The feeding ecology, growth and spatialetemporal abundance and distribution of Pomatoschistus microps (Krøyer, 1838) and Pomatoschistus minutus (Pallas, 1770) were studied between June 2003 and June 2004, based on beam trawl surveys and macrobenthic samples conducted in the Mondego estuary, Portugal. Polychaetes, molluscs and amphipods were the most important items in the diet of P. microps, while for P. minutus the dominant preys were polychaetes, mysids and decapods. Pomatoschistus microps' recruitment lasted for six months and was composed of three new cohorts per year. Pomatoschistus minutus had an uncommon long reproductive season, from April to November, and population segregation was found, corresponding to the two reproductive peaks. Populations of both species were composed mainly of 0-group individuals with sand gobies presenting a more extended life span. In the Mondego estuary, inter-and intra-specific spatial segregation occurred between the two species and between the 0C and 1C age groups of P. microps. Ó 2005 Elsevier Ltd. All rights reserved.Keywords: Pomatoschistus; diet overlap; life cycle; competition; resource partitioning; Mondego estuary IntroductionHigh fish abundance concentrated in particular areas, is a common feature in estuarine fish communities (Elliott et al., 2002). Consequently, co-occurrence of several similar morphological types (e.g. species of Soleidae, Mugilidae, Gobiidae) with overlap of ecological niches within the communities is expected. Spatial and temporal distribution, abundance patterns of fish assemblages as well as resource partitioning, are therefore, important and interesting issues for understanding the structure and dynamics of these communities (Cabral, 2000). Competition exists when the requirements of two or more individuals for a particular resource exceed the supply of that resource in the environment; or, if their demands do not exceed the supply, but they compete directly to obtain this resource. The study of diet is often used to evaluate competition between fish species (Elliott et al., 2002).Trophic and habitat segregation are among the most important aspects of resource partitioning in fish communities but it has been difficult to assess and prove the main force behind this process (Ross, 1986a). Evidences of coexistent Gobiidae species exhibiting vertical spatial segregation, temporal segregation in spawning and absence of niche shifts when one species was temporarily absent have been reported by NorteCampos and Temming (1994). The Gobiidae is a particularly successful family in both tropical and temperate seas, well represented in estuarine and freshwater environments. Gobiidae present more than 2000 species (Bouchereau and Guelorget, 1998) and virtually all gobies exhibit demersal eggs, male parental care and highly variable number of spawnings per season (Miller, 1984).In the Mondego estuary, four species of Gobiidae are present: Pomatoschistus microps (Krøyer, 1838), Pomatoschistus and Miller, 1966). Although it is usually an annual spe...

Methamphetamine (METH) is a psychostimulant that causes neurologic and psychiatric abnormalities. Recent studies have suggested that its neurotoxicity may also result from its ability to compromise the blood-brain barrier (BBB). Herein, we show that METH rapidly increased the vesicular transport across endothelial cells (ECs), followed by an increase of paracellular transport. Moreover, METH triggered the release of tumor necrosis factor-alpha (TNF-α), and the blockade of this cytokine or the inhibition of nuclear factor-kappa B (NF-κB) pathway prevented endothelial dysfunction. Since astrocytes have a crucial role in modulating BBB function, we further showed that conditioned medium obtained from astrocytes previously exposed to METH had a negative impact on barrier properties also via TNF-α/NF-κB pathway. Animal studies corroborated the in vitro results. Overall, we show that METH directly interferes with EC properties or indirectly via astrocytes through the release of TNF-α and subsequent activation of NF-κB pathway culminating in barrier dysfunction.

Nevertheless, from the management point of view, it could be stated that although some variations occurred due to environmental stress, the main core of the Mondego Estuary fish community remained relatively unchanged.