromedusa species consumed embryo through gastrula or prism stages, but few pluteus larvae; (2) An amphipod and a chaetognath species ate motile pre-pluteus stages, but not unhatched embryos or plutei; (3) Two fish species ate unhatched embryos, prism and pluteus larvae, but ate few blastulae or gastrulae; (4) Two ctenophore species ate few or no prey during experiments. The observed patterns of predation were presumably caused by behavioral and morphological changes that occur during embryonic and larval development of the prey, and vary between groups of predators that use different feeding mechanisms. The nine invertebrate predator species consumed few, if any plutei, while the two fish species ate plutei in substantial numbers. It is suggested that field rates of predation upon plutei are lower than those upon pre-pluteus stages where invertebrate predators predominate. Conversely, where planktivorous fish are common, plutei may be consumed at high rates.
Species specific aggressive interactions have been found among West Indian and Indo-Pacific scleractinian corals. When the polyps of different corals touch each other, the species which are "stronger" aggressors extrude mesenterial filaments over their "less aggressive" neighbors, dissolving those tissues within reach by extracoelenteric forms of digestion. Interspecific aggression by corals may occur under natural or experimental conditions. For any population, the interactions of different species have a definite and consistent hierarchical structure.Most highly aggressive species belong to the suborder Faviina, have massive or encrusting growth forms, construct relatively small coralla, and are usually minor components of coral reef communities. They use aggressive interactions as a defense against overgrowth by the more rapidly expanding ramose and foliose corals, and to clear space for their own growth. Some faviids are moderately strong aggressors which construct primary reef framework in many West Indian habitats. Ramose and encrusting corals of the family Acroporidae, which occupy an intermediate position in the aggression hierarchy, also construct reef framework; interspecific aggression is common in mixed acroporid reefs. Weak aggressors include the foliose agariciids, which may form the predominant cover in deep reef zones.
Descriptions of three new species (including one subspecies raised to specific rank) and redescriptions of the four other species of the parasitic isopod genus Munidion Hansen 1897 are presented. The genus, whose validity had been questioned, is shown to be valid and is redefined. The seven species (all parasitic on galatheid crabs) now in the genus include Munidion princeps Hansen (host: Munida refulgens Faxon, Pacific coast of Colombia); Munidion pleuroncodis, n. sp. (host: Pleuroncodes planipes Stimpson, coast of California and Baja California); Munidion parvum Richardson (host: Munida quadrispina Benedict, coast of Washington and British Columbia); Munidion cubense Bourdon (new status; originally = M. parvum cubensis) (hosts: Munida stimpsoni A. Milne Edwards, Cuba; and M. flinti Benedict, near Venezuela); Munidion irritans Boone (host: Munida irrasa A. Milne Edwards, Atlantic coast of Florida and near British Honduras); Munidion longipedis, n. sp. (hosts: Munida longipes A. Milne Edwards, Atlantic and Gulf coasts of Florida and near Isla de Providencia, and M. schroederi Chace, Cuba); and Munidion laterale Richardson (hosts: unidentified galatheid, Dumalag Island, Philippines, and Munida scabra Henderson, Java Sea). Some taxonomic problems of the genus and the distribution of its species are discussed. Keys to all species, based on mature females, are presented.
A review of the species heretofore known as Pagurus brevidactylus (Stimpson) and Pagurus miamensis Provenzano has shown that the identity of the former species has been misinterpreted. Stimpson's species is identical with P. miamensis, and the species, to which the name, P. brevidactylus, has been applied, represents a new species. The group to which these species are assigned has been redefined and renamed.
A new species of ocellated octopus, Euaxoctopus pillsburyae, is described from material collected from the R/V John Elliott Pillsbury in the tropical Western Atlantic. It is compared with its nearest relative, Euaxoctopus panamensis, from the Eastern Pacific. The genus Euaxoctopus is emended in order to contain the new species; the genus is the first in the octopodines to contain species in which either the third right or the third left arm is hectocotylized.
Fifty species of cephalopods are identified from the Straits of Florida from the 698 specimens collected by the R/V Gerda. This raises the total number of species known from the Straits from 49 to 64. Four are new records for the Western Atlantic: Pterygioteuthis gemmata, Abraliopsis pfefferi, Corynoma speculator and Helicocranchia pfefferi. Two others, Rossia bullisi and Abraliopsis atlantica, are reported for the second time in the literature. The male of Abralia redfieldi is described for the first time. The first mature specimen of Danoctopus schmidti is reported with drawings of its radula and ligula. Pelagic distributions are analyzed with respect to mean depth of capture and concentration in particular geographic regions of the Straits. Benthic distributions are analyzed regarding bottom type and concentration in geographic regions of the Straits. Diel migration is discussed for several species. The zoogeography of all species reported in the Straits is discussed.
The genus Chrionema Gilbert, 1905 is reviewed. Four species are recognized: C. squamentum and C. squamiceps, previously placed in Chriomystax Ginsburg, 1955, and C. chryseres and C. chlorotaenia. Chrionema is readily separable from other percophidid genera by the absence of maxillary tentacles and the number of fin elements. The four species are distinguishable on the basis of squamation, meristic characters, and pigmentation pattern. The disjunct distributions of the species are discussed and compared with similar patterns in other families.
Based on abundant material, four species of the genus Stephanocyathus are distinguished in the western Atlantic: S. (S.) diadema (Moseley), S. (S.) paliferus n. sp., S. (S.) laevifundus n. sp., and S. (O.) coronatus (Pourtalès). These four species are fully described and illustrated; their bathymetric and geographic ranges are provided. The taxonomic position of Stephanocyathus discoides (Moseley) is discussed.
The formerly monotypic genus Comactinia is found to comprise two valid species. One of these is further divided into two subspecies. The variability of the genus is examined and illustrated. A discussion of ecology, affinities, and zoogeography is included.
Recent collcctions of crinoids from the intertidal zone to 1,650 m in the tropical western Atlantic have provided significant range extensions for more than half of the 44 comatulid and stalked species known from the region. Of the 34 comatulid species, over 60% are endemic to the region; of the 10 stalked species, 90% are endemic. At the familial level, this fauna has its strongest affinities with the tropical Indo-Pacific region. Comatulids are most abundant above 300 m, while stalked species occur primarily between 100 and 700 m. Species that occur primarily above 600 m (the deepest penetration of the 10°C isotherm in the region) have depth ranges generally narrower than 200 m. Species that are found below 1,000 m generally have much broader depth ranges.
The reef-dwelling marine slug Tridachia crispata (Opisthobranchia, Sacoglossa) possesses endosymbiotic chloroplasts which contribute photosynthetically fixed carbon to the animal host. One of the predominant ways in which the slug utilizes chloroplast products is in the synthesis of mucopolysaccharide by the pedal gland.Chemical analysis of the secreted mucopolysaccharide shows that it is acidic, sulphated, of large molecular weight (> 2 × 106), and is composed of glucose, glucuronic acid, glucosamine, galactosamine, and traces of galactose. The protein moiety contains leucine, glutamic acid, aspartic acid, glycine, serine, valine, proline, and alanine. Many of these substances are derived from chloroplast photosynthesis.The synthesis and secretion of photosynthetically derived materials by animals with autotrophic endosymbionts is widespread, and is viewed as an important aspect of the recycling of organic matter in coral-reef ecosystems.
During investigations on the larval development of western Atlantic scyllarid lobsters, larvae of the sand lobster Scyllarus planorbis Holthuis were hatched in the laboratory and were reared to the eighth instar, which attained the final (gilled) phyllosoma stage of development. The sequence of larval instars is described and illustrated. The length of larval life is estimated to be about 8 weeks at water temperatures near 25°C. Phyllosomas of this species in all instars can be distinguished from those of the western Atlantic species S. americanus and S. depressus, but closely resemble those of S. chacei.
Chlorophyll a, b, a+b, a:b, carotenoids, TAN (Titrable Acid Number), proteins, polyphenols, and tannin content of 14 species of mangroves viz. Aegiceras comiculatum, Aglaia cucullata, Avicennia officinalis, Bruguiera parviflora, B. sexangula, Ceriops decandra, Cynometra iripa, Excoecaria agallocha, Heritiera fomes, H. littoralis, H. macrophylla, Kandelia candel, Rhizophora mucronata and Xylocarpus granatum found in the mangrove forests of Bhitarkanika and the Mahanadi delta of Orissa were estimated. Total chlorophyll content varied from 0.21% in A. cucullata and C. decandra to 0.56% in A. corniculatum. Calculated chlorophyll a:b ratio was the minimum (1.55) in A. officinalis and the maximum (3.50) in B. sexangula. The carotenoids also varied from 0.04% in B. sexangula to 0.17% in A. corniculatum. Analysis of Variance showed intra- and interspecific variations in photosynthetic activities. TAN values revealed appreciable variations from 20.00 to 45.00 in A. officinalis and H. littoralis respectively. TAN values showed negative correlation with chlorophyll b and carotenoids, but highly significant positive correlation was noted with chlorophyll a:b ratio among the species. Total leaf protein content significantly varied from 12.21% in H. macrophylla to 29.22% in H. fomes. The quantitative analysis of tannin and polyphenols from the leaves of mangroves showed significant variation, 8.39% to 44.27% in A. cucullata and B. sexangula and 11.39% to 52.89% in A. officinalis and C. decandra respectively, Statistical analysis of the endogenous level of polyphenols and tannins showed no interdependence with leaf proteins.
A new species of the gorgonacean Nicella is described from deep-reef habitats along the coast of Jamaica and elsewhere in the Caribbean and is named N. goreaui for its discoverer. It is compared with other known species of Nicella from the western Atlantic, and its spicular characters are illustrated by scanning electron micrographs as well as by drawings.
The gross anatomy of two new species of pleurotomariid gastropods from the Western Atlantic, Perotrochus midas and P. lucaya, is described and the external features, the stomach, and the buccal cavity of P. midas, are figured. Reference is made to resemblances and differences between these species and those previously described, and with trochid organization.
The coral reef ecosystem is seen as a specialized chemical environment converting dissolved calcium carbonate ions into insoluble calcitic and aragonitic calcium carbonate. The movement of the calcareous material is a potent dynamic factor in the morphogenesis of the coral reefs. There is a precarious balance between accretion and ablation in the system.This paper is concerned with the sedimentary phases of the calcareous biota and the initial patterns of distribution and deposition of the calcareous material within the reefs, and not with the long-term depositional changes induced by erosion, diagenesis, and lithification.The calcareous material is deposited into two distinct phases: a rigid framework (built by primary hermatypes) and a clastic framework (contributed by secondary hermatypes). The reef builders, fillers, and cementers are eventually sediment producers.The unconsolidated skeletal remains of hermatypes make (mostly due to fragmentation) ramparts of imbricated shingles in the reef crest and land-ward side. In the deeper seaward slope, the corals produce talus cones (by steady biodegradation of corals or by gravitational slump). Silty and muddy sediments accumulate on the fore-reef slope; outcrops and pinnacles there support a rich diverse biota.The hermatypic calcareous algae are significant sediment producers. There is a relation of algal generic diversity to the available substrate. The lithophytes are present at greater depths than the psammophytes. In the fore reef, Halimeda constitutes about 80 per cent of the algal debris. Remains of Halimeda form the largest single part of the total carbonate produced in the whole reef. It is suggested that algal populations should be assessed by their turnover rates, rather than by species diversity or biomass.The main structural and biotic zones with their depth ranges and local variabilities are summarized.
A new species of pinnotherid crab, Orthotheres haliotidis, is described from two species of Australian abalone, Haliotis asinina Linnaeus, 1758, and H. squamata Reeve, 1846. Its morphology is recorded using light and scanning electron microscopy. The report is the second record of the predominantly American genus Orthotheres in the western Pacific, the first confirmed record of a pinnotherid crab from any species of abalone, and the first record of a pinnotherid associated with H. squamata.
Asaphis deflorata in the Bahamas is found in dense concentrations among rocky gravel in the highest intertidal zone, where it is the only bivalve present. Sexes are separate and sexual maturity is reached after 2 to 3 years at a size of 25 mm or greater. Mass spawning occurs in late summer and larvae develop to the pediveliger stage within 10 to 13 days. This stage is very brief, lasting only 24 h. Estimates of long-term sustained growth rates are 10 to 15 mm/year and fit the von Bertalanffy growth equation using probit and computer analysis of size frequency distributions. Natural mortality relating to both size-dependent predation and size-independent catastrophic burial by sand is evident in empty shell assemblages.
The tiger lucine Codakia orbicularis is a large edible clam being investigated as a mariculture candidate in the Bahamas Islands. Gonad development and spawning seasons were assessed by monthly sampling of C. orbicularis from Grand Bahama Island, Bahamas and Key Biscayne, Florida. Histological examination of clams showed most of the populations sampled to be ripe between April and November. Natural spawning probably occurs May to October. Codakia orbicularis is dioecious, seldom responding to standard spawning techniques, including physical and chemical stimuli. Artificial fertilization by carefully stripping gonads produced 15-20% viable embryos. Eggs are 108-112 μm in diameter and are singularly encased in a thick capsular membrane. Following fertilization, the gastrula, trochophore and early veliger stages develop within the capsular membrane. Upon hatching, planktonic veligers range from 150-174 μm in shell length and develop to the pediveliger stage in approximately 12 days at 24°C. Metamorphosis occurs approximately 16 days after fertilization. Larval development within the superfamily Lucinacea is characterized by formation of a gelatinous capsule. The long planktonic development and facultative planktotrophy of C. orbicularis is unusual for lecithotrophic bivalve larvae. Larvae of C. orbicularis and other lucinids may also derive nutrition from chemosynthetic bacteria located within their tissues, as reported for adults.
Fighting conch, Strombus pugilis, larvae were reared from hatching to settlement under two feeding schedules: larvae were fed during 12 light hours (06:00-18:00, Set A) and larvae were fed during 12 dark hours (18:00-06:00, Set B). The study evaluated the effect of food availability during the day or night on larvae development, growth and survival. Adult heart appeared at 8 d in the larvae fed at night and after 11 d for larvae fed during light hours. The settlement period was significantly shorter in larvae of Set B. The veligers fed at night were competent for settlement in between 27 to 29 d, while the settlement had not been reached 100% for the larvae fed during the day. The percentage of survival at settlement was significantly lower for larvae fed during the day (29%), while larvae fed at night presented 37%. Average larval growth was 23.26 μm d−1 for day feeding and 41.43 μm d−1 for night feeding. The siphonal length at settlement for larvae fed at night was 1496 μm. Results obtained indicate that the larvae are more efficient if cultivated when they are fed at night.
In this study, the gastric evacuation rates of cuttlefish (Sepia officinalis), fed a single meal of shrimp, Paleomonetes varians, were measured in the laboratory at four temperatures (15.5, 18, 21 and 23°C). Linear, square root, and exponential models were fitted to the percentage of the original meal remaining (ash free dry weight). The square-root model gave the best fit for experiments performed at 15.5°C and 18°C, whereas the exponential model gave the best fit for experiments carried out at 23°C. The square-root model showed an increase in the amount of food remaining after the fifth hour in all four experiments. There was a significant difference in gastric evacuation rates between the temperatures tested. Gastric evacuation rates were higher at higher temperatures (0.442 h−1 at 23°C) in comparison with lower temperatures (0.198 h−1 at 15.5°C, 0.212 h−1 at 18°C, and 0.323 h−1 at 21°C). Significant differences in gastric evacuation rates between size and maturation stage have been calculated for experiments performed at 23°C.
In this study, stomach contents of 108 swordfish specimens, Xiphias gladius Linnaeus, 1758 were examined from the southern Aegean Sea. The taxonomic distribution of major prey categories in stomachs was 81.5% teleosts, 17.8% cephalopods, and 0.7% crustaceans. Teleosts (97%) were the most important prey regarding the frequency of occurrence values, followed by cephalopods (59.2%), and crustaceans (5.8%). In total, 1230 individuals (1001 teleosts, 220 cephalopods, nine crustaceans) belonging to 34 species (15 teleosts, 18 cephalopods, one crustacean) were identified.
Gastropod shells used by the three dominant hermit crabs, Diogenes pugilator (Roux, 1829), Paguristes eremita (Linnaeus, 1767), and Pagurus forbesii Bell, 1845, of the detritic littoral bottoms from Barbate Bay (Cadiz, Spain) were analyzed. The study showed that these hermit crabs species have different patterns of gastropod shell use. Paguristes eremita, the largest and strongest species, inhabits heavier gastropod shell species with wider aperture (belonging to the Muricidae family), while, Diogenes pugilator and Pagurus forbesii, inhabit smaller and lighter shells (mainly those belonging to the family Turridae). Diogenes pugilator, despite being clearly the more abundant species, does not use the most abundant species of the gastropod community (Turritella turbona), which instead is used by Pagurus forbesii. However, no morphological relationships between these hermit crabs and the diameter of shell aperture have been found, either in relation with the whole gastropod shells used or in relation with the more specifically used shells. On the other hand, specimens of D. pugilator with cephalothoracic shield widths larger than the shell aperture have been found, however, this result has not been found in P. forbesii or in Paguristes eremita. Also, in these three species no differences in shell use by sexes exist. These and other data indicate that D. pugilator does not make a strong shell selection, perhaps in part, due to a competition with P. forbesii and a scarcity of available useful shells in the area, which are a fundamental limiting factor. On the contrary, P. eremita seems to use adequate shells, a point that allows us to speculate that this species makes (with or without competition with the other hermit crabs) a real selection. Finally, the data about relative growth of the cheliped of D. pugilator in different areas, in which they use different shells, are similar. These data contrasts with the stunting hypothesis.
Larval stages of the Atlantic grapsid crab, Plagusia depressa, were cultured in the laboratory beyond the first stage for the first time, and are described and illustrated. The observed development consisted of a pre-zoeal, at least five, and probably six, zoeal stages; no megalopal stage was obtained. Based on laboratory rearing the minimum duration for completion of larval development is 60 days, which may account in part for the widespread distribution of the species in the Atlantic Ocean. Morphological characters of the first zoeal stage of P. depressa are compared with those noted for the same stage in Plagusia chabrus and P. dentipes from the Indo-Pacific region, and a provisional synopsis of larval characters for the subfamily Plagusiinae is advanced.
The shell, anatomy, and habits of the mesogastropod Cerithium atratum (Born) are described from animals collected intertidally at the Research Station of the Oceanographic Institute, near Ubatuba, Brazil. The species has been reported from Florida and the West Indies, southward to Argentina, but is not described in the recent literature. Its relationship with allied species, such as C. algicola C. B. Adams, C. eburneum Brugière, and C. striatissimum Sowerby, is discussed but not settled.
A comparative study of Anomalocardia brasiliana (Gmelin) and Tivela mactroides (Born), as well as a detailed study of the structure, adaptation, and functional morphology of these species was made. A. brasiliana is distributed from the West Indies to Brazil, and, according to Carcelles, its range extends to the Magellanic Region. T. mactroides is found from the West Indies to Brazil, Santa Catarina State. A. brasiliana lives in soft muddy beaches in quiet waters, and T. mactroides in sand or muddy sand where there is some disturbance of the bottom deposits, so that the water contains a large amount of suspended material. Both species have some biological similarities. They are eaten by the coastal population, and A. brasiliana is also found in the markets of the principal towns of the State of São Paulo. The shell, mantle, and siphons are described in detail. Special attention was paid to the ctenidia, labial palps and stomach. A comparative study of these organs was made.
Wide variability in colony morphology of Montastraea annularis has traditionally been viewed as a largely phenotypic response to variation in environmental conditions. This perspective is challenged, however, by the coexistence of discrete colony morphologies at the same sites, often with little evidence of intermediate forms. Differences among colony morphotypes in proteins, aggressive reactions, and corallite morphology define three broadly sympatric shallow-water species. We redescribe the species that corresponds to the type specimen of M. annularis and two previously synonymized species, M. faveolata and M. franksi. Montastraea franksi is distinguished by larger, unevenly arrayed polyps that give the colony its characteristic irregular surface. Colony form is variable, and the skeleton is dense with poorly developed annual bands. Montastraea faveolata grows in heads or sheets, the surface of which may be smooth or have keels or bumps. Septa are highly exsert, and the skeleton is much less dense than in the other two species. Montastraea annularis grows in columns that exhibit rapid and regular upward growth. In contrast to the other species, margins on the sides of columns are typically senescent. A dominance hierarchy characterizes short-term aggressive reactions and can be used to identify these species in the field; M. annularis is the least aggressive and M. franksi the most aggressive. The species overlap broadly at intermediate depths, although M. faveolata has the shallowest distribution and M. franksi the deepest. Montastraea faveolata is the most distinctive species biochemically. Substantial biological differences among the species require that they be distinguished in future studies.
A 6-month study consisting of collections and observations revealed that a diverse fauna of reef-fishes inhabit the rubble mounds constructed by the sand tilefish Malacanthus plumieri (Perciformes: Malacanthidae). In the Santa Marta region, on the Caribbean coast of Colombia, M. plumieri occurs on sandy areas just beyond the coral zone. The population density is correlated with the geomorphology of the bays; the composition of the material utilized depends on its availability. Experiments showed that debris was distributed over a distance of 35 m. Hard substrate must be excavated to reach their caves. In the area around Santa Marta the sponge Xestospongia muta was often used by the fish as a visual signal for suitable substratum. The rubble mounds represent a secondary structure within the “coral reef” ecosystem. These substrate accumulations create structured habitats in the fore reef, which are distributed like islands in the monotonous sandy environment and where numerous benthic organisms are concentrated. The tilefish nests attract other organisms because they provide shelter and a feeding site in an area where they would not normally be found. At least 32 species of fishes were found to be associated with the mounds. Some species lived there exclusively during their juvenile stage, indicating that the Malacanthus nests serve as a nursery-habitat. M. plumieri plays an important role in the diversification of the reef environment.
The common octopus Octopus vulgaris is the most important demersal species in landings from the whole Gulf of Cádiz. Monthly samplings from trawl and artisanal gears were carried out in 1996, due to the remarkable multifleet nature of the octopus fishery in the study area. Yearly sex ratio was estimated as 1.06:1 (male:female). There were no significant seasonal differences in the sex ratio. A four stage maturity scale was used for both sexes. The reproductive period was determined from the monthly evolution of these stages as well as that of several maturity and condition indices. The breeding season extended from February to October, with spawning peaks in April-May and August. Dorsal mantle length and body weight at maturity were estimated at 17.6 cm and 2023 g for females and at 10.4 cm and 671 g for males. Mature males occurred throughout the year. Total fecundity ranged between 70,060 and 605,438 oocytes (mean = 315,197 ± 135,865). Residual oocytes represented 6.2% on average of the total of ovarian oocytes. The maximum number of fully developed spermatophores was 276 in a male of 21 cm and 3350 g. The mean length of mature spermatophores in mature males was 51.3 mm (±10.2).
Using data from the Spanish octopus (Octopus vulgaris Cuvier, 1797) fishery occurring on the Saharan Bank (Northwest Africa between 21°N and 26°N), oscillations on the spatio-temporal abundance of the species are analyzed by means of a Geographic Information System (GIS) and by applying Generalized Additive Models (GAM) as exploratory tools. GIS analyses show two differenciated fishing grounds respectively located north and south of Dakhla (25°N). During the recruitment period of octopus, fishing activity tends to concentrate at both areas in relatively small high density spots from where it gradually extends to occupy almost the whole region at the end of the fishing season. The intermediate zone between these two major fishing grounds is rarely exploited at any time of the year. A GAM fitted to the data also reveals the existence of those two zones of high abundance of octopus in the Saharan Bank indicating that its intra-annual variability is mostly related to the latitude, the longitude (depth) and specially to the period of the year being maximum in October-November when sea surface temperature is highest. Nevertheless, major fluctuations in octopus abundance seem to occur at an inter-annual scale and some evidence suggests that they could be related to anomalies in the mean annual sea temperature in the region. Previous observations are reviewed and hypotheses are put forward suggesting possible relationships between spatio-temporal changes in octopus abundance and distribution and environmental factors.
The aim of this work was to investigate biochemical changes during the reproductive cycle of the common octopus, Octopus vulgaris, Cuvier, 1797. Proximate composition, fatty acids, cholesterol and amino acids were determined monthly in the mantle of O. vulgaris caught off in three different areas of the Portuguese coast. The moisture content exhibited significant seasonal and spatial variations, with a maximum value in Viana do Castelo in April (81.4%) and a minimum value in Tavira in October (76.5%); the mineral content tended to be similar to the results of other studies (1.4-1.9%). Nitrogen compounds were the major organic compounds (16.1-20.7%) and seem to be the most important energetic fuel in sexual maturation, spawning and brooding. In fact, the maturation of gonads and periods of feed deprivation (during brooding) can result in tissue depletion with marked decreases in the content of protein in muscle. With the profiles of SDS-PAGE it can be speculated that the exhaustion of these energetic sources, at the end of the reproductive cycle, might be explained by the decrease of the major myofibrillar proteins content (paramyosin, myosin and actin), due to the enhancement of the protease activity in the muscle. Glutamic acid (2.1-2.7 g 100 g−1), aspartic acid (1.4-1.9 g 100 g−1 wet weight) and leucine (1.3-1.8 g 100 g−1 wet weight) were found to be the major components within muscle proteins. The total lipid content (0.1-0.6%) and the major polyunsaturated fatty acids DHA (C22:6w3) and EPA (C20:5w3) showed variations which could be related to oogenesis and spermatogenesis. The cholesterol content can be correlated with the rapid maturation process, because the production of sexual hormones are related with the cholesterol metabolism. Some data of metabolic state, sexual maturation and reproduction, related with the biochemical composition of Octopus vulgaris, are certainly important to a better knowledge of octopus life-cycle.
Biomineralization in cephalopod statocysts in unusual in that ions are secreted into a comparatively large volume of fluid before deposition, rather than being secreted by a membrane applied to the mineralized structure. Ionic composition of statocyst fluid in the squid Alloteuthis subulata is similar to that of blood with the exception of magnesium which has a concentration about 1% of that found in its blood and in seawater. Higher levels inhibit calcification. Natural statocyst fluid inhibits precipitation of calcium carbonate in an artificial statocyst fluid in dilutions of 1:1,000 by increasing the time required for nucleation and slowing the precipitation rate. Preliminary indications of an organic component that reversibly polymerizes with increased pH, together with data on the ionic composition of the statocyst fluid, suggests possible mechanisms by which “diurnal” growth increments are formed in molluscs.
The precopulatory behavior patterns of the common intertidal hermit crab Clibanarius vittatus are described. Males precopulatory movements involve rotation of the female with the ambulatory legs and tapping lightly with one or both chelipeds in the aperture of the female's shell. Bouts of these courtship patterns alternate with period of guarding in which the female is held by the male's ambulatory legs with her shell aperture against the substrate. Females that copulated were not soft from a recent moult and brought out a new batch of eggs in less than an hour following copulation. Male-male competition for access to females was intense. The results of experiments demonstrated that courted females give off a pheromone that stimulates male reproductive activity. Males occupying the sinistrally-spiralled shells of Busycon contratrium (Conrad, 1840) were at a distinct disadvantage in obtaining matings.
A new species of notaspidean, Pleurobranchus garciagomezi, is described from Ilha do Sal, Cape Verde Archipelago off the coast of West Africa. The color of the mantle with its conspicuous opaque white network, the shape of the shell and the anatomy of the reproductive system distinguish this species from all other Atlantic Pleurobranchus. A color plate of P. garciagomezi together with two other species of the genus is given to illustrate the distinctiveness of this species.
The carapace length-brood size (CL-BS) relationship of female Panulirus argus from northern Quintana Roo, México, was examined. Ovigerous females were sampled in April-November 1987, July-September 1988, and April-November 1989. No significant differences were found in the relationship either seasonally or interannually, indicating that the mean brood size of females of equal carapace lengths remained fairly similar throughout the study period, despite the passage of two hurricanes over Puerto Morelos in 1988. No differences were apparent in the relative size of the eggs throughout their development, but eggs in all development stages were smaller in autumn than in spring or summer. This suggests that the spring spawn is the first of the breeding season, and that eggs are smaller in subsequent spawnings. Female P. argus from Puerto Morelos have a CL-BS relationship more similar to females from Brazil than from Cuba. Females between 105 and 120 mm CL contribute 42% of the total egg production from the population. The potential egg production of female P. argus in Puerto Morelos is much higher than in the Florida Keys and the Bahamas.
The five zoeal stages of the soldier crab Mictyris longicarpus cultured in the laboratory and the megalopa collected from a sandy beach soon after settlement are described and illustrated. The morphology of the first zoea is compared with the previous description of the first zoeal stage of M. longicarpus (the only other mictyrid zoeal description yet published). Factors contributing to the failure of the fifth stage zoeae to metamorphose in the laboratory are discussed.
Collection and observation of living salps in the genus Pegea Savigny, 1816, has enabled us to distinguish three species: Pegea bicaudata (Quoy and Gaimard, 1826), P. confoederata (Forskål, 1775), and P. socia (Bosc, 1802). The last of these has previously been considered a synonym of P. confoederata. Characters used to separate the species include body shape and color, test thickness, body muscle arrangement, and muscle fiber number. Differences in muscle fiber number among the species may be responsible for supposed latitudinal variations in fiber number, reported previously in the literature.
Some aspects of the life cycle of the ascidian Phallusia nigra at São Sebastião (southern Brazil) were studied and compared with its life history traits studied at Jamaica. Population dynamics was monitored on natural substrates sampled on a monthly basis. Longevity, recruitment and mortality rates were obtained by monitoring permanent quadrats. The breeding period was assessed by dissection of animals and searching for full gonoducts. P. nigra adults are 5-8 cm long and are distributed mostly on vertical and inclined surfaces. Recruits are found throughout the year, but a marked peak of abundance was observed during the fall (April to June). Adults had full gonoducts during summer (November to February). High mortality was observed during the first 3 mo after juveniles were observed the first time. Most animals died before the first year of life, but a few would persist for at least 2 yrs. Some life history traits of the Brazilian population, such as timing of reproduction and the number of recruitment peaks per year, are similar to those shown by the Caribbean population. On the other hand, size of adults, mean longevity and abundance of recruits were all lower in the Brazilian animals.
Priapulid worms (Priapulus caudatus) were a conspicuous component of the meiofauna (<0.500 mm) and macrofauna (>0.500 mm) in Auke Bay, Alaska (58°N, 134°W) from 1985-1988. The smallest priapulid larva collected had a lorica of 0.050 mm length, while total lengths of adults exceeded 150 mm. Priapulids were usually the third most abundant meiofaunal organisms, following nematodes and harpacticoid copepods, with densities to 58,000⋅m-2 at subtidal stations of 25-55 m depth. Priapulids were much less abundant in the macrofauna, never exceeding 85⋅m-2. Large interannual variation in densities of larval priapulids occurred. The smallest larval stages were found during the winter months, the apparent spawning period, with greatest densities of larvae occurring in early spring. Growth rates suggested by length-frequency distributions support a 2-year larval period.