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- Does an invasive bivalve outperform its native congener in a heat wave scenario? A laboratory study case with Ruditapes decussatus and R. philippinarumPublication . Crespo, Daniel; Leston, Sara; Rato, Lénia D.; Martinho, Filipe; Novais, Sara C.; Pardal, Miguel A.; Lemos, Marco F. L.Global warming and the subsequent increase in the frequency of temperature anomalies are expected to affect marine and estuarine species’ population dynamics, latitudinal distribution, and fitness, allowing non-native opportunistic species to invade and thrive in new geographical areas. Bivalves represent a significant percentage of the benthic biomass in marine ecosystems worldwide, often with commercial interest, while mediating fundamental ecological processes. To understand how these temperature anomalies contribute to the success (or not) of biological invasions, two closely related species, the native Ruditapes decussatus and the introduced R. philippinarum, were exposed to a simulated heat wave. Organisms of both species were exposed to mean summer temperature (~18 C) for 6 days, followed by 6 days of simulated heat wave conditions (~22 C). Both species were analysed for key ecological processes such as bioturbation and nutrient generation—which are significant proxies for benthic function and habitat quality—and subcellular biomarkers—oxidative stress and damage, and energetic metabolism. Results showed subcellular responses to heat waves. However, such responses were not expressed at the addressed ecological levels. The subcellular responses to the heat wave in the invasive R. philippinarum pinpoint less damage and higher cellular energy allocation to cope with thermal stress, which may further improve its fitness and thus invasiveness behaviour.
- Contrasting links between growth and survival in the early life stages of two flatfish speciesPublication . Primo, Ana Ligia; Vaz, Ana Catarina; Crespo, Daniel; Costa, Filipe; Pardal, Miguel; Martinho, FilipeUnderstanding the causes of variation in recruitment of marine fishes has been a central goal over the last century. However, the relationship between year class strength and larval growth and survival is poorly known for most species. The main goal of this study was to investigate the relationships between larval traits and year class strength of two flatfish species in an nursery estuary. We examined the effects of the variation in the early life characteristics (pelagic larval growth, pelagic larval duration, size-at-hatching and size-at-settlement) on post-settlement survival of flounder Platichthys flesus and common sole Solea solea in the Mondego estuary (Portugal) over a 5-year period (2011–2015). The two flatfish species showed distinct larval traits variation during the study period, mainly related with location of the spawning ground and intrinsic biologic patterns. Flounder was able to delay metamorphosis while gathering energy and/or waiting for suitable environmental cues from estuarine origins while sole take advantage of better environmental conditions due to a later hatching. Early fast growth were strongly related with subsequent growth, affecting larval survival. Both growth and larval traits variation during the studied period were strongly related with temperature. This study highlights the importance of early growth for fish survival and contributes with key information on fish early life stages that will support a better management of fish stocks.
- Surf zone zooplankton communities from the west coast of the Iberian Peninsula: influence of season, substrate type and environmental factorsPublication . Guerreiro, Milene Alexandra; Marques, Sónia Cotrim; Martinho, Filipe; Azeiteiro, Ulisses Miranda; Pardal, Miguel Ângelo; Primo, Ana LígiaStudies on surf zone zooplankton biodiversity and population dynamics processes remain scarce in comparison to other coastal areas. In this work, we analysed the seasonal (winter/summer) variability of the surf zone zooplankton assemblage structure and copepod biomass of distinct areas with different substrate types (sandy beaches/rocky shores) at the west coast of the Iberian Peninsula (Portugal). Cypris of Cirripedia and Acartia clausi prevailed during summer at both areas. In the winter, Paracalanus parvus and Temora longicornis were the most abundant species at sandy beaches, while Harpacticoida n.id.1 and Euterpina acutifrons dominated at rocky shores. Copepod biomass was higher during the winter and in sandy beaches. Zooplankton showed distinct community structure according to season and substrate type, with Harpacticoids and cirripeds being the main responsible for seasonal differences, while fish eggs and harpacticoids were mainly responsible for differences among substrates. Surf zone assemblages were influenced by temperature, chlorophyll a and local hydrodynamics, which reflects species seasonal reproduction and drift in the water column.