bluuebunny/crossref_metadata_2025 huggingface dataset:
Isopods of the genus Arcturella (Valvifera: Arcturidae) from the expedition FAUNA I (S. Spain) with description of a new species
Authors: Rodríguez Sánchez L. , Junoy J.
Published: October 2008

Three specimens of the genus Arcturella (Crustacea: Isopoda: Valvifera: Arcturidae) were collected in the oceanographic expedition FAUNA I (S Spain). The specimens are fully described and illustrated, and a new species, Arcturella estherae sp. nov., is established. The two female specimens of this new species can be distinguished from all other species of the genus chiefly by the shape and ornamentation of the pereonite IV. The third specimen resembles Arcturella carlosoteroi, but shows certain anatomical differences from the only known specimen of this species.
Pilumnus reticulatus Stimpson, 1860 (Decapoda: Brachyura: Pilumnidae): a reappraisal of larval characters from laboratory reared material
Authors: Spivak Eduardo D. , Rodríguez Antonio
Published: October 2008

The pilumnid crab Pilumnus reticulatus Stimpson, 1860 is known to range from the Caribbean Sea to Argentina (Atlantic). It has also been recorded from the Pacific coast of Panama. Larvae of Pilumnus reticulatus from females collected in the mouth of the Rio de la Plata were reared in the laboratory from zoea I to megalopa. A reappraisal of larval characters is made by comparing the results of this present study with the previous descriptions of Montú et al. (1989) and with those from other Pilumnus species: P. dasypodus, P. sayi, P. vespertilio, P. hirtellus, P. kempi, P. scabriusculus and P. minutus.
A quantitative technique for sampling motile macroinvertebrates in beds of the seagrass Posidonia oceanica (L.) Delile
Authors: Borg Joseph A. , Attrill Martin J. , Rowden Ashley A. , Schembri Patrick J. , Jones Malcolm B.
Published: October 2008

Techniques for sampling motile macroinvertebrates associated with Posidonia oceanica seagrass meadows have mainly involved the use of hand-nets and suction samplers or collection by hand. These techniques give unreliable quantitative estimates or have practical difficulties. A large cylindrical saw-rimmed corer was designed and used successfully to obtain quantitative samples of macroinvertebrates from both foliage and root-rhizome matrix of a Posidonia oceanica meadow in Malta (central Mediterranean). Choice of the appropriate sample unit size was assessed by comparing the relative accuracy, precision and efficiency of three different core diameters: 25 cm, 35 cm and 45 cm. The results suggest that for comparison of macrofaunal species richness and abundance between different meadows/sites the 25 cm diameter corer is recommended. For surveys aimed at estimating total diversity within a particular site, the 35 cm diameter corer is more appropriate.
Exploitation patterns of Octopus vulgaris in two Mediterranean areas
Authors: Tsangridis Alexis , Sánchez Pilar , Ioannidou Despina
Published: October 2008

Exploitation patterns of the common octopus, Octopus vulgaris, in two Mediterranean areas were studied in three ports, two in the Thracian Sea (Greece, Eastern Mediterranean) and one in the Catalan Sea (Spain, Western Mediterranean). The study period of one year (July 1998-June 1999) included a monthly collection of data on commercial landings, fishing effort and length distribution of O. vulgaris. Many gears exploit this species in both areas. Specialised and highly productive artisanal gears (fyke nets, pots and traps) have been developed. Herein it is shown that: (1) trawls are responsible for most octopus landings; (2) trawls exploit mostly the small and immature individuals while the artisanal fleets exploit the large and mature ones; (3) there is a marked seasonality of catches; (4) there is little or no interaction between the gears fishing octopus, indicating that each gear affects a certain size range; (5) and the octopus specimens from the Greek area are clearly smaller than the ones from the Spanish area. Our results suggest that octopus fisheries require more effective management strategies. The creation of marine harvest refuges may be beneficial.
Stelletta ruetzleri sp. nov., a new ancorinid from the Southwestern Atlantic (Porifera, Astrophorida)
Authors: Mothes Beatriz , M. Silva Carla Maria
Published: October 2008

Stelletta ruetzleri sp. nov., a new ancorinid sponge from the Southwestern Atlantic (Porifera, Astrophorida), collected at 128 and 200 m depth off Rio Grande do Sul State coast, Brazil (31°20´-32°24´S/49°52´-50°15´W), is described and illustrated with SEM images of the spicules. The new species is based on the presence of one category of oxeas, dichotriaenes, oxyasters and spheroxyasters.
Recruitment dynamics of eight fishery species in the northwest Mediterranean Sea
Authors: Lloret Josep , Lleonart Jordi
Published: October 2008

The recruitment dynamics into the fishery of eight species in the northwestern Mediterranean Sea was studied on the basis of a monthly length sampling on commercial landings lasting one year (March 1999-February 2000). The results show that three species or groups of species (Mullus barbatus and M. surmuletus, Eledone cirrhosa and Loligo vulgaris) recruited mostly during a well-defined and regular season, while recruitment of the rest of species (Merluccius merluccius, Micromesistius poutassou, Phycis blennoides, Sepia officinalis and Trisopterus minutus capelanus) took place all year round, though with seasonal peaks. Landings of small Merluccius merluccius showed a progressive declining trend from the early 1990s, while the opposite was found for Mullus barbatus and M. surmuletus
Experimental evidence of polymorphysm of sexual development in Capitella sp. B (Polychaeta: Capitellidae) from Barcelona, Spain
Authors: Méndez Nuria
Published: October 2008

The development and growth of Capitella sp. B obtained from Barcelona were studied under culture conditions. Trochophore and metatrochophore larvae hatched non-simultaneously (two release periods) from single brood tubes. This is the first laboratory evidence of polymorphysm of sexual development in the Capitella capitata species-complex. During the first release period, only free swimming trochophores hatched. The females, still bearing larvae inside the brood tube, were transferred to another dish. After three days, ciliated metatrochophores hatched from 8.7% of the transferred broods. In a culture experiment, larvae maintained in sediment enriched with artificial food grew to immature and mature adults. In this condition, the larvae that hatched during the first release reached the immature adult stage, while the larvae derived from the second release became mature adults. Oogenesis was observed three times in one female from the second release, though no spawning and fertilization occurred under incubation with sib mature males. Two different sizes of coelomic oocytes were observed. Polymorphysm of sexual development is discussed as an advantageous reproductive strategy enhancing survival in organic enriched sediments.
Age, growth and longevity of the gray triggerfish, Balistes capriscus (Gmelin, 1788), from the Southeastern Brazilian Coast
Authors: Ávila Bernardes Roberto
Published: October 2008

Age, growth and longevity of gray triggerfish Balistes capriscus from the coast near São Paulo were estimated from first dorsal spine sections of 1,800 fish. The translucent zone was formed during winter (June, July and August) and the reproductive period (December, January, February). The von Bertalanffy growth equations were: FL = 514.9 [1 - e -0.2625 (t + 0.0391)] for males, and FL = 504.6 [1 - e-0.2748 (t -0.0304)] for females. The longevity estimated was 11 years old for males and females. The instantaneous mortality rates estimated were 0.26 for males and 0.27 for females. The weight-length relationships for both sexes of gray triggerfish together were Wt = 0.000004 FL3.299.
Distribution patterns of the sublittoral epibenthic assemblages on a rocky shoal in the Ligurian Sea (NW Mediterranean)
Authors: Cocito Silvia , Bedulli Daniele , Sgorbini Sergio
Published: October 2008

Acquiring baseline data on highly diverse communities such as coralligenous ones is very valuable in order to determine possible shifts in communities and define strategies for their preservation. Distribution of sciaphilic epibenthic communities belonging to the `coralligène de la roche littorale´ was investigated at 30 photostations from 17 to 24 m depth on a rocky shoal off the island complex in the Gulf of La Spezia (Ligurian Sea, NW Mediterranean). Four communities displayed a sharp zonation: Paramuricea clavata characterised deeper, vertical surfaces, whereas on horizontal and medium inclination, sediment-covered substrata, Leptogorgia sarmentosa, together with Eunicella singularis and Eunicella verrucosa, characterised the upper stratum of the deeper community. Shallow vertical walls were characterised by a facies with sponges and zoantharians, whereas community dominated by large, massive colonies of Pentapora fascialis with a basal stratum of sciaphilic algal species patched with sediment on shallow rocky slopes of medium inclination. Bathymetric distribution of assemblages is influenced by high seawater turbidity (mean annual transparency: 11.9 ± 5.7 m at the western site, 6.2 ± 1.6 m at the eastern site), which induces a shift of the upper limit of distribution of these facies to unusually shallow depths. Quantitative data provide a baseline on the study site that will be useful to understand the influence of not only biotic and abiotic factors, but also mass-mortality events, particularly on these communities characterised by high resilience.
Pulsing versus constant supply of nutrients (N, P and Si): effect on phytoplankton, mesozooplankton and vertical flux of biogenic matter
Authors: Svensen Camilla , Nejstgaard Jens C. , Egge Jorun K. , Wassmann Paul
Published: October 2008

An experiment with eight vertically stratified seawater enclosures of 27 m3 (depth 9.3 m, diameter 2 m, 90% penetration of PAR) was run in order to test whether pulsed addition of nutrients may cause: 1, higher primary production; 2, higher build-up of phytoplankton biomass; 3, larger temporal mismatch between herbivores and phytoplankton biomass; and 4, higher sedimentation rates, distinguishing in each case between silicate and non-silicate fertilised systems. Nitrate and phosphate were added to all enclosures (NP), while silicate was added to four of the enclosures (NPS). Each enclosure received the same total amount of nutrients, but the nutrients were supplied at four different intervals ranging from one single load to continuous additions. Spring bloom-like systems developed where nutrients were added in one or two pulses as they were characterised by high primary production, high suspended biomass of chlorophyll a (Chl a) and particulate organic carbon (POC) and high sedimentation rates. In contrast, the seawater enclosures receiving nutrients about every third day or in a continuous supply resembled regenerated systems with low concentrations of suspended Chl a and POC and with low and stable loss rates. Due to a typical autumn inoculum with dominance of dinoflagellates and flagellates, diatoms did not dominate the NPS enclosures. The only significant effect of the silicate addition was higher vertical flux of particulate organic nitrogen in the NPS enclosures, and higher microzooplankton biomass. The mesozooplankton did not show responses to the different frequencies of nutrient additions. However, accumulation of mesozooplankton biomass was higher in the NP-mesocosms, probably reflecting better feeding conditions. We conclude that the frequency of nutrient additions had a stronger influence on the development of the phytoplankton and vertical flux of carbon than the +/- silicate treatment in this experiment.
Estimated total abundance and numbers at age of longtail hake (Macruronus magellanicus) in the Southwest Atlantic during the years 1987-2000
Authors: Giussi Analía R. , Hansen Jorge E. , Wöler Otto C.
Published: October 2008

Delta-based estimates of longtail hake biomass off Argentina were derived from the results of summer trawl surveys carried out on an irregular basis since 1987. Annual estimates of biomass within the whole area ranged from 1.2 to 4.5 million tons, consistent with those obtained by sequential population analysis. There was no clear trend throughout the period 1987-1995, but the 1987 estimate was higher than those for the same area during the years 1992-1995, and estimates since 1997 were much higher than the mean for the four-year period 1992-1995. Since 1992 the largest concentrations of fish have been between 50 and 100 m deep. Most of those were adults, small fish being scarce. Analysis of numbers-at-age showed the dominance of 4-8 year old fish in 1987 and from 1992 to 1994 and the existence of two very strong year-classes, those of 1993 and 1995.
Trophic niche overlap between flatfishes in a nursery area on the Portuguese coast
Authors: Cabral Henrique N. , Lopes Marta , Loeper Ralf
Published: October 2008

The diets and the trophic niche overlap between seven flatfish species were studied in a coastal nursery adjoining to the Tagus estuary (Portugal). Fish were sampled monthly, from March to November 1999, using a beach seine. Arnoglossus imperialis (Rafinesque, 1810), Arnoglossus laterna (Walbaum, 1792) and Arnoglossus thori Kyle, 1913, fed mainly on crustaceans. The diets of Buglossidium luteum (Risso, 1810) and Dicologoglossa cuneata (Moreau, 1881) were mainly composed of Bivalvia and Polychaeta, while for Scophthalmus rhombus (Linnaeus, 1758) the main food items were Mysidacea and Teleostei. The diet of Pegusa lascaris (Risso, 1810) was mainly composed by Cumacea, Bivalvia, Decapoda and Amphipoda. Based on diet similarities two main groups were identified: one composed of A. imperialis, A. laterna, A. thori and S. rhombus, and the other grouping B. luteum, P. lascaris and D. cuneata. For the most common flatfishes, a similar pattern of diet seasonal variation was found, such that Amphipoda presented higher indices values in the period from March to June, while from July to November, Decapoda were more abundant. Although high values of diet overlap were obtained among some of the species, the main items in the diet of flatfishes are probably the most abundant prey in this coastal area, which suggests a generalist and opportunistic utilization of these food resources. Furthermore, niche overlap between these species is probably minimized by differences in resource use in other niche dimensions, namely time and space.
Influence of the Barrie de la Maza dock on the circulation pattern of the Ría of A Coruña (NW-Spain)
Authors: Gómez-Gesteira Moncho , Decastro Maite , Prego Ricardo , Martins Flavio
Published: October 2008

A 3D hydrodynamical model is applied to the ria of A Coruña to analyze the evolution of the circulation pattern in the ria after the building of a breakwater (Barrie de la Maza dock) in the sixties. This circulation pattern has changed greatly. On the one hand, the circulation, which was almost parallel to the shore line under the original conditions, now shows a gyre near the end of the dock. On the other hand, a considerable increase (about 30%) in the velocities near the end of the breakwater and in the main channel of the estuary has been observed after the building of the dock. A stronger bottom shear stress has been generated in the estuary areas where the velocity increased. The bottom shear stress increase was particularly great (over 100%) near the end of the dock. This increase in the shear stress produced bottom erosion and matter resuspension, and consequently major changes in the bathymetry. In addition, in situ sedimentary measurements carried out by Lopez-Jamar (1996) corroborate the bottom erosion in the main chanel of the estuary and at the end of the dock produced by the velocity increase generated by the building of the breakwater.
Effect of nitrogen and phosphorus supply on growth, chlorophyll content and tissue composition of the macroalga Chaetomorpha linum (O.F. Müll), Kütz, in a Mediterranean Coastal Lagoon
Authors: Menéndez Margarita , Herrera Jorge , Comín F. A.
Published: October 2008

The effect of dissolved nutrients on growth, nutrient content and uptake rates of Chaetomorpha linum in a Mediterranean coastal lagoon (Tancada, Ebro delta, NE Spain) was studied in laboratory experiments. Water was enriched with distinct forms of nitrogen, such as nitrate or ammonium and phosphorus. Enrichment with N, P or with both nutrients resulted in a significant increase in the tissue content of these nutrients. N-enrichment was followed by an increase in chlorophyll content after 4 days of treatment, although the difference was only significant when nitrate was added without P. P-enrichment had no significant effect on chlorophyll content. In all the treatments an increase in biomass was obseved after 10 days. This increase was higher in the N+P treatments. In all the treatments the uptake rate was significantly higher when nutrients were added than in control jars. The uptake rate of N, as ammonium, and P were significantly higher when they were added alone while that of N as nitrate was higher in the N+P treatment. In the P-enriched cultures, the final P-content of macroalgal tissues was ten-fold that of the initial tissue concentrations, thereby indicating luxury P-uptake. Moreover, at the end of the incubation the N:P ratio increased to 80, showing that P rather than N was the limiting factor for C. linum in the Tancada lagoon. The relatively high availability of N is related to the N inputs from rice fields that surround the lagoon and to P binding in sediments.
Efficacy of a remote control closure of cod-end used in a bottom trawl experience
Authors: Sardà Francesc , Company Joan B. , Estevez Miguel A.
Published: October 2008

A total of 26 effective trawl hauls using a remotely operated trawl cod-end closure system were carried out to determine whether samples collected in a rear section of the cod-end and in a front section of the cod-end were homogeneous, and can be used as reliable replicates for community sampling and resource assessment. Comparative analyses of these sample hauls and 25 other hauls that did not use the cod-end closure system were also performed. The results indicate certain technical difficulties in the practical operation of the system and that samples were not homogeneous either between the cod-end sections in the same haul or between hauls. The causes of the sample variability in catches from trawl surveys are discussed.
Relation between recruitment, sea surface temperature, and the density-independent mortality of the Pacific sardine (Sardinops caeruleus) off the southwest coast of the Baja California Peninsula, Mexico
Authors: Morales-Bojórquez Enrique , Gómez-Muñoz Víctor Manuel , Félix-Uraga Roberto , Alvarado-Castillo Reyna
Published: October 2008

The density-independent mortality, considered in the stock-recruitment model of Ricker, was related to the interannual variability of the sea surface temperature (SST) during 1981 to 1993 in Bahía Magdalena, Baja California Sur and Isla Cedros, Baja California, Mexico. From the stock-recruitment curve fitted to the observed data the variation in the density-independent mortality was estimated, maintaining fixed the value of the density-dependent coefficient. The density-independent parameters estimated in this way were related to the SST by using a functional relationship that considers six principal components. This function permitted identification of the changes of the density-independent mortality and its relation to the recruitment of the Pacific sardine Sardinops caeruleus. We determined density-independent mortality greater than 3.38 as years with recruitment greater than 25,000 t, and density-independent mortality less than 3.38 as years with recruitment less than 15,000 t. The seasons of greatest influence on the density-independent mortality in relation to the SST were autumn, winter and spring in both regions (Bahía Magdalena and Isla Cedros). In these seasons when the SST > 19.3°C (warmer waters) the variations in recruitment of Pacific sardine were observed.
Some biological parameters of the peacock wrasse, Symphodus (Crenilabrus) tinca (L. 1758) (Pisces: Labridae) from the middle eastern Adriatic (Croatian coast)
Authors: Pallaoro A. , Jardas I.
Published: October 2008

Data on sex ratio, length-weight relationship, age, growth and survival rate were analysed for peacock wrasse, Symphodus (Crenilabrus) tinca L., (total = 1443; males = 848, females = 595) collected in the eastern middle Adriatic island area during the reproductive period (April and May) from 1995 to 1999. The total length of sampled specimens ranged from 8.9 to 42.5 cm and the weight from 7.9 to 764.2 g. The overall sex ratio was 1.43:1 in favour of males. All individuals larger than 28.9 cm were males as an effect of faster growth. The oldest females were 12 and the oldest males 13 years old. The von Bertalanffy growth formula was estimated for females (L∞ = 28.14; k = 0.294; t0 = - 0.775) and males (L∞ = 42.24; k = 0.214; t0 = - 0.628). The slopes (b values) of total length - weight regressions indicated allometric growth for males (b = 2.7205) and both sexes (b = 2.8147) and isometric growth for females (b = 2.9901). Survival rate of males (S = 0.80) was slightly greater than that for females (0.756).
Characterisation and standardisation of a red shrimp Aristeus antennatus, (Risso, 1816) fishery off the Alicante gulf (SE Spain)
Authors: García Rodríguez Mariano
Published: October 2008

The red shrimp (Aristeus antennatus) is a target species of a deep trawl fishery in the Gulf of Alicante. This paper describes the fishery by following the activity of this trawl fleet between 1992 and 1999. Principal Components Analysis (PCA) of specific catch compositions identified five main components that explained 92% of the variability, and the catches were grouped into three main species: red shrimp, hake and blue whiting. Hierarchical Clustering Grouping of the percentage species catch composition allowed the fleet to be considered as two main groups, according to monthly landings and by differentiating the origin of the catches (slope or shelf). The species composition of the catch and the red shrimp catch rates (CPUE) differed between the two fleet groups. The application of Generalised Linear Modelling (GLM) to the CPUE series gave consistent indices of abundance. The fleet group, year and season had significant effects on shrimp catch rates, with the fleet group being the most important, and these models explained up to 62% of the total deviance. The abundance indices showed little variation from 1992, although 1994 had the highest value and 1997-1998 the lowest. Comparison with survey indices showed similar trends, while mean uncorrected CPUE differed. Monthly variations of shrimp indices showed a lower abundance in summer, which was attributed to the reproductive patterns of the species. As a result, the use of some fleet grouping techniques is recommended before standardising CPUEs to obtain trends or to calibrate assessment in a fishery.
Cephalopods from the pacific coast of Mexico: biological aspects of the most abundant species
Authors: Sánchez Pilar
Published: October 2008

The cephalopod fauna collected in six oceanographic surveys carried out in the northeastern Pacific Ocean off Mexico between March 1990 and June 1992 is analysed. A total of 11 cephalopod species were found at depths of between 16 and 828 m. All the cephalopods were preserved on board and identified in the laboratory. Data on size frequency distribution, and length-weight relationship for the most abundant species (Dosidicus gigas, Lolliguncula diomedeae and L. panamensis) are presented. The maturity status of D. gigas was also determined in both surveys. Stomach contents revealed that D. gigas fed mainly on crustaceans and D. gigas itself. The relationship between mantle length and two measurements of the fins of L. diomedeae and L. panamensis and the bathymetric distribution of both species show clear species-specific differences.
Population study of the fan shell Pinna nobilis L. in Malo and Veliko Jezero of the Mljet National Park (Adriatic Sea)
Authors: Siletic Tihana , Peharda Melita
Published: October 2008

Although previous studies have noted the presence of the bivalve Pinna nobilis Linnaeus, 1758 in Mljet National Park, there is a lack of basic knowledge of this endangered species. The present study was initiated as part of a long-term investigation of P. nobilis density and growth with the aim of gaining a better understanding of this species´ population dynamics, as well as evaluating the efficiency of protection measures of P. nobilis in Mljet National Park. Density, population structure, growth of tagged individuals and epibionts on P. nobilis were studied using SCUBA diving in 1998 and 2000 along four transects in Mljet inlets, Adriatic Sea. The density of P. nobilis ranged from 0.20 ind/m2 on transect MLJ-9 in Malo Jezero in 1998 to 0.02 ind/m2 on transect MLJ-5 in Veliko Jezero in 2000. Individuals measured in 1998 were significantly smaller than those measured in 2000. Growth curves were constructed from data collected by tagging and re-measuring 47 individuals. A decrease in density along some of the transects and the disappearance of 24 tagged individuals in 2000 is suggestive of poaching. The results of the present study indicate recovery of the P. nobilis population in Mljet lakes, but also provide evidence for the illegal removal of this protected species.
The caprellidean Amphipoda from the subantarctic islands of New Zealand and Australia with the description of a new genus and two new species
Authors: Guerra-García José Manuel
Published: October 2008

The Caprellidea of The Snares, Antipodes Islands, Auckland Islands, Campbell Island and Macquarie Island are reported from collections made between 1973 and 1977 by the Australian Museum, and collections made between 1967 and 1972 by researchers associated with the United States Antarctic Program (USAP). One new genus, Caprellaporema, and two new species, Caprellaporema subantarctica and Pseudaeginella campbellensis are described, Caprella manneringi McCain, 1979 is redescribed, and lateral view figures of the remaining species of the subantarctic islands are also provided.
Gross and histological observations of ovarian development in twaite shad, Alosa fallax fallax, from Rivers Mira and Guadiana (Portugal)
Authors: Pina Teresa , Esteves Eduardo , Andrade José Pedro
Published: October 2008

In order to describe the stages of oogenesis of twaite shad, Alosa fallax fallax, 265 females were collected between March and June 1997, February and June 1998 and January and April 1999 in the Rivers Mira and Guadiana. From the histological study of ovaries a total of eight developmental stages were delineated. Gross examination of paired ovary revealed that they could be placed into one of seven maturity stages according to their stage of development. Two stages of atresia, alfa and beta, were identified. Upon cessation of spawning, the ovaries still contained some oocytes at various stages of development but with a greater number of atretic oocytes. The simultaneous occurrence of oocytes at different stages of development in the ovary indicates asynchronous oocyte development. Oocyte size frequency distributions do not show a gap in size between cortical alveoli and vitellogenic oocytes during the spawning season. This may represent the ability of twaite shad to push oocytes through vitellogenesis from a previtellogenic condition during the spawning period. This has important implications for twaite shad fecundity, because fish with this type of oocyte development depend on estimates of batch fecundity and spawning frequency to determine potential annual fecundity.
A new species of Paraeupolymnia Young and Kritzler, 1986 (Polychaeta, Terebellidae) from Brazil
Authors: De Matos Nogueira Joao Miguel
Published: October 2008

A new species of the previously monotypic Paraeupolymnia found in large numbers in biogenic structures such as algae, oyster shells, and sabellariid reefs on rocky shores in the State of São Paulo is described here. Paraeupolymnia uspiana is characterised by the absence of both lateral lappets on anterior segments and pigmentation on buccal tentacles, and by the eyespots, which are larger and more numerous than those of P. carus, the type species of the genus. The diagnosis of Paraeupolymnia is emended, based on features of both species, after the analysis of Brazilian material and the holotype of P. carus. It is suggested that, after a comprehensive phylogenetic analysis of the group is undertaken, Paraeupolymnia will most probably be synonymised with Eupolymnia.
Larval development of Clastotoechus nodosus (Streets, 1872) (Crustacea: Decapoda: Porcellanidae), under laboratory conditions
Authors: Hernández Gonzalo , Magán Isabel , Graterol Karen , Gaviria Juan Ignacio , Bolaños Juan Antonio , Lira Carlos
Published: October 2008

The larval development of Clastotoechus nodosus is described and illustrated from specimens obtained from four females collected in shallow waters from Cubagua island, Venezuela (southeastern Caribbean) and reared in the laboratory. C. nodosus hatches as a prezoea of less than 60 minutes´ duration and then molts through two subsequent zoeal stages of 5-7 and 9-13 days´ duration respectively, at 25ºC and 37‰ salinity, before attaining the megalopa. There are major differences between the two zoeal stages and megalopa of C. nodosus and the only other congeneric species with known larval development [i.e. C. vanderhorsti (Schmitt, 1924); sin. Madarateuchus vanderhorsti]. Interspecific differences are striking in the setal formula of several appendages (e.g. antennulae, antennae, maxillulae, maxillae, and maxillipeds). The postorbital spines exhibited by the second zoeal stage of C. nodosus are a novelty for larvae of any porcellanid species described so far from the Americas.
Microsatellite variation in the Mexican rockfish Sebastes macdonaldi
Authors: Rocha-Olivares Axayácatl , Leal-Navarro Raul A. , Kimbrell Karol , Lynn Eric A. , Vetter Russell D.
Published: October 2008

The Mexican rockfish Sebastes macdonaldi is the Northeast Pacific rockfish with the southernmost distribution, featuring isolated populations in the Gulf of California. We analysed seven microsatellite loci in 111 organisms collected throughout most of its geographical range to test long-standing hypotheses regarding its disjunct distribution. One locus was fixed and the number of alleles in polymorphic loci ranged from 2 to 24 (average 13.5). We found very high levels of polymorphism (overall He = 0.75) comparable to other congeneric species but no significant differences in genetic diversity among localities or between Pacific and Gulf of California populations (p > 0.1). Significant shifts in allelic and genotypic frequencies were detected at three loci, which resulted in a small but significant partitioning of genetic variance among California, Baja California and Gulf of California populations (FST = 0.007, p = 0.03) and between Gulf and Pacific populations (FST = 0.01, p = 0.004). The latter but not the former result was corroborated by analyses of molecular variance (AMOVA) using the number of distinct alleles (FST) and the sum of square differences of allele sizes (RST) as Euclidean distances. The evidence argues against contemporary gene flow between the gulf and the Pacific ocean and against an ancient invasion of the gulf with a founder effect. The small level of divergence favours a recent dispersal but a larger data set including DNA sequences amenable to phylogenetic analyses will help to test alternative hypotheses of dispersal versus vicariance.
Determination of effective effort on hake Merluccius merluccius in a Mediterranean trawl fishery
Authors: Alemany Francisco , Álvarez Federico
Published: October 2008

The direct control of fishing effort as a management tool is of special interest in the Mediterranean, where the lack of effective international management systems and the high diversity of the catches significantly increases the complexity of implementing TAC´s as an indirect control of fishing effort. However, its enforcement should be based on the precise knowledge of the relationship between the fishing effort and its corresponding fishing mortality. In this sense, the general aim of this study was to develop an approach for analysing this relationship. In order to estimate the annual effective fishing effort on hake, a relational data base including daily landings by vessel and species of trawl fleet based on the port of Palma, Mallorca island (western Mediterranean) during the period 1983-1991 was built. Fishing mortalities were available from VPA. Fishing effort and fishing mortality were split by subfleets or métiers which were identified by cluster analysis. Significant linear relationships between the two parameters were obtained when fishing effort was considered as the number of days in which hake catch was higher than 10 kg multiplied by GRT of correspondent vessels. These CPUE values are mainly obtained when trawlers operate in the muddy bottoms of the shelf and on the upper slope, where hake populations are mostly distributed. On the other hand, no clear trends in catchability by métier were found during the period analysed.
Spatial patterns and temporal trends in the fisheries landings of the Messolonghi-Etoliko lagoons (Western Greek Coast)
Authors: Katselis George , Koutsikopoulos Constantin , Dimitriou Evagelos , Rogdakis Yiannis
Published: October 2008

The Messolonghi-Etoliko lagoon is one of the largest lagoon system in the northern Mediterranean coast. This area contains six clearly distinct lagoons with different topographic and hydrological features. The fishery landings of the lagoons are based on the ontogenic and seasonal migrations of the species. The total annual fishery landings of the barrier fish traps are estimated as 195 mt and are mainly composed of 16 species belonging to 8 families. Eel (Anguilla anguilla), the four species of Mugilidae (Liza saliens, L. aurata, L. ramada and Mugil cephalus), the two species of Sparidae (Sparus aurata and Diplodus annularis) and one species of Mullidae (Mullus barbatus) represent more than 92% of the total annual landings. The composition of the fishery landings varies between lagoons. The cluster analysis showed three groups of lagoons. The first group comprised lagoons in which the landings were dominated by eel, the second group was dominated by Mugilidae species and S. aurata, and the third by L. ramada and M. cephalus. The diversity index of the fishery landings is fairly constant in time, except for the Etoliko lagoon, where repeated anoxic crises decreased the diversity index value to almost zero in 1992. All the landing series showed a dominant annual cycle. Two seasonal patterns of the fishery landings were observed and linked to the fish spawning behaviour and/or their reaction to environmental forcings. The first one concerns species caught from summer to early autumn and the second pattern concerns species trapped during their autumn to winter offshore migration.
Den ecology of Octopus vulgaris Cuvier, 1797, on soft sediment: availability and types of shelter
Authors: Katsanevakis Stelios , Verriopoulos George
Published: October 2008

To avoid predation, octopuses select and actively modify shelters (also called dens) in the substratum, where they remain most of the time, especially during daylight hours. The main questions that this study deals with are: Is den availability a significant constraint for the distribution of Octopus vulgaris on soft sediment? What kind of dens does O. vulgaris use on soft sediment and what factors affect the selection of one type instead of another? With population density measurements by SCUBA diving and enrichment experiments with artificial dens, we concluded that the availability of solid materials necessary for den construction is a limiting factor for the distribution of O. vulgaris on soft sediment. O. vulgaris used four different types of den on soft sediment: well (a vertical hole in the sediment), rock/stone (the octopus uses a rock or a large stone to dig a cavity under it), shell (an empty shell is used), human origin (a solid material of human origin is used). The relative proportion of the four types of den in the areas studied was: 38.7% human origin, 29.7% well, 21.5% rock/stone, 2.9% shell. Also, 7.3% of the octopuses were found outside their den. The main types of den were found in different relative proportions in relation to the depth, the distance from shore, the octopus size and the granulometry of the sediment.
Sibling species of copepods in association with Mediterranean gorgorians
Authors: Conradi Mercedes , Megina César , López-González Pablo J.
Published: October 2008

Hitherto a single species of Doridicola Leydig (Poecilostomatoida: Rhynchomolgidae) has been found reported in association with gorgonians in Europe: Doridicola botulosus (Stock and Kleeton, 1963), living on the Mediterranean gorgonian Eunicella singularis (Esper, 1791). During a survey along the Iberian Mediterranean coast, several specimens of D. botulosus were collected from its reported host. Furthermore, an undescribed species of Doridicola was discovered living in association with Paramuricea clavata (Risso, 1826), a Mediterranean gorgonian usually living in overlaps with that of E. singularis. Although the new species is close to D. botulosus, they differ in the oral appendages. A common origin of these two species was suggested. This is a good example of sibling species produced by the colonisation of two hosts with overlapping habitats
Population dynamics and production of Streblospio benedicti (Polychaeta) in a non-polluted estuary in the Basque coast (Gulf of Biscay)
Authors: García-Arberas Loreto , Rallo Ana
Published: October 2008

Population dynamics and production of a population of Streblospio benedicti from the Gernika estuary (Basque coast, Gulf of Biscay) were studied monthly for one year, from May 1991 to May 1992. S. Benedicti was present in the muddy sand community of Gernika throughout the period of study except in March, when it all but disappeared. Continuous recruitment was observed throughout the year, even though it was stronger in autumn. Abundance fluctuations were principally due to the incorporation of recruits and so the highest density in Gernika was recorded in autumn, and the lowest in spring, with an annual mean of 6346 ± 4582 ind m-2. The same pattern of seasonal variation was shown in biomass: the annual mean biomass of S.benedicti in Gernika was estimated at 0.80 ± 0.54 g dry weight m-2. Secondary production was 3.57 g dry weight m-2 year, giving a P/B ratio of 4.46. S. benedicti in Gernika behaved similarly to those described for Mediterranean Streblospio populations as regards practically continuous recruitment, but the number of individuals and the annual average density were considerably lower on the Basque coast.
Physiological responses and scope for growth of Ruditapes decussatus from Ria Formosa, southern Portugal, exposed to increased ambient ammonia
Authors: Sobral Paula , Fernandes Sandra
Published: October 2008

In this study we investigate the effects of exposure to increased ambient ammonia-N concentrations as a cause of decreased scope for growth and mortality of R.decussatus during the summer months in Ria Formosa, southern Portugal. The physiological measurements were performed at 20 ºC and average total ammonia-N concentrations (TA-N) were 9, 48, 85, 134 and 260 µmol l-1 (corresponding to 0.2, 1.1, 2.0, 3.2 and 6.2 µmol l-1 NH3). No mortality was observed. Our results show that during short term exposure to TA-N concentrations >48 µmol l-1 (1.1 µmol NH3), R.decussautus survives at the expense of energy reserves. No energy is available for growth and reproduction. Though it is uncertain how intermittent exposures during tidal cycles will affect the long-term survival of R.decussatus in the Ria Formosa, high ammonia concentrations together with unfavourable physical and chemical summer gradients in the sediment can clearly contribute to the high mortality that has been registered in recent years (Ferreira et al. 1989). The sensitivity of the physiological energetics approach and the need to assess tolerance of infaunal bivalves addressing endpoints that can provide insight into the condition for growth and reproduction of the population is stressed.
Effects of wave action on nesting activity in the littoral five-spotted wrasse, Symphodus roissali, (Labridae), in the northwestern Mediterranean Sea
Authors: Raventos Nuria
Published: October 2008

The nesting activity of the littoral five-spotted wrasse, Symphodus roissali, was investigated near Blanes (northwestern Mediterranean Sea). Males construct and defend several nests over the entire reproductive period while females spawn asynchronously in these nests. Nesting activity continued from around the end of March to the end of June in the case of the study population. Nesting intensity, nesting success and nest destruction varied between years and sites. Differences between the numbers of nests that survive the nesting cycle and those that are destroyed can be related to environmental conditions, primarily wave height. Sufficiently protracted periods (> 1 week) of favourable sea conditions allow nests to survive and complete their cycle.
Studies on some reproductive aspects of Pseudotolithus elongatus in Cross River estuary, Nigeria
Authors: Ekanem Sunday Ben , Achima Marilyn Joan , Ekere Mfon Michael
Published: October 2008

To determine the spawning time of Pseudotolithus elongatus the Cross River estuary, ovarian development, egg diameter, gonadosomatic index (GSI) and hepatosomatic index (HSI) of the female fish were studied from January to December 1998. All ovary developmental stages, including the spawning stage, were present every month, which indicated year-round spawning. High mean values of GSI and egg diameter in December-March and July-September indicated these as the two peak spawning periods for the species. The egg diameter ranged from 1 µm to 590 µm. The highest number of eggs found in an individual fish was 808911. Absolute fecundity of the species in The Cross River estuary can be calculated in relation to standard length using the formula F = 17557SL0.768 or F = 45532W0.277 in relation to weight. There were evidences to suggest that the species is an asynchronous partial spawner. The stock might be effectively conserved by the imposition of a closed fishing season during the two peak spawning periods.
Behaviour of Southern sea lions in presence of killer whales during fishing operations in Central Chile
Authors: Hückstädt Luis , Antezana Tarsicio
Published: October 2008

The killer whale is an opportunistic top-predator of ecosystems worldwide and its diet varies locally and seasonally, which is reflected in diverse feeding behaviours associated with its prey. We report the occurrence of killer whales presumably predating on southern sea lions associated with the jack mackerel fishing fleet in central Chile. The presence of killer whales was recorded during 4 fishing sets. All sightings consisted of 3-5 individual pods of females and calves. The number of sea lions was not significantly affected by the presence of killer whales, but their behaviour was, by reducing the number of behavioural displays, as they stopped feeding and resting activities and stayed close to the hull of the vessel after net retrieval ended. We propose that killer whales could be using the fishery as an indirect source of prey to benefit from the aggregation of sea lions around the vessel, far away from land.
Ultrastructural studies of oogenesis in Bolinus brandaris (Gastropoda: Muricidae)
Authors: Amor María José , Ramón Monserrat , Durfort Mercé
Published: October 2008

Ultrastructural studies of oogenesis in Bolinus brandaris are described. Although the initial phase of oogenesis is common to most animal species, vitellogenesis can be considered a species-specific characteristic. In the vitellogenesis of B.brandaris, mitochondria and endoplasmic reticula play a relevant role in the formation of myelinised membranous systems. Nuclear envelope, Golgi body and the oocyte plasma membrane invaginations are three possible origins for annulate lamellae. The latter can be considered membranous reservoirs. There are two sources for the vitellum: exogenous (from follicular cells) and endogenous (from the endoplasmic reticulum of the same oocyte).
Abbreviated larval development of Tunicotheres moseri (Rathbun, 1918) (Decapoda, Pinnotheridae), a rare case of parental care in brachyuran crabs
Authors: Bolaños Juan , Cuesta José A. , Hernández Gonzalo , Hernández Jesús , Felder Darryl L.
Published: October 2008

Tunicotheres moseri (Rathbun, 1918) presents a rare case of post-hatching parental care not recorded previously among brachyuran decapods. The complete larval development takes place within a brooding enclosure of the parental female, formed by flexure of the broad abdomen against the sternum. The first crab instar is the earliest stage observed to leave this enclosure, doing so without active help from the parental female. The development of stages preceding the first crab was investigated by in vitro culture of eggs obtained from ovigerous crabs inhabiting the atrial cavity of the tunicate Phallusianigra Savigny, 1816, in Venezuela. Eggs were hatched in the laboratory and reared through two zoeal stages and the megalopa. Additional samples of the larval stages were obtained directly from abdominal enclosures of aquarium-held females. All larval stages were described and illustrated in detail. Morphological comparisons were made between larvae from two different populations. Comparisons were also made with other previously described larvae of Pinnotherinae, which led us to conclude that Tunicotheres should not be assigned to the Pinnotherinae sensu stricto. Relationships between the three known disjunct populations assigned to T.moseri remain questionable, especially since the potential for larval dispersal appears to be very limited.
Quantifying environmental effects on the recruitment of the Brazilian sardine (Sardinella brasiliensis), 1977-1993
Authors: Jablonski Silvio , Loureiro Legey Luiz Fernando
Published: October 2008

The recruitment process for Brazilian sardine (Sardinella brasiliensis) from 1977 to 1993 was investigated by taking into account the effects of spawning stock biomass (SSB), the intensity of the wind and the sea surface temperature (SST). Nonparametric models were applied. Best fits resulted from relating recruitment to a combination of SSB and Ekman transport. Transformation of Ekman transport is nearly dome-shaped, with lower and upper limits of 520 and 700 kg s-1 m-1 respectively. Fitting explained 94% of recruitment variability. Regions of maximum values in the transformations were for predictors related to wind, such as wind stress and turbulence index, whose limits were respectively 0.035-0.045 N m-2 and 30-45 m3 s-3. These values correspond approximately to winds of 3.0-4.5 m s-1. SST transformations also follow an apparent dome-shaped curve optimising around 24.75 and 25.5ºC. Inclusion of SST as a third predictor variable led to the loss of the dome-shaped relationship, as shown by the transformations with two predictor variables. Biomass curves are almost logarithmic, their critical point oscillating around 200,000-250,000 t, below which value the stock becomes more dependent on recruitment. The biomass range is greater than previous estimates.