64 resultados para Sparidae


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The red pandora, Pagellus bellottii Steindachner, 1882, is a tropical and subtropical demersal Sparidae (Porgies) that lives over hard or sandy bottoms in coastal marine waters. It mostly occurs at depths ranging from 10 to 50 metres. It is distributed in the eastern Atlantic, from the Strait of Gibraltar to Angola and the Canary Islands where it is occasionally recorded (Bauchot and Hureau, 1986; Franqueville, 1983). The species is also recorded in the southwestern Mediterranean, in the Alboran Sea, off the Algerian coasts and in the Gulf of Gabes (Oral, 2010). The records of the species in the eastern Mediterranean, Syrian and Israeli waters (Fricke, et al. 2014, Fig. 1) is questioned. We consider these records are misidentification of Pagrus pagrus (Linnaeus, 1758). Pagellus bellottii was also included in the checklist of the fishes from Portugal as a consequence of records coming from the Algarve region, about 36°59′ N, 8° W, the northernmost records in Atlantic waters (de Castro, 1967; Erzini et al., 1996; Carneiro et al., 2014; Carneiro com. pers.). Some specimens were also recorded in Spanish Mediterranean waters, in the Bay of Almería about 36°47′ N, 2°25′ W (Lucena, et al. 1982), the northernmost records for the Mediterranean waters. Herein, the first record of P. bellottii in the Bay of Biscay is reported.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação de mest. em Estudos Marinhos e costeiros, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 1998

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Partial sequences of the mitochondrial control region and its comparison with previously published cytochrome b (cyt-b) and microsatellite data were used to investigate the influence of island isolation and connectivity on white seabream genetic structure. To achieve this, a total of 188 individuals from four island localities (Castellamare and Mallorca, Mediterranean Sea; Azores and Canary Islands, Atlantic Ocean) and five coastal localities (Banyuls, Murcia and Tunisia, Mediterranean Sea; Galicia and Faro, Atlantic Ocean) were analysed. Results showed high haplotype diversity and low to moderate nucleotide diversity in all populations (except for the Canary Islands). This pattern of genetic diversity is attributed to a recent population expansion which is corroborated by other results such as cyt-b network and demographic analyses. Low differentiation among Mediterranean/Atlantic and coastal/island groups was shown by the AMOVA and FST values, although a weak phylogeographic break was detected using cyt-b data. However, we found a clear and significant island/ distance effect with regard to the Azores islands. Significant genetic differentiation has been detected between the Azores islands and all other populations. The large geographical distance between the European continental slope and the Azores islands is a barrier to gene flow within this region and historic events such as glaciation could also explain this genetic differentiation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Acanthopagrus butcheri completes its entire life history within estuaries and coastal lakes of southern Australia, although adults occasionally move between estuaries via the sea. Consequently, it is expected that populations of A. butcheri in different estuaries will be genetically distinct, with the magnitude of genetic divergence increasing with geographic isolation. However, previous genetic studies of A. butcheri from southeast Australia yielded conflicting results; allozyme variation exhibited minimal spatial structuring (θ = 0.012), whereas mitochondrial DNA distinguished the majority of populations analyzed (θ = 0.263) and genetic divergence was positively correlated with geographic isolation. This discrepancy could reflect high male gene flow, which impacts nuclear but not mitochondrial markers. Here we estimated allele frequencies at five nuclear microsatellite loci across 11 southeast Australian populations (595 individuals). Overall structuring of microsatellite variation was weaker (θ = 0.088) than that observed for mitochondrial DNA, but was able to distinguish a greater number of populations and was positively correlated with geographic distance. Therefore, we reject high male gene flow and invoke a stepping-stone model of infrequent gene flow among estuaries for both sexes. Likewise, management of A. butcheri within the study range should be conducted at the scale of individual or geographically proximate estuaries for both sexes. The lack of allozyme structuring in southeast Australia reflects either the large variance in structuring expected among loci under neutral conditions and the low number of allozymes surveyed or a recent colonization of estuaries such that some but not all nuclear loci have approached migration-drift equilibrium.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Samples of Boops boops ranging from 7.4 to 30.5 cm were obtained mainly by longline, supplemented by beach seining in the Ria Formosa lagoon, and by market sampling in the Algarve (southern Portugal). The macroscopic analyses of the gonads and the gonad somatic index showed that the south coast of Portugal B. boops spawn mainly from late winter to spring, between February and May. The length at first maturity was similar for males and females and the value for both sexes combined was estimated to be 15.22 cm, corresponding to an age range of 1-3. Age was determined by reading growth bands on otoliths. Age determination was validated by marginal increment analysis. The estimated parameters were L-infinity = 28.06, K = 0.22 and t(0) = -1.42. Mortality rates were calculated for fish captured with longlines, and the estimated parameters were M = 0.33, Z = 1.04 and F = 0.71. Relative yield per recruit analysis and sensitivity analysis showed that the resource is moderately exploited. From the perspective of sustainability, these results provide support for the use of longlines as a gear that is among the least harmful for species such as the bogue.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Studies that combine both the ecological responses of marine species and protection measures with movement patterns and habitat use are of major importance in order to better understand the performance of marine protected areas (MPA) and how species respond to their implementation. However, few studies have assessed MPA performance by relating local individual movement patterns and the observed reserve effects. In this study, we combined acoustic telemetry with abundance estimates to study the early effects of a recently established small coastal MPA on the local populations of white seabream. The results show that even small, recently established coastal MPAs can increase the abundance and biomass of commercial fish species, provided that target species have small home ranges and exhibit high site fidelity.