Specific Merluccius otolith growth patterns related to phylogenetics and environmental factors

5 pages, 2 figures, 2tablesA comparative morphological study was performed on the otolith growth patterns of 11 species of the genus Merluccius. The otolith growth pattern, based on the radius of the first eight growth increments (GI) from the otolith core, was determined from transverse sections of sagitta otoliths. The structure and periodicity of the GI were identified based on previous knowledge. Two cluster analyses were performed using GI width as a proxy for otolith growth. The first cluster analysis corresponded to the juvenile (immature) period of the ¢sh including the mean width of the first four GI. The second analysis compared the mean width of the next four GI, i.e. those corresponding to mature fish. The results showed an important environmental influence in immature fish; while after maturation, the GI pattern was also related to an endogenous influence depending on the phylogenetic line.This work was supported by the EU FAIR project CT 95-0655. Gabriel Torres’s contribution was funded under the doctoral fellowship grant provided by the Spanish International Co-operation Agency (AECI) and the Latin-American-Catalonian Co-operation Institute (ICCI).Peer reviewe

Summer diet of European Shags Phalacrocorax aristotelis desmarestii in southern Mallorca

16 pages, 4 pages, 3 tablesAnalysis of pellets of European Shags Phalacrocorax aristotelis desmarestii collected at a non-breeding roost site in southern Mallorca identified 36 species of fish prey, belonging to 27 genera and to 16 families. This diversity is higher than in the diet of P. a. aristotelis in the Atlantic, and higher than in the previous literature for P. a. desmarestii in the Mediterranean. European Shags in southern Mallorca foraged mainly on fishes with a mean estimated length of 11.6 cm (84.1% ranging from 6.1–15.0 cm in estimated length), most being pelagic species (59.6 %). The most important fish in numerical frequency (43.9%) and estimated biomass (37.2%) was the Bogue Boops boops (Sparidae). This species has not been reported in European Shag diet in the Atlantic, and its importance was low in other Ph. a. desmarestii populations studied. The second most frequent prey was sand smelt Atherina (15%), but its contribution to biomass was low (1.4% of estimated biomass) because of its small size, as has been reported from other Mediterranean locations. The occurence of Scorpaenidae (10.7% by frequency, 17.4% of estimated biomass) was higher than in previous studies of Ph. a. desmarestii. Scorpaenids have not been found in the diet of Ph. a. aristotelis. Sandeels (Ammodytidae), a key prey for Ph. a. aristotelis in the Atlantic, were very scarce in this study, as in other recent Mediterranean studies. The relative abundance of species anatomically well protected against predation, such as scorpaenids and trachinids, and the diversity of prey probably reflects the scarcity or absence of other preferred prey. This study reflects the opportunistic behaviour of European Shags in the Mediterranean Sea, foraging on fish with very different ecological requirements, in an environment that is poor but diverseThis paper is included as a colateral research in the DGICYT Research Projects CGL2012–38089 and MINECO Research Project CTM2010–19701. Dr. Victor M. Tuset has a contract JAE-DOC (CSIC) co-funded by the European Social FoundationPeer reviewe

Contribución al conocimiento faunístico de los formícidos de la Sierra de Collserola (Barcelona)

A total of 27 species of Formicidae were found. A direct relationship between vegetation structure and ant communities was observed. A clear difference between three communities can be recognised. There was a total of 10 ant species in the littoral holm-oak wood, with a density of 31 nests/100 m2. Aphaenogaster subterranea was the dominant species. In the disturbed holm-oak wood, 16 species with a mean density of 52 nests/100 m2 were found, Leptothorax lichtensteini being the most common. Twenty one species with a density of 65 nests/100 m2 were found in the secondary pinewood; the most common species was Plagiolepis pygmaea. Lasius myops is considered a different species from Lasius Javus. A group of pioneer species from the surrounding pinewwood were found in the disturbed holm-oak wood.Hemos encontrado en la sierra de Collserola un total de 27 especies de formicidos. Existe una relación directa entre la estructura de las comunidades vegetales y las poblaciones de hormigas que se encuentran en ellas. Podemos diferenciar tres tipos de poblaciones. En el encinar litoral hay un total de 10 especies con una densidad de 3 1 nidos por 100 m2; la especie dominante es Aphaenogaster subterranea. En el encinar litoral alterado hay 16 especies con una densidad medida de 52 nidos por 100 m2 y la especie niis ahundantc es Leptothorax lichtensteini.En el pinar secundario el número de especies es de 21 y la densidnd es la máxima con 65 nidos por 100 m2; la especie con una mayor abundancia es aquí Plagiolepis pygmaea. Lasius myops es considerada como una especie bien diferenciada de Lasius Javus. En el pinar alterado se detectan un grupo de especies "pioneras" procedentes del pinar circundante

Selección de puntos homólogos (landmarks) y equidistantes (semilandmarks) en peces para análisis de morfometría geométrica: un estudio comparativo basado en métodos analíticos

We applied and compared three different sets of landmarks and semilandmarks commonly used in studies of fish assemblages to identify a standardized method of landmark selection that includes the maximum amount of morphological information of species. The different landmark-based methods used produced differences regarding the distribution of case-study species within the morphospace. We suggest that adding landmarks and semilandmarks that provide more specific information about anatomical structures with important roles in the biology of species, such as transformed fins or sensory organs, contributes to a clearer differentiation of species within the morphospace and a better interpretation of their occupancy. In addition, three types of method were used to establish how species are distributed within morphospace. The results demonstrated that aggregation points methods, including analyses based on quadrants or distances, are more appropriate for this purpose than indices of morphological disparity. The results also confirmed that although numerical methods are needed to test the statistical significance of outcomes, graphical methods provide a more intuitive interpretation of morphospace occupancy. The kernel density and Gabriel graph were useful to infer the morphospace zone where species are more densely grouped, improving the knowledge of space occupancy and structural complexity of fish assemblages.En el presente estudio se compara la estructura de una comunidad de peces a partir del análisis morfológico de puntos homólogos (landmarks) y equidistantes (semilandmarks) en las especies de dicha comunidad. Para este propósito, se utilizaron tres metodologías distintas descritas en la literatura a la hora de definir dichos puntos con el fin de identificar cuál de ellas incluía la máxima cantidad de información morfológica posible sobre las especies. Las tres opciones proporcionaron diferentes resultados en relación a la distribución de las especies dentro del morfoespacio. Los resultados sugirieron que la incorporación de puntos que proporcionen información más específica sobre estructuras anatómicas que tienen papeles importantes en la biología de las especies, como aletas modificadas u órganos sensoriales, contribuye a una diferenciación más clara de las especies y a una mejor interpretación de la ocupación del morfoespacio. Adicionalmente, varios métodos numéricos y gráficos se emplearon con el fin de establecer cómo las especies se distribuyen dentro del morfoespacio. Los resultados demostraron que los métodos de agregación de puntos, incluyendo análisis basados en cuadrantes o distancias, fueron más apropiados para este propósito que los índices de disparidad morfológica. Además, los resultados también confirmaron que aunque los métodos numéricos fueron necesarios para evaluar la significancia estadística de los mismos, los métodos gráficos proporcionaron una interpretación más intuitiva y clara de la distribución de las especies dentro del morfoespacio. La densidad de Kernel y los gráficos de Gabriel se mostraron muy útiles a la hora de deducir la zona del morfoespacio donde las especies estaban más densamente agrupadas, hecho que ayudó a mejorar el conocimiento de la ocupación del espacio y de la complejidad estructural en comunidades de peces

Ultrastructural damage of Loligo vulgaris and Illex coindetii statocysts after low frequency sound exposure

There is a considerable lack of information concerning marine invertebrate sensitivity to sound exposure. However, recent findings on cuttlefish and octopi showed that exposure to artificial noise had a direct consequence on the functionality and physiology of the statocysts, sensory organs, which are responsible for their equilibrium and movements in the water column. Owing to a lack of available data on deep diving cephalopod species, we conducted a noise exposure comparative experiment on one Mediterranean squid, Illex coindetii, and on the European squid Loligo vulgaris. Scanning electron microscopy (SEM) revealed similar injuries in the inner structure of the statocysts, as those found in cuttlefish and octopi. In addition to the ultrastructural description of the lesions, we publish here the first images of the crista-cupula system and inner statocyst cavity of I. coindetii

The macrofauna associated to the bamboo coral Isidella elongata: to what extent the impact on isideidae affects diversification of deep-sea fauna

Macrofauna associated with the bamboo coral Isidella elongata was analysed in the Balearic Basin at depths of 697–1308 m. The diversity of associated macrofauna and the specific associations identified depended on different morphological characteristics of colonies, such as height or density of rami. Species associated with Isidella consisted mainly of sessile fauna, such as cnidarians (the actinian Amphianthus dornhii and the solitary coral Desmophyllum dianthus) and cirripeds (Gibossaverruca sp.). The strongest relationship (commensalism) occurred for the Pontogeneiidae amphipod Dautzenbergia megacheir, living attached to colonies of Isidella and represented by all population stages from adult (oostegal) females and males to juveniles. Species-coral relationships between Dautzenbergia and bamboo corals (Isididae) are plausible. Dautzenbergia spp. showed morphological differences between Atlantic (described by Walker 1897 as “eyes wanting”) and Mediterranean (with well-developed reddish eyes) specimens. This would suggest diversification of this genus, as has been recently suggested for Pleustidae associated with deep gorgonians. The diversity of the macrofaunal community associated with I. elongata was higher in the most mature (larger colonies with higher density) fields found NW of Mallorca, with higher colonies than in other parts of the Mediterranean. This was the only site where Gibossaverruca sp. (a first Mediterranean faunal record) and D. dianthus were collected. These complex associations between macrofauna and deep-water corals may provide arguments to protect these fragile ecosystems as a source of faunal diversity and diversification.Versión del editor3,87

Back to the future: restoring historical communities

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Farmed salmon show no pathological alterations when exposed to acoustic treatment for sea lice infestation

The use of bioacoustic methods to address sea lice infestation in salmonid farming is a promising innovative method but implies an exposure to sound that could affect the fish. An assessment of the effects of these techniques related to the salmon's welfare is presented here. The fish were repeatedly exposed to 350 Hz and 500 Hz tones in three-to four-hour exposure sessions, reaching received sound pressure levels of 140 to 150 dB re 1 µPa, with the goal of reaching total sound exposure levels above 190 dB re 1 µPa s. Gross pathology and histopathological analysis performed on exposed salmons' organs did not reveal any lesions that could be associated to sound exposure. The analysis of their otoliths through electron microscopy imaging confirmed that the sound dose that was used to impair the lice had no effects on the fish auditory organs