Browsing by Author "Cabral, Henrique"
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- Assessment of catches, landings and fishing effort as useful tools for MPA managementPublication . Batista, Marisa I.; Costa, Bárbara Horta e; Gonçalves, Leonel; Henriques, Miguel; Erzini, Karim; Caselle, Jennifer E.; Gonçalves, Emanuel João; Cabral, HenriqueMarine protected areas (MPAs) have been widely recognized as a tool to achieve both fisheries management and conservation goals. Simultaneously achieving these multiple goals is difficult due to conflicts between conservation (often long-term) and economic (often short-term) objectives. MPA implementation often includes additional control measures on fisheries (e.g. vessel size restrictions, gear exclusion, catch controls) that in the short-term may have impacts on local fishers’ communities. Thus, monitoring fisheries catches before, during and after MPA implementation is essential to document changes in fisheries activities and to evaluate the impact of MPAs in fishers’ communities. Remarkably, in contrast with standard fisheries-independent biological surveys, these data are rarely measured at appropriate spatial scales following MPA implementation. Here, the effects of MPA implementation on local fisheries are assessed in a temperate MPA (Arrábida Marine Park, Portugal), using fisheries monitoring methods combining spatial distribution of fishing effort, on-board observations and official landings statistics at scales appropriate to the Marine Park. Fisheries spatial distribution, fishing effort, on-board data collection and official landings registered for the same vessels over time were analysed between 2004 and 2010. The applicability and reliability of using landings statistics alone was tested (i.e. when no sampling data are available) and we conclude that landings data alone only allow the identification of general patterns. The combination of landings information (which is known to be unreliable in many coastal communities) with other methods, provides an effective tool to evaluate fisheries dynamics in response to MPA implementation. As resources for monitoring socio-ecological responses to MPAs are frequently scarce, the use of landings data calibrated with fisheries information (from vessels, gear distribution and on-board data) is a valuable tool applicable to many worldwide coastal small-scale fisheries.
- Contrasts in genetic structure and historical demography of marine and riverine populations of Atherina at similar geographical scalesPublication . Francisco, Sara Martins; Cabral, Henrique; Vieira, Maria Natividade; Almada, Vítor CarvalhoIn this paper, we compare the genetic structure and the historical demography of two populations of the sand smelt Atherina boyeri from the rivers Tagus and Mondego (Portugal) with two groups of samples of the closely related marine Atherina presbyter collected on the shore at comparable latitudes. A. presbyter is a pelagic marine inshore fish, while A. boyeri is typically found in coastal lagoons, estuaries and freshwaters bodies. Analysis of mtDNA control region sequences showed that the marine A. presbyter did not display signs of genetic differentiation between sites some hundreds of kilometers apart. On the contrary, A. boyeri showed clear differences between populations. The populations of A. boyeri showed a much lower genetic diversity and younger coalescence times when compared with A. presbyter. We suggest that these differences reflect the interplay between differences in ecology between the two species and the historical impact of the glaciations. While A. presbyter likely moved to the south evading the cold periods, A. boyeri probably went extinct and its populations in Western Europe are recent recolonizations from western Mediterranean refugia.
- Fishers’ Behaviour in Response to the Implementation of a Marine Protected AreaPublication . Costa, Bárbara Horta e; Batista, Marisa I.; Gonçalves, Leonel; Erzini, Karim; Caselle, Jennifer E.; Cabral, Henrique; Gonçalves, Emanuel JoãoMarine Protected Areas (MPAs) have been widely proposed as a fisheries management tool in addition to their conservation purposes. Despite this, few studies have satisfactorily assessed the dynamics of fishers’ adaptations to the loss of fishing grounds. Here we used data from before, during and after the implementation of the management plan of a temperate Atlantic multiple-use MPA to examine the factors affecting the spatial and temporal distribution of different gears used by the artisanal fishing fleet. The position of vessels and gear types were obtained by visual surveys and related to spatial features of the marine park. A hotspot analysis was conducted to identify heavily utilized patches for each fishing gear and time period. The contribution of individual vessels to each significant cluster was assessed to better understand fishers’ choices. Different fisheries responded differently to the implementation of protection measures, with preferred habitats of target species driving much of the fishers’ choices. Within each fishery, individual fishers showed distinct strategies with some operating in a broader area whereas others kept preferred territories. Our findings are based on reliable methods that can easily be applied in coastal multipurpose MPAs to monitor and assess fisheries and fishers responses to different management rules and protection levels. This paper is the first in-depth empirical study where fishers’ choices from artisanal fisheries were analysed before, during and after the implementation of a MPA, thereby allowing a clearer understanding of the dynamics of local fisheries and providing significant lessons for marine conservation and management of coastal systems.
- Genetic evidence fails to discriminate between Macroramphosus gracilis Lowe 1839 and Macroramphosus scolopax Linnaeus 1758 in portuguese watersPublication . Robalo, Joana Isabel; Santos, Carla Sousa; Cabral, Henrique; Castilho, Rita; Almada, Vítor CarvalhoFish belonging to the genus Macroramphosus are distributed throughout the Atlantic, Indian and PaciWc oceans. Some authors consider this genus monotypic, Macroramphosus scolopax being the only valid species. Other authors consider (based on several morphological and ecological characters) that another species (Macroramphosus gracilis) exists and occurs frequently in sympatry with the Wrst one. Intermediate forms are also reported in literature. In this paper, using the mitochondrial control region and the nuclear Wrst S7 intron markers, we failed to Wnd genetic diVerences between individuals considered to belong to both species as well as the intermediate forms. Our results suggest that in the northeastern Atlantic, Macroramphosus is represented by a single species, M. scolopax, with diVerent morphotypes interbreeding in the sampling areas.
- Habitat associations and behavioural patterns of Symphodus spp. (Pisces: Labridae)Publication . Rodrigues, Diana Duarte; Costa, Bárbara Horta e; Cabral, Henrique; Gonçalves, Emanuel JoãoThe complexity and diversity of physical and biotic habitats are important features influencing the composition of shallow water reef fish assemblages, especially in temperate regions where abundant and diverse algal cover may have an important habitat-forming role. Coastal fish have adapted to these diverse habitats and to the temporal and spatial variations of algal assemblages in different ways. Wrasses are an important group of coastal rocky reef fish which present particular associations to algae in temperate systems. In this study, habitat associations were analysed in three species of wrasses: Symphodus bailloni, Symphodus melops and Symphodus roissali, and their behaviour was recorded. Eight main behavioural categories (comprising a total of 42 different behaviours) were identified: exploring, foraging, resting, agonistic interactions, cleaning, courtship, reproduction and nesting. S. melops occurred on shallower depths and was frequently involved in both intra- and interspecific agonistic interactions with the other wrasse species, although rarely with S. bailloni. S. roissali was associated with microhabitats of smaller size where it frequently hides. Feeding occurred mostly on bedrock habitat when compared to other microhabitats. Foraging and resting showed a marked seasonality in the three wrasses, related to shifts in biotic habitat structure and to changes in the behavioural repertoire during the breeding season.
- Ichthyofauna of the Selvagens Islands. Do small coastal areas show high species richness in the northeastern Atlantic?Publication . Almada, Frederico José Oliveira de; Abecasis, David; Villegas-Ríos, David; Henriques, Sofia; Pais, Miguel P.; Batista, Marisa I.; Costa, Bárbara Horta e; Martins, Joana; Tojeira, Inês; Rodrigues, Nuno Vasco; Araújo, Ricardo; Souto, Miguel; Alonso, Hany Rafael de Drummond Ludovice Garcia; Falcón, Jesús M.; Henriques, Filipe; Catry, Paulo; Cabral, Henrique; Biscoito, Manuel; Almada, Vítor CarvalhoThe Selvagens Islands are located in the northeastern Atlantic between the Canary Islands and Madeira Island. As a result of their small size, remote location and harsh sea conditions only a few studies have been conducted to describe their marine species diversity. We were able to identify 29 new coastal fish species, an increase of 33% in the ichthyofauna described for these islands (n = 88). There is a prevalence of species with tropical affinities and only 2.3% (n = 2) are endemic to Macaronesia. Considered a stepping-stone colonization vector from the nearest continental shore, as proposed by other authors for this region, the Selvagens Islands host 34.1% of the ichthyofauna described for the much larger Canary Islands (nspecies = 258, submerged area nSelvagensIs. = 2.3%) and 47.3% of the ichthyofauna described for the more distantly located Madeira Island (nspecies = 186, submerged area nSelvagensIs. = 17.9%). Interestingly, 6.8% (n = 6) of the species failed to bridge the gap between the Selvagens Islands and Madeira Island. Data collected so far showed no trend toward an increasing number of species with high dispersal capability. The Selvagens Islands are an example of a high coastal species diversity occurring even in very small areas of the northeastern Atlantic Ocean.
- Ontogenetic shifts in patterns of microhabitat utilization in the small-headed clingfish, Apletodon dentatus (Gobiesocidae)Publication . Gonçalves, Emanuel João; Barbosa, Miguel; Cabral, Henrique; Henriques, MiguelThe patterns of microhabitat utilization by the clingfish Apletodon dentatus were investigated, based on SCUBA diving surveys at the Arr´abida Marine Park (Portugal). In all inspected microhabitats, this species was only found in algal turfs, sea urchins and boulders. The association of A. dentatus with sea urchins is here analysed for the first time. There was a differential utilization of the microhabitats, with small juveniles recruiting to algal turfs, intermediate individuals found in association with the sea urchins Paracentrotus lividus and Sphaerechinus granularis and larger fish occurring mainly in boulders. The depth distribution patterns are also analysed.
- Phylogenetic relationships of the North-eastern Atlantic and Mediterranean forms of Atherina (Pisces, Atherinidae)Publication . Francisco, Sara Martins; Congiu, Leonardo; Stefanni, Sergio; Castilho, Rita; Brito, Alberto; Ivanova, P. P.; Levy, André; Cabral, Henrique; Kilias, Georgio; Doadrio, Ignacio; Almada, Vítor CarvalhoInexistente
- A rapid and inexpensive molecular technique to discriminate the north-eastern Atlantic and Mediterranean Atherina species and its potential applications in ecology and larval identificationPublication . Almada, Vítor Carvalho; Francisco, Sara Martins; Rosa, Inês; Domingues, Vera dos Santos; Cabral, Henrique; Almada, Frederico José Oliveira de; Henriques, Miguel; Robalo, Joana IsabelThis note describes a rapid and inexpensive Restriction Fragment Length Polymorphism technique to discriminate all species of Atherina (Pisces: Atherinidae) of the north-eastern Atlantic and the Mediterranean. This technique is based on digestion of a fragment of the 12S ribosomal RNA (12SrRNA) gene region of mitochondrial DNA with restriction enzymes that recognize species-specific nucleotide sites. The three currently recognized species in the area, as well as two additional forms awaiting formal description, can be discriminated using a set of four endonucleases. We argue that this simple and fast technique may be of great help in the identification of young stages and in ecological surveys.