bluuebunny/crossref_metadata_2025 huggingface dataset:
Associations between pycnogonids and hydroids from the Buenos Aires littoral zone, with observations on the semi-parasitic life cycle of Tanystylum orbiculare(Ammotheiidae)
Authors: Genzano Gabriel N.
Published: October 2008

Abundance and seasonality of Tanystylum orbiculare Wilson, 1878 populations (Pycnogonida; Ammotheidae) associated with Sarsia sarsii (Loven, 1836) and Tubularia crocea (Agassiz, 1862) (Hydrozoa; Anthomedusae) are analysed and the semi-parasitic life cycle of this species is described. In the analysed population, the first larval stages were found exclusively as parasites of S. sarsii. During the attachment to the hydranths, protonymphon larvae of T. orbiculare feed by sucking the hydranths of the cnidarian. Change of host is not obligatory; juveniles and adults were found both on S. sarsii as on T. crocea, and adults were also observed on other invertebrates. In the Mar del Plata intertidal, Tanystylum orbiculare was the most common pycnogonid species on colonies of T. crocea and S. sarsii. Anoplodactylus petiolatus was less abundant on both species and A. assimilis was found only on T. crocea. Endeis spinosa is absent on hydroids from the Mar del Plata intertidal zone but ectoparasitic larvae and adults were found on Obelia longissima colonies from Mar del Plata harbour together with adults of T. orbiculare and A. petiolatus. Endoparasitic larvae of A. petiolatus were found associated with colonies of Bougainvillidae.
Depth segregation phenomenon in Donax trunculus (Bivalvia: Donacidae) populations of the Algarve coast (southern Portugal)
Authors: Gaspar Miguel B. , Chícharo Luis M. , Vasconcelos Paulo , García Alexandra , Santos Ana R. , Monteiro Carlos C.
Published: October 2008

A study was undertaken to evaluate the existence of depth segregation between size classes of Donax trunculus populations that occur along the Algarve coast (southern Portugal). Five collecting areas were sampled in the Ria Formosa barrier islands, namely in the Culatra, Barreta and Armona Islands, between March and June 1998. The study was based on size frequency distribution analysis and shell biometric relationships. The size frequency distribution showed the predominance of smaller individuals (< 25 mm) in the renewal area (0.5-1.0 m depth) and the prevalence of larger individuals (? 25 mm) at greater depths (4.0-6.0 m depth). The biometric study revealed the existence of significant differences in the type of growth between size classes in relation to depth distribution and burrowing activity. On the basis of these results, some specific management measures were proposed for this important bivalve fishery, taking into account the distinct fishing strategies and operations (manual and boat-operated dredging) performed at different depths.
The genus Paguristes (Crustacea: Decapoda: Diogenidae) from Cuba (Western Atlantic). A new record and a new species
Authors: Manjón-Cabeza María Eugenia , García Raso José Enrique , Martínez Iglesias Juan Carlos
Published: October 2008

The present paper presents an overview of the studies on the genus Paguristes from the Caribbean Sea and more specifically from Cuban waters. Additionally, the hermit crabs belonging to the genus Paguristes collected during different surveys of the Instituto de Oceanología de Cuba on the Cuban coast have been listed. A new species of hermit crab, Paguristes hologuinensis sp. nov., is described and remarks on a new record, Paguristes paraguanensis MacLaughlin and Provenzano, 1974, are given.
How fast hake grows? A study on the Mediterranean hake (Merluccius merluccius, L.) comparing whole otoliths readings and length frequency distributions data
Authors: García Rodríguez Mariano , Esteban Antonio
Published: October 2008

The hake (M. merluccius) is a target species of the Mediterranean trawl fleets. In this study, its growth was compared by two means: whole otolith readings and length frequency distribution analysis. Two growth hypotheses, fast and slow, were assumed using the results of otolith readings: (1) two rings were formed every year and (2) a single ring was formed every year. The monthly length distributions covered the period from 1992 to 1998, and the otoliths were obtained from monthly samplings between 1992 and 1995. The variability observed in the results for the number of rings counted was shown especially in the range of lengths for each group of individuals that had the same number of rings. A high correlation was found between the rings counted in the otoliths and the length of the individual in cm. The sex factor did not influence the relationship, unless the sexually undifferentiated individuals were included. The best fit with the growth data according to the length frequencies occurred in the two-ring hypothesis (Hypothesis 1), meaning faster growth rates than had been accepted till now, especially in females. We suggest the consideration of the hypothesis of faster growth in future studies.
Reproductive biology of three gadiform fish species through the Mediterranean deep-sea range (147-1850 m)
Authors: Rotllant Guiomar , Moranta Joan , Massutí Enric , Sardà Francisco , Morales-Nin Beatriz
Published: October 2008

Knowledge of deep-sea reproductive biology is slight and interpretations of reproductive strategies in deep-sea fishes are controversial. Since the Mediterranean is a fairly stable and constant sea, we might expect a consistent pattern of reproduction of deep-sea species. Three gadiforms species with a succesive bathymetric and an ecological and economical importance in the Mediterranean fishing industry, Phycis blennoides, Mora moro and Lepidion lepidion, were selected for the present study. These three species of gadiforms are sexually dimorphic and their reproductive population is located at the lower zone of their bathymetric range. Females were always bigger than males. The smallest mature male was observed at 19, 32 and 18 cm TL (total length) and the smallest mature female at 20, 34 and 20 cm TL for P. blennoides, M. moro and L. lepidion respectively. The three species are iteroparous and females could be all-at-once or batch-spawners. An autumn mature season was observed for P. blennoides, whereas M. moro and L. lepidion had mature individuals all year round except in summer. Hence, physical constancy at greater depths is able to lengthen the reproductive season and the deepest species has a quasi-continuous reproductive pattern. Similar reproductive tissues have been found in the three species studied, and they show analogous structure with other deep-sea gadiforms and their shallow-water congeners.
The distribution and biochemical composition of biogenic particles across the subtropical Front in June 1993 (Azores-Madeira region, Northeast Atlantic)
Authors: Vezzulli Luigi , Povero Paolo , Fabiano Mauro
Published: October 2008

Water samples were collected in the north-east Atlantic Ocean between the Azores and Madeira (33°N-36°N and 24°W-26°W) during the Oceanographic Cruise SEMAPHORE in June 1993. Temperature, salinity, nutrients (nitrate and phosphate) and particulate organic matter (organic carbon, organic nitrogen, carbohydrates, proteins and phytopigment) were investigated in the water column to a depth of 2000 m. The presence of the subtropical front (STF) separating warmer more saline Western Atlantic Water (WAW) from colder and fresher Eastern Atlantic Water (EAW) in the upper 100 m, and a tongue of salt water arising from the influence of Mediterranean Water (MW) at a depth of 1000 m, were well identified by the physical and chemical parameters. POC and PON concentrations, in the surface layer (0-100 m), ranged between 23.3-64.5 and 2.9-9.1 µg l-1 respectively, while concentration between 12.4-30.5 and 1.1-4.0 µg l-1 prevailed below the thermocline (100-2000 m). The very low POC and PON concentrations together with the low nutrient and chlorophyll-a concentrations confirmed the oligotrophic nature of the Azores-Madeira region. Statistical analysis was carried out to investigate the difference in the quantity and quality of POM between water masses. Regression analysis showed a high correlation between POC and PON but the slopes and intercepts of the regression lines did not differ significantly between WAW and EAW. In contrast, an examination of vertical profiles as well as mean integrated values of biochemical variables in the upper 100 m suggest a difference in the quantity and quality of biogenic particles between the water masses. WAW showed the lowest integrated concentrations of particulate organic carbon, particulate organic nitrogen, particulate protein and particulate carbohydrate. In contrast, frontal stations showed the highest values while EAW stations showed intermediate values. All these results, coupled with the occurrence of the highest POC:Chl-a ratio in EAW, suggest a temporal offset in the production cycle between the two water masses. Alternatively, the WAW is a more stratified and oligotrophic body of water than is EAW, and it always has lower biomass and nutrients than the more productive EAW. High chlorophyll-a concentrations were linked to the STF; moreover the average depth of the subsurface chlorophyll maximum (DCM) appeared to shift to shallower values at the frontal stations, suggesting a close association between the STF-Azores Current (AC) physical structure and the distribution of chlorophyll-a in this area.
Nanoplankton protists from the western Mediterranean Sea. I. Occurrence, ultrastructure, taxonomy and ecological role of the mixotrophic flagellate Ollicola vangoorii (Chrysomonadidae = Chrysophyceae p.p.)
Authors: Novarino Gianfranco , Oliva Emilia , Pérez-Uz Blanca
Published: October 2008

We give an account of the loricate mixotrophic nanoflagellate Ollicola vangoorii (basionym Codonomonas Van Goorii, synonym Calycomonas Van Goorii) (Chrysomonadidae = Chrysophyceae p.p. ) in the plankton of the western Mediterranean Sea. Using digital imaging and field-emission scanning electron microscopy (SEM), we describe the lorica morphology and ultrastructure based on some 150 specimens occurring either as dispersed (unattached) cells or cells attached to suspended particulate matter in coastal waters off Barcelona (Catalonia, Spain) in July 1998. The spectrum of morphological variation includes that of Calycomonas gracilis sensu Wulff non Lohmann, Calycomonas gracilis sensu Espeland & Throndsen non Lohmann, Calycomonas wulffii Conrad et Kufferath, Ollicola cylindrical (Conrad et Kufferath) Vørs (= Calycomonas cylindrical (Conrad et Kufferath) Lund, Codonomonas cylindrica Conrad et Kufferath), Ollicola dilatata (Conrad et Kufferath) Vørs (= Calycomonas dilatata (Conrad et Kufferath) Lund, Codonomonas dilatata Conrad et Kufferath), suggesting that those taxa are conspecific with Ollicola vangoorii. By contrast, Ollicola pascheri (van Goor) Vørs (basionym Codonomonas pascheri van Goor) is best maintained as a separate species and retained in the genus Codonomonas van Goor. From an ultrastructural viewpoint, the basic architecture of the lorica is that of a fibrillar ribbon coiled around the cell and eventually hardened as a result of inorganic mineralization from the environment. The appearance of the fibrillar component and the degree of mineralization may vary considerably. The cell apex is modified in a newly documented apical cytostome, substantiating an existing observation that cells are capable of ingesting bacteria. Although the statistical correlation between SEM-based nanoflagellate cell counts and epifluorescence-based bacterial cell counts is at best only weakly significant, it is possible that in the Barcelona populations O. vangoorii relies partly on bacterivory and therefore its ecological role is partly that of a carbon consumer. We also hypothesize that the presence of an external lorica increases the probability of intercepting bacterial prey, ready to be ingested by the cell in the apical cytostome.
Pattern of shell utilization by the hermit crab Paguristes tortugae (Diogenidae) from Anchieta Island, Southern Brazil
Authors: Mantelatto F. L.M. , Domiciano L. C.C.
Published: October 2008

The objective of this study was to characterize the pattern of shell utilization by Paguristes tortugae, from infralittoral areas of Anchieta Island (Ubatuba, São Paulo State, Brazil) using the percentage of the different shell types occupied and the morphometric relationship between hermit crabs and occupied shells. Specimens were collected monthly (January to December 1998) by SCUBA diving. The animals and the shells were measured and weighed. A total of 2,429 hermit crabs were captured occupying 21 species of gastropod shells. The shells more occupied were Pisania auritula (35.49%), Cerithium atratum (27.83%), Morula nodulosa (12.70%) and Leucozonia nassa (6.83%), respectively. There was differential shell occupation between sexes: males and ovigerous females occupied in higher percentage P. auritula shells while the non-ovigerous females occupied C. atratum. Regression analysis showed best correlation between the size of the crabs (shield length) and shell dry weight. This study showed that shell occupation by P. tortugae involves inter- and intraspecific competition as well as shell type availability in the field.
Group-synchronous ovarian development, spawning and spermiation in the European sea bass (Dicentrarchus labrax L.) could be regulated by shifts in gonadal steroidogenesis
Authors: Asturiano Juan F. , Sorbera Lisa A. , Ramos Jesus , Kime David E. , Carrillo Manuel , Zanuy Silvia
Published: October 2008

European sea bass (Dicentrarchus labrax L.) is a species with group-synchronous ovarian development. A mechanism is required which enables maturation to occur in the first clutches of oocytes without inducing maturation in subsequent clutches. The present study examined the individual plasma variations of testosterone (T), 17,20?-dihydroxy-4-pregnen-3-one (17,20?P) and 17,20?,21-trihydroxy-4-pregnen-3-one (20?S) in both sexes, estradiol (E2) and vitellogenin (VTG) in females (n=15) and 11-ketotestosterone (11KT) in males (n=21), in an effort to elucidate the hormonal control of the reproductive cycle in this species. A sample of oocytes was obtained at every sampling from each female and the stage of development of the most advanced clutch of oocytes was determined and related to the individual hormone plasma levels. Total expressible milt was collected from males at each sampling during the spawning period and variations in the sperm production were related to hormone plasma levels. Successive elevations of plasma T and E2 levels were observed prior to peaks of progestagens, which resulted from the shift in gonadal steroidogenesis and coincided with the maturation-ovulation of the different clutches of oocytes or with increases in the sperm production. Following each progestagens wave, a new shift in gonadal steroidogenesis, resulting in a new elevation in plasma T and E2, was observed. This hormonal pattern was repeated several times depending on the number of ovulations per female. Results from the present study suggest a mechanism, based on shifts in gonadal steroidogenesis, which may be responsible for regulation of group-synchronous ovarian development, ovulation and spermiation in this species. In addition, evidence is presented which supports a role for both 17,20?P and 20?S as the maturation-inducing steroids (MIS) in male and female European sea bass.
Estimation of heading gyrocompass error using a GPS 3DF system: Impact on ADCP measurements
Authors: Ruiz Simón , Font Jordi , Griffiths Gwyn , Castellón Arturo
Published: October 2008

Traditionally the horizontal orientation in a ship (heading) has been obtained from a gyrocompass. This instrument is still used on research vessels but has an estimated error of about 2-3 degrees, inducing a systematic error in the cross-track velocity measured by an Acoustic Doppler Current Profiler (ADCP). The three-dimensional positioning system (GPS 3DF) provides an independent heading measurement with accuracy better than 0.1 degree. The Spanish research vessel BIO Hespérides has been operating with this new system since 1996. For the first time on this vessel, the data from this new instrument are used to estimate gyrocompass error. The methodology we use follows the scheme developed by Griffiths (1994), which compares data from the gyrocompass and the GPS system in order to obtain an interpolated error function. In the present work we apply this methodology on mesoscale surveys performed during the observational phase of the OMEGA project, in the Alboran Sea. The heading-dependent gyrocompass error dominated. Errors in gyrocompass heading of 1.4-3.4 degrees have been found, which give a maximum error in measured cross-track ADCP velocity of 24 cm s-1.
Structure and growth dynamics of Cymodocea nodosa meadows
Authors: Cancemi Gianluigi , Buia Maria Cristina , Mazzella Lucia
Published: October 2008

The seasonal changes in the structure and growth dynamics of a Cymodocea nodosa meadow off the island of Ischia (Tyrrhenian Sea) were studied from July 1988 to August 1989 using leaf and rhizome marking methods. High levels of leaf production (3.1 g dw m-2 d-1) significantly related to water temperature regimes, were observed. The number of new leaves per year (16 leaves y-1), the leaf Plastochrone Interval (23 days) and the life span of the single leaves (from 2 to 6 months) were also calculated. Relevant yearly fluctuations of the leaf canopy, representing about 20% of the total meadow biomass, testify the strong seasonal variability of leaf phenological parameters and shoot density (the latter, between 925 ± 323 and 1925 ± 267 shoots • m-2). On the other hand, a constant and well developed layer of rhizomes and roots is present throughout the year (80% of total biomass), with an annual rhizome elongation of about 30 cm. In spite of the temporal variability of the above-ground compartment (CV=55%), the below-ground portion represents the conservative compartment of the meadow (CV=7%). Nevertheless, the remarkable number of seeds present in this meadow (up to 2112 m-2), does not seem to effect the stability of the system through the sexual reproduction. Although similar growth trends have been reported for C. nodosa meadows from different geographical areas and habitats (eutrophic zones, confined shallow waters, estuaries), remarkable differences may be found in the highest and lowest values of growth rate. This comparison highlights the ability of this species to grow in different habitats and that growth process seems to be amplified by a high influence of environmental constraints. Moreover, differences from P. oceanica, both in the growth rate and reproductive patterns, are identified in order to explain the dynamics of these vegetated systems and their role in the Mediterranean basin.
Temporal variability and production of Temora turbinata (Copepoda: Calanoida) in the Cananéia Lagoon estuarine system, São Paulo, Brazil
Authors: Ara Koichi
Published: October 2008

Diel and seasonal variations in abundance, population structure, biomass and production rate of the planktonic calanoid copepod Temora turbinata were studied in the Cananéia Lagoon estuarine system, São Paulo, Brazil. Zooplankton sample collections were carried out at 4-h intervals over multiple 24-h periods, from February 1995 to January 1996. Temora turbinata was present in the plankton all year round (temperature, 18.6-29.6°C; salinity, 8-33 psu; chlorophyll a concentration, 1.32-15.33 µg l-1). Temora turbinata showed considerable diel variations in abundance. Abundance of T. turbinata was higher from June to October when temperature was lower than ca. 24°C and salinity was higher than ca. 20 psu. The biomass varied from 0.0005 ± 0.0014 to 3.715 ± 2.360 mgC m-3 (daily mean ± SD). The daily production rates estimated by the Hirtst-Sheader models varied from 0.0002 ± 0.0006 to 1.115 ± 0.261 mgC m-3 d-1 (mean ± SD). The P/B ratios varied from 0.17 to 0.45 d-1. These results showed that T. turbinata constituted 8.3 and 7.8% of the annual copepod community biomass and production rate respectively.
Two new cumacean species (Crustacea: Peracarida) from shallow waters off Thailand
Authors: Corbera Jordi , Martín Daniel
Published: October 2008

The examination of a collection of benthic macroinvertebrates from the Gulf of Thailand led to the erection of two new species of cumaceans (Crustacea), namely Pseudosympodomma carinatum sp. nov. (Vaunthompsoniinae, Bodotriidae) and Paradiastylis capillata sp. nov. (Diastylidae). Among the four species of the genus Pseudosympodomma, P. carinatum sp. nov. is related to P. indicum by having the first uropodal endopod article shorter than the second, but differs from it in lacking spines on the articles of the third maxilliped, as well as in having a high number of setae on the mandible and a more developed median carina on pedigerous somites two to four. The genus Paradiastylis is characterized by the absence of an exopod on the third maxilliped of females. Among the species of the genus, P. capillata sp. nov. is related to P. bathyalis by lacking folds in the carapace and having a long telson with a cylindrical pre-anal part. However, the two species may be differentiated by the relative length of the uropod endopod (longer than the exopod in P. capillata) and the basis of the third maxilliped (non-distally produced in P. bathyalis)
Feeding habits of Cataetyx alleni (Pisces: Bythitidae) in the deep western Mediterranean
Authors: Carrassón Maite , Matallanas Jesús
Published: October 2008

This study examines the feeding habits of Cataetyx alleni, the fifth most abundant species below 1000 m depth on the deep slope of the Catalan sea (western Mediterranean), between 1000 and 1800 m depth. Cataetyx alleni is a euryphagic predator, feeding on small epibenthic and endobenthic crustaceans and polychaetes. Predominate prey are small isopods and gammaridean amphipods and, in some cases, endobenthic and epibenthic decapods. Cataetyx alleni has bathymetric changes in diet marked by the capture of different prey-items and also by the reduction in the size of the prey with increasing depth. Seasonal fluctuations in the feeding pattern are clearly seen among the individuals of the same depths.
Fish larvae from the Gulf of California
Authors: Aceves-Medina Gerardo , Jiménez-Rosenberg S. Patricia A. , Hinojosa-Medina Alejandro , Funes-Rodríguez René , Saldierna Ricardo J. , Lluch-Belda Daniel , Smith Paul E. , Watson William
Published: October 2008

Taxonomic composition of fish larvae was analysed from 464 plankton samples obtained during 10 oceanographic surveys in the Gulf of California between 1984 and 1988. We identified 283 taxa: 173 species, 57 genera, and 53 families. Tropical and subtropical species predominated except during the winter, when temperate-subarctic species were dominant. The most abundant species were the mesopelagic Benthosema panamense, Triphoturus mexicanus and Vinciguerria lucetia, but the coastal pelagic species Engraulis mordax, Opisthonema spp., Sardinops caeruleus and Scomber japonicus were also prominent. The taxonomic composition of the ichthyoplankton shows the seasonality of the Gulf as well as environmental changes that occurred between the 1984-1987 warm period and the 1956-1957 cool period previously reported. The presence of E. mordax larvae as one of the most abundant species in the Gulf provides evidence of the reproduction of this species two years before the development of the northern anchovy fishery and the decline of the sardine fishery in the Gulf of California.
Karyotype supporting Mugil curema Valenciennes, 1836 and Mugil gaimardianus Desmarest, 1831 (Mugilidae: Teleostei) as two valid nominal species
Authors: Nirchio Mauro , Cervigón Fernando , Revelo Porto Jorge Iván , Pérez Julio Eduardo , Gómez Juan Antonio , Villala Janzel
Published: October 2008

In this study, we present the karyotypic features of two taxa, curema and gaimardianus (genus Mugil), supposed to be synonyms by some authors. Their cytogenetic differences are conspicuous and unambiguous, providing evidence that Mugil curema and Mugil gaimardanus are two valid nominal species.
Genetic differentiation of Solea solea (Linnaeus, 1758) and Solea senegalensis Kaup, 1858, (Pisces: Pleuronectiformes) from several estuarine systems of the Portuguese coast
Authors: Cabral Henrique N. , Castro Filipe , Linhares Diana , Alexandrino Paulo
Published: October 2008

The genetic differentiation of Solea solea and Solea senegalensis from several estuarine systems along the Portuguese coast was studied. Nine polymorphic isozyme loci (ACP-1*, ACP-2*, GPI-1*, GPI-2*, sMDH*, ME-1*, ME-2*, MPI* and PGM*) were analysed using starch gel electrophoresis and isoelectric focusing. Differentiation between the species was high (mean average Nei distance of 0.93). The most efficient loci in the diagnosis of the two species were ACP-1*, ME-2* and GPI-2*. S. solea showed a higher genetic diversity than S. senegalensis. Within each species a low genetic differentiation between the samples analysed was found. Although with a low magnitude the interpopulational genetic differentiation of S. solea was higher than that of S. senegalensis. This could probably be explained by some particularities of the life cycles of these species, namely the more extended period of occurrence of larval stages of S. senegalensis in the plankton. Although no clear evidence about the population structure model emerged from the analysis of several Atlantic and Mediterranean populations of S. solea, the significant correlations obtained between genetic and geographical distances support an isolation by distance model.
Reproductive biology and relative growth in the spider crab Maja crispata (Crustacea: Brachyura: Majidae)
Authors: Carmona-Suárez Carlos A.
Published: October 2008

A series of life-history traits in the spider crab Maja crispata were studied on the island of Ischia (Italy) during four sampling periods in 1982: sex ratio, relative growth, sexual maturity, reproductive season, number of eggs per female, copulation and brood sequence. A total of 104 males and 86 females were captured. Mature animals were present year around. The greatest relative abundance of mature animals in both sexes was found in the warmer season. Three postlarval growth stages were distinguishable in males: crabs with juvenile morphological characteristics and immature gonads (between 1.69 and 5.03 cm carapace length), crabs with juvenile morphological characteristics and mature gonads (between 3.59 and 6.11) and crabs with adult morphological characteristics and mature gonads (between 4.98 and 7.16). In females, only two postlarval stages were detected: juveniles (between 1.87 and 4.62) and adults (between 3.56 and 6.11). Mature females with full seminal receptacles were always present. Breeding period extends from May to September. Mean number of eggs was 11473 per female. Breeding sequences in two females kept in the laboratory varied between 5 and 7 broods per year, at intervals of between 21 and 32 days.
Spiochaetopterus creoceanae, a new species of Chaetopteridae (Polychaeta) from the Persian Gulf belonging to the costarum complex
Authors: Bhaud Michel , Martin Daniel , Gil Joao
Published: October 2008

Examination of a collection of Chaetopteridae (Annelida: Polychaeta) from the Iranian coast of the Persian Gulf led to the erection of a new species of Spiochaetopterus: S. creoceanae sp. nov. This is a small, oculate Spiochaetopterus with a single specialised, enlarged cutting seta on each A4 parapodium; this seta is roughly heart-shaped (cordate) in end view and with the outer lobe of the oblique section more developed than the inner one. The new species is mainly characterised by the presence of 10 segments in the anterior region, while all other species described to date have only 9. The description of this new species of Spiochaetopterus is a contribution to the growing evidence supporting the hypothesis that Spiochaetopterus costarum, formerly considered to be a cosmopolitan species, has in fact been used for several distinct species. In addition, the habitat preferences of the new species are also discussed.
Mass mortality event in a small saline lake (Lake Rogoznica) caused by unusual holomictic conditions
Authors: Baric Ante , Grbec Branka , Kuspilic Grozdan , Marasovic Ivona , Nincevic Zivana , Grubelic Ivana
Published: October 2008

The study of a small saline eutrophic lake was performed under meromictic and holomictic conditions. The meromictic period was characterised by anoxic conditions in the bottom layer with high sulphide and nutrient concentrations. The depth of the nutricline varied as affected by thermohaline conditions in the water column. In late summer 1997, holomictic conditions replaced ordinary meromitic conditions in the lake. This transformation caused anoxia to spread throughout the water column and mass mortality of almost all the organisms occured. Thereafter, oxic conditions were re-established slowly as the new phytoplankton population developed. As a consequence of the particulate organic matter decay, inorganic N and P concentrations increased and had doubled approximately six weeks after the mass mortality. The revitalisation of the phytoplankton population was initiated immediately after the mass mortality by the development of "microflagellate" species, which were favoured by the high ammonia concentrations. The larger phytoplankton species (diatoms and dinoflagellatae) developed at the expense of smaller ones when nitrate became the dominant nutrient in the water column. A year after the mass mortality the composition of the phytoplankton population was the same as before.
The East Asian shore crab Hemigrapsus sanguineus (Brachyura: Varunidae) in the Mediterranean Sea: an independent human-mediated introduction
Authors: Schubart Christoph D.
Published: October 2008

A single adult male specimen of the East Asian crab Hemigrapsus sanguineus (de Haan, 1835) was collected in August 2001 in the northern Adriatic Sea along the northwest coast of the peninsula of Istra. This is the first record of this genus and species from the Mediterranean Sea. Previously, Hemigrapsus sanguineus had been reported to invade the Atlantic coasts of North America and of western France, while the congeneric East Asian species, Hemigrapsus penicillatus (de Haan, 1835), has established breeding populations along the Atlantic coast of Europe. The current absence of Hemigrapsus sanguineus in southern Europe and the western Mediterranean suggests an independent human-mediated introduction of the Croatian specimen. Preliminary genetic analyses reveal that specimens from Istra, North America, and Japan have identical DNA haplotypes corresponding to the mitochondrial large subunit rRNA gene (16S mtDNA), while the homologous sequence from a specimen of Taiwan differs in two out of 525 nucleotides.
Lack of mitochondrial differentiation between Red sea and Mediterranean populations of the Lessepsian rabbitfish, Siganus rivulatus (Perciformes: Siganidae)
Authors: Bonhomme François , Baranes Avi , Golani Daniel , Harmelin-Vivien Mireille
Published: October 2008

A lack of genetic differentiation between Red Sea and Mediterranean populations of the Lessepsian rabbitfish, Siganus rivulatus, was evidenced using mitochondrial DNA (cytochrome b). This result implies that Mediterranean populations were not founded by a few individuals, but rather that immigration of S. rivulatus into the Mediterranean is a continuous process.
Life history of the Pomadasys incisus (Osteichthyes: Haemulidae) of the Canarian Archipelago
Authors: Pajuelo José G. , Lorenzo José M. , Gregoire Muriel , Domínguez-Seoane Rosa
Published: October 2008

Pomadasys incisus is one of the most abundant coastal demersal species around the Canary Islands. It is a gonochoric species with similar biological characteristic in males and females. The adult sex ratio is not significantly different from 1:1, and the mean size of males and females is similar. It reaches first maturity at the end of the second year of life (183 mm). Spawning takes place throughout the year. Growth analysis reveals that the species is fast-growing and relatively short-lived (7 years). Length at age is well described by the von Bertalanffy growth model. Individuals grow quickly in their immature first year, attaining approximately 45% of their maximum length. After one year, the annual growth rate drops rapidly. The direct effects of fishing result in changes in abundance, with an 80% reduction from the unexploited equilibrium level. Recruitment into the commercial fisheries occurs before size at sexual maturity, resulting in all spawners being accessible using the current fishing pattern. The length at first capture (168 mm) is less than the length at maturity; 45% of the total catch are smaller than this, indicating a danger of recruitment-overfishing.
Selectivity of diamond and square mesh cod ends for horse mackerel (Trachurus trachurus), European hake (Merluccius merluccius) and axillary seabream (Pagellus acarne) in the shallow groundfish assemblage off the south-west coast of Portugal
Authors: Campos Aida , Fonseca Paulo
Published: October 2008

The effects of an increase in cod end mesh size from 65 to 70 and 80 mm and a change of mesh configuration from 65 mm diamond to 65 mm square mesh on the size selectivity of horse mackerel (Trachurus trachurus), hake (Merluccius merluccius) and axillary seabream (Pagellus acarne) of the shallow groundfish assemblage off the Portuguese southwest coast were evaluated. The increase in mesh size had a small but significant effect on size selectivity for the three species, while the change in mesh configuration led to a much more pronounced increase in the selectivity parameters. For horse mackerel, the L50 estimates ranged from 14.4 to 16.0 cm in the diamond mesh cod ends-values that are close to the minimum landing size of 15 cm. For hake, L50 of 17.0 and 18.3 cm were estimated for the 70 and 80 mm diamond cod ends respectively, while for the axillary seabream the L50 estimated was 13.9 cm for the 80 mm diamond mesh cod end. These values are well below the minimum landing sizes of 27 and 18 cm for these species. The corresponding estimates in the square mesh cod end were 21.9, 32.4 and 19.6 cm, with the loss of a high percentage (76%) of horse mackerel above the minimum landing size. For all the cod ends tested, the observed retention was presented as a function of maximum girth/mesh perimeter, which allowed a better understanding of the selection process for the species in study. Selectivity estimates for horse mackerel and hake were also compared to those obtained by Campos et al. (2003) for the same species in 1993 off the south coast, where they are captured as a by-catch in the crustacean fishery.
Fecundity of the common cuttlefish, Sepia officinalis L. (Cephalopoda, Sepiida): a new look at the old problem
Authors: Laptikhovsky Vladimir , Salman Alp , Önsoy Bahadir , Katagan Tuncer
Published: October 2008

The potential fecundity (PF) of advanced maturing and mature pre-spawning cuttlefish S. officinalis in the Aegean Sea varies from 3,700 to 8,000 (mean 5,871) oocytes, whereas the number of large yolk oocytes increases with mantle length from 130 to 839. Small oocytes predominate at all maturity stages. Spawning animals have a PF of some 1,000-3,000 eggs below that of pre-spawning females. This shows that intermittent spawning, which occurs in captivity, is a normal process in natural habitats. Empty follicular sheaths are resorbed very rapidly, and their number does not represent the number of eggs laid by the female prior to sampling. Regulative oocyte resorption was observed at early maturation in some cuttlefishes.
In vitro metabolism of steroid hormones by ovary and hepatopancreas of the crustacean Penaeid shrimp Marsupenaeus japonicus
Authors: Summavielle Teresa , Riberiro Rocha Monteiro Pedro , Reis-Henriques María Armanda , Coimbra Joao
Published: October 2008

Radioimmunoassay (RIA) was applied to identify selected metabolites obtained in in vitro incubations of ovarian and hepatopancreatic tissues from female Marsupenaeus japonicus in previtellogenic and vitellogenic maturation stages. Depending on the precursors used, progesterone, 17?-hydroxyprogesterone or testosterone, it was possible to observe the presence of several enzymatic activities through metabolites detected in incubations. The present study provides evidence that the ovary of the shrimp M. japonicus is capable of synthesising 17?-estradiol from progesterone, evidencing the presence of 17?-hydroxylase, C17-C20 lyase, 17?-hydroxysteroid dehydrogenase (17?-HSD) and aromatase. Enzymatic activities of aromatase, 3?-HSD and 17?-hydroxylase were detected in hepatopancreas, but not that of C17-C20 lyase. These results suggest that 17?-estradiol could be the vitellogenesis stimulating ovarian hormone (VSOH), and together with former in vivo and in vitro studies this leads us to propose that in fact there may be a physiological role for steroid hormones in the maturation cycle of crustaceans.
Occurrence and genetic analysis of a Kemp's Ridley sea turtle (Lepidochelys kempii) in the Mediterranean Sea
Authors: Tomás Jesús , Formia Ángela , Fernández Mercedes , Raga Juan Antonio
Published: October 2008

We report on a juvenile Kemp´s ridley sea turtle, Lepidochelys kempii, captured alive by fishermen in the waters off Alicante (western Mediterranean, Spain) on October 15th 2001. The analysis of a 460 base pair fragment of the mt DNA control region revealed a perfect match with haplotype D previously described in this species. This is the second report of L. kempii in the Mediterranean basin.
Some litholid crabs (Crustacea, Decapoda, Lithodidae) from the Salomon Islands (SW Pacific Ocean) with the description of a new species
Authors: Macpherson Enrique
Published: October 2008

Four species of Lithodid crabs from the Solomon Islands were collected during the Solomon 1 cruise carried out off the Solomon Islands. One new species, Paralomis mendagnai, is described and illustrated. Three other species, Neolithodes nipponensis, Paralomis dawsoni and P. haigae, are reported for the first time from these islands. The new species of Paralomis closely resembles P. medipacifica Takeda, 1974, from Midway Islands (Central Pacific) and is characterised by the dorsal surface of the carapace thickly covered with rounded, more or less prominent granules of different sizes. Both species are easily distinguished by the armature of the scaphocerite and pereiopods. A key to the species of the genus Paralomis from the western and central Pacific Ocean is presented.
Population dynamics and secondary production of the cockle Cerastoderma edule (L.) in a backbarrier tidal flat in the Wadden Sea
Authors: Ramón Montserrat
Published: October 2008

The population biology of the bivalve Cerastoderma edule was studied by monthly sampling from April 1994 to September 1995 at Neuharlingersieler Nacken, a backbarrier tidal flat near Spiekeroog island (East Frisian Wadden Sea, North Sea). Four stations located along a tidal gradient from 56 to 80% immersion time were established in order to analyse cockle growth, mortality and production. The highest densities were recorded at the beginning of the study (1000-1250 ind. M-2) with an intense and progressive decrease through 1995. A spatial distribution pattern was observed during summer 1994, with juveniles (3-12 mm long) being found in the high intertidal whereas adults occurred along the middle and lower intertidal. Based on growth increment data from tagging-recapture experiments, the parameters of the von Bertalanffy growth curve were estimated to be: asymptotic length L??= 40 mm, and growth constant K = 0.404 y-1. A growth ring was formed in summer (July-August 1994). Annual somatic production ranged between 38.16 and 59.33 g AFDW . m-2. y-1. Total mortality ranged between Z = 0.52 year-1 and Z = 3.03 year-1. The distribution of the population was affected by passive displacements of juvenile cockles from the upper part of the intertidal toward lower zones in combination with high mortality at the station farthest from the coast, probably resulting from mussels overlying.
Preliminary results of the empirical validation of daily increments in otoliths of jack mackerel Trachurus symmetricus murphyi (Nichols, 1920) marked with oxytetracycline
Authors: Araya Miguel , Medina Marianela , Arancibia Hugo
Published: October 2008

The frequency of microincrement formation in sagittae otoliths of jack mackerel Trachurus symmetricus was validated using experiments on captive fish. Adult jack mackerel were injected with a dose of 100 mg of oxytetracycline/kg of fish. A second injection was performed 30 days later. The fish were then sacrificed and their sagittae otoliths were extracted. Thin sections of the otoliths were prepared and observed through an epifluorescent microscope using ultraviolet light. Two fluorescent marks corresponding to the two injections were clearly visible. The average number of microincrements between the two fluorescent marks was 29 (n=10; S.D.=1.63) and the median was 29.3. The Wilcoxon signed-rank test indicated that this value was not significantly different from 30. This result indicates that microincrements in otoliths of adult jack mackerel of between 28.4 and 37.7 cm fork length are formed with a daily frequency.
Contribution of larval growth rate vairability to the recruitment of the Bay of Málaga anchovy (SW Mediterranean) during 2000-2001 spawning seasons
Authors: García Alberto , Cortés Dolores , Ramírez Teodoro , Giráldez Ana , Carpena Ángel
Published: October 2008

Daily growth rates were estimated from larval anchovy (Engraulis encrasicolus) sampled in their main nursery grounds off the Bay of Málaga (SW Mediterranean) during the 2000 and 2001 spawning seasons. Significantly higher growth rates were observed in the 2001 larval population, representing a 20% increase through the larval size classes analysed. The decimated SW Mediterranean anchovy population experienced a successful anchovy recruitment during this year estimated at 13,000 tons for the Bay of Málaga by the acoustic evaluation of small pelagic resources. The size distribution of the recruited anchovy juveniles during 2000 and 2001 showed an increase of approximately 2 cm. Their corresponding anchovy spawning seasonality agrees with the estimates from the growth model fits of each year. Data on the environmental background for the two years sampled are provided by a historical quarterly monitoring project. Zooplankton showed a two-fold significant increase during July 2001, coastwise as well as offshore. No significant changes in surface temperature were observed between years. Instead of the usual summer spawning peak, anchovy peak spawning shifted towards early spring during the 2001 spawning season. The study provides evidence from field data on the relationships of larval growth variability and recruitment.
Ocean wave mapping from ERS SAR images in the presence of swell and wind-waves
Authors: Rousseau Stéphan , Forget Philippe
Published: October 2008

We present a method for estimating the significant wave height of ocean waves (SWH) in coastal zones from satellite SAR images and using the value of the width of the spectral azimuthal cutoff. The method deals with the case of an energetic swell propagating over a wind wave system. It requires the preliminary retrieval of swell parameters using the wave-SAR spectral quasi-linear relationship. The method is applied to two ERS-1 SAR images in coastal zones.
Biomass and elemental composition of eggs and larvae of a mangrove crab, Sesarma rectum Randall (Decapoda: Sesarmidae) and comparison to a related species with abbreviated larval development
Authors: Anger Klaus , Moreira Gloria S.
Published: October 2008

We measured biomass and elemental composition (dry mass, W; carbon, hydrogen, nitrogen, CHN) in eggs and larvae of a mangrove crab, Sesarma rectum. The results are compared with previously published data from a closely related species with abbreviated development (S. curacaoense). Egg size of S. rectum increased during embryogenesis, while egg biomass, C content (%W), and the C:N ratio decreased. Initial biomass of eggs and larvae in S. rectum was about half of that in S. curacaoense, also showing lower percentage values of C and H and a lower C:N ratio (indicating a lower lipid content). After hatching, however, the zoeae of S. rectum showed higher growth rates than those of S. curacaoense (presumably due to partial utilisation of internal energy reserves in the latter) and a longer period of development to the megalopa (passing though three vs. only two zoeal stages); as a consequence of these differential growth patterns, S. rectum compensated for the initially lower biomass. Interspecific comparison among neotropical Sesarmidae suggests an intermediate degree of dependence on planktonic food sources in S. rectum, which is lower than in estuarine species with small eggs and an extended mode of development (e.g. Armases angustipes), but higher than in relatives with larger egg biomass and an abbreviated development (e.g. A. miersii, S. curacaoense, S. fossarum, Metopaulias depressus). This should allow S. rectum larvae to develop partially within the parental mangrove system, but requiring a limited export towards coastal marine waters with planktonic food sources.
Comparison of the population structure of the fiddler crab Uca vocator (Herbst, 1804) from three subtropical mangrove forests
Authors: Delevati Colpo Karine , Negreiros-Fransozo Maria Lucia
Published: October 2008

The population structure of U. vocator was investigated during a one-year period in three mangrove forests in southeast Brazil. The study specifically addressed comparisons on individual size , juvenile recruitment and sex-ratio. The structure of the mangrove forests, i.e. density, basal area, and diameter, and the physical properties of sediments, i.e. texture and organic matter contents, were also examined. A catch-per-unit-effort (CPUE) technique was used to sample the crab populations using 15-min sampling periods by two people. Males always outnumbered females, probably due to ecological and behavioural attributes of these crabs. The median size of fiddler crabs differed among the sampled populations. The mangroves at Indaiá and Itamambuca showed higher productivity than those at Itapanhaú, where oil spills impacting the shore were reported. Marked differences were found regarding individual size , either their size at the onset of sexual maturity or their asymptotic size, suggesting that food availability may be favouring growth in the studied populations.
Insular stock identification of Serranus atricauda (Pisces: Serranidae) through the presence of Ceratothoa steindachneri (Isopoda, Cymothoidae) and Pentacapsula cutanea (Myxozoa, Pentacapsulidae) in the Canary Islands
Authors: Cuyás Concepción , Castro José Juan , Santana-Ortega Ana Teresa , Carbonell Enrique
Published: October 2008

Ceratothoa steindachneri (Isopoda: Cymothoidae) and Pentacapsula cutanea (Myxozoa: Pentacapsulidae) parasites infecting the blacktail-comber (Serranus atricauda) were considered suitable as biological tags for stock identification around the islands of La Palma and Gran Canaria, in the Western and Eastern areas of the Canarian archipelago, respectively. The ecological parameters of both species differed significantly between the islands. While individuals caught off La Palma showed a high degree of infection by the isopod, a single infected fish was found off Gran Canaria. Also, the myxozoans showed a high level of infection on fish from Gran Canaria but it was reported on only a single specimen from La Palma