http://hdl.handle.net/10174/14284 2026-09-05T23:07:55Z http://hdl.handle.net/10174/42548 Title: Tactile stimulation enrichment affects behavioural and physiological responses of a marine commercial fish species, the gilthead seabream Sparus aurata Authors: Soares, Marta C.; Gauy, Ana Carolina dos Santos; Macieira, Júlia; Silva, Bianca Cambiaghi e; Banha, Filipe; Gesto, Manuel; Gonçalves-de-Freitas, Eliane; Saavedra, Margarida Abstract: Fish welfare is gaining increasing attention in both public awareness and research, reflecting a growing recognition and appreciation of its ethical importance in aquaculture. As in nature, reared fish exhibit a range of behaviours and physiological responses suggesting their capacity to experience pain and distress when exposed to deleterious stimuli, however there is a pressing need to aim at the positive aspects of sentience. This study investigated physical and tactile contact as a potential enrichment method for reducing stress and improving welfare in the gilthead seabream Sparus aurata (Linnaeus, 1758). To provide tactile contact, an apparatus made of plastic rods and silicone bristles was used as treatment, while a control setup included only the plastic rods, without the silicone bristles. The experiment lasted 21 days, with fish housed in groups of four per tank. Behavioural assessments were conducted through daily 30-min video recordings, quantifying fish crossing through the bristles, and aggressive displays and attacks. Additionally, half of the fish underwent a confinement stress test on the 22nd day, with cortisol levels and brain monoamines measured to evaluate metabolic stress responses and brain signalling. Individuals in the bristle enrichment group were less inclined to display aggression and showed lower cortisol response after acute stress. Regarding brain monoaminergic activity, differences occurred mostly at two main regional sections: midbrain (central brain section) and hindbrain, both involved in seabream response to acute stress and in connection with bristle enrichment. This is the first demonstration that exposure to tactile stimulation during a limited amount of time is enough to produce behavioural change, mitigate stress responses and modify brain monoaminergic signalling in this important commercial species. 2026-01-01T00:00:00Z http://hdl.handle.net/10174/42546 Title: Living on the Edge: Challenges for Freshwater Mussel Conservation in Mediterranean-Type Temporary Stream Authors: Álvarez, María G.; Rolo, Filipe; Godinho, Francisco; Pinheiro, Paulo; Gil, María; Pires, Daniel; Banha, Filipe; Gama, Mafalda; Anastácio, Pedro M.; Sousa-Santos, Carla; Lima, Cristina Silva; Cardoso, Ana Cristina; Reis, Joaquim Abstract: Mediterranean temporary streams are characterized by high hydrological variability that climate change is expected to intensify, increasing drought frequency and severity. These conditions represent a major threat to freshwater mussels, an imperiled group with limited mobility and strict habitat and host requirements. This study explored key factors shaping freshwater mussel community structure, including the spatial distribution, species compo sition and abundance of coexisting species, in two temporary streams of the Guadiana river basin (southwestern Iberian Peninsula). Pool systems in both streams were characterized and compared under average dry season and extreme drought conditions using aerial imagery, whereas mussel abundance patterns and host–mussel relationships were assessed in the larger and more hydrologically stable stream. Results showed that drought severity had different effects on pool refugia persistence, longitudinal distribution and host fish availability between streams. The smaller stream experienced extensive pool desiccation during extreme drought, causing widespread mussel mortality, whereas the larger stream retained numerous pools that allowed mussel persistence. Mussel abundance showed no relationship with pool size. However, Unio tumidiformis abundance was positively associated with native fish abundance, particularly in upstream reaches. These results highlight hydrological stability and host availability as key drivers of freshwater mussel persistence in Mediterranean temporary streams. 2026-01-01T00:00:00Z http://hdl.handle.net/10174/42545 Title: Moderators of Organic Matter Decomposition in Portuguese Streams: A Field Study and Literature Review Authors: Ferreira, Verónica; Serra, Sónia R. Q.; Calapez, Ana Raquel; Sousa-Santos, Carla; Banha, Filipe; Favas, Paulo J. C.; Graça, Manuel A. S.; Seena, Sahadevan; Rita F., Carvalho; Ribeiro, Filipe; Álvarez, María G.; Pereira, Joana V.; Reis, Joaquim; Canning-Clode, João; Ramalhosa, Patrício; Álvarez, Soledad; Gama, Mafalda; Martelo, Joana; Bedmar, Sergio; Domingues, Andreia; Oliveira, Roberto; Ramos, Jaime; Feio, Maria João Abstract: 1. Organic matter decomposition is a fundamental ecosystem process in streams, which have a large aquatic-terrestrial interface. The sensitivity of organic matter decomposition to changes in environmental conditions promoted by human activities is relatively well understood at large and local scales. In contrast, less is known about the natural variability of organic matter decomposition along natural gradients, especially at intermediate spatial scales. This gap undermines the use of organic matter decomposition as a tool to assess stream functional integrity in biomonitoring programmes. This study aimed at identifying the main moderators of organic matter decomposition under undisturbed conditions to establish natural baseline variation in organic matter decomposition rates in Portuguese streams. 2. A field study was carried out to assess organic matter decomposition rates in 37 least-disturbed streams distributed throughout continental Portugal and Madeira Island. This study addressed gaps in empirical research by using poplar organic matter, including wood, and undertaking the incubation in spring, while previous studies were carried out preferably in autumn/ winter and used alder and oak leaf litter. A systematic literature review was also conducted to compile organic matter decomposition rates from least-disturbed streams across continental Portugal and the Azores archipelago. 3. Organic matter type (leaves or wood), shredder access (fine-mesh or coarse-mesh bags), season (autumn/winter or spring/ summer), water nitrate concentration, the presence of exotic vegetation, distance to the source, and percentage shade emerged as main moderators of organic matter decomposition in the field study. 4. Organic matter type and identity (genus), shredder access, season, stream type (national Water Framework Directive typologies), hydrological regime (permanent or intermittent), water temperature, conductivity, and soluble reactive phosphorus concentrations were also important moderators of organic matter decomposition for the compilation of the field data and literature review data. 5. There was considerable variation in organic matter decomposition across least-disturbed streams, reflecting differences in organic matter type and identity, shredder access, season, and environmental conditions. Therefore, for organic matter decomposition to be used as a tool to assess stream functional integrity, it is necessary to standardise the protocol by selecting specific organic matter types and species, mesh types, and incubation seasons to minimise variation caused by these factors. Choosing stream typologies relevant for the decomposition process (e.g., as outlined in the Water Framework Directive), along with identifying reference decomposition ranges for each typology, may facilitate the assessment of deviations in stream functioning from reference conditions. 2026-01-01T00:00:00Z http://hdl.handle.net/10174/42544 Title: The impact of oxybenzone on the neurophysiological and oxidative stress response, dispersal and aggressiveness of the Invasive Red Swamp Crayfish (Procambarus clarkii) Authors: Lopes, Cristiana; Banha, Filipe; Pires, Silvia; Brandão, Pedro; Oliveira, Daniel; Luchiari, Ana; Anastácio, Pedro M.; Rodrigues, Andreia; Soares, Marta C. Abstract: Oxibenzone (BP-3) is a widely used UV filter and an emerging aquatic pollutant. The red swamp crayfish, Procambarus clarkii, a globally widespread species recognized both as food and as an invasive species, may be affected. However, the effects of BP-3 on its physiology, dispersal, aggressiveness, remain unclear. Throughout a holistic experimental trial, this study evaluated biochemical, physiological, and behavioral responses of P. clarkii after 15 days of exposure to 10, 100, and 1000 μg/L BP-3. Behavioral assays assessing dispersal and aggressiveness showed no significant effects. However, biochemical results revealed sex-dependent impacts. Muscle tissue showed oxidative damage through increased lipid peroxidation at higher concentrations. A decrease in acetylcholinesterase activity in the eyes of larger individuals seemed linked to growth-related physiological changes. Metabolic biomarkers also indicated altered energy storage, with elevated lipid and protein content in muscle. Overall, findings highlight P. clarkii capacities to cope with the ecological risks of sunscreen-derived pollutants. 2026-01-01T00:00:00Z