Enzymatic activity on sediments and nematode assemblage responses during seagrass beds habitat recovery following the disturbance of the traditional digging activity of bivalves harvesting.

Sediment digging is an anthropogenic activity connected to the exploitation of living resources in estuarine and marine environments. The knowledge on the functional responses of the benthic assemblages to the physical disturbance is an important baseline to understand the ecological processes of the habitat recovery and restoration and to develop tools for the management of the harvesting activities. To investigate the effects of the digging activity of the bivalves on Zostera noltii seagrass beds a manipulative field experiment was conducted that included the enzymatic activity of sediments and the associated nematode assemblages. Four plots (two undisturbed serving as control and two dug to collect bivalves - treatment) with 18 subplots were randomly located at seagrass beds in the Mira estuary at the SW coast of Portugal. Samples were randomly and unrepeatably collected from three subplots of each plot in five different occasions, before sediment digging (T0) up to six months after disturbance (T5). Microbial activity in sediments was assess by determining the extracelular enzymatic activity of six hydrolytic enzymes (sulfatase, phosphatase, b -N-acetilglucosaminidase, b-glucosidase, urease, protease) and two oxidoreductases (phenol oxidase and peroxidase). The microbial community status was also assessed through the measurement of dehydrogenase, which reflects microbial respiration. The nematode assemblages composition, biodiversity and trophic composition at different sampling occasions were also analyzed. The fluorometric and biochemical parameters analysed of the Z. noltii plants during the experimental period showed a recovery of the seagrass beds, and it was detected an increase of the enzymatic activity of the sediments after disturbance. The nematodes assemblages were similar in all sampling occasions. The seagrass beds and the nematodes assemblages associated showed a high resilience to the stress caused by the traditional bivalves digging activity. The obtained results allow the development of a management programme for the commercial fishing activity to maintain the good environmental status and minimized the secondary environmental effects on marine and estuarine habitats through the establishment of a baseline for the regulation of the harvesting frequency.

Development of a novel molecular tool for the rapid assessment of the biodiversity changes of benthic nematodes assemblages. Mares Conference Marine Ecosystems Helath and conservation

The molecular profiling system was developed using directed terminal-restriction fragment length polymorphism (dT-RFLP) to characterize soil nematode assemblages by relative abundance of feeding guilds and validation by comparison to traditional morphological method. The good performance of these molecular tools applied to soil nematodes assemblages create an opportunity to develop a novel approach for rapid assessment of the biodiversity changes of benthic nematodes assemblages of marine and estuarine sediments. The main aim of this research is to combine morphological and molecular analysis of estuarine nematodes assemblages, to establish a tool for fast assessment of the biodiversity changes within habitat recovery of Zostera noltii seagrass beds; and validate the dT-RFLP as a high-throughput tool to assess the system recovery. It was also proposed to develop a database of sequences related to individuals identified at species level to develop a new taxonomic reference system. A molecular phylogenetic analysis of the estuarine nematodes has being performed. After morphological identification, barcoding of 18S rDNA are being determined for each nematode species and the results have shown a good degree of concordance between traditional morphology-based identification and DNA sequences. The digest strategy developed for soil nematodes is not suitable for marine nematodes. Then five samples were cloned and sequenced and the sequence data was used to design a new dT-RFLP strategy to adapt this tool to marine assemblages. Several solutions were presented by DRAT and tested empirically to select the solution that cuts most efficiently, separating the different clusters. The results of quantitative PCR showed differences in nematode density between two sampling stations according the abundance of the nematode density obtained by the traditional methods. These results suggest that qPCR could be a robust tool for enumeration of nematode abundance, saving time.

Changes in trophic ecology of fish assemblages after no take Marine Protected Area designation in the southwestern coast of Portugal.

Changes in fish assemblage structure caused by human activities, such as fishing, can alter trophic relations in fish assemblages. In this context, Marine Protected Areas (MPA) are efficient tools for habitat recovery and ideal environments for evaluating changes on the trophic structure resulting from human activities. The present work targeted fish assemblages from two no-take MPAs from the northern half of South Alentejo and Costa Vicentina Marine Park, established in 2011. Previous works reported positive effects on local fish assemblages after no-take MPA designation, and it is therefore important to further study its impact on local fish assemblages, especially concerning trophic interactions. Local fish assemblages were sampled (summer 2011, winter 2012, summer 2013 and winter 2013) using trammel nets. Diets were characterized and digestive tract contents of the 10 most abundant fish species were compared between the no take MPAs (treatment) and adjacent areas (controls), and changes evaluated as a function of time since protection. Results revealed significant differences between the diets of fish from protected and non protected areas, with crabs being the preferential prey in both protected and control areas but being more ingested outside the no-take areas. However, these differences were evident since the beginning of the study. Fish assemblages from the northern area presented significantly larger niche breadth and significantly increasing with time. This way, the main effects of no-take MPA implementation were directly visible on the niche breadth but did not directly impact the diet composition of the sampled fish assemblages, contributing however to reinforce the already naturally existent differences. This work provides important information regarding the effect of changes in the fish assemblage caused by MPA designation on the trophic ecology of fish.

Exploited anadromous fish in Portugal: Suggested direction for conservation and management.

Sea lamprey (Petromyzon marinus) and allis shad (Alosa alosa) have been fished for centuries in mainland Portugal during their upstream spawning migration. Here, biological information is compared for the two species and governance and monitoring data from Portugal are reviewed to propose species-specific courses of future action. Despite a national fisheries legislation common for the two species and the designation of Sites of Community Interest (SCIs) for both, the current conservation needs for sea lamprey and allis shad in Portugal are considered to be distinct. For sea lamprey, conservation priorities must focus on planning fisheries managementinarticulationwithhabitatrecoverytoguaranteecost-effective monitoring andsustainablelong-termexploitationthataddsvaluetolocalcommunitiesandpaysdue taxation. Onthecontrary,conservationconcernsandactionsforallisshadmuststrengthenandbemore proactive in the reduction of fishing mortality, both target (in rivers) and by catch (at sea).There is a need to make better use of the opportunities inherent in the Habitats Directive and the possibility to define specific management actions within SCIs. To this effect, it will be necessary to revise existing legislation and guarantee better articulation between jurisdictional authorities. A good example in this direction is the articulation already established in the river Mondego where habitat restoration, fish monitoring and effective species-specific fisheries control measures have been taken and implemented in recent years by a large institutional partnership.