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- The Atlantic blue crab Callinectes sapidus Rathbun, 1896 expands its non-native distribution into the Ria Formosa lagoon and the Guadiana estuary (SW-Iberian Peninsula, Europe)Publication . Morais, Pedro; Gaspar, Miguel; Garel, Erwan; Baptista, Vânia; Cruz, Joana; Cerveira, Inês; Leitão, Francisco; Teodosio, MariaThe Atlantic blue crab Callinectes sapidus Rathbun, 1896 is native in the western Atlantic, however it is a non-indigenous species across Europe since 1900, among other world regions. In this paper, we report the first occurrences of this species in the Ria Formosa lagoon and in the Guadiana estuary (SW-Iberian Peninsula, Europe) which occurred in 2016 and July 2017, respectively. We hypothesize that the introduction of this species into these ecosystems might be due to the expansion of the Guadalquivir estuary population through natural processes (larval advection, active movement), or due to unintended introduction events after being transported aboard fishing boats, or, less likely, through ballast water. Changes in Guadiana's river flow after the construction of the Alqueva dam might also explain the presence of another non-indigenous species in the Guadiana estuary. The hypotheses presented, regarding the introduction of the Atlantic blue crab into these ecosystems and of its co-occurrence with other decapod species, are framed in a broader context to serve as a future research framework. The use of the Atlantic blue crab as a new fishing resource is also proposed, namely if it is to be used exclusively by local communities and if no deleterious impacts upon other fisheries and the ecosystem occur from this new fishery.
- Influence of oceanography and larvae behaviour on recruitment of temperate fishes: the importance of physics-biology links to manage fisheries at a local scalePublication . Baptista, Vânia; Teodósio, Maria A.; Leitão, Francisco; Wolanski, EricA central question in the ecology of fishing resources is understanding the mechanisms behind recruitment variability. This thesis aimed to analyse the factors responsible for recruitment variability of two economically relevant species, in Portugal, white seabream (Diplodus sargus) and two-banded seabream (Diplodus vulgaris). The temporal variability in sea surface temperature (SST) was studied over specific regions of the Portuguese coast, along the last decades. The effects of changes in environmental variables and fishing pressure on these resources were evaluated, using a multi-model approach. Swimming capabilities of fish larvae and their behavioural responses to environmental cues, potentially relevant for the selection of nursery areas and recruitment, were determined using Ria Formosa coastal lagoon and white seabream as a case study. The analysis of SST during the period 1980-2010 showed a generalized warming along the Portuguese coast, with region- and season-variable tendencies. The effects of environmental and fishing variability on the landings were species-specific, and also varied depending on region and season. The swimming ability of white seabream larvae, as well as their exploratory activity, increased during ontogeny. However, this species did not select any of the environmental stimuli tested. The exploratory behaviour of white seabream larvae presented consistent individual differences throughout ontogeny, indicating that the personality traits emerge early in their life cycle.The integration of these results into an individual-based model showed that both the location of spawning sites and directional swimming capabilities are important determinants of the ingress success of white seabream into a nursery area, as the Ria Formosa lagoon. Thus, the integration of region- and season-specific oceanographic and fishing processes, as well as fish larvae behaviour and dispersion modelling, and supported climate change scenarios, are required for improving the estimates of fish recruitment.