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- Performance of the long-snouted seahorse, Hippocampus guttulatus, under warming conditionsPublication . Costa, Ana Beatriz; Correia, Miguel; Silva, Gonçalo; Lopes, Ana Filipa; Faria, Ana MargaridaTemperature is a determinant cue for several behavioral, physiological, and metabolic processes in fish, which occur within a range set to optimize species fitness. Understanding how ocean warming will impact species, at individual and population levels, is, therefore, of utmost relevance for management and conservation purposes. This knowledge assumes particular relevance when it comes to species with unique life history traits that experience multiple threats, such as seahorses. This study aimed to assess the effects of warming on growth, feed intake, and behavioral patterns of the long-snouted seahorse, Hippocampus guttulatus. Fish were collected, before the breeding season, in the Sado estuary, Portugal, and subsequently exposed for an 8-week period to three different temperatures: 17°C, 20°C, and 24°C. Three times a week, behavioral observations were performed. Feed intake was measured every day and individuals were weighed once a week. Results indicate differences in behavioral responses of seahorses exposed to increasingly warming conditions. Under extreme temperature conditions (24°C), fish were more active, and fed more, but this increment of energy through feeding did not translate into increased growth in weight. Altogether, these results indicate that Sado’s population of H. guttulatus may become under thermal stress when exposed, for a long term, to warming conditions that are expected to occur by the end of the century.
- Prolonged exposure to elevated temperature leads to severe thermal stress in the broad-nosed pipefish, Syngnathus typhlePublication . Miranda, Leonor M.; Correia, Miguel; Barraca, Catarina; Baylina, Nuria; Faria, Ana MargaridaChanges in water temperature may have profound effects on phy-siology, metabolism, and fish behaviour. However, much of theexisting research is based on relatively short-term experiments. Inthe context of climate change, where water temperatures areincreasing seasonally, and the frequency and duration of extremeheatwave events are rising, incorporating longer exposure periodswill provide a better understanding of the potential effects ofwarming on marine species. Here, we tested the effects of pro-longed exposure to elevated temperature on broad-nosed pipefish,Syngnathus typhle. Fish were exposed to ambient (20ºC) and high(24ºC) temperatures for a four-month period, during which activitylevels, growth and survival were monitored. Fish under high tem-perature were less active when compared to fish under ambienttemperature, grew less, and survival was dramatically decreased.These findings have significant implications for the long-term sus-tainability of broad-nosed pipefish populations, as the species maystruggle to adapt to future ocean conditions.
- Impact of anthropogenic noise on the survival and development of meagre (Argyrosomus regius) early life stagesPublication . Trabulo, Rita; Amorim, Clara; Fonseca, Paulo J.; Vieira, Manuel; Matos, André B.; Marin-Cudraz, Thibaut; Lemos, Marco F.L.; Moutinho, Ariana B.; Novais, Sara C; Pousão-Ferreira, Pedro; Candeias-Mendes, Ana; Faria, Ana MargaridaThe growth of human populations has been driving an unprecedent and widespread increase in marine traffic, posing a real threat to marine biodiversity. Even though we are now aware of the negative effects of shipping noise exposure on fish, information about the impact on their early life stages continues to lack. Meagre (Argyrosomus regius) is a vocal fish that uses estuaries with high levels of anthropogenic noise pollution as both breeding areas and nurseries. Here, the effects of boat noise exposure on the development and survival of meagre larvae were studied. Embryos and larvae were exposed to either noise (boat noise playback) or control treatments (coils producing a similar electric field to the speakers) and hatching rate, survival rate, morphometric traits and stress-related biomarkers, at hatching and at 2 days-post-hatching (dph) were analyzed. Results showed no conclusive effects of the impact of boat noise playback, even though there was an increased lipid droplet consumption and a decrease in body depth at 2dph larvae under this stressor. The assessment of oxidative stress and energy metabolism-related biomarkers at hatching showed a marginal decrease in superoxide dismutase (SOD) activity and no changes in DNA damage or electron transport system activity (ETS), although it cannot be disregarded that those effects could only be visible at later stages of larval development. Whether these morphological and developmental results have implications in later stages remains to be investigated. Further studies with longer exposure and wild meagre could help deepen this knowledge and provide a better understanding of how anthropogenic noise can impact meagre early stages