• European Marine Science
• Mediterranean Marine Science close

The genus Pinna includes two species in the Mediterranean Sea: Pinna nobilis and Pinna rudis. Both these species are under threat from multiple stressors. Pinna nobilis, in particular, has been exhibiting mass mortality events (MMEs) since 2016. The population and distribution of these species have never been comprehensively explored in the Maltese archipelago, and in this work, we collate information collected between 2006 and 2019 through a number of SCUBA underwater visual census monitoring programs. The logistical barriers surrounding SCUBA-based sampling techniques and the low-density distribution of these species constitute significant obstacles to an extensive conventional population assessment. Citizen science was thus also deployed in this study to supplement the data collected through SCUBA surveys: recreational SCUBA divers worked as citizen scientists, providing data on the distribution of these two endangered species from areas never explored before. This information can be used for assessing the conservation status of P. nobilis and P. rudis in Maltese waters, whilst contributing to the next generation of ocean-literate citizens.

Human activities have put the ocean under unprecedented pressure. Nevertheless, levels of public awareness of ocean issues remain low. Ocean literacy is a global movement that aims to improve the understanding of the ocean and provide an incentive for positive change in people's behaviour. To date, there is no validated scale targeted to adults to measure ocean literacy that includes measuring people's knowledge about the ocean, as well as surveying their attitudes and willingness to act. The Blue Survey, an on -line instrument meant to measure ocean literacy in adult populations, was developed by a multidisciplinary team of experts. Using factor analysis, the present study explores the validity and internal consistency of the Blue Survey in a purposive online sample of 251 adults. We found ocean literacy to consist of six sub-dimensions captured by 34 survey items, viz. knowledge of ocean-related topics, personal interest in ocean-related aspects, ocean stewardship, ocean as an economic resource, ocean-friendly behaviour, and willingness to act responsibly towards the ocean. Our analysis resulted in the development of a new validated instrument to measure the various dimensions of ocean literacy. These results may help researchers and practitioners to better understand the factors which contribute to shaping an ocean-literate person. Further research should be carried out to assess the validity of the Blue Survey across different populations, including those closely related to the sea, such as maritime professionals.

Paracaprella pusilla MAYER, 1980 is a tropical caprellid amphipod species first described from Brasil and very common along the Atlantic coast of Central America. Since its original description, P. pusilla has been found at numerous widespread locations in tropical and subtropical seas around the world, primarily associated with fouling communities in harbours. An established population of P. pusilla was recently found in Cádiz, southern Spain, which is both the northernmost collection and first record of this species in European coastal waters. Ship fouling is the most probable vector for its introduction. The species was always found associated with the native hydroid Eudendrium racemosum (CAVOLINI, 1785) and appeared to display a mutualistic relationship with this host.

An evaluation of the performance of artificial networks (ANNs) to estimate the weights of blue crab (Callinectes sapidus) catches in Yumurtalık Cove (Iskenderun Bay) that uses measured predictor variables is presented, including carapace width (CW), sex (male, female and female with eggs), and sampling month. Blue crabs (n=410) were collected each month between 15 September 1996 and 15 May 1998. Sex, CW, and sampling month were used and specified in the input layer of the network. The weights of the blue crabs were utilized in the output layer of the network. A multi-layer perception architecture model was used and was calibrated with the Levenberg Marguardt (LM) algorithm. Finally, the values were determined by the ANN model using the actual data. The mean square error (MSE) was measured as 3.3, and the best results had a correlation coefficient (R) of 0.93. We compared the predictive capacity of the general linear model (GLM) versus the Artificial Neural Network model (ANN) for the estimation of the weights of blue crabs from independent field data. The results indicated the higher performance capacity of the ANN to predict weights compared to the GLM (R=0.97 vs. R=0.95, raw variable) when evaluated against independent field data.

Human activities are increasingly impacting biodiversity. To improve conservation planning measures in an ecosystem-based management context, we need to explore how the effects of these activities interact with different biodiversity components. In this study, we used a semi-quantitative method to assess the cumulative impacts of human activities on three biodiversity components (species richness, phylogenetic diversity, and functional diversity) in Tunisia's exclusive economic zone. For each of the nine activities considered, we developed an understanding of their effects from local studies and the expert opinion of stakeholders with country-speciic experience. We mapped the cumulative effects and the three biodiversity components and then assessed the degree to which these elements overlapped using an overlap index. This is the first time such an assessment has been made for Tunisia's marine ecosystems and our assessment highlight the inappropriateness of current conservation measures. The results of this study have specific application for the prioritization of future management actions. International audience

An adult individual of swordfish (Xiphias gladius L.) was reported for the first time aggregated at coastal Mediterranean fish-farm facilities. This record highlights the necessity to assess the potential ecological changes on wild fish assemblages by coastal farming activity, especially on this type of endangered large migratory fish predators, which might be taken into account for further management strategies.

Both heat shock proteins (HSPs), which have key roles in vital cell functions, as well as members of the mitogen-activated protein kinases (MAPKs), which adjust gene expression by transducing cellular signals to the nucleus, are necessary for normal embryonic development in vertebrates. Therefore, protein expression levels of HSP70 and HSP90 and the activation of members of the MAPK protein family, such as p38 MAPK, ERKs, and JNKs were studied in the early developmental stages of the Gilthead sea bream, Sparus aurata Linnaeus, 1758. The protein expression of HSP70 and the phosphorylation ratio of JNKs remained at equal levels at all examined developmental stages, while the other examined proteins exhibited a differential profile. HSP90 levels were mostly increased at the 16-cell stage and towards the morula stages, and the lowest values were observed at the two- to four-cell and one-half epiboly stages. While p38 MAPK phosphorylation ratio exhibited increased values mostly in the early developmental stages, the opposite was observed concerning ERK phosphorylation ratio, where increased values were observed in the later embryonic stages (high blastula to one-half epiboly stages). These differential profiles of the examined protein expression levels highlight the importance of these proteins during embryogenesis and pave the way for further research to unveil their distinct role in early development.