Feeding habits and helminth parasites of sardine (S. pilchardus) and anchovy (E. encrasicolus) in the Adriatic Sea

We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet

First record of small tropical calanoid copepod Parvocalanus crassirostris (Copepoda, Calanoida, Paracalanidae) in the Adriatic Sea

In December 2014 the adult females and copepodites of alien paracalanid copepod Parvocalanus crassirostris were identified in the Central Adriatic port of Šibenik. The most probable transmission vector for this small copepod were ballast waters from the cargo ships that are regularly discharged at these locations. This paper is focused on P. crassirostris morphology and the state of population in the port of Šibenik. The possible path of introduction of Parvocalanus crassirostris into the Adriatic Sea is also discussed

Feeding habits and helminth parasites of sardine (S. pilchardus) and anchovy (E. encrasicolus) in the Adriatic Sea

We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet

Analysis of phytoplankton community in the vicinity of domestic sewage outflow during stratified conditions

The response of phytoplankton community structure to anthropogenically-derived nutrient from the submarine sewage outflow was analysed in a shallow coastal area of the middle Adriatic Sea. The study was conducted during the eight-year period (2002-2010) at six stations in the Brač Channel, aiming to assess the potential change in the state of biological and environmental parameters before and after the sewage commissioning. The research was particularly focused on phytoplankton producers during the summer which is considered to be critical due to water stratification and low water dynamics. The results show an increase in phytoplankton biomass in the deep layer after the discharge activation that was significant (M-W test; U=584.5, p<0.01), but not related to any intense phytoplankton bloom or oxygen deficiency. Temporal variability of total phytoplankton abundances throughout the research period indicated a significant increase in 2005, the year following the sewage outflow activation. Pairwise Dunn's multiple comparison test emphasised the difference in the years before the sewage activation (2002, 2003) compared to 2005 (2002 vs. 2005, R=-60.92 p<0.001; 2003 vs. 2005, R=-63.92 p<0.001). This situation was soon followed by the rapid equalization in phytoplankton abundances. Considering the entire research period, there were no changes in contributions of major phytoplankton groups, but the increase in overall species diversity was recorded, supporting the view that moderate inputs may stimulate plankton taxonomic diversity in coastal ecosystems. Increased ciliate and copepod nauplii abundance was also observed but was considered to be caused by natural variability

Host-Parasite Interaction between Parasitic Cymothoid Ceratothoa Oestroides and Its Host, Farmed European Sea Bass (Dicentrarchus labrax)

Parasitic isopod Ceratothoa oestroides (Cymothoidea, Isopoda) is a common and generalist buccal cavity-dweller in marine fish, recognised for its detrimental effect in fingerling and juvenile farmed European sea bass (Dicentrarchus labrax). Although distributed throughout the Mediterranean, the isopod provokes acute outbreaks mainly limited to particular endemic areas in Croatia (Adriatic Sea) and Greece (Aegean Sea). While numerous studies have previously evidenced its gross effect on farmed fish (i.e. decreased condition index, slower growth rate, lethargy and mortality), details on the host-parasite interaction are still lacking. Therefore, using a multimethodological approach, we closely examined the structure and appearance of isopod body parts acting in the attachment and feeding (stereomicroscopy, scanning and transmission electron microscopy), and the extent of host tissues damage (histology, immunohistochemistry, micro-computational tomography) induced by parasitation. Interestingly, while hematophagous nature of the parasite has been previously postulated we found no unambiguous data to support this; we observed host tissues fragmentation and extensive hyperplasia at the parasitation site, and no structures indicative of heme detoxifying mechanisms in the parasite gut, or other traces of a blood meal. The bacterial biofilm covering C. oestroides mouthparts and pereopods suggests that the isopod may play a role in conveying secondary pathogens to the infected host, or alternatively, it serves the parasite in normal interaction with its environment

Achieving coherence between the Marine Strategy Framework Directive and the Maritime Spatial Planning Directive

Alignment and coordination of the Marine Strategy Framework Directive (MSFD) with other key policies is considered indispensable to accomplish its objectives. To ensure that economic activities do not generate unsustainable pressures in the marine environment, it is imperative to streamline the MSFD with the Maritime Spatial Planning Directive (MSPD), the policy regulating the spatial dimension of maritime activities and their planning. To investigate the coherence between the MSFD and MSPD, an analysis was performed in the framework of MEDREGION project (11.0661/2018/794286/SUB/ENV.C2) on the conceptual relations of the two processes. The needs and challenges encountered by MSFD Competent Authorities (CAs) in the implementation of the Directives were considered, while the Programmes of Measures (PoMs) established by Mediterranean Member States (MSs) for selected MSFD Descriptors were analysed to see whether measures can contribute to the integration of the two Directives. The MSPD implementation considers the MSFD provisions, however, there are still challenges and gaps for an effective integration. Herein, recommendations are made to face these challenges and facilitate the alignment of the two Directives. Moreover, the analysis of the MSFD PoMs shows that the MSFD identifies, directly or indirectly, human activities related to Maritime Spatial Planning (MSP) sectors and addresses them with specific measures. Therefore, MSFD PoMs constitute a concrete basis for the planning of the marine space, thus, bridging the two Directives, avoiding conflicts and facilitating synergies.The research leading to these results has received funding from the European Commission Directorate General for the Environment under grant agreement n° 11.0661/2018/794286/SUB/ENV.C2 – MEDREGION project (Support Mediterranean Member States towards implementation of the MSFD New GES Decision and programmes of measures and contribute to regional/subregional cooperation).Peer reviewe