Insights into population structure of Diplodus vulgaris along the SW Portuguese coast from otolith elemental signatures

The common two-banded sea bream (Diplodus vulgaris) is an important fish in the marine ecosystems of the NW Atlantic and Mediterranean. In southern Portugal it is a major fishery resource being targeted mainly by the artisanal fleets. Although there is some knowledge of the age, growth and reproductive biology of the species, information about its population structure is scarce and somewhat limited to the Mediterranean Sea. In this study the otolith elemental signatures of 90 specimens of D. vulgaris of the same age group (2+ years) and cohort collected from the important fishery regions of SW Portugal (Sesimbra, Sagres and Faro) have been analysed by inductively coupled plasma mass spectrometry (ICP-MS). Two different methodologies have been applied: solution based analysis of the whole otoliths; representative of the entire life-history prior to capture, and laser ablation analysis of otolith cores; representative of the larval and early post-settlement phase. Whole otolith comparisons utilised Sr/Ca, Ba/Ca, Mn/Ca, Li/Ca and Ni/Ca to demonstrate regional population structure. Classification accuracy rates from linear discriminant function analyses (LDFA) of whole otolith chemistry data were high for each region; Faro - 93%, Sagres - 90% and Sesimbra - 80%. Comparison of the otolith core chemistry utilised Sr/Ca, Ba/Ca, Mn/Ca and Mg/Ca and Zn/Ca. LDFA for the otolith core chemistry also achieved accurate classification for samples from Sesimbra (73%), but there was high overlap of otolith chemistry between samples from Faro and Sagres (47 and 43% classification accuracy respectively). The whole otolith results suggest that D. vulgaris are resident in the regional fishing areas during the juvenile phase. Both the core and whole otolith chemistry data supported separation of the Sesimbra fishery region from the more southern and closely associated Faro and Sagres regions for management purposes. However, while the whole otolith data indicated that the populations at Faro and Sagres likely remained separated in the juvenile stage, the otolith core chemistry data was inconclusive as to whether recruitment to these two areas was derived, or not, from different spawning areas.

Population structure of the black seabream Spondyliosoma cantharus along the south-west Portuguese coast inferred from otolith chemistry

The chemistry of black seabream Spondyliosoma cantharus otoliths from three main fishery grounds (Olhao, Sagres and Sesimbra) located along c. 400 km of the Portuguese south and west coasts was examined. Element:Ca ratios were determined in whole otoliths and otolith cores of young adult specimens of 23 years of age. Using the data from whole otoliths, it was possible to discriminate among S. cantharus from the three fishing grounds with an average accuracy of 91%. Differences among fishing grounds were significant for all element:Ca ratios, and otoliths from Sagres had significantly higher levels of all ratios compared to the other fishing grounds. In contrast, the chemical composition of the otolith core, representative of the larval stage, showed limited variation among the fishing grounds, with an average discrimination accuracy of only 44%, although the Mg:Ca ratio of the otolith cores was also significantly higher for the Sagres samples. The data suggest that larval stages experienced a homogenous environment consistent with an offshore oceanic spawning. Juveniles appeared to display local residency on the inshore fishing grounds, areas probably characterized by greater environmental heterogeneity. Spondyliosoma cantharus population structure is consistent with distinct local population units that share a spawning ground providing recruits to different coastal fishery areas.

Non-indigenous Japanese oyster drill Pteropurpura (Ocinebrellus) inornata (Récluz, 1851) (Gastropoda: Muricidae) on the south-west coast of Portugal

The Japanese oyster drill or rock snail Pteropurpura (Ocinebrellus) inornata (Récluz, 1851), a marine mollusc, belonging to the family Muricidae, is reported from Portugal for the first time. This non-indigenous species, most likely introduced accidentally from French oyster rearing areas into mainland Portugal, has been regularly sampled in shellfish-culture and nearby environments in Sagres, Algarve, Southwest Portugal since 2005–2008. Detailed studies are urgently needed in order to assess whether or not it has become an invasive species due to a range expansion beyond its point of initial introduction. Outputs should provide information to decision-makers to predict and limit further spread which might result in biodiversity loss and negative economical consequences in locally species-rich areas.

CARTOGRAFIA ANTIGA

CARTOGRAFIA ANTIGA Resumo: A cartografia, ou seja, a ciência de preparar cartas, mapas e planos para os mais variados fins, com diversos níveis de complexidade e informação, baseados em elementos científicos, técnicos e artísticos de extremo apuro, tendo por base os resultados da observação direta ou da análise de documentos, remonta a tempos muito antigos. Conhecem-se cartas ou representações de território ou do mundo que ia sendo descoberto, desde Ptolomeu que os realizou baseado nas referências de viajantes e mercadores, e no material coligido por geógrafos que o antecederam, dados sobre a Europa, Ásia e África. Uma das representações mais remotas que existe é uma reconstituição (de autor não identificado) do mapa de Eratóstenes, de cerca de 220 a.C. O matemático grego e bibliotecário da Alexandria usou os levantamentos do mundo conhecidos, após as conquistas de Alexandre, o Grande. Posteriormente nos mapas-mundo medievais, a Terra não tem forma geográfica, mas geográfica ou anti geográfica -como se poderá observar em Psalter, manuscrito em papel velino, anónimo, 1265). Mais tarde o Planisfério de Cantino (1502), constitui-se como a mais antiga carta náutica portuguesa conhecida, mostrando o resultado das viagens de Vasco da Gama à Índia, Colombo à América Central, Gaspar Corte Real à Terra Nova e Pedro Álvares Cabral ao Brasil, representando a superfície terrestre em seu conjunto, apresentando os dois hemisférios lado a lado. A época dos descobrimentos, foi para Portugal, altura em que a ciência da cartografia se desenvolveu de forma muito assinalável, sendo de referir inúmeros cartógrafos reais, de entre os quais André Homem, Bartolomeu Velho, Fernando Álvaro Seco, João Teixeira Albernaz, o Moço, João Teixeira Albernaz, o Velho, Lopo Homem, Pedro Reinel, Pedro Teixeira Albernaz, Diogo Ribeiro, entre muitos outros. Os portugueses também se destacaram na produção de portulanos, especialmente no período do Infante D. Henrique e da lendária "Escola de Sagres “. A partir do século XVI a designação de ‘'portulano'' disseminou-se e começou a ser aplicado a qualquer coleção de instruções náuticas, assim como aos mapas que as acompanhavam. A partir do século XIX o termo passou a designar, de forma genérica, as cartas marítimas produzidas até aos fins do século XVI. A cartografia, foi desde sempre um conjunto de documentos fundamentais, para que homens e bens pudessem circular, que as diferentes civilizações, nas mais distantes partes do mundo se conectassem. Como elementos de orientação terrestre ou marítima foram a representação de territórios novos a explorar. Mais ou menos guarnecidos de cor ou representações fantásticas de gentes e animais procuraram transmitir a visão dos homens coevos.