Reproductive strategy of white anglerfish (Lophius piscatorius) in Mediterranean waters: implications for management

14 pages, 7 figures, 2 tablesReproductive parameters of the white anglerfish (Lophius piscatorius) in the northwestern Mediterranean Sea were studied in 556 specimens collected monthly aboard commercial fishing vessels that were trawling at depths of 12-836 m. The main spawning season occurred from February through June. The size at maturity was estimated to be 48.8 cm in total length (TL) for males, 59.9 cm TL for females, and 51.3 cm TL for both sexes combined. The white anglerfish has group-synchronous oocyte development and determinate fecundity. It is a total spawner (spawns all its eggs once during a spawning season) and has a batch fecundity ranging from 661,647 to 885,214 oocytes, a relative batch fecundity of 66-128 oocytes per gram of female gutted weight, and a potential fecundity with values from 54,717 to 104,506 oocytes per kilogram of female total weight. This study is the first to provide the reproductive biology of white anglerfish in the northwestern Mediterranean Sea and provide valuable information that can be used to improve the stock assessment and ensure proper management of this speciesPeer Reviewe

Estrategias de vida de un relevante pez de arrecife, la fula negra Similiparma lurida (Pomacentridae) en el Noroeste Atlántico

Similiparma lurida is a common fish inhabiting shallow-water rocky bottoms of the northeastern Atlantic oceanic archipelagos, and the coasts from Portugal to Senegal. This study was conceptualized to integrate information relative to key population traits of S. lurida, including length and age structure, growth, reproduction and length at maturity, with a description of abundance patterns on shallow reefs, including temporality of recruitment and habitat preferences by juveniles, sub-adults and adults. We then hypothesized that seasonal cycles of spawning and recruitment were synchronized. This species reaches a total length (TL) of up to 15.7 cm and an age of 18 years. Males grow faster and longer (K=0.28 years–1, L∞=14.487 cm TL) than females (K=0.23 years–1, L∞=13.461 cm TL), which affects the overall ratio of males to females (1:0.26). The size at which 50% of sexual maturity is reached was 10.344 cm TL for males and 8.471 cm TL for females. Fish increase growth during the spawning season, which occurs from November to March, including a maximum in February. After two months of this peak, juveniles reached maximum abundances (April) in high relief reef areas. Adults, however, show a preference towards rocky bottoms covered with algae interspersed with sand patches, suggesting ontogenetic changes in microhabitat preferences when juveniles turn into adultsSimiliparma lurida es un pez común que habita en aguas poco profundas de fondos rocosos someros de los archipiélagos oceánicos del Atlántico Norte, y las costas desde Portugal a Senegal. Este estudio se conceptualizó para integrar información relativa a atributos poblacionales clave de S. lurida, incluyendo: estructura de tallas y edad, crecimiento, reproducción y talla de primera madurez con la descripción de los patrones de abundancia en arrecifes poco profundos, incluyendo la temporalidad en el reclutamiento y preferencias de hábitat por juveniles, sub-adultos y adultos. Esta especie alcanza hasta 15.7 cm de longitud total (LT) y 18 años de edad. Los machos crecen más rápido y son más largos (K=0.28 years–1, L∞=14.487 cm LT) que las hembras (K=0.23 years–1, L∞=13.461 cm LT), lo que afecta a la sex ratio de machos y hembras (1:0.26). El tamaño en el que se alcanza el 50% de la madurez sexual fue 10.344 cm (LT) para los machos y 8.471 cm (LT) para las hembras. El crecimiento es mayor durante la temporada de desove, que ocurre de noviembre a marzo, incluyendo un máximo reproductivo en febrero. Dos meses después de este pico (abril), los juveniles alcanzaron abundancias máximas en zonas de arrecifes de gran relieve. Los adultos, sin embargo, muestran una preferencia hacia los fondos rocosos cubiertos de algas intercaladas con parches de arena, lo que sugiere cambios ontogenéticos en las preferencias de micro-hábitat cuando los juveniles se desarrollan en adultos

Thinking of fish population discrimination: population average phenotype vs. population phenotypes

The genetic polymorphism and phenotypic variation are key in ecology and evolution. The morphological variability of the contour of fish otoliths has been extensively used for the delimitation of stocks. These studies are conventionally based on average phenotype using elliptic Fourier analysis and lineal discriminant analysis as classifier. Considering new analytical options, such as the wavelet transformand non-parametric algorithms, we here analyzed the otolith shape of Trachurus picturatus (blue jack mackerel) from mainland Portugal, Madeira, and the Canaries. We explore the phenotypic variation throughout a latitudinal gradient, establish a hypothesis to explain this variability based on the reaction norms, and determine how the use of average phenotype and/or morphotypes influences in the delimitation of stocks. Four morphotypes were identified in all regions, with an increase of phenotypes in warmer waters. The findings demonstrated that stocks were clearly separated with classification rates over 90%. The use of morphotypes, revealed seasonal variations in their frequencies and per region. The presence of shared phenotypes in different proportions among fishing grounds may open new management approaches in migratory species. These results show the importance of the phenotypic diversity in fisheries management.Preprin

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

The shell phenotypic variability of the keyhole limpet Fissurella latimarginata: insights from an experimental approach using a water flow flume

Hydrodynamics are a major environmental factor on intertidal rocky shores. Morphological responses to this factor are expected to strongly influence spatial distribution of species across environmental gradients. We here analysed the shell phenotypic variability of the limpet Fissurella latimarginata using geometric mor phometric analysis. The limpets were obtained from a sheltered intertidal coastal area and a wave-exposed environment. To determine whether the shell shape variation of the intertidal molluscs is linked to their resistance to differential intertidal wave exposure, mesocosm studies were developed in a hydraulic flume to explore the effects of hydrodynamic forces on this limpet species. A unidirectional current was used to test the impacts of step-by-step increased current flow velocities for each limpet. The phenotypic variability observed in the populations of F. latimarginata was associated with habitats characterized by contrasting wave exposure. Limpets from exposed environments showed a flattened, round to laterally wider and posteriorly narrower shell shape, larger foot and higher full limpet height, and were dislodged at higher velocities. A more laterally compressed and peaked shape was found in limpets from sheltered areas and these showed a lower resistance to wave action by dislodging at lower velocities.info:eu-repo/semantics/publishedVersio

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

Mesozooplankton size structure in the Canary Current System

Changes in plankton composition influences the dynamics of marine food webs and carbon sinking rates. Understanding the core structure and function of the plankton distribution is of paramount importance to know their role in trophic transfer and efficiency. Here, we studied the zooplankton distribution, abundance, composition, and size spectra for the characterization of the community under different oceanographic conditions in the Canaries-African Transition Zone (C-ATZ). This region is a transition zone between the coastal upwelling and the open ocean showing a high variability because of the physical, chemical, and biological changes between eutrophic and oligotrophic conditions through the annual cycle. During the late winter bloom (LWB), chlorophyll a and primary production were higher compared to that of the stratified season (SS), especially in the upwelling influenced area. Abundance distribution analysis clustered stations into two main groups according to the season (productive versus stratified season), and one group sampled in the upwelling influenced area. Size-spectra analysis showed steeper slopes during daytime in the SS, suggesting a less structured community and a higher trophic efficiency during the LWB due to the favorable oceanographic conditions. We also observed a significant difference between day and nighttime size spectra due to community change during diel vertical migration. Cladocera were the key taxa differentiating an Upwelling-group, from a LWB- and SS-group. These two latter groups were differentiated by Salpidae and Appendicularia mainly. Data obtained in this study suggested that abundance composition might be useful when describing community taxonomic changes, while size-spectra gives an idea of the ecosystem structure, predatory interactions with higher trophic levels and shifts in size structure

First record of African brown snapper Lutjanus dentatus in the Canary Islands (north-eastern Atlantic Ocean)

3 pages, 1 figureThe African brown snapper Lutjanus dentatus is a fish native of the West African coastal zone of the Atlantic Ocean. Here we document the first recorded capture of this species in the Canary Islands, an archipelago close to Africa, in August 2013Peer reviewe

Identificación de especies de peces de origen lessepsiano mediante el otolito sagita

11 pages, 5 figures, 2 tables[EN] Lessepsian species are marine organisms that enter the Mediterranean through the Suez Canal, a phenomenon that has dramatically increased in recent decades. The present study describes the morphological characteristics of the sagittal otoliths of 22 Lessepsian fish species collected at four locations in the Mediterranean Sea. These structures are commonly used in the identification of species found in the digestive tracts of predators, and their morphological description is mainly needed as a tool for trophic studies. Here we used the Automated Taxon Identification (ATI) system of the AFORO web database to determine the accuracy of classifying Lessepsian fish otoliths compared with otoliths of native Mediterranean species. The otolith contour analysis correctly classified 92.5% of the specimens, showing that these species have otoliths that can be clearly distinguished from native ones. Four different groups of otoliths were identified according to the morphological differences between the otoliths and the ATI analysis results: a) unusual shapes with no similarities to native species; b) unusual shapes with similarities to phylogenetically distant native species; c) common shapes with similarities to phylogenetically close native species; and d) common shapes with morphological characters related to other native congeners, although they are not classified with them[ES] Las especies lessepsianas son aquellos organismos marinos que invaden el Mediterráneo a través del Canal de Suez, fenómeno que se ha incrementado drásticamente en los últimos años. El presente trabajo describe las características morfológicas del otolito sagita de 22 especies de peces recolectadas en cuatro localidades del Mediterráneo. Estas estructuras son empleadas normalmente en la identificación de las especies presentes en los tubos digestivos de sus depredadores, y su descripción morfológica es necesaria en la mayoría de estudios tróficos. En este estudio, se empleó el sistema automatizado de reconocimiento específico (ATI) de la web AFORO con el objeto de determinar la precisión en la clasificación de estas especies respecto a otras especies nativas que cohabitan en el Mediterráneo. El porcentaje correcto de clasificación alcanzó el 92.5% de los casos, mostrando que estas especies tienen otolitos claramente diferenciables. Cuatro grupos de otolitos se identificaron teniendo en consideración las diferencias morfológicas encontradas y los resultados del análisis de ATI: a) formas peculiares no análogas a otras especies nativas, b) formas peculiares con analogías con especies nativas filogenéticamente muy distintas, c) formas comunes con analogías con especies nativas filogenéticamente cercanas, y d) formas comunes con caracteres morfológicos similares a otras especies nativas, si bien no fueron clasificadas con ellasThis research was carried out within the project ‘The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea’, and supported by the AFORO3D project (CTM2010-19701)Peer reviewe

Otolitos de peces del Mediterráneo occidental y del Atlántico central y nororiental

Final version of the paper available at: http://www.icm.csic.es/scimar/index.php/secId/6/IdArt/3723/.[EN] The sagittal otolith of 348 species, belonging to 99 families and 22 orders of marine Teleostean fishes from the north and central eastern Atlantic and western Mediterranean were described using morphological and morphometric characters. The morphological descriptions were based on the otolith shape, outline and sulcus acusticus features. The morphometric parameters determined were otolith length (OL, mm), height (OH, mm), perimeter (P; mm) and area (A; mm2) and were expressed in terms of shape indices as circularity (P2/A), rectangularity (A/(OL×OH)), aspect ratio (OH/OL; %) and OL/fish size. The present Atlas provides information that complements the characterization of some ichthyologic taxa. In addition, it constitutes an important instrument for species identification using sagittal otoliths collected in fossiliferous layers, in archaeological sites or in feeding remains of bony fish predators[ES] Se han descrito morfológica y morfométricamente los otolitos sagitta de 348 especies, pertenecientes a 99 familias y 22 ordenes, procedentes de Atlántico Oriental Central y Norte y el Mediterráneo occidental. La descripción morfológica se ha basado en las caraterísticas de la forma del otolito, de su contorno y del surco acústico. Se han dterminado los parámetros biométricos siguientes: longitud del otolito (OL, mm), anchura (OH, mm), perímetro (P; mm) y área (A; mm2) y se han expresado con distintos índices de forma: circularidad (P2/A), rectangularidad (A/(OL×OH)), aspecto (OH/OL; %) y OL/longitud del pez. Este atlas da nueva información para complementar la caracterización de algunos taxones ictiológicos. Además, constituye un instrumento importante para identificar especies mediante otolitos sagitta en yacimientos fósiles y arqueológicos o en estudios de alimentación de especies ictiófagasPeer reviewe