First record of Salacia tetracythara Lamouroux, 1816 (Hydrozoa, Sertulariidae) as an alien hydroid for the Atlantic Ocean

We present here the first record of Salacia tetracythara as an alien species for the Atlantic Ocean, specifically the coast of the state of Sergipe, northeast Brazil. The species was found attached to an artificial experimental plate installed in the rainy period (July-October 2017), in an estuarine region of the Sergipe River near the Sergipe Harbour. Salacia tetracythara is characterized by a small triangular space below each hydrotheca and two types of microbasic mastigophore nematocysts that differ in shape, size, and location. The species was described from Australia and has been recorded only for tropical to temperate regions of the Indo-Pacific. Salacia tetracythara seems to be a recent introduction into the Atlantic Ocean and, its introduction probably derived from ship transport between the Sergipe Harbour and regions of Oceania and/or Asia. Further investigation should be conducted to determine whether the species is established in the region and how far inside the estuary it has gone.Postprin

Time-constrained sampling: A little-explored alternative for marine hard bottom communities.

Marine hard bottoms support the highest proportion of marine biodiversity. In addition, there are a wide range of sizes and forms among the benthic species of a hard bottom community: solitary or modular, from small organisms to large erected colonies, epibionts, encrusting fauna, mobile predators, etc. These habitats and their biological communities have a high heterogeneity at different spatio-temporal scales. The high diversity and heterogeneity of the hard bottom habitats can present considerable difficulties to obtain accurate and statistically comparable data for community monitoring. Thus, marine hard bottoms are complex habitats where monitoring protocols vary considerably. We review the main approaches used in the study of this type of habitat, assessing some of their main advantages and disadvantages, and highlight a not sufficiently explored alternative where the sampling effort is controlled by a set period of sampling time. Time-constrained searches have been routinely used in terrestrial ecological studies but few explore in marine habitats. However, it is an acceptable alternative that would be worth further exploring for studding marine hard bottom communities. Time-constrained meth- odology presents a good cost-benefit balance: It provides a good representation of the diversity of hard bottom communities, the costs (both in time and economic resources) for sampling and sorting are lower, and the quantification of taxa allows their relative abundance to influence the result

Anti-herbivory protection by mutualism in marine ecosystems: The case of the kelps and hydroids.

Plant–herbivore interactions are critical for the functioning of ecosystems, particularly when habitat-forming species are involved. Kelp forests are among the most diverse and productive ecosystems in the world and, along the Chilean coast, they have a high economic importance. Lessonia trabeculata constitutes the main component of the subtidal shallow habitats in Chile. We quantified the consumption of kelp tissues by the snail Tegula tridentata (one of the most important grazers in Chilean kelp habitats), and the modification in this consumption by a guild of epibiotic hydroids growing on kelps. We performed two different sets of experiments with and without the possibility for the snails to select between kelps with hydroids and kelps without them. The consumption by T. tridentata on kelps without hydroids was between 3 and 4 times higher than on kelps with hydroids. Kelp is protected from herbivores by hydroids and can gain nitrogen during low concentration periods of this nutrient in water. Hydroids gain a substratum, and an elevated position above the seafloor where particle capture is facilitated by the effect of kelp in water currents. Predictions using densities of T. tridentate observed in different forests of L. trabeculata along Chilean coasts, show that herbivory pressure can drastically change depending on this density; in forests with high densities, the presence/absence of hydroids could be crucial. Hydroids have shown to be ubiquitous components of the fauna inhabiting the kelp holdfast and forming a rich community in comparison with other epibionts. Despite its low overall biomass, hydroids can be key elements in kelp productivity (affecting, therefore, the community associated to kelps). The kelp-hydroid mutualistic relationship can change the interactions kelp-herbivore

Physiological recovery after bottom trawling as a method to manage discards: The case study of Nephrops norvegicus and Squilla mantis.

The European Fisheries Policy aims at a progressive elimination of discards. An exception from this regulation includes the release of species with high survival rates after capture. In south-western Atlantic waters of Europe, Norway lobster (Nephrops norvegicus) and spottail mantis shrimp (Squilla mantis) are amongst the most important crustacean species captured by bottom trawling. We evaluated their short-term survival probability, survival rates and recovery capacities after being trawled by an oceanographic vessel. Seasonal differences were considered by sampling in spring and autumn. In order to characterise the full recovery after capture, physiological responses were also analysed along a time-course of 24 h. Our results confirm that bottom trawling is a stressful process to these crustacean species, as seen by changes in plasma and muscle metabolites, hemocyanin and immune system parameters. However, maintaining captured animals in onboard water tanks evidenced the full physiological recovery of survivors after 6 h and before 24 h. Survival in Norway lobster and spottail mantis shrimp varied according to the season, being higher in spring (68.4 � 7.1% and 87.0 � 4.7%, respectively) than in autumn (33.8 � 7.8% and 63.8 � 9.3%, respectively), probably due to the higher temperatures registered after summer months. The employment of the presented techniques for the evaluation of other crustaceans, fishing gears and geographical areas can be contemplated. Fisheries stakeholders might use this approach to better manage discards in Europ