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Karim Erzini - One of the best experts on this subject based on the ideXlab platform.

  • home range residency and movements of Diplodus sargus and Diplodus vulgaris in a coastal lagoon connectivity between nursery and adult habitats
    Estuarine Coastal and Shelf Science, 2009
    Co-Authors: David Abecasis, Luis Bentes, Karim Erzini
    Abstract:

    Abstract Acoustic telemetry and standard tag-recapture were used to determine the home range and residency of juveniles and sub-adults of Diplodus sargus and Diplodus vulgaris in the Ria Formosa (Portugal) coastal lagoon. Maximum time between recaptures for the standard tag-recapture method was 128 days for D. sargus and 30 days for D. vulgaris . The majority of the fish were recaptured in the vicinity of the tagging location. Fish tagged with acoustic transmitters had a maximum period of time between first and last detections of 62 days for D. sargus and 260 days for D. vulgaris . Minimum convex polygons areas ranged between 148 024 m 2 and 525 930 m 2 for D. sargus and between 23 786 m 2 and 42 134 m 2 for D. vulgaris . Both species presented a high residency index between first and last detections. Two D. sargus tagged with acoustic tags were recaptured by fishermen outside the coastal lagoon at distances of 12 km and 90 km from the tagging position, providing evidence that this species leaves the Ria Formosa during the winter time for the adjacent coastal waters. The results of this study reinforce the importance of Ria Formosa as a nursery for D. sargus and D. vulgaris in the south coast of Portugal.

  • Diplodus spp assemblages on artificial reefs importance for near shore fisheries
    Fisheries Management and Ecology, 2009
    Co-Authors: Francisco Leitao, Miguel N Santos, Karim Erzini, C C Monteiro
    Abstract:

    Artificial reefs have been deployed along the southern coast of Portugal (Algarve) since 1990 to enhance artisanal fisheries. The objectives of this study were to: (1) describe the colonisation process; (2) assess the role of the artificial reefs in terms of juvenile recruitment and growth and as mating/spawning areas and (3) evaluate the potential of artificial reefs as near shore artisanal fishing grounds for three economically important fish species, Diplodus bellottii (Steindachner), Diplodus sargus (L.) and Diplodus vulgaris (Geoffroy Saint-Hilaire). The fish assemblages were monitored after the deployment of a large artificial reef (Faro/Ancao) in 2002. Colo- nisation rates for the three species were fast. Artificial reefs play a multiple role for Diplodus spp., acting as recruitment, growth and nursery areas for juveniles, and spawning/mating areas for adults, and can thus be considered essential fish habitat. Three months after deployment of the artificial reefs, exploitable biomass was 16, 29 and 8 kg per reef group, respectively, for D. bellotti, D. sargus and D. vulgaris. These results indicate that artificial reefs quickly become good fishing grounds, where suitable financial yields may be obtained by fisher. Moreover, the artificial reefs became new and alternative fishing grounds, allowing reduction of fishing effort over traditional rocky areas that are scarce along the Algarve coast. Management measures for artificial reefs, in terms of fishing strategies, are discussed.

  • ageing seabreams a comparative study between scales and otoliths
    Fisheries Research, 2008
    Co-Authors: David Abecasis, Luis Bentes, Rui Coelho, C Correia, Pedro G Lino, Pedro Monteiro, Jorge M S Goncalves, J Ribeiro, Karim Erzini
    Abstract:

    Otoliths and scales were used to determine age and growth of: Boops boops (Linnaeus, 1758), Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817), Diplodus sargus (Linnaeus, 1758), Lithognathus mormyrus (Linnaeus, 1758), Pagellus acarne (Risso, 1827), Pagellus erythrinus (Linnaeus, 1758) and Spondyliosoma cantharus (Linnaeus, 1758). These structures came from previous studies conducted in southern Portugal, and complemented by market sampling and beach seining. Von Bertalanffy growth functions were estimated with otolith and scale readings. Results indicate that otoliths are better structures for ageing these species but scales can also be used as a non-destructive technique and with satisfactory results. The exceptions were P. erythrinus and S. cantharus for which scales provided better results.

  • Maturation and gill-net selectivity of two small sea breams (genus Diplodus) from the Algarve coast (south Portugal)
    Fisheries Research, 1998
    Co-Authors: Miguel N Santos, Karim Erzini, Carlos C. Monteiro, Gerard Lasserre
    Abstract:

    Abstract Diplodus annularis and Diplodus bellottii , two species of small sea breams from the Algarve coast (south Portugal), were studied to obtain information on the spawning period, first maturity, weight–length relationship and gill-net selectivity curves. These species are important in local gill-net catches, and there is no information on their biology and selectivity in the Algarve waters. Spawning lasts for 6 months. Total length (TL) at first maturity for females was 13.4 cm in case of D. annularis and 11.4 cm in case of D. bellottii . The relationships between weight and length were W =0.0132 TL 3.096 for D. annularis and W =0.0093 TL 3.193 for D. bellottii . The Sechin method was used to estimate gill-net selectivity curves. The estimated selectivity curves correspond closely to the catch curves of the legal mesh size (60 mm), but were narrower for the other meshes. D. annularis and D. bellottii will be caught using the legal mesh size in the following length ranges: 13–19 cm and 11–19 cm.

  • Maturation and gill-net selectivity of two small sea breams (genus Diplodus) from the Algarve coast (south Portugal)
    Fisheries Research, 1998
    Co-Authors: Miguel Neves Santos, Karim Erzini, Carlos C. Monteiro, Gerard Lasserre
    Abstract:

    Diplodus annularis and Diplodus bellottii, two species of small sea breams from the Algarve coast (south Portugal), were studied to obtain information on the spawning period, first maturity, weight-length relationship and gill-net selectivity curves. These species are important in local gill-net catches, and there is no information on their biology and selectivity in the Algarve waters. Spawning lasts for 6 months. Total length (TL) at first maturity for females was 13.4 cm in case of D. annularis and 11.4 cm in case of D. bellottii. The relationships between weight and length were W = 0.0132 TL3.096 for D. annularis and W = 0.0093 TL3.193 for D. bellottii. The Sechin method was used to estimate gill-net selectivity curves. The estimated selectivity curves correspond closely to the catch curves of the legal mesh size (60 mm), but were narrower for the other meshes. D, annularis and D. bellottii will be caught using the legal mesh size in the following length ranges: 13-19 cm and 11-19 cm. (C) 1998 Elsevier Science B.V. All rights reserved

Giandomenico Ardizzone - One of the best experts on this subject based on the ideXlab platform.

  • Are developmental shifts the main driver of phenotypic evolution in Diplodus spp. (Perciformes: Sparidae)?
    BMC Evolutionary Biology, 2019
    Co-Authors: Paolo Colangelo, Daniele Ventura, Paolo Piras, Jacopo Pagani Guazzugli Bonaiuti, Giandomenico Ardizzone
    Abstract:

    Background Sparid fishes of the genus Diplodus show a complex life history. Juveniles have adaptations well suited to life in the water column. When fishes recruit into the adult population, individuals develop a radically differentiated shape that reflects their adaptation to the new benthic environment typical of the adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern . By using a geometric morphometric approach, we investigated the pattern of shape variation across ontogenetic stages that span from early settlement to the adult stage in four species of the genus Diplodus . Landmarks were collected on the whole body of fishes to quantify the phenotypic variation along two well defined life stages, i.e. juvenile and adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern. Subsequently, we investigated the patterns of integration and modularity as proxy for the alteration of the developmental processes. This have allowed to give an insight in morphological developmental patterns across ecologically and ontogenetically differentiated life stages and to investigate the process leading to the adult shape. Result Our results suggest that the origin of morphological novelties in Diplodus spp. arise from shifts of the ontogenetic trajectories during development. During the settlement phase, the juveniles’ morphological shapes converge towards similar regions of the morphospace. When the four species approach the transition between settlement and recruitment, we observe the lowest level of inter- and intra-specific disparity. After this transition we detect an abrupt shift of ontogenetic trajectories, i.e. the path taken by species during development, that led to highly divergent adult phenotypes. Discussion We suggest that the evolution of new ecomorphologies, better suited to exploit different niches (pelagic vs. benthonic) and reduce inter-specific competition in Diplodus spp., are related to the shift in the ontogenetic trajectory that in turn is associated to changes in modularity and integration pattern.

  • are developmental shifts the main driver of phenotypic evolution in Diplodus spp perciformes sparidae
    BMC Evolutionary Biology, 2019
    Co-Authors: Daniele Ventura, Paolo Colangelo, Paolo Piras, Jacopo Pagani Guazzugli Bonaiuti, Giandomenico Ardizzone
    Abstract:

    Sparid fishes of the genus Diplodus show a complex life history. Juveniles have adaptations well suited to life in the water column. When fishes recruit into the adult population, individuals develop a radically differentiated shape that reflects their adaptation to the new benthic environment typical of the adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern. By using a geometric morphometric approach, we investigated the pattern of shape variation across ontogenetic stages that span from early settlement to the adult stage in four species of the genus Diplodus. Landmarks were collected on the whole body of fishes to quantify the phenotypic variation along two well defined life stages, i.e. juvenile and adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern. Subsequently, we investigated the patterns of integration and modularity as proxy for the alteration of the developmental processes. This have allowed to give an insight in morphological developmental patterns across ecologically and ontogenetically differentiated life stages and to investigate the process leading to the adult shape. Our results suggest that the origin of morphological novelties in Diplodus spp. arise from shifts of the ontogenetic trajectories during development. During the settlement phase, the juveniles’ morphological shapes converge towards similar regions of the morphospace. When the four species approach the transition between settlement and recruitment, we observe the lowest level of inter- and intra-specific disparity. After this transition we detect an abrupt shift of ontogenetic trajectories, i.e. the path taken by species during development, that led to highly divergent adult phenotypes. We suggest that the evolution of new ecomorphologies, better suited to exploit different niches (pelagic vs. benthonic) and reduce inter-specific competition in Diplodus spp., are related to the shift in the ontogenetic trajectory that in turn is associated to changes in modularity and integration pattern.

  • Are developmental shifts the main driver of phenotypic evolution in Diplodus spp. (Perciformes: Sparidae)?
    BMC evolutionary biology, 2019
    Co-Authors: Paolo Colangelo, Daniele Ventura, Paolo Piras, Jacopo Pagani Guazzugli Bonaiuti, Giandomenico Ardizzone
    Abstract:

    Sparid fishes of the genus Diplodus show a complex life history. Juveniles have adaptations well suited to life in the water column. When fishes recruit into the adult population, individuals develop a radically differentiated shape that reflects their adaptation to the new benthic environment typical of the adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern. By using a geometric morphometric approach, we investigated the pattern of shape variation across ontogenetic stages that span from early settlement to the adult stage in four species of the genus Diplodus. Landmarks were collected on the whole body of fishes to quantify the phenotypic variation along two well defined life stages, i.e. juvenile and adult. A comparative analysis of ontogenetic trajectories was performed to assess the presence of divergence in the developmental pattern. Subsequently, we investigated the patterns of integration and modularity as proxy for the alteration of the developmental processes. This have allowed to give an insight in morphological developmental patterns across ecologically and ontogenetically differentiated life stages and to investigate the process leading to the adult shape. Our results suggest that the origin of morphological novelties in Diplodus spp. arise from shifts of the ontogenetic trajectories during development. During the settlement phase, the juveniles’ morphological shapes converge towards similar regions of the morphospace. When the four species approach the transition between settlement and recruitment, we observe the lowest level of inter- and intra-specific disparity. After this transition we detect an abrupt shift of ontogenetic trajectories, i.e. the path taken by species during development, that led to highly divergent adult phenotypes. We suggest that the evolution of new ecomorphologies, better suited to exploit different niches (pelagic vs. benthonic) and reduce inter-specific competition in Diplodus spp., are related to the shift in the ontogenetic trajectory that in turn is associated to changes in modularity and integration pattern.

  • temporal partitioning of microhabitat use among four juvenile fish species of the genus Diplodus pisces perciformes sparidae
    Marine Ecology, 2015
    Co-Authors: Daniele Ventura, Giovanna Jona Lasinio, Giandomenico Ardizzone
    Abstract:

    Timing, microhabitat selection and behavior from the onset of settlement to recruitment to the adult population of juvenile fishes of the genus Diplodus (Pisces: Sparidae) were investigated along a rocky coastline in the Central Mediterranean Sea. The settlement periods in Diplodus sargus and Diplodus annularis were concentrated in spring, between late May and early June, and the recruits leave the nursery grounds in late September–October. Juvenile fishes of Diplodus puntazzo and Diplodus vulgaris showed a partial time overlapping, sharing the same zones in winter and early spring, from February to May. Multiple correspondence analysis showed that sea breams settle in well-defined habitats. The smallest juveniles of D. sargus and D. puntazzo settled primarily in the shallowest sheltered pebbly areas, located in sciaphilous crannies covered by red algae. Diplodus vulgaris settlers were observed on a wider range of substrata: rock on sand, gravel and pebbles without algal cover or large boulders, generally in deeper waters. The intermediate-size juveniles of D. sargus, D. puntazzo and D. vulgaris showed a preference for rocky substrata with substantial algal cover, with arborescent structures (Phaeophyceae). Diplodus annularis juveniles showed high fidelity to seagrass beds (Posidonia oceanica). The home range increased over time in all species, highlighting a loss of substrate specificity: larger juveniles were even observed in deeper and different microhabitats outside nursery grounds. This study suggests that shallow infra-littoral rocky communities with photophilic algae play a key role in recruitment of sparid fishes, affecting the distribution and abundance of juvenile fishes and therefore determining the renewal of populations and the structure of adult assemblages.

Paolo Guidetti - One of the best experts on this subject based on the ideXlab platform.

  • Extending full protection inside existing marine protected areas, or reducing fishing effort outside, can reconcile conservation and fisheries goals
    Journal of Applied Ecology, 2020
    Co-Authors: Mokrane Belharet, Antonio Di Franco, Antonio Calò, Lorenzo Mari, Joachim Claudet, Renato Casagrandi, Marino Gatto, Josep Lloret, Charlotte Sève, Paolo Guidetti
    Abstract:

    1. Most fish stocks world-wide are fished at maximum sustainable yield (MSY) or overfished, as many fisheries management strategies have failed to achieve sustainable fishing. Identifying effective fisheries management strategies has now become urgent. 2. Here, we developed a spatially explicit metapopulation model accounting for population connectivity in the north-western Mediterranean Sea, and parameterized it for three ecologically and economically important coastal fish species: the white seabream Diplodus sargus, the two-banded seabream Diplodus vulgaris and the dusky grouper Epinephelus marginatus. 3. We used the model to assess how stock biomass and catches respond to changes in fishing mortality rate (F) and in the size of fully protected areas within the existing system of multiple-use marine protected areas (MPAs). For each species, we estimated MSY and the corresponding values of stock biomass (B MSY ) and fishing mortality rate (F MSY ), providing crucial reference points for the assessment of fisheries management. 4. Diplodus sargus is currently in low overfishing, while D. vulgaris and E. marginatus are in high overfishing. Stock recovery to B MSY for the last two species requires a reduction of current F around 50%. This would guarantee an increase in both stock biomass (around 50% and 75% for D. vulgaris and E. marginatus respectively) and catch (around 15% and 30%) after a transient time of ~15–30 years. Alternatively, doubling the size of fully protected areas over fishable areas within the existing network of MPAs would lead to positive conservation effects for all three species without substantially affecting the overall productivity of the fishery and the total economic value of the catch.

  • Appendix A. Results of three-factor ANOVA examining density of Diplodus sargus, Diplodus vulgaris, Coris julis, Paracentrotus lividus, and Arbacia lixula; and cover of barrens, coarse sediment, algal turf, branched-erect macroalgae, unbranched-erect
    2016
    Co-Authors: Paolo Guidetti
    Abstract:

    Results of three-factor ANOVA examining density of Diplodus sargus, Diplodus vulgaris, Coris julis, Paracentrotus lividus, and Arbacia lixula; and cover of barrens, coarse sediment, algal turf, branched-erect macroalgae, unbranched-erect macroalgae, calcified-erect macroalgae, sponges, anthozoans, and other sessile invertebrates at each of the four sampling times between two levels of protection, between two protected and two unprotected locations, and between two sites within location

  • Consumers of sea urchins, Paracentrotus lividus and Arbacia lixula, in shallow Mediterranean rocky reefs
    Helgoland Marine Research, 2004
    Co-Authors: Paolo Guidetti
    Abstract:

    Underwater observations on fish and asteroid consumers (i.e. predators and scavengers) of sea urchins, Paracentrotus lividus and Arbacia lixula , were carried out at several locations in shallow Mediterranean rocky reefs. Observations conducted in the marine reserve of Torre Guaceto (Adriatic Sea) revealed that sparid fishes, Diplodus sargus and D. vulgaris , are the main fish predators of small (4 cm) sea urchins, whereas medium and small Diplodus preyed mainly upon small sea urchins. The number of sea urchins preyed upon by fishes was negatively related to sea urchin size for both species. P. lividus appeared to be subject to higher predation levels than A. lixula . The scavenger guild comprised 11 fish species, with D. sargus , D. vulgaris , Coris julis and Chromis chromis accounting for about 80% of scavenger fishes. Observations performed at several locations in the Mediterranean on the predatory asteroid Marthasterias glacialis revealed that only 3% of the detected individuals were preying upon sea urchins. Due to the importance of sea urchins for assemblage structure and functioning of Mediterranean rocky reef ecosystems, these results may have also important implications for management of fishing activities.

  • Effects of seagrass canopy removal on fish in shallow Mediterranean seagrass ( Cymodocea nodosa and Zostera noltii ) meadows: a local-scale approach
    Marine Biology, 2002
    Co-Authors: Paolo Guidetti, Simona Bussotti
    Abstract:

    The importance of the canopy of small-sized seagrasses (Cymodocea nodosa and Zostera noltii) to fish assemblages was investigated in experimental plots at three shallow sites in NE Sardinia (Italy, western Mediterranean). Fish were assessed by underwater visual census in four habitats: (1) seagrass in its natural state, (2) cut seagrass, (3) uncut seagrass (with a simulation in time and effort equivalent to those spent at the treated patches) and (4) unvegetated sand. The disturbance associated with removing seagrass canopies was not found to affect fish. Multivariate analyses showed that fish assemblages from seagrass habitats, with seagrass patches removed and unvegetated sand differed significantly among each other. Univariate analyses revealed that species richness, total fish abundance, and densities of Atherinidae, Diplodus sargus and Sarpa salpa were unaffected by the habitat type. The seagrass leaf canopy was most important for Symphodus ocellatus, Labrus viridis, Diplodus annularis and Sparus aurata, the last three species being chiefly represented by small-sized fishes. Gobiids were most abundant in habitats devoid of seagrass vegetation (i.e. sand and removed patches), while Coris julis and Diplodus vulgaris appeared to prefer unvegetated sand, even compared with the removed patches. Other species, such as Symphodus cinereus, Symphodus tinca and Mullus surmuletus, did not display any distinct distribution patterns attributable to the habitat type. For a number of littoral fish species, including some of commercial importance (e.g. S. aurata), small-sized seagrasses in NE Sardinia were thus demonstrated to exert an ecological role, which involves important implications for the protection and management of these coastal habitats and suggests the need for further research at larger spatial scales.

Ciro Rico - One of the best experts on this subject based on the ideXlab platform.

  • Isolation of eight microsatellites loci from the saddled bream, Oblada melanura and cross-species amplification in two sea bream species of the genus Diplodus
    Conservation Genetics, 2007
    Co-Authors: Séverine Roques, Enrique Macpherson, Juan A. Galarza, George F. Turner, Josep Carreras-carbonell, Ciro Rico
    Abstract:

    We have developed eight new microsatellite markers for the saddled bream (Oblada melanura) from an enriched genome library protocol. All these loci are polymorphic, with mean allelic diversity of 14.75 (range 3–22), and expected and observed heterozygosities from 0.233 to 0.918 and 0.212 to 0.913, respectively. Cross-species tests in two close relatives of the genus Diplodus (D. sargus and D. vulgaris) revealed successful amplifications at 6 out of 8 loci, with means allele number of 6.67 (range 4–10) and 6.50 (range 4–10), respectively. These results are consistent with the close phylogenetic relationships between the three species, indicating this set of primers might proved useful for studying the levels of genetic diversity and population differentiation in these three species and in other phylogenetically close species of the genus Diplodus and Sparus.

  • Isolation and characterization of nine polymorphic microsatellite markers in the two-banded sea bream (Diplodus vulgaris) and cross-species amplification in the white sea bream (Diplodus sargus) and the saddled bream (Oblada melanura)
    Molecular Ecology Notes, 2006
    Co-Authors: Séverine Roques, Enrique Macpherson, Juan A. Galarza, George F. Turner, Ciro Rico
    Abstract:

    AbstractWe have developed nine new microsatellite markers for the two-banded sea bream ( Diplodusvulgaris ) from an enriched genome library protocol. All these loci are polymorphic, withmean allelic diversity of 13 (range 5–21), and expected and observed heterozygosities from0.641 to 0.932 and 0.428 to 0.914, respectively. Cross-species tests in two close-related speciesof the genus Diplodus ( D. sargus and O. melanura ) revealed successful amplifications at 8out of 9 loci, with mean allele number of 4.75 (range 2–8) and 5.50 (range 3 –10), respectively.These results are consistent with the close phylogenetic relationships between the threespecies, indicating this set of primers might prove useful for studying the levels of geneticdiversity and population differentiation in these three species and in other phylogeneti-cally close species of the genus Diplodus and Sparus . Keywords : Diplodus , microsatellite, Oblada melanura , sea bream, Sparidae Received 22 October 2006; revision accepted 13 November 2006

Catarina Vinagre - One of the best experts on this subject based on the ideXlab platform.

  • Thermal sensitivity of native and invasive seabreams
    Marine Ecology, 2013
    Co-Authors: Catarina Vinagre, Maria Jose Costa, Henrique N. Cabral, Luís Narciso, Rui Rosa
    Abstract:

    This study compared the mortality and metabolic response of the Senegal seabream, Diplodus bellottii, an African species recently reported in Southern Europe and the white seabream Diplodus sargus, a native species, across a range of temperatures. The temperatures tested were 18, 26, 28 and 30 °C. Mortality was zero at 18 °C and very low at all other temperatures for both species, with the exception of D. bellottii, which experienced 32% mortality at 30 °C. Metabolic rates increased steadily with increasing temperatures, with a steep increase at 30 °C for D. bellottii. Thermal sensitivity ranged between 2 and 3 for both species and for all thermal intervals, with the exception of the thermal sensitivity between 28 and 30 °C for D. bellottii, which was 7. It was concluded that D. bellottii is under thermal stress at 30 °C. Diplodus bellottii may have expanded its distribution northwards due to an increase in sea surface temperatures. However, further warming may result in habitat loss for the juveniles, since Southern European estuarine systems will reach temperatures that may lead to lower fitness in juveniles of this species.

  • Thermal tolerance and potential impacts of climate change on coastal and estuarine organisms
    Journal of Sea Research, 2012
    Co-Authors: Diana Madeira, Henrique N. Cabral, Luís Narciso, Catarina Vinagre
    Abstract:

    Abstract The study of thermal tolerance is the first step to understanding species vulnerability to climate warming. This work aimed to determine the upper thermal limits of various fish and crustaceans in a temperate estuarine ecosystem and an adjacent coastal area. Species were ranked in terms of thermal tolerance and intraspecific variability was evaluated. The method used was the Critical Thermal Maximum (CTMax). The CTMax was found to be higher for species typically found in thermally unstable environments, e.g. intertidal, supratidal, southern distributed species and species that make reproduction migrations because they are exposed to extreme temperatures. Subtidal, demersal and northern distributed species showed lower CTMax values because they live in colder environments. Species from different taxa living in similar habitats have similar CTMax values which suggests that they have evolved similar stress response mechanisms. This study showed that the most vulnerable organisms to sea warming were those that occur in thermally unstable environments because despite their high CTMax values, they live closer to their thermal limits and have limited acclimation plasticity. Among the demersal species studied, two sea-breams ( Diplodus bellottii and Diplodus vulgaris ) are potentially threatened by sea warming because their CTMax values are not far from the mean water temperature and they are already under thermal stress during current heat waves.

  • relative importance of estuarine nurseries for species of the genus Diplodus sparidae along the portuguese coast
    Estuarine Coastal and Shelf Science, 2010
    Co-Authors: Catarina Vinagre, Henrique N. Cabral, M J Costa
    Abstract:

    The relative importance of estuarine nursery areas for species of the genus Diplodus and their relations with several environmental variables was evaluated along the Portuguese coast. Nine estuarine systems were sampled with beam trawl surveys. Species of the genus Diplodus were only present in estuaries south of the Ria de Aveiro (40°38′). A latitudinal gradient of increasing species richness and abundance towards the south was found. Estuarine nurseries of Diplodus vulgaris, Diplodus sargus and Diplodus puntazzo were characterized by mud substrate, lower salinity and lower dissolved oxygen, with the exception of Ria Formosa. Diplodus bellottii was associated with estuaries with large areas and high volumes, the Tejo and the Sado. Diplodus bellottii nursery grounds were characterized by low depth. Diplodus annularis was associated with seagrass and saltmarsh habitats, certainly because it is the only species of the genus Diplodus which recruits exclusively to seagrass meadows. Diplodus annularis nursery grounds were also characterized by sand substrate, higher salinity and higher dissolved oxygen. Niche breath varied widely amongst species and location. Diplodus vulgaris generally presented the highest values of niche breath, except when D. bellottii was present. Niche overlap was not high, the highest value being that between D. vulgaris and D. sargus in the Mira estuary, with 76% spatial niche overlap. Considerations were made on these species progress towards the north in a climate warming context, taking into account the habitat associations described here.