The Portuguese coast has overlapping distributions of species of both boreal and Lusitanian origins; a large number of cold-and warm-water species have their southern or northern distributional range edges here. A latitudinal gradient in ocean climate, particularly sea surface temperature (SST) and primary production, has been described along this coast. Here, we took advantage of this gradient in ocean climate to explore affinities in the biogenic landscape structure of subtidal shallow reefs (the abundance of habitat patches), as well as in the assemblage structure of macroalgae and associated fishes, between each of 3 regions: Viana do Castelo (41.5°N), Peniche (39.2°N) and Sines (37.8°N). Five reefs were sampled to determine the abundance of biogenic habitats and the assemblage structure of macroalgae and fishes in each region. The structure of the landscape, and of macroalgal and fish assemblages, differed between Viana do Castelo and Peniche and between Viana do Castelo and Sines, but not between Peniche and Sines. Viana do Castelo was the only region with conspicuous kelp forests, while Peniche and Sines were dominated by patches of foliose turf-forming and filamentous algae. Our study revealed an abrupt macroecological change from northern Portugal to central and southern Portugal, suggesting a possible biogeographical reconfiguration and recognition of a wider transitional area from the Atlantic into Mediterranean waters.KEY WORDS: Latitude · Macroecology · Habitat structure · Assemblage structure · Kelps · Fishes · Rocky reefs · Atlantic Ocean Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 466: [9][10][11][12][13][14][15][16][17][18][19] 2012 distribution, abundance and fitness of organisms may be relevant for predicting the effects of climate change, because shifts in distribution patterns along these gradients are among the principal detectable responses to climate change by both aquatic and terrestrial organisms (Southward et al. 1995, Walther et al. 2002, Parmesan & Yohe 2003, Poloczanska et al. 2007, Hawkins et al. 2009, Wernberg et al. 2011b.In the marine realm, biogeographic classifications are a crucial tool for reaching international agreements in marine conservation. Biogeographic units have been defined using sets of hierarchical criteria, within which the biogeographic affinities of biological entities and assemblages are a key component (Lüning 1990, Spalding et al. 2007. Considerable heterogeneity in the composition and abundance of biological communities may exist within any particular biogeographic level, mainly within large spatial units, and so a more detailed classification system is recommended (Spalding et al. 2007, Waters et al. 2010. This is particularly pertinent as shifts in the distributional ranges of several species are occurring in most oceans of the globe as a result of global change (e.g. Southward et al. 1995, Last et al. 2011, Philippart et al. 2011, Wernberg et al. 2012. In this context, it is crucial to tes...

No abstract

After Bakun (1990) formulated his hypothesis of upwelling intensification caused by increasing global warming, contradictory results have been published on whether primary productivity is increasing or decreasing in Eastern Boundary Upwelling Ecosystems (EBUE). The present work is focused in comparing three net primary production (NPP) models-the VGPM (Vertically Generalized Production Model), the Eppley-VGPM and the CbPM (Carbon-based Production Model)-in the Canary Current (CanC) EBUE during the 1998-2015 period, making use of both SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MODIS (MODerate-resolution Imaging Spectroradiometer) derived data. We looked for the first time for seasonal to interannual trends of NPP under a regional perspective, with the aim of searching for temporal patterns that could support or reject the intensification hypothesis. According to previous studies based on the seasonality of the upwelling regime, the CanC EBUE was divided into three subregions: a seasonal upwelling zone (SUZ; 13-20 • N), a permanent upwelling zone (PUZ; 20-26 • N) and a weak permanent upwelling zone (WPUZ; 26-33 • N). Although differences in the output of the models are important, both at regional and subregional scales, our analyses do not show significant increasing trends in NPP with any of the productivity models used. Our results are in accordance with previous published studies that indicate, that unlike other EBUE, winds have weakened (or at least not intensified) in the CanC upwelling over time scales ranging up to 60 years. Nevertheless, the comparison made in this work shows disagreements between some of the best-known NPP models and calls for a validation effort in this region. Seasonal to decadal anomalies of NPP and sea-surface temperature (SST) are estimated and analyzed in relation to selected climate indices, yielding only significant correlations between SST and the North Atlantic Oscillation (NAO) indices.

Striped seabream, Lithognathus mormyrus L. (n=731) caught off the Canary Islands from January 1999 to June 2000 were studied. Fish ranged in size from 113 to 372 mm total length, weighing from 21.1 to 748.2 g total weight. Weight increased allometrically with size (b=2.9071). Fish age was 0–10‐years‐old. Growth was relatively slow (k=0.88 years−1), with females growing at a slightly faster rate than males. The species displayed protandric hermaphroditism. Male : female ratio was unbalanced in favour of males (1 : 0.85). Males predominated in smaller sizes, females in larger sizes, and intersexual individuals were in intermediate sizes. The reproductive season extended from June to December, with a peak in spawning activity in August–September. Males reached maturity at 207 mm (2 years) and females at 246 mm (3 years). The real value of instantaneous rate of natural mortality was between 0.30 and 0.45 years−1.

No abstract