Browsing by Author "Pereira, Fabio"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Habitat structure shaping megabenthic communities inhabiting subtidal soft bottoms along the Algarve coast (Portugal)Publication . Rufino, Marta M.; Pereira, Alexandre M.; Pereira, Fabio; Moura, Paula; Vasconcelos, Paulo; Gaspar, MiguelThe present study analysed the megabenthic diversity in subtidal soft bottoms and assessed the main environmental drivers of megabenthic community organisation along the Algarve coast (southern Portugal). We tested the hypothesis that megabenthic communities respond to the same environmental drivers than macrofauna. We found that similar to macrofauna, megafaunal communities were organised in relation to the depth of closure, light reaching the bottom, and the hydrodynamic conditions related with exposure within the shallower areas. The influence of the main river outflow prevailed over other drivers, but only up to 9 m depth. We found that seven different spatial units should be considered, each characterised by different indicator species. Additionally, among a total of 412 taxa collected between 4 and 50 m depth, we provide the characteristics of the 64 commonest species in terms of occurrence, frequency, distribution, abundance, bathymetric and sedimentary preferences, which constitutes most valuable information for ecosystem modelling. Megabenthic alpha diversity decreased with depth, contrary to evenness and was higher in the proximity of the river Guadiana and in highly exposed shores. We conclude that the megafauna, which is significantly quicker to collect and analyse, can provide an accurate alternative to macrofauna sampling, as their communities are shaped by the same drivers.
- Recent and consecutive records of the Atlantic Blue Crab (Callinectes sapidus Rathbun, 1896): rapid westward expansion and confirmed establishment along the Southern Coast of PortugalPublication . Vasconcelos, Paulo; Carvalho, Andre N.; Pilo, David; Pereira, Fabio; Encarnação, João; Gaspar, Miguel; Teodosio, MariaThe present study reports six new and consecutive records of the Atlantic blue crab (Callinectes sapidus Rathbun, 1896) in the southern coast of Portugal. Specimens were caught during less than two months (22nd November 2018 - 18th January 2019) as bycatch of trammel nets operated by small-scale fishing boats in scattered locations along the Algarve coast and in the Ria Formosa lagoon. Four adult males (221-236 mm carapace width) and two adult females (191-207 mm carapace width) were caught at relatively shallow depths (1-6 m), on muddy and sandy bottoms in the Ria Formosa lagoon and in the Algarve coast. Morphometric parameters of the specimens are compiled and the respective occurrences are mapped for biogeographic purposes. These first three occurrences in the Algarve coast and the second, third and fourth records in the Ria Formosa lagoon, further supported by additional anecdotal evidences and recent sales at the wholesale market, reveal a rapid westward expansion and confirm the establishment of C. sapidus along the southern coast of Portugal. Possible sources of introduction and causes for the distributional expansion are evaluated. The potential impacts of this invasive species on local ecosystems and fishing/harvesting resources are discussed.
- Reproductive cycle of the commercially harvested sea urchin (Paracentrotus lividus) along the western coast of PortugalPublication . Machado, Ines; Moura, Paula; Pereira, Fabio; Vasconcelos, Paulo; Gaspar, MiguelHarvested populations of the sea urchin (Paracentrotus lividus) from the northwestern (Carreco) and southwestern (Aljezur) coasts of Portugal were surveyed to describe the species reproductive cycle and assess possible relationships with geographical location and seawater temperature. Individuals were sampled monthly to analyze gonad histology, mean gonadal index (GI), and gonadosomatic index (GSI) during 2 consecutive years (November 2010-November 2012). Both populations presented an annual reproductive cycle, with synchronous gonad maturation and gamete release between sexes. Gonad maturation occurred throughout autumn-winter, followed by a single but prolonged spawning season during spring-summer. The duration of the spawning season displayed a latitudinal gradient likely related to the north-south increasing trend in seawater temperature, with the northwestern population (Carreco) exhibiting a shorter spawning period compared to the southwestern population (Aljezur). The timing and duration of the spawning season was compared with several populations throughout the distributional range of P. lividus in the Atlantic Ocean and Mediterranean Sea. In the population from Carreco, the size at first sexual maturity (test diameter = 35.9 mm) was considerably smaller than the minimum conservation reference size (MCRS) of 50 mm test diameter legally established for P. lividus. This study confirms that sustainable exploitation depends on harvesters' awareness of and compliance with the MCRS and provides useful information for the eventual establishment of a closed season in the harvesting of P. lividus.
- Socio-economic, operational and technical characterisation of the harvesting of gooseneck barnacle (Pollicipes pollicipes) in SW Portugal: Insights towards fishery co-managementPublication . Carvalho, Andre N.; Vasconcelos, Paulo; Pilo, David; Pereira, Fabio; Gaspar, MiguelThe present study characterised the socio-economic, operational and technical aspects of harvesting the gooseneck barnacle (Pollicipes pollicipes) along the southwestern coast of Portugal. For this purpose, face-to-face interviews were conducted with commercial harvesters of the two most representative fishery associations (covering 51% licensed harvesters) in the area of the Parque Natural do Sudoeste Alentejano e Costa Vicentina. Based on traditional ecological knowledge, this study confirmed the local importance, ancestral character and family traditions of this activity, which constitutes the exclusive occupation of nearly half of the interviewed harvesters and an important source for household incomes. In addition, data was also gathered on preferential fishing zones, harvesting effort and duration, daily catches and selling prices. The main concerns, problems and difficulties experienced in this activity relate to the excessive number of recreational harvesters, creating problems at the levels of exploitation, commercialisation, management and inspection. The study further confirms the rising interest and involvement of the commercial harvesters in enhancing the competences of the local fishery associations. In particular, local harvesters want to encourage the development of a co-management system comprising spatial-temporal measures to avoid conflicts of use over space and resources, as well as innovative marketing strategies to improve the recognition, value and traceability of the shellfish. Overall, the information gathered is most valuable for adopting an alternative approach based on the cooperation and co-responsibility at local and regional levels, involving the stakeholders in the proposal of management measures adapted to the specificities of this area, activity and resource.
- Tanaidaceans (Crustacea: Peracarida: Apseudidae) from southern Portugal with description of the new species Apseudopsis formosus, report of five first records and a biogeographic overview: unexpected expansion or understudied hotspot?Publication . Carvalho, Andre N.; Pereira, Fabio; Piló, David; Gaspar, Miguel; Esquete, PatriciaThis study describes Apseudopsis formosus sp. nov., a new apseudomorph tanaidacean species from the Ria Formosa lagoon (southern Portugal). Species description was based on 223 individuals (22 juveniles, 60 males and 141 females), comprising diverse developmental stages (juveniles II, males I and II, preparatory, copulatory and intermediate females). The total length of the studied population ranged from 2.2 to 3.0 mm in juveniles, 2.5 to 4.8 mm in males and 2.9 to 4.9 mm in females. Overall, Apseudopsis formosus sp. nov. differs from congeneric tanaidaceans from the Atlantic Ocean and Mediterranean Sea by the presence of combined different morphological characters such as short pointed rostrum, posterolateral pointed corners on pereonites 2-6, hyposphenium only on pereonite 6, antennular outer flagellum 7- to 10-segmented, inner flagellum 3-segmented and five spines on propodus of pereopod 1, and sexual dimorphism evidenced by a pronounced mid-dorsal triangular wing-shaped protuberance on male merus cheliped, unique in Apseudopsis genus. At each studied developmental stage, some individuals presented abnormalities in spination, having only four spines in one of the propodus of pereopod 1. Additionally, five first records of Apseudopsis from the Algarve coast (A. adami, A. bacescui, A. elisae, A. mediterraneus and A. uncidigitatus) are reported for Portuguese waters. A biogeographic overview of the genus Apseudopsis is presented through the compilation and mapping of all worldwide reported occurrences. Passive dispersion can explain the most recent species distribution, yet not disregarding that the study area is taxonomically understudied. This study contributes to improve the current knowledge on tanaidacean taxonomy and updates the geographical distribution range of the Apseudopsis-complex.