Percorrer por autor "Candeias-Mendes, Ana"
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- Characterization of spawning rhythms of a sparidae aquaculture species, the white seabream (Diplodus sargus), in the south of PortugalPublication . Santos, Cátia; Soares, Florbela; Candeias-Mendes, Ana; Pousão‐Ferreira, Pedro; Dinis, Maria Teresa; Oliveira, CatarinaOne of the most visible features of fish reproduction is seasonality; however, daily rhythmicity is present in most species and should not be disregarded. This study investigated the seasonal and daily spawning rhythms of the white seabream (Diplodus sargus) in captivity, and a possible endogenous control of the daily rhythm. Spawns were monitored daily, during an entire reproductive season by using an automatic and programmable egg collector. The spawning season lasted 5 months, from January until June, when temperatures oscillated between 11.5 and 24.4 degrees C. Female fecundity was higher between 17.5 and 20.4 degrees C, suggesting a temperature influence in spawning. This species showed a very clear daily spawning rhythm (Cosinor analysis, p < 0.001), strongly related with photoperiod. Eggs started to be released at sunset and peaked around 21:00 h. Egg quality parameters also changed along the spawning period, with viability and hatching rates, increasing towards the end of the night period. The spawning rhythm persisted (Cosinor analysis, p < 0.001) for 5 days under constant light conditions, suggesting the presence of an endogenous clock mechanism which controlled this circadian pattern. The present results represent an advantage for the optimization of egg production protocols in this species, and an added value to the current knowledge of marine fish physiology.
- Effect of dietary l-glutamine supplementation on the intestinal physiology and growth during Solea senegalensis larval developmentPublication . Matias, Ana Catarina; Viegas, Ana Rita; Couto, Ana; Lourenço-Marques, Cátia; Aragão, Cláudia; Castanho, Sara; Gamboa, Margarida; Candeias-Mendes, Ana; Soares, Florbela; Modesto, Teresa; Pousão-Ferreira, Pedro; Ribeiro, LauraThe maturation of the intestinal digestive and absorptive functions might limit the amount of absorbed nutrients to fulfil the high requirements of the fast-growing marine fish larva. Glutamine (Gln) has been described to improve intestinal epithelium functions, due to its involvement in energy metabolism and protein synthesis. The purpose of this study was to evaluate dietary 0.2% Gln supplementation on aspects of intestinal physiology, protein metabolism and growth -related genes expression in Senegalese sole larvae. Experiment was carried out between 12 and 33 days post hatching (DPH) and fish were divided into two experimental groups, one fed Artemia spp. (CTRL) and the other fed Artemia spp. supplemented with Gln (GLN). GLN diet had two times more Gln than the CTRL diet. Samples were collected at 15, 19, 26 and 33 DPH for biometry, histology, and digestive enzymes activity, and at 33 DPH for gene expression, protein metabolism and AA content determination. Growth was significantly higher for Senegalese sole fed GLN diet, supported by differences on protein metabolism and growth -related gene expression. Slight differences were observed between treatments regarding the intestinal physiology. Overall, GLN diet seems to be directed to enhance protein metabolism leading to higher larval growth.
- Effects of environmental enrichment on the welfare of gilthead seabream broodstockPublication . Oliveira, Ana Rita; Cabrera-Álvarez, María J.; Soares, Florbela; Candeias-Mendes, Ana; Arechavala-Lopez, Pablo; Saraiva, JoãoThe intensification of aquaculture practices in the last decade has led to the reduction in welfare of farmed fish. Recently, one of the tools that has been considered important to guarantee or improve the welfare of captive fish is the application of environmental enrichment (EE). The physiological state and behaviour of fish can be used as indicators of the welfare of the animal, as well as of the positive impact of the EE in their well-being. In this study, behavioural and physiological indicators were measured to assess the effects of structural environmental enrichment on the welfare of gilthead seabream broodstock. Over the course of 5 months, 60 adult seabreams were distributed in six 3000 L cylindrical tanks. Three of the tanks were enriched with nine hanging organic ropes on 1 m2 floating structures, while the other three tanks had no enrichment. Fish were filmed regularly before, during, and after feeding, cleaning, and sampling procedures. Operational welfare indicators (OWIs) recently developed for farmed seabream were used and adapted to build an ethogram for the broodstock behaviour analysis. According to our results, fish reared in enriched tanks hardly schooled and presented a more independent swimming activity compared to fish from non-enriched tanks. Moreover, structural enrichment seemed to increase the spatial use of the bottom of the tank, and promoted seabream natural behaviour (hierarchical competitions, foraging, etc.). In addition, fish in enriched tanks presented a higher growth rate, and further studies will determine if such enrichment structures also affect reproductive potential of seabream broodstocks as well as epigenetic effects on offspring.
- Movements of hatchery-reared dusky groupers released in a northeast atlantic coastal marine protected areaPublication . Silva, Ana Filipa; Horta E Costa, Barbara; Costa, José Lino; Pereira, Esmeralda; Marques, João Pedro; Castro, João J.; Lino, Pedro G.; Candeias-Mendes, Ana; Pousão-Ferreira, Pedro; Sousa, Inês; Bentes, Luis; Gonçalves, Jorge Manuel Santos; de Almeida, Pedro Raposo; Quintella, Bernardo RuivoNo-take areas are key instruments to promote the effectiveness of Marine Protected Areas (MPAs), particularly concerning the protection of endangered species such as the dusky grouper (Epinephelus marginatus). However, despite the establishment of no-take areas and the prohibition of catching this species in a southwestern Portuguese MPA (SACVMP—‘Sudoeste Alentejano’ and ‘Costa Vicentina’ Marine Park) since 2011, there is still no evidence of population recovery. By using acoustic biotelemetry, this work aimed to evaluate the feasibility of restocking hatchery-reared adult dusky groupers in two no-take areas within the SACVMP. In 2019 and 2021, thirty groupers were tagged with acoustic transmitters and the site attachment and movements of the groupers were assessed in the releasing sites (no-take areas). None of the tagged fish settled down in either of the areas, leaving the no-take areas mainly at dusk and night. Some individuals displayed extended movements of more than a hundred kilometers along the Portuguese coast which was rarely reported for this species. At least in some coastal stretches, those movements were performed close to the shore, which may evidence the importance of coastal MPAs to protect and promote the connectivity of species more associated with rocky reef habitats. Following studies should focus on the conditions that promote site attachment and fidelity by hatchery-reared dusky groupers so that future large-scale restocking programs can be successful in MPAs with appropriate habitats.
- Reduction of skeletal anomalies in meagre (Argyrosomus regius, Asso, 1801) through early introduction of inert dietPublication . Martins, Gil; Ribeiro, Laura; Candeias-Mendes, Ana; Diogo, Patricia; Gamboa, Margarida; Barata, Marisa; Leonor Cancela, M.; Pousao-Ferreira, Pedro; J. Gavaia, PauloThe consolidation of meagre (Argyrosomus regius) in aquaculture requires an understanding and optimization of larval rearing and nutritional conditions. The aim of this study was to analyse the effects of an early introduction of inert diets during larval rearing, on growth performance, digestive enzymes activity and development of skeletal anomalies. This study evaluated the effects of three different timings for the introduction of inert diet during larval rearing: a control group (CTRL) where inert diet was initiated at 14 days after hatching (DAH) and two treatment groups that had an earlier introduction of inert diet at 8 DAH (T1) and 11 DAH (T2). Meagre larvae exhibited similar pancreatic and intestinal enzymatic activities among the different dietary treatments. No differences in the overall prevalence of anomalies were observed between treatments at 25 or 50 DAH, however, a significant reduction was observed in all groups with the transition from larval to juvenile stage. The precocious introduction of inert diet shifted the distribution of vertebral anomalies to a more anterior vertebral column region. Altogether, this study shows that earlier introduction of inert diets in meagre hatcheries can be beneficial for meagre production in aquaculture.
- Restocking trials with hatchery-reared dusky groupers in a marine protected area of the southwestern portuguese coastPublication . Silva, Ana Filipa; Horta e Costa, Barbara; Costa, José Lino; Pereira, Esmeralda; Marques, João Pedro; Castro, João J.; Lino, Pedro G.; Candeias-Mendes, Ana; Pousão-Ferreira, Pedro; Sousa, Inês; Bentes, Luis; Gonçalves, Jorge Manuel Santos; Almeida, Pedro Raposo de; Quintella, Bernardo RuivoMarine Protected Areas (MPAs) have played an important role in the protection of endangered species such as the dusky grouper (Epinephelus marginatus), and the no-take areas have been particularly crucial for this purpose. Yet, despite the establishment of no-take areas and the legislation banning dusky groupers’ catches since 2011 in a southwestern Portuguese MPA (SACVMP—‘Sudoeste Alentejano’ and ‘Costa Vicentina’ Marine Park), there is still no evidence of this population’s recovery. In the face of this, the present work aimed to monitor the experimental hatchery-reared adult dusky groupers’ restocking of two no-take areas of SACVMP with acoustic biotelemetry. In 2019 and 2021, thirty groupers tagged with acoustic transmitters were released in two no-take areas, and the site attachment and their movements were assessed. None of the tagged fish set residency in either of the releasing areas, mostly leaving there at dusk and night. A rarely reported event for this species was also observed, as some individuals moved for more than a hundred kilometers along the Portuguese coast. At least some of those ranging movements were performed close to the rocky shore, which may point out the importance of coastal MPAs in promoting the connectivity of fish species associated with rocky reef habitats. Future studies must focus on the conditions that promote the site attachment and the site fidelity of released hatchery-reared dusky groupers so that large-scale restocking programs can be successfully implemented in MPAs with appropriate habitats.
- Sound production in the Meagre, Argyrosomus regius (Asso, 1801): intraspecific variability associated with size, sex and contextPublication . Pereira, Beatriz P.; Vieira, Manuel; Pousão-Ferreira, Pedro; Candeias-Mendes, Ana; Barata, Marisa; Fonseca, Paulo J.; Amorim, Maria Clara P.Many fish taxa produce sound in voluntary and in disturbance contexts but information on the full acoustic repertoire is lacking for most species. Yet, this knowledge is critical to enable monitoring fish populations in nature through acoustic monitoring.
- Structural enrichment promotes natural behaviour and welfare of captive gilthead seabream broodstockPublication . Oliveira, Ana Rita; Cabrera-Álvarez, María José; Soares, Florbela; Diáz-Gil, Carlos; Candeias-Mendes, Ana; Saraiva, João; Arechavala-Lopez, PabloThe intensification of aquaculture practices in the last decade can compromise the welfare of farmed fish. However, one strategy to be considered to improve the welfare of captive fish is the implementation of structural enrichment in the rearing environment. The behavioural and physiological effects of suspended ropes inside rearing tanks were experimentally assessed on gilthead seabream (Sparus aurata) breeders, evaluating the potential use of such structures in production units. Over the course of six months, 60 adult gilthead seabreams, were reared in cylindrical tanks with and without structural enrichment. Fish were video recorded regularly before, during and after feeding. Biometry and blood samples for biochemical analyses of plasma (cortisol, glucose and lactate) were taken throughout the experiment. Suspended ropes modified the horizontal distribution of fish after feeding, influencing the swimming activity and social interactions throughout the experimental period. In addition, structural enrichment promoted foraging and anticipatory behaviour of gilthead seabream. No effects of structural enrichment were detected on gilthead seabream condition or growth, although there was an apparent positive yet fading effect of enrichment on plasma cortisol and glucose. In general, structural enrichment had diverse positive effects on the behaviour diversity and natural repertoire of captive gilthead seabream, and therefore, on fish welfare. This type of structural environmental enrichment can be easily incorporated into land-based flow-through and recirculating aquaculture systems, both for experimentation and commercial purposes.