6 pages, 4 figures ; The occurrence of the rendezvous fish, Polymetme corythaeola (Alcock, 1898) in Mediterranean Sea is here reported for the first time. A single individual of this benthopelagic fish was caught in February 2020 during a scientific trawl survey. The specimen was collected at a depth of 369 m (upper slope) in the Gulf of Roses (Catalonia, north-western Mediterranean). This circumglobal species could have naturally expanded its distribution through the Strait of Gibraltar, but we cannot totally exclude that its Mediterranean occurrence has been overlooked thus far. This finding highlights the importance of continuous monitoring of Mediterranean deep-sea habitats for a better understanding of their diversity and ongoing transformation ; The ICATMAR-PESCAT project (ref: ARP/1256/2018) was financed by funding from the Catalan Government and European Union FEMP ; With the institutional support of the 'Severo OchoaCentre of Excellence' accreditation (CEX2019-000928-S) ; Peer reviewed
8 pages, 7 figures, 2 tables ; [EN] The sagittal otolith and eye diameter of two sympatric species of the genus Aphanopus, A. carbo and A. intermedius, from North Atlantic waters were investigated. The study objectives were to find morphometric variables of otoliths to identify the two species and relate ecomorphological characters of otolith and eye diameter to the depth distribution of each species. The otoliths of the two species are very similar, although significant differences in shape, otolith height and weight and the sulcus acusticus area were detected. The ratio between eye diameter and cephalic length (ED:CL ratio) was also significantly different. In both analyses A. carbo obtained higher values, which suggests that A. carbo and A. intermedius live in different spatial niches, and that A. carbo inhabits deeper waters. The ratio between the sulcus and otolith areas (S:O) was low compared to other fish species, which suggests that the hearing capacity of Aphanopus spp. is adapted to low frequency sound. This adaptation may be related to the oceanographic conditions in which these species live, and in particular to the characteristics of sound transmission in the "SOFAR channel" ; [ES] El otolito sagitta y el diámetro del ojo de dos especies simpátricas del género Aphanopus, A. carbo y A. intermedius, del Atlántico Norte fueron analizados. Los objetivos del estudio se centraron en encontrar las variables morfométricas del otolito que pudiesen ser empleadas en la diferenciación de ambas especies y en establecer una correspondencia entre la profundidad de distribución de las especies y las características ecomorfológicas del otolito y del diámetro del ojo. Los otolitos de ambas especies resultaron ser parecidos, si bien se detectaron diferencias significativas en la forma, en el peso y la anchura del otolito y en el área del sulcus acusticus. La proporción entre el diámetro del ojo y la longitud cefálica (ED:CL) también puso de manifiesto diferencias significativas entre ambas especies. En ambos análisis, los resultados indicaron que A. carbo alcanza valores mayores. Ello proporciona evidencias para poder afirmar que A. carbo y A. intermedius viven en nichos espaciales diferentes, habitando A. carbo aguas más profundas. La proporción entre al área del sulcus y el área del otolito (S:O) alcanzó valores bajos en comparación con otras especies, lo cual sugiere que la capacidad auditiva de Aphanopus spp. está adaptada a sonidos de baja frecuencia. Dicha adaptación podría estar relacionada con las condiciones oceanográficas donde viven estas especies y, en particular, con las características de la transmisión del sonido dentro del denominado "canal SOFAR" ; This study was co-funded by the research project PESCPROF 3 (ref: 05/MAC/4.2/M11 and co-financed by EU Interreg III-B programme), and pursued in collaboration with the pilot projects RAI-AP 36/2005 and 37/2005 co-financed by the EU and the Spanish Government ; Peer reviewed
12 pages, 4 figures, 2 tables ; [EN] 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 ; [ES] 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 ; Data of this study were financed by the projects "ESCAL 1" (Ref. PCC30004/99) and "ESCAL 2" (Ref. 02P30015) of the Directorate General of Fisheries of the Government of Catalonia, and "CONFLICT" (Ref. CGL2008-00047) of the Spanish National Research Council. Marc Farré Foix acknowledges a pre-doctoral grant and a third cycle tuition fee grant from the Government of Andorra, ATC-010-AND and AMTC010-AND/2013, academic years 2013-2014 and 2014-2015 ; Peer Reviewed
10 pages, 8 figures, 4 tables ; [EN] The sagittae otolith morphology of marine fishes has been used in many ecomorphological studies to explain certain ecological adaptations of species to habitat. Our study compares the sagittal otolith shapes of ten species of snappers (Family Lutjanidae) inhabiting the Persian Gulf. We used a morphometric analysis of the otolith measurements (length, height, perimeter, area and weight) and of the ratio between the area of the sulcus acusticus and the area of the otolith (S:O). The otolith contour was also analysed using wavelets as a mathematical descriptor. Morphological variations in the otoliths were associated with the morphology and external colouration of snappers as well as ecological traits. An analysis of the interspecific S:O ratio suggested that the highest ratios occurred in snappers inhabiting shallower waters. A categorical multivariate analysis, including morphological, ecological and otolith size factors, showed that the species adapted to dim light conditions had a greater otolith perimeter. An analysis of variance of the otolith contour revealed zones with a higher interspecific variability, although only the antero-dorsal zone showed differing patterns. Although the otolith patterns appear to have a phylogenetic component, they might also be related to diel activity rhythms or to the light conditions in the habitat. The results of the study showed that variation in otolith morphology can be used to explain the coexistence of sympatric species ; [ES] La morfología del otolito sagitta de peces marinos se ha empleado en estudios de ecomorfología al objeto de explicar las adaptaciones ecológicas de las especies al hábitat. Nuestro estudio compara la forma del otolito de diez especies de pargos (familia Lutjanidae) del Golfo Pérsico. El análisis morfológico se realizó a partir de medidas del otolito (longitud, anchura, perímetro, área y peso) y la proporción entre el área del sulcus acusticus y del otolito (S:O). También se analizaron los contornos de los otolitos mediante descriptores matemáticos denominados wavelets. Las variaciones morfológicas en los otolitos se asociaron a la morfología y la coloración externa de los pargos, así como a diversos caracteres ecológicos. Las especies con valores más elevados en la proporción S:O habitan en aguas someras. El análisis multivariante categórico de factores, ecológicos y morfológicos del otolito (forma y tamaño), puso de manifiesto que las especies adaptadas a con- diciones tenues de luz presentan el perímetro del otolito más grande. El análisis de varianza del contorno del otolito reveló la presencia de zonas con gran variabilidad inter-específica, si bien solo la parte antero-dorsal permitió distinguir patrones claros de variación. Aunque dichos patrones parecen tener un componente filogenético, también estarían relacionados con el ritmo de actividad diaria o las condiciones de luminosidad en las que viven las especies. Los resultados del este estudio demuestran que la variación morfológica del otolito puede ser usada para explicar la coexistencia de especies simpátricas ; This study was co-funded by the research project AFORO3D (MICIN CTM2010-1970) of the Spanish Government ; Peer reviewed
12 pages, 5 figures, 2 tables ; The identification of fish species using otolith shape has been common in many fields of the marine science. Different analytical processes can be applied for the morphological discrimination, but reviewing the literature we have found conceptual and statistical limitations in the use of shape indices and wavelets (contour analysis), being specially worrying in the first case due to their widespread routine use. In the present study, 42 species were classified using otolith shape indices and wavelets and applying traditional and machine learning classifiers and performance measures (accuracy, Cohen's kappa statistic, sensitivity, and precision). Our results were conclusive; wavelets were a more adequate option for the classification of species than shape indices, independently of classifiers and performance measures considered. The artificial neural network and support vector machine provided the highest values for all performance measures using wavelets. In all cases, the measures of sensitivity and precision pointed out a higher confusion between some otolith patterns using shape indices. Therefore, we strongly discourage the routine use of shape indices for the identification of species ; This study was supported by the Catalan Government project PESCAT (FEM/DARP/1256/2018). With the funding support of the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI) ; Peer reviewed
8 pages, 6 figures, 2 tables, supplementary material https://dx.doi.org/10.1016/j.wasman.2019.07.004 ; Fisheries are one of the main economic sectors affected by marine litter, which can damage gear, reduce catch, and require time to repair or clean nets. This study aims to evaluate the type and density of marine litter in two shallow fishing grounds in the NW Mediterranean Sea, both belonging to the Natura 2000 network. Moreover, it quantifies the fraction of marine litter within the total catch to help understand the potential influence of marine litter on fisheries. Two study areas were selected, one in the vicinity of urban populated areas and high navigational traffic and one in a rural site off an agricultural area. The urban area had more benthic marine litter (393 to 198 kg km) including clinker (residue from coal-burning steamships), fabric, plastics, and processed wood and accounting for up to 38% of the total catch. The rural area had far less marine litter (34–56 kg km), accounting for only 5% of the total catch. Marine litter may have potential negative effects on fisheries; thus we propose that government credit trading programs could be promoted to help recover litter from fishing catches, to reduce fishing costs and hazards to marine ecosystems ; This paper is a result of the research project "Evaluación y seguimiento del Plan de Gestión de Dragas para Embarcación", ref. AG-2016-233, funded by the Department d'Agricultura, Ramaderia i Pesca (Generalitat de Catalunya) ; Peer Reviewed
