Protocolo de anestesia y recuperación para estudio de morfometría de juveniles de caballito de mar, (Hippocampus hippocampus (Linnaeus, 1758)

Anaesthetic and Recovery Protocol for morfometric study of Atlantic seahorse, Hippocampus hippocampus (Linnaeus, 1758), juveniles. Some morphometric studies in marine organism need anaesthetics in order to avoid animal?s sacrifice and allow its recovery. In this study different natural clove essential concentrations has been tested in Atlantic seahorses, Hippocampus hippocampus (Linnaeus, 1758) aged 13 (trunk length 7,48 ± 1,14 mm) and 22 days (trunk length 9,09 ± 1,62 mm). An inversed relation was observed between anaesthetic concentration and effective time. The concentration allowing measures was 25 ppm. This procedure allowed 100% survival rate.

Efecto de la primera alimentación en la supervivencia y el crecimiento de crías de caballito de mar, Hippocampus hippocampus (Linnaeus, 1758)

[EN]Effects of first feeding on survival and growth of Atlantic seahorse juveniles, Hippocampus hippocampus, (Linnaeus, 1758). In this study, two experimental protocols were tested: a first treatment (RA), in which larvae were fed exclusively on rotifers until day 5, and then on Artemia, and a second treatment (A) where larvae were only fed on Artemia. We attempted to improve survival and growth by comparing different diets in the first days of life. The results showed excellent survival (60% average) and growth in juveniles exclusively fed with Artemia, with better values than those obtained by other authors for this species. In comparison, high mortality and poor growth were observed on the first days in larvae fed rotifers.

Effect of rearing technique over skeletal deformities incidence and osteological development in red porgy Pagrus pagrus (Linnaeus, 1758) larvae

[EN]Red porgy is a candidate species for marine aquaculture diversification.The objective of the present study was to describe the osteological development and the occurrence of skeletal deformities in Pagrus pagrus larvae in relation to the intensification of the rearing system. Fish samples were periodically collected along the development from hatching to juveniles (95days after hatching). Osteological development and the presence of skeleton abnormalities were evaluated. X-ray studies revealed a high number of fish (Semi-intensive:38.8%; Intensive:46.5 %) with skeletal deformities. No significant interaction was found on the incidence of lordosis and fused vertebrae with the rearing tecnique. However, cranial abnormalities and kyphosis incidences were significantly higher in intensive system cultured red porgy. Also, the position of fused vertebrae in this fish was located mainly in the caudal area instead of pre-hemal area for semi-intensive system reared red porgy. Present results, suggest a relationship among feeding sequence, osteological development and deformity incidence and location in red porgy larvae

Experiencias preliminares de cultivo de crías de Hippocampus hippocampus (Linnaeus, 1758) en Gran Canaria

[EN]Seahorses husbandry constitute an innovative aspect on the recovery of wild populations. In this study, two aeration levels were tested (normal and strong) in seahorse juveniles fed on Artemia. Survival and growth were evaluated. The results showed higher survivals (11% average) with strong aerations levels after 90 days. In addition, these juveniles were able to reproduce after 4 months, denoting the early sexual maturation of this species. However, sizes of second-generation larvae at day 0 were smaller compared with those produced by their parents

Reproductive biology of Boops boops (Linnaeus, 1758) off Gran Canaria (Canary Islands): a preliminary study

[EN] Preliminary data of the length-weight relationship and reproduction of the bogue Boops boops off Gran Canaria (Canary Islands, Central-east Atlantic) are provided. Two thousand and twenty-one individuals of bogue, ranging from 4 to 34 cm TL, were obtained from purse seine commercial landing. Reproduction parameters as sex determination, duration of spawning season, size at first maturity and GSI variation along time were determinated based on macroscopic evaluation of gonads. The results obtained suggest that bogue is a total spawner, with a long spawning season extending from January to May. Size at first maturity was 16.7 and 17.9 cm TL for males and females, respectively. The length-weight relationship obtained showed a positive allometry in both sexes

Efecto del color del oponente en el comportamiento agresivo del Grapsus grapsus (Linnaeus, 1758) (Crustacea, Decapoda)

[ES] El comportamiento agresivo del cangrejo moro (Grapsus grapsus) ante un modelo de competidor potencial no varió en función del color corporal de este último. No obstante, se observaron cambios en dicho comportamiento en función del tamaño del individuo residente, aumentado la intensidad de los ataques cuanto menores eran las asimetrías en talla

Caracterización histológica del desarrollo del sistema visual en larvas de Dorada Sparus aurata (Linnaeus 1758)

[ES] El objetivo del presente estudio es aportar nuevos conocimientos sobre el desarrollo del sistema visual en los primeros estadios larvarios de dorada. El entendimiento de la ontogenia del sistema visual puede contribuir a la mejora en las condiciones de iluminación en el cultivo, las cuales podrían tener repercusiones en la obtención de larvas de mejor calidad y unas mayores tasas de supervivencia en el cultivo larvario. Las larvas de la mayoría de los peces son predadores visuales, lo que indica la gran importancia que juega el sistema visual en desarrollo (BLAXTER, 1986). El comportamiento trófico de la larva estará intimamente ligado al desarrollo de su capacidad visual, que depende directamente de la organogénesis de la retina. El estudio muestra que durante el desarrollo post-embrionario y en las primeras etapas de vida larvaria, el sistema visual de dorada Sparus aurata, histologicamente, es muy similar al descrito por otros autores para especies similares, Pagrus major (KAWAMURA,1984), Pagrus auratus (PANKHURST, 1996) y Pagrus pagrus (L. 1758 ) (ROO et al.,1998). El tercer día de vida de la larva es uno de los mas importantes, necesita estar preparada para capturar y digerir sus presas. En este día la larva muestra todas las estructuras necesarias para la función visual. El epitelio pigmentario bien definido, el músculo de la lente esta presente y el iris esta completamente formado. Las condiciones de iluminación que se utilizan en los criaderos comerciales difieren bastante de las condiciones naturales, pudiendo ser un factor a tener en cuenta para la obtención de una mejor calidad de larvas así como unas mejores tasas de supervivencia.

Effect of different live prey, Grapsus grapsus Linnaeus 1758 and Plagusia depressa Fabricius, 1775 zoeas,over histology and biochemical composition of common octopus, octopus vulgaris Cuvier, 1797 paralarvae

[EN] Since paralarval rearing is still the main bottleneck for the development of octopus culture, the aim of the present study was to obtain some information on the feeding strategy and nutritional requirements during paralarval stage. For that purpose just hatched out octopus paralarvae were fed with live preys in three different combinations, trying to match their natural food: Enriched Artemia metanauplii, Grapsus grapsus zoeas supplemented with enriched Artemia, and Plagusia depressa zoeas supplemented with enriched Artemia. Paralarval treatments were carried out during 28 days in triplicates; fibre glass 120 l tanks in flow through system were used. Growth, in terms of dry body weight, mantle length and width, was determined each seven days. A histological study of the paralarval development was carried out. Biochemical composition of preys and paralarvae were determined. Growth was significantly better in paralarvae fed with zoeas and Artemia than in those fed only with Artemia, from day 8 after hatching. Besides a clear effect on the digestive gland histology morphology was observed.

Aspectos biológicos y ecológicos del tiburón ángel "Squatina squatina" (Linnaeus 1758) en la isla de Gran Canaria

Esta tesis contiene los cambios sugeridos por el tribunal

Genetic variability and structuring of deep Corallium rubrum (Linnaeus, 1758) populations

ABSTRACT Given the decline of shallow-water red coral populations resulting from over-exploitation and mass mortality events, deeper populations below 50 metres depth (mesophotic populations) are currently the most harvested; unfortunately, very little is known about their biology and ecology. The persistence of these populations is tightly linked to their adult density, reproductive success, larval dispersal and recruitment. Moreover, for their conservation, it is paramount understand processes such as connectivity within and among populations. Here, for the first time, genetic variability and structuring of Corallium rubrum populations collected in the Tyrrhenian Sea ranging from 58 to 118 metres were analyzed using ten microsatellite loci and two mitochondrial markers (mtMSH and MtC). The aims of the work were 1) to examine patterns of genetic diversity within each geographic area (Elba, Ischia and Praiano) and 2) to define population structuring at different spatial scales (from tens of metres to hundreds of kilometres). Based on microsatellite data set, significant deviations from Hardy-Weinberg equilibrium due to elevated heterozygote deficiencies were detected in all samples, probably related to the presence of null alleles and/or inbreeding, as was previously observed in shallow-water populations. Moreover, significant levels of genetic differentiation were observed at all spatial scale, suggesting a recent isolation of populations. Biological factors which act at small spatial scale and/or abiotic factors at larger scale (e.g. summer gyres or absence of suitable substrata for settlement) could determine this genetic isolation. Using mitochondrial markers, significant differences were found only at wider scale (between Tuscany and Campania regions). These results could be related to the different mutation rate of the molecular makers or to the occurrence of some historical links within regions. A significant isolation by distance pattern was then observed using both data sets, confirming the restricted larval dispersal capability of the species. Therefore, the hypothesis that deeper populations may act as a source of larvae helping recovery of threatened shallow-water populations is not proved. Conservation strategies have to take into account these results, and management plans of deep and currently harvested populations have to be defined at a regional or sub regional level, similarly to shallow-water populations. Nevertheless, further investigations should be needed to understand better the genetic structuring of this species in the mesophotic zone, e.g. extending studies to other Mediterranean deep-water populations.

Identification of stock units of Mullus barbatus (Linnaeus, 1758) in the Italian seas: development of genomic 2b-RAD markers and biological variation analysis.

This thesis is settled within the STOCKMAPPING project, which represents one of the studies that were developed in the framework of RITMARE Flagship project. The main goals of STOCKMAPPING were the creation of a genomic mapping for stocks of demersal target species and the assembling of a database of population genomic, in order to identify stocks and stocks boundaries. The thesis focuses on three main objectives representing the core for the initial assessment of the methodologies and structure that would be applied to the entire STOCKMAPPING project: individuation of an analytical design to identify and locate stocks and stocks boundaries of Mullus barbatus, application of a multidisciplinary approach to validate biological methods and an initial assessment and improvement for the genotyping by sequencing technique utilized (2b-RAD). The first step is the individuation of an analytical design that has to take in to account the biological characteristics of red mullet and being representative for STOCKMAPPING commitments. In this framework a reduction and selection steps was needed due to budget reduction. Sampling areas were ranked according the individuation of four priorities. To guarantee a multidisciplinary approach the biological data associated to the collected samples were used to investigate differences between sampling areas and GSAs. Genomic techniques were applied to red mullet for the first time so an initial assessment of molecular protocols for DNA extraction and 2b-RAD processing were needed. At the end 192 good quality DNAs have been extracted and eight samples have been processed with 2b-RAD. Utilizing the software Stacks for sequences analyses a great number of SNPs markers among the eight samples have been identified. Several tests have been performed changing the main parameter of the Stacks pipeline in order to identify the most explicative and functional sets of parameters.

Studio della presenza di capodogli (Physeter macrocephalus, Linnaeus 1758) in due aree del Mar Balear mediante metodi acustici passivi

I capodogli (Physeter macrocephalus) sono mammiferi marini con distribuzione cosmopolita; sono presenti anche nel Mar Mediterraneo, soprattutto nella zona occidentale del bacino. Per individuare la presenza di questi animali possono essere utilizzate differenti modalità. Questo studio è stato condotto tramite l’uso di metodi acustici passivi, in quanto i capodogli (P. macrocephalus) sono animali che emettono suoni. L’uso di metodi acustici ha alcuni vantaggi, infatti permette di individuare la presenza di un animale anche se si trova al di sotto della superficie dell’acqua, purché stia emettendo suoni. Le registrazioni possono essere effettuate indipendentemente dalle condizioni meteorologiche e per lunghi periodi di tempo, permettendo la continuità nella raccolta dei dati. Il lavoro di tesi è stato svolto nell’ambito di un Progetto di Ricerca de L’Oceanogràfic di Valencia. Le registrazioni sono state effettuate tramite lo strumento EAR (Ecological Acoustic Recorder) in due aree del Mar Balear, il Mar di Bamba e il Parco Nazionale di Cabrera, in differenti periodi, profondità e con diverse frequenze di campionamento (50 kHz e 5 kHz). I dati ottenuti sono stati analizzati tramite i programmi X-BAT (Extensible Bioacoustic Tool) e Adobe Audition 3.0 al fine di rilevare i pulsi emessi dai capodogli. Per entrambe le aree di studio i dati sono stati elaborati in modo da ottenere modelli giornalieri e stagionali delle ore positive e del numero di pulsi emessi. La presenza di P. macrocephalus è stata confermata in entrambe le aree di studio, e dal confronto delle analisi spettrali dei pulsi si può affermare che, nonostante le differenze, i pulsi registrati in entrambe le aree sono effettivamente emessi da capodogli. Il lavoro di Tesi permette di suggerire che per futuri studi sia applicata la frequenza di registrazione di 20 kHz utilizzando lo strumento SAMARUC, alla cui progettazione ha partecipato L’Oceanogràfic di Valencia.