bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential loggerhead by-catch and direct mortality due to surface longlines according to boat strata and gear type
Authors: Camiñas Juan A. , Báez José C. , Valeiras Xulio , Real Raimundo
Published: October 2008

Surface longline gears are used to fish different species, mainly albacore Thunnus alalunga (Bonnaterre, 1788), bluefin tuna Thunnus thynnus (Linnaeus, 1758), and swordfish Xiphias gladius Linnaeus, 1758, and are considered highly dangerous for threatened marine turtles. Loggerheads Caretta caretta (Linnaeus, 1758) can be incidentally captured by surface longlines. A number of captured individuals die during the fishing operation, which we consider direct mortality due to fishing. We analysed the relative loggerhead by-catch and direct mortality associated with each type of boat and gear from April to December during the period 1999-2004 in the Spanish surface longline fleet that fishes in the western Mediterranean Sea, an important fishing area for this fleet. We used different indices to compute the catch per unit effort (CPUE) according to the number of hooks and to the number of fishing operations for each type of boat and gear. Both by-catch and direct mortality differed significantly according to the type of boat and gear. With respect to the number of hooks, boats longer than 12 m not using a roller and targeting bluefin tuna captured the highest number of loggerheads, whereas boats longer than 12 m with a roller that targeted swordfish caused the highest direct mortality. With respect to the number of fishing operations, boats longer than 12 m without a roller that targeted albacore captured the highest number of loggerheads; the highest direct mortality was caused by this type of boat and by boats longer than 12 m using a roller and targeting swordfish.
Genetic and morphologic differentiation of the Lusitanian toadfish (Halobatrachus didactylus) between estuarine and coastal areas in Portugal
Authors: Marques Joana F. , Rego Ana Luísa , Lino Costa José , Costa Maria José , Cabral Henrique N.
Published: October 2008

The Lusitanian toadfish, Halobatrachus didactylus (Bloch and Schneider, 1801), is distributed from the Ghana coast to the Iberian Peninsula, being particularly abundant on the south coast of Portugal. The differentiation of this species along the Portuguese coast was assessed through the analysis of 10 samples, considering morphological characters (20 morphometric and 16 meristic) and genetic markers (10 allozymes, 11 loci). Southern samples included estuaries and their adjacent coastal areas, given that this species inhabits both environments, whereas western samples only comprised estuaries. Morphometric and meristic data discriminant analysis evidenced some differentiation between estuarine and coastal populations. This was not entirely corroborated by the genetic analysis, which showed an overall pattern of low FST (0.042) and Nei’s genetic distance, even between geographically distant areas. However, higher values of these parameters were found between estuaries of the south coast and their adjacent coastal areas, suggesting that estuarine systems play a major role in such differentiation. Results are discussed regarding toadfish life-history pattern and Portuguese coast geomorphology, giving an insight into the biological and environmental factors influencing population sub-structuring.
Spatial distribution of fiddler crabs (Genus Uca) in a tropical mangrove of northeast Brazil
Authors: Arruda Bezerra Luis Ernesto , Braga Dias Carolina , Ximenes Santana Givanildo , Matthews-Cascon Helena
Published: October 2008

The influence of abiotic factors on the spatial distribution of the fiddler crabs Uca leptodactyla, U. maracoani, U. rapax and U. thayeri was studied in a tropical mangrove of northeast Brazil. Eight transects were delimited in a mangrove area of the Pacoti River. On each transect, three 0.25 m2 squares were sampled during spring low tide periods from September 2003 to August 2004. The sediment of the squares at each transect was analysed for grain size, organic matter and humidity. Morphology of the second maxilliped was studied considering the number of spoon-tipped setae to help explain the ecological distribution of the species. U. leptodactyla and U. rapax were found living in medium sand, U. thayeri was collected in fine and very fine sand, while U. maracoani was found living in very fine sand. U. leptodactyla showed a negative correlation with organic matter and humidity while U. thayeri showed a positive correlations for both factors. U. maracoani and U. rapax were not correlated with organic matter or humidity. The analysis of the second maxilliped revealed that U. leptodactyla and U. rapax show a high quantity of spoon-tipped setae while U. maracoani and U. thayeri show a greater quantity of plumose setae.
The exploited population of the brackish river prawn (Macrobrachium macrobrachion Herklots 1851) in the Cross River estuary, Nigeria
Authors: Nwosu Francis M. , Holzlöhner Sieghard , Enin Udeme I.
Published: October 2008

The dynamics of the exploited population of Macrobrachium macrobrachion in the Cross River estuary, Nigeria, were studied based on monthly length-frequency data collected from January 1997 to June 1998 (18 months), from the landings of the artisanal Macrobrachium fishery. Sexual dimorphism was indicated in the growth and mortality parameters. For the males, the von Bertalanffy growth parameters were estimated as L∞ = 141.35 mm, K = 1.21 year-1, C = 1.0 and WP = 0.15. For the females, they were L∞ = 117.55 mm, K = 1.60 year-1, C = 0.81 and WP = 0.51. The instantaneous rate of total mortality (Z) was estimated as 9.53 year-1 (males) and 9.14 year-1 (females). The instantaneous rate of natural mortality (M) was estimated as 2.44 year-1 (males) and 3.09 year-1 (females), while the instantaneous rate of fishing mortality (F) was estimated as 7.09 year-1 (males) and 6.05 year-1 (females). The exploitation rate (E) obtained was 0.74 for the males and 0.66 for the females, suggesting that the prawn population was over-fished for both sexes. It is necessary to analyse the catch and effort data for the last 10 years and to apply other methods of stock assessment in order to estimate the long term trends in the fishery.
Direct Survival Analysis: a new stock assessment method
Authors: Ferrandis Eduardo , Hernández Pilar
Published: October 2008

In this work, a new stock assessment method, Direct Survival Analysis, is proposed and described. The parameter estimation of the Weibull survival model proposed by Ferrandis (2007) is obtained using trawl survey data. This estimation is used to establish a baseline survival function, which is in turn used to estimate the specific survival functions in the different cohorts considered through an adaptation of the separable model of the fishing mortality rates introduced by Pope and Shepherd (1982). It is thus possible to test hypotheses on the evolution of survival during the period studied and to identify trends in recruitment. A link is established between the preceding analysis of trawl survey data and the commercial catch-at-age data that are generally obtained to evaluate the population using analytical models. The estimated baseline survival, with the proposed versions of the stock and catch equations and the adaptation of the Separable Model, may be applied to commercial catch-at-age data. This makes it possible to estimate the survival corresponding to the landing data, the initial size of the cohort and finally, an effective age of first capture, in order to complete the parameter model estimation and consequently the estimation of the whole survival and mortality, along with the reference parameters that are useful for management purposes. Alternatively, this estimation of an effective age of first capture may be obtained by adapting the demographic structure of trawl survey data to that of the commercial fleet through suitable selectivity models of the commercial gears. The complete model provides the evaluation of the stock at any age. The coherence (and hence the mutual “calibration”) between the two kinds of information may be analysed and compared with results obtained by other methods, such as virtual population analysis (VPA), in order to improve the diagnosis of the state of exploitation of the population. The model may be drawn up in a deterministic format, but the main concepts may be interpreted as expectations if stock and catch are considered as stochastic processes.
A new alien bryozoan Celleporaria brunnea (Hincks, 1884) in the Aegean Sea (eastern Mediterranean)
Authors: Koçak Ferah
Published: October 2008

The ascophoran Bryozoa Celleporaria brunnea, a new record for the Mediterranean Sea, was found on Mytilus galloprovincialis collected in the inner part of Izmir Bay (Aegean Sea, Turkey) in September 2004. The species was previously reported from the Pacific coast of the United States. Its occurrence in the polluted inner part of Izmir Bay, near Alsancak Harbour, suggests that it has been newly introduced to the area, possibly via ship hulls. The morphological, ecological and zoogeographical characteristics of the species are given and discussed.
Relationship between viral and prokaryotic abundance on the Bajo O’Higgins 1 Seamount (Humboldt Current System off Chile)
Authors: Chiang Oscar E. , Quiñones Renato A.
Published: October 2008

There is little known about the ecology of microbial communities living in the water column over seamounts. Here, for the first time, the spatial distribution and abundance of virus-like particles (VLP) are described over a seamount. The association between VLP distribution, prokaryotic abundance, and environmental variables is also analyzed. Sampling was conducted in December 2004 on the Bajo O’Higgins 1 seamount (32°54’S, 73°53’W) located in the Humboldt Current System off Chile. A oxygen minimum layer (OMZ) was clearly present between 130 and 280 m in the water column over the seamount. Water samples were taken with Niskin bottles at 10 oceanographic stations over the seamount at depths of 5, 20, 50, 75, 100, and 150 m and at the benthic boundary layer (BBL; 5-12 m over the sediments). Temperature, salinity, oxygen, chlorophyll , and phaeopigments were measured at each station. Viral and prokaryotic abundances were determined with fluorochrome SYBR Green I. Viral abundance ranged from 1.53 x 109 VLP L-1 - 16.48 x 109 VLP L-1, whereas prokaryotic abundance ranged from 1.78 x 10 8 cell L-1 - 14.91 x 108 cell L-1. The virus-like particle/prokaryote ratio varied widely among the analyzed layers (i.e. surface, OMZ, and BBL), probably due to the presence of different prokaryotic and viral assemblages in each layer. Our results indicate that the environmental conditions, mainly the concentration of dissolved oxygen in the water column over Bajo O’Higgins 1 seamount, shape the association between viral and prokaryotic abundance.
Hydromedusae (Cnidaria) of the Chilean southern channels (from the Corcovado Gulf to the Pulluche-Chacabuco Channels)
Authors: Palma Sergio , Apablaza Pedro , Silva Nelson
Published: October 2008

Hydromedusae collected in epipelagic waters of the channels in southern Chile, between the Corcovado Gulf and the Pulluche-Chacabuco channels, were analysed. A total of 23 species were identified and recorded for the first time in this region. The most abundant species were Hydractinia minuta (44.4%), Clytia spp. (21.0%), Solmundella bitentaculata (14.5%), and Amphogona apicata (9.8%). H. minuta was the only species whose maximum abundance occurred in interior, low temperature, low salinity waters. Most of the species identified in the southern channels are common inhabitants of the Humboldt Current System, although a rare species (Heterotiara minor) was recorded for the first time in Chilean waters. High-diversity values (> 2.5 bits) were recorded in the oceanic waters of the adjacent Pacific Ocean.
A review of the Tripterygion tripteronotus (Risso, 1810) complex, with a description of a new species from the Mediterranean Sea (Teleostei: Tripterygiidae)
Authors: Carreras-Carbonell Josep , Pascual Marta , Macpherson Enrique
Published: October 2008

We compared specimens of Tripterygion tripteronotus from 52 localities of the Mediterranean Sea and adjacent waters, using four gene sequences (12S rRNA, tRNA-valine, 16S rRNA and COI) and morphological characters. Two well-differentiated clades with a mean genetic divergence of 6.89±0.73% were found with molecular data, indicating the existence of two different species. These two species have disjunctive geographic distribution areas without any molecular hybrid populations. Subtle but diagnostic morphological differences were also present between the two species. T. tripteronotus is restricted to the northern Mediterranean basin, from the NE coast of Spain to Greece and Turkey, including the islands of Malta and Cyprus. T. tartessicum n. sp. is geographically distributed along the southern coast of Spain, from Cape of La Nao to the Gulf of Cadiz, the Balearic Islands and northern Africa, from Morocco to Tunisia. According to molecular data, these two species could have diverged during the Pliocene glaciations 2.7-3.6 Mya.
Stable C and N isotope concentration in several tissues of the loggerhead sea turtle Caretta caretta from the western Mediterranean and dietary implications
Authors: Revelles Mónica , Cardona Luis , Aguilar Alex , Borrell Assumpció , Fernández Gloria , San Félix Manuel
Published: October 2008

The isotopic concentrations of carapace scutes, skin, muscle and blood of loggerhead sea turtles (Caretta caretta) from the Balearic Archipelago were analysed to investigate the pattern of variation between tissues and to assess the position of this species in the trophic webs of the Algerian Basin. Skin showed higher δ13C values than muscle or carapace scutes and these showed higher values than blood. Conversely, muscle showed higher δ15N values than skin, skin showed higher values than blood and blood showed higher values than carapace scutes. Dead and live sea turtles from the same habitat did not differ in the concentration of stable isotopes. However, some of the tissues of the turtles caught in drifting longlines in the oceanic realm showed higher δ13C values than those from the turtles caught by hand or in trammel nets over the continental shelf, although they did not differ in the δ15N. Comparison of the concentration of stable isotopes in the turtles with that of other species from several areas of the Algerian Basin revealed that they consumed planktonic prey and that the trophic level of the sea turtles was higher than that of carnivorous cnidarians but lower than that of zooplanktophagous fish and crustaceans.
Description of larvae and juveniles of Bairdiella ronchus (Sciaenidae: Teleostei) in southeastern Brazil
Authors: Kengo Itagaki Michael , Hidekazu Ohikawara Márcio , Ferraz Dias June , Katsuragawa Mario
Published: October 2008

Developmental stages from flexion larvae to early juvenile of Bairdiella ronchus were described and illustrated from specimens collected along the margins of tidal creeks in the southern zone of the Cananéia-Iguape System on the southeastern coast of Brazil. The B. ronchus larvae were identified working backwards from the juvenile using characteristics common to successively earlier ontogenetic stages. The number of myomeres was 25 (11+14). The flexion of notochord was completed by 5.5 mm SL. The fin formation began in the following sequence: caudal, second dorsal and anal, pelvic fins, first dorsal and pectoral. It was fully completed in this sequence: principal caudal, second dorsal, anal, first dorsal, pelvic and pectoral fins. Squamation began between 10.0 mm SL and 11.1 mm SL, and was entirely completed by 35.0 mm SL. The major head spines included the posterior preocular, supraocular and post-temporal. The larval morphology and pigmentation, mainly the swath pigmentation pattern, were very similar to those described for B. chrysoura in the South Atlantic Bight of the United States. Among sciaenid larvae co-occurring in the study area, Stellifer rastrifer shows larval characteristics more similar to those of B. ronchus, mainly in the preflexion and flexion stages, and in the contraction of the swath pigmentation. They can be differentiated by the fact that in S. rastrifer there is a post-anal lateral pigmentation or caudal pigment on the ventral midline radiating dorsally, which is absent in B. ronchus.
Sequence of hydrographic changes in NW Mediterranean deep water due to the exceptional winter of 2005
Authors: Font Jordi , Puig Pere , Salat Jordi , Palanques Albert , Emelianov Mikhail
Published: October 2008

Time series measurements at a mooring site on the deep slope of the NW Mediterranean from October 2003 to July 2005 revealed the sequence of effects of the anomalously dry, markedly cold, and very windy winter of 2005 in deep water thermohaline properties. At the end of January, a dense water mass that was warmer and saltier than usual reached the deep slope mooring site. Almost simultaneously, the start of deep dense shelf water cascading episodes was observed in the Gulf of Lions’ submarine canyons. 30 days later, colder, fresher and even denser waters reached the mooring, with a 5-day delay from an intensification of the Gulf of Lions’ cascading. The signature of these waters was detected for 35 days, and by late spring 2005 a new stable water mass situation was reached, with higher thermohaline values than those that characterised the deep layer from October 2003 to January 2005.
Survival probabilities of loggerhead sea turtles (Caretta caretta) estimated from capture-mark-recapture data in the Mediterranean Sea
Authors: Casale Paolo , Mazaris Antonios D. , Freggi Daniela , Basso Roberto , Argano Roberto
Published: October 2008

Survival probabilities of loggerhead sea turtles (Caretta caretta) are estimated for the first time in the Mediterranean by analysing 3254 tagging and 134 re-encounter data from this region. Most of these turtles were juveniles found at sea. Re-encounters were live resightings and dead recoveries and data were analysed with Barker’s model, a modified version of the Cormack-Jolly-Seber model which can combine recapture, live resighting and dead recovery data. An annual survival probability of 0.73 (CI 95% = 0.67-0.78; n=3254) was obtained, and should be considered as a conservative estimate due to an unknown, though not negligible, tag loss rate. This study makes a preliminary estimate of the survival probabilities of in-water developmental stages for the Mediterranean population of endangered loggerhead sea turtles and provides the first insights into the magnitude of the suspected human-induced mortality in the region. The model used here for the first time on sea turtles could be used to obtain survival estimates from other data sets with few or no true recaptures but with other types of re-encounter data, which are a common output of tagging programmes involving these wide-ranging animals.
Interactions between small cetaceans and the purse-seine fishery in western Portuguese waters
Authors: Wise Laura , Silva Alexandra , Ferreira Marisa , Silva Mónica A. , Sequeira Marina
Published: October 2008

Marine mammal interactions with Portuguese purse-seine fisheries operating in four different ports (Figueira da Foz, Sesimbra, Setúbal, Sines) were studied (July-October 2003). Observers accompanied commercial fishing vessels and monitored 48 fishing trips. An interview survey of skippers was also carried out (n = 36). Three species of marine mammals were observed in 31 sightings during the commercials trips but only the species Delphinus delphis and the category Delphinidae were observed to interact with fishing activities. Small cetaceans were observed to sink, gather or disperse school fishes and damage gear. Mean CPUE and fishing effort values did not change significantly in the presence of dolphins (H = 0.06 and H = 0, both p>0.05). Results from Figueira da Foz indicate that cetaceans are attracted to fishing grounds with a high abundance of their prey-species. Fishermen reported three by-catch events off Figueira da Foz. Compared with other fisheries, purse-seine fishing does not seem to be among the most damaging to marine mammals.
Larval development of Dagetichthys marginatus (Soleidae) obtained from hormone-induced spawning under artificial rearing conditions
Authors: Thompson Ernst F. , Strydom Nadine A. , Hecht Thomas
Published: October 2008

Dagetichthys marginatus (formerly Synaptura marginata) larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys, which is represented by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL) and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown.
The reproductive biology of Diplodus sargus sargus in the Gulf of Tunis (central Mediterranean)
Authors: Mouine Nejla , Francour Patrice , Ktari Mohamed-Hédi , Chakroun-Marzouk Nadia
Published: October 2008

The sexual activity of Diplodus sargus sargus in the Gulf of Tunis takes place from January to May. Spawning occurs in spring (March to May), as the water temperature rises from 15 to 18°C, just after the winter minimum. The spawning period increases as the latitude decreases. The overall male to female ratio was statistically different from unity. Size at sexual maturity (TL50) was 21 cm (4 years old). The length-weight relationship for all individuals was described by the following parameters: a = 0.015 and b = 3.051. D. s. sargus from the Gulf of Tunis is a rudimentary hermaphrodite with partial protandry.
Demersal and epibenthic assemblages of trawlable grounds in the northern Alboran Sea (western Mediterranean)
Authors: Abad Esther , Preciado Izaskun , Serrano Alberto , Baro Jorge
Published: October 2008

The composition and abundance of megabenthic fauna caught by the commercial trawl fleet in the Alboran Sea were studied. A total of 28 hauls were carried out at depths ranging from 50 to 640 m. As a result of a hierarchical classification analysis four assemblages were detected: (1) the outer shelf group (50-150 m), characterised by Octopus vulgaris and Cepola macrophthalma; (2) the upper slope group (151-350 m), characterised by Micromesistius poutassou, with Plesionika heterocarpus and Parapenaeus longirostris as secondary species; (3) the middle slope group (351-640 m), characterised by M. poutassou, Nephrops norvegicus and Caelorhincus caelorhincus, and (4) the small seamount Seco de los Olivos (310-360 m), characterised by M. poutassou, Helicolenus dactylopterus and Gadiculus argenteus, together with Chlorophthalmus agassizi, Stichopus regalis and Palinurus mauritanicus. The results also revealed significantly higher abundances in the Seco de los Olivos seamount, probably related to a higher food availability caused by strong localised currents and upwellings that enhanced primary production. Although depth proved to be the main structuring factor, others such as sediment type and food availability also appeared to be important. Differences between shelf and slope assemblages could be in part related to a greater dependence on benthic resources in the former and a higher use of planktonic resources in the latter.
Bioeconomic simulation analysis of hake and red mullet fishery in the Gulf of Saronikos (Greece)
Authors: Merino Gorka , Karlou-Riga Constantina , Anastopoulou Ioanna , Maynou Francesc , Lleonart Jordi
Published: October 2008

Hake (Merluccius merluccius) and red mullet (Mullus barbatus) are two of the most important species in Greek fisheries due to their high commercial interest. Both have been reported to be overexploited and in need of management to preserve the continuity of their exploitation. Hake is exploited by trawlers and red mullet by both trawlers and beach seiners in Saronikos Gulf (Greece). The MEFISTO bioeconomic simulation model is applied in order to test the interaction between trawlers and beach seiners through the age-specific fishing mortality applied by each fleet to the red mullet stock. The effects of the withdrawal of some beach seiners in 2002 and the increase in trawl mesh size that has already been implemented (from 28 mm to 40 mm stretched mesh) are tested jointly with alternative management scenarios such as the complete withdrawal of beach seiners and effort reduction in trawler activity. The analysis of the simulation results is based on the evolution of biological and economic indicators through 15-year stochastic projections. It is shown that limiting fishing effort and improving selectivity patterns of the trawl fleet would be beneficial for the recovery of the populations and for the profitability of the fishery. In addition to the increase in trawl mesh size, a further fishing effort reduction of 12% is recommended for the trawling fleet. Conversely, limiting or completely removing the beach seiner fleet would protect red mullet juveniles but would not significantly increase the profitability of the trawling fleet, and it would cause unemployment.
Effort dynamics in a fisheries bioeconomic model: A vessel level approach through Game Theory
Authors: Merino Gorka , Maynou Francesc , García-Olivares Antonio
Published: October 2008

Red shrimp, Aristeus antennatus (Risso, 1816) is one of the most important resources for the bottom-trawl fleets in the northwestern Mediterranean, in terms of both landings and economic value. A simple bioeconomic model introducing Game Theory for the prediction of effort dynamics at vessel level is proposed. The game is performed by the twelve vessels exploiting red shrimp in Blanes. Within the game, two solutions are performed: non-cooperation and cooperation. The first is proposed as a realistic method for the prediction of individual effort strategies and the second is used to illustrate the potential profitability of the analysed fishery. The effort strategy for each vessel is the number of fishing days per year and their objective is profit maximisation, individual profits for the non-cooperative solution and total profits for the cooperative one. In the present analysis, strategic conflicts arise from the differences between vessels in technical efficiency (catchability coefficient) and economic efficiency (defined here). The ten-year and 1000-iteration stochastic simulations performed for the two effort solutions show that the best strategy from both an economic and a conservationist perspective is homogeneous effort cooperation. However, the results under non-cooperation are more similar to the observed data on effort strategies and landings.
Taxonomic and morphometric analyses of the Haplosyllis spongicola complex (Polychaeta: Syllidae: Syllinae) from Spanish seas, with re-description of the type species and descriptions of two new species
Authors: Lattig Patricia , San Martín Guillermo , Martin Daniel
Published: October 2008

This is the first contribution to a worldwide taxonomic revision of the closely related genera Haplosyllis (the main goal is to describe species within the Haplosyllis spongicola complex) and Geminosyllis. The type species, Haplosyllis spongicola, is re-described based on the syntypes and other material collected from Spanish seas. A combined taxonomic and morphometric (i.e. PCA and discriminant analysis) approach was used to study species of the Haplosyllis spongicola complex from Spanish seas. Two of them are described here as new: Haplosyllis carmenbritoae n. sp. from the Canary Islands, and Geminosyllis granulosa n. sp. from Iberian and western Mediterranean waters, and which is attributed to Geminosyllis due to the presence of a pharyngeal trepan. The third species, which also belongs to Geminosyllis, is morphologically very close to, and morphometrically indistinguishable from, H. spongicola, except for the presence of the trepan. This casts serious doubts on the relevance of this structure for separating the two genera and thus prevents us from describing this last species as new.
Relationships between deep-water polychaete fauna and environmental factors in the southeastern Gulf of California, Mexico
Authors: Méndez Nuria
Published: October 2008

Polychaetes inhabiting deep-sea soft bottoms in the southeastern Gulf of California were collected during four oceanographic cruises in 2000 and 2001 at a depth range of 732-2110 m. A total of 84 taxa, representing 32 families, were collected. The relationships between density, species number and diversity and depth, dissolved oxygen, temperature, granulometry and organic matter content in sediments were analysed. Cluster analyses and MDS plots based on density allowed faunal assemblages to be established for each environmental variable: 700-1100 m, 1100-1600 m, 1900-2100 m and 2100-2200 m (depth); 0.00-1.20 ml/L, 1.20-2.00 ml/L and 2.00-2.40 ml/L (oxygen); 2.0-2.5°C, 2.5-4.0°C, 4.0-6.0°C and 6-6.5°C (temperature); 8-16%, 16%-18% and 18-20% (organic matter), 20-30%, 60-70% and 80-100% (mud). Polychaetes were not distributed according to gradients of any of these environmental variables. The dominant and frequent species of each group were not restricted to unique assemblages. Results of a canonical correspondence analysis indicated that depth, oxygen and temperature were the main environmental variables responsible for polychaete distribution. The dominance of muddy sediments with high organic matter content (8.26 to 18.78%) throughout the study area reduces the importance of these parameters for polychaete distribution, since the dominant and frequent species belong to the detritivore families Ampharetidae, Maldanidae and Cirratulidae.
Colossendeis species (Pycnogonida: Colossendeidae) collected during the Italica XIX cruise to Victoria Land (Antarctica), with remarks on some taxonomic characters of the ovigers
Authors: Cano Esperanza , López-González Pablo J.
Published: October 2008

The pycnogonid fauna of the genus Colossendeis collected during the Italica XIX cruise to Victoria Land (Ross Sea, Antarctica) was studied. A total of 19 specimens of six species were collected: Colossendeis australis (6), C. wilsoni (3), C. scotti (2), C. robusta (3), C. lilliei (2) and C. megalonyx (3). In the present contribution the observed variability of all collected Colossendeis species is described and illustrated. The previously synonymised C. lilliei is considered a different species from C. robusta. The observations made in this study lead us to discuss a controversy about the total number of oviger segments in this genus. Despite the currently established 10-segmented status, a short basal element is here considered to be a possible 11th segment. A detailed SEM study of the last oviger segment is carried out in all collected species, showing some intraspecific and the interspecific variability in the structures examined (shape and number of rows of compound spines, morphology of terminal claw, etc.). Finally, we discuss the taxonomic value of these characters of the last strigilis segment for distinguishing the Colossendeis species, and their possible utility in establishing internal phylogenetic relationships in future contributions.
A new species of Marumomysis (Mysidacea: Mysidae: Erythropini) from the benthos of the Bellingshausen Sea (Southern Ocean)
Authors: San Vicente Carlos
Published: October 2008

A new mysid species, Marumomysis Antarctica n. sp., is described from specimens sampled with a suprabenthic sled in the Bellingshausen Sea (Southern Ocean). The new mysid is characterised by the small eyes lacking visual elements and with a long horn projecting anteriodorsally, the trilobate labrum and the shape and armature of the endopod of the uropod and telson. This new species is the first Marumomysis species described from the benthos (1320-1895 m depth) of the Southern Ocean.
The occurrence of pycnogonids associated with the volcanic structures of Bransfield Strait central basin (Antarctica)
Authors: Munilla Tomás , Soler-Membrives Anna
Published: October 2008

Fifty-four specimens of pycnogonids belonging to twenty-two species, eight genera and six families were collected with a rocky dredge during the cruise Gebrap-96 in the central basin of Bransfield Strait, from depths between 647 and 1592 m. The richest station in terms of abundance and biomass was DR6 (south of Livingston Island), which was also the shallowest one; at this relatively shallow depth food is more available than in deeper waters. The families Nymphonidae and Colossendeidae had the same number of specimens (21 specimens; 39% abundance each). The most abundant species were Nymphon villosum and N. proximum. Pallenopsis buphthalmus was collected for only the third time. The collections increased the geographical distribution of three species and the depth range of six species. The volcanic structures sampled were inactive during 1996, since none of the specimens showed signs of hydrothermal phenomena. This collection was typically representative of the west Antarctic benthic zone.
Stressors affecting the macrobenthic community in Rapallo Harbour (Ligurian Sea, Italy)
Authors: Covazzi Harriague Anabella , Misic Cristina , Petrillo Mario , Albertelli Giancarlo
Published: October 2008

An annual survey was carried out in Rapallo Harbour (Ligurian Sea, NW Mediterranean) to study the main stressors affecting the macrobenthic communities. The harbour was characterised by a relevant organic enrichment (between 51.9 mg g–1 and 109.6 mg g–1), which did not affect the water column oxygenation, and low but detectable heavy-metal contamination (on average Cu=135.0 µg g–1 and V=23.8 µg g–1). The seasonal changes in the heavy metal concentrations suggested a significant increase in tourist activities (i.e. boat movements) during summer and autumn. In the inner, more protected sampling site, the harbour structures and the vessel movements increased both organic enrichment and sediment instability, resulting in macrobenthic communities dominated by indicator species associated with these stressors. In addition, during summer and autumn, despite a relevant chlorophyll-a flux to the sediment, the settling material was dominated by phaeopigments and refractory proteins, which reduced its trophic value for benthic consumers. In the outer part of the harbour the main stressor was a polluted freshwater inflow, as indicated by the dominance of indicator species such as Capitella spp. (on average 79.5%), Neanthes caudata, Malacoceros girardi and Diopatra neapolitana.
Immediate effect of intertidal non-mechanised cockle harvesting on macrobenthic communities: a comparative study
Authors: Sousa Leitão Francisco Miguel , Baptista Gaspar Miguel
Published: October 2008

In Ria Formosa cockles (Cerastoderma edule) have traditionally been harvested with a harvesting-knife (HK). However, over the last six years there has been an increase in the use of a hand-dredge (HD) to exploit cockle beds. A comparative study on the impact of these harvesting methods on the benthic macrofauna was undertaken with the aim of evaluating the possible introduction of the hand-dredge in the fishery. Macrofaunal mortality was very low regardless of the gear. However, the total mortality resulting from using the HK was superior to the one observed for the HD. For the same fishing time the hand-dredge covers an area approximately five times greater that the one covered by the knife, with the former yielding 5 times the catch of the latter. Consequently, the use of hand-dredges increases the fishing effort, which may lead to the overexploitation of the cockle populations. Our results revealed that the immediate effect of both gears on macrobenthic communities was similar and minimal. Therefore, we believe that introducing the hand-dredge in the cockle fishery should only be authorised if other management measures, such as daily quotas, closed areas and limiting the number of fishing licenses, are implemented.
Revision of the Indo-Pacific genus Nembrotha (Nudibranchia: Dorididae: Polyceridae), with a description of two new species
Authors: Pola Marta , Cervera J. Lucas , Gosliner Terrence M.
Published: October 2008

Anatomical examination of new material collected from the Indo-Pacific and the review of several collections from around the world allows for the revision of the genus Nembrotha Bergh, 1877. Two new species, Nembrotha rosannulata n. sp. and Nembrotha aurea n. sp., are described. The oldest available name for the genus is Nembrotha nigerrima Bergh, 1877, which was subsequently designated as the type species by O’Donoghue, 1924. The study of the original type material of N. nigerrima confirmed that it is a senior synonym of another name introduced subsequently, Nembrotha kubaryana Bergh, 1877, the name most commonly used for this species. However, according to the provisions of the International Code of Zoological Nomenclature (Article 23.9.1), there is no reason to invalidate the senior name Nembrotha nigerrima, since it has been used as valid after 1899. Nembrotha cristata Bergh, 1877, N. lineolata Bergh, 1905, N. purpureolineata O’Donoghue, 1924, N. livingstonei Allan, 1933, N. megalocera Yonow, 1990 and N. guttata Yonow, 1993, which are poorly known, are redescribed. Nembrotha rutilans (Pruvot-Fol, 1931) is synonymised with N. purpureolineata. Nembrotha yonowae Goethel and Debelius, 1992 is synonymised with N. guttata. The radulae of Nembrotha milleri Gosliner and Behrens, 1997 and N. mullineri Gosliner and Behrens, 1997 are redescribed.
Meiofauna and nematode diversity in some Mediterranean subtidal areas of the Adriatic and Ionian Sea
Authors: De Leonardis Cristiana , Sandulli Roberto , Vanaverbeke Jan , Vicx Magda , De Zio Susanna
Published: October 2008

Sediments of three different subtidal areas (15-705 m depth) of the Italian coasts (Manfredonia, Brindisi and Gallipoli) were investigated to study meiofauna and nematode composition. The nematodes were identified to the genus level and their abundances compared using multivariate analysis. Our data showed an evident depth gradient in meiofauna abundance: the shallowest sites had more diverse and abundant meiobenthic communities than the deeper ones. Nematodes were the dominant taxon (83-100%) at all sites, followed by Copepoda (0.5-8%). Sabatieria, Astomonema, Dorylaimopsis, Terschellingia and Daptonema were among the dominant nematode genera in the three areas. Nematode genus H’ diversities were not significantly dissimilar, though at community level some differences were detected among the study areas. The greatest differences were observed in the comparison of the communities from Manfredonia and Gallipoli. Furthermore, there was a difference between shallow (<200 m) and deep sites due to high differential abundances of common genera, i.e. Astomonema, Dorylaimopsis, Sabatieria and Terschellingia.
Dynamics of dinoflagellates and environmental factors during the summer in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea)
Authors: Drira Zaher , Hamza Asma , Belhassen Malika , Ayadi Habib , Bouaïn Abderrahmen , Aleya Lotfi
Published: October 2008

The summer spatial distribution of the dinoflagellate community along an open coastal sea gradient in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea), together with environmental factors, were studied. The most dominant families were represented by Gymnodiniaceae (32%), Peridiniaceae (20%), Prorocentraceae (15%), Ceratiaceae (13%) and Ebriaceae (10%). The dinoflagellate community was spatially more concentrated along the coast of the gulf than in the open sea. Eight toxic dinoflagellates were recorded, including Karenia cf. selliformis (37% of total toxic dinoflagellates) which was evenly distributed in both the neritic and open sea areas. Dinocysts contributed 33% of the total motile cells and were more abundant along the coast than in the open sea. This high concentration may be ascribed to nitrogen inputs in the coastal waters of Gabes. The Modified Atlantic Water governed dinoflagellate development in the open sea. The degradation of the water quality due to eutrophication in the Gulf of Gabes may have significant socioeconomic consequences. We suggest that a management framework, similar to that used in freshwater ecosystems, should be developed for the Gulf coast in order to drastically reduce urban interferences.
Photoinhibition and photosynthetic pigment reorganisation dynamics in light/darkness cycles as photoprotective mechanisms of Porphyra umbilicalis against damaging effects of UV radiation
Authors: Aguilera José , Figueroa Félix L. , Häder Donat-P. , Jiménez Carlos
Published: October 2008

Porphyra umbilicalis L. Kutzing collected from the upper intertidal zone at Helgoland, North Sea, was exposed to different spectral ranges of UV radiation under both 12/12 h light/dark cycles and continuous irradiation. In light/dark cycles, oscillations of the optimal quantum yield (Fv /Fm) were observed during the experiments, reaching maximal values at the end of the light phase followed by lower values during the dark phase. Decreased Fv /Fm was observed in thalli illuminated with photosynthetic active radiation (PAR) plus UV-A and PAR+UV-A+UV-B, compared with the PAR control, indicating a certain degree of UV-induced photoinhibition. In addition, a decrease in the percentage of change of the linear initial slope and maximum electron transport rate (ETR) estimated from ETR vs. irradiance curves was induced by UV radiation during the light phase. Recovery during the 12 h dark phase was almost completed in UV-A treated plants. PAR+UV-A seemed not to affect the photosynthesis, measured as O2 production. However, a decrease in O2 production was observed in the PAR+UV-A+UV-B treatment, but it recovered to initial values after 48 h of culture. No changes in total content of photosynthetic pigments were observed. However, thallus absorptance and the in vivo absorption cross-section in the PAR range (400-700 nm) normalised to Chl a (a* parameter) fluctuated during light/dark cycles and were positively correlated with changes in the optimum quantum yield, thus indicating that daily pigment reorganisation in the light-harvesting complex may play a key role in the photosynthetic performance of the algae. Both UV-A and UV-B treatments under continuous irradiation induced a significant reduction in the optimal quantum yield, ETR efficiency and photosynthetic oxygen production during the first 36 h to values around 30% of the initial ones. Thus, different protective mechanisms against UV stress can be observed in P. umbilicalis: dynamic photoinhibition when UVA is combined with PAR, followed by full recovery of photosynthesis during the dark phase, and a more pronounced photoinhibition under UV-B, with only partial recovery after longer time periods, in which photosynthetic pigment reorganisation plays an important role.
A new species of Curidia (Crustacea: Amphipoda: Ochlesidae) from northeastern Brazil
Authors: De Souza-Filho Jesser Fidelis , Serejo Cristiana S.
Published: October 2008

A new species of Curidia from the Fernando de Noronha Chain (located off the northeastern Brazilian coast), and the continental shelf of Bahia State is described. Curidia wakabarae n. sp. is similar to C. debrogania Thomas, 1983 and C. magellanica Coleman and Barnard, 1991 in the maxillipedal palp, which is slender and has a long apical seta extending beyond the outer plate. It does, however, differ from these species in article 1 of antenna 1 not reaching the end of article 3, the ventrodistal acute process of article 2 extending to 1/5 of first flagellar article 1, the absence of a posterodorsal acute carina on pereonite 7, and the apically rounded telson. This is the first record of Ochlesidae from the northeast Brazilian coast. A world key of the known Curidia species is given.
Morphological characteristics of five bycatch sharks caught by southern Chilean demersal longline fisheries
Authors: Valenzuela Andrea , Bustamante Carlos , Lamilla Julio
Published: October 2008

The by-catch of sharks in artisanal demersal pink cusk-eel (Genypterus blacodes) and yellownose skate (Dipturus chilensis) fisheries is frequent within their fishing effort. Nevertheless, there is no registry of landings, which could help to control this problem. This is particularly evident for endemic species, which includes most coastal and deep water Chilean sharks. The main systematic characteristic of these Chondrichthyan species is the external morphology of the neurocraneum. The form and arrangement of the teeth and dermal denticles allow specific differences to be identified. The objective of this paper is to contribute to the biology and systematic knowledge of demersal shark species, teeth and dermal denticle morphology and neurocraneum morphometrics of two species of Scyliorhinids, the redspotted catshark (Schroederichthys chilensis) and the dusky catshark (Halaelurus canescens), as well as three Squaliforms, the granular dogfish (Centroscyllium granulatum), the birdbeak dogfish (Deania calcea) and the spiny dogfish (Squalus acanthias).
Spatial and temporal characteristics of benthic invertebrate communities at Culbin Sands lagoon, Moray Firth, NE Scotland, and impacts of the disturbance of cockle harvesting
Authors: Mariyam Mendonça Vanda , Raffaelli David George , Boyle Peter , Hoskins Steve
Published: October 2008

In the present study, Culbin Sands lagoon, a protected site in NE Scotland, was surveyed every 2 to 4 weeks during a three-year period (1994-1996) to study benthic invertebrate communities. Beds of Mytilus edulis covered 18000 m2. 53 macroinfaunal species were identified outside these areas. The most conspicuous were: the lugworm Arenicola marina (mean up to 55 casts m-2); and bivalves Cerastoderma edule (mean up to 158 ind. m-2) and Macoma balthica (mean up to 79 ind. m-2) after settlement. The standing stock ranged from 20 to 32 g AFDW m-2 yr-1 respectively from more exposed to more sheltered areas. Most species showed a clear recruitment peak in autumn, but others (e.g. Capitella capitata, and Spionidae) displayed several peaks in a year. Communities were also compared between the sampling sites before and after an incidental disturbance caused by cockle Cerastoderma edule harvesting, which took place in June 1995. One site showed –0.7% variation in the total standing stock, but +22% for smaller-cockles, as larger filter-feeding cockles were removed therefore enhancing their own larval settlement. Polychaete Spionidae populations also increased after larger cockles were removed. The polychaete Arenicola marina population returned to its normal activities just after the dramatic disturbance of the sediment.