Non-commercial invertebrate discards in an experimental trammel net fishery

Abstract  Non-commercial invertebrate discards in an experimental trammel net fishery were studied in relation to selectivity of the gear, depth, soak time and season. Forty experimental fishing trials were carried out over a 1-year period with six combinations of small mesh (100, 120 and 140 mm) inner and large mesh (600 and 800 mm) outer panels. On average, 43.8 ± 12.2 (SD) (individuals 1000 m⁻¹ of net) of non-commercial invertebrates were discarded, accounting for 48% and 65% of the total catch and total discards by numbers, respectively. Within non-commercial invertebrates discards, the six most abundant species by number were Phallusia mammillata (Cuvier) (27.5%), Cymbium olla (L.) (13.0%), Sphaerechinus granularis (Lamarck) (11.3%), Paracentrotus lividus (Lamarck) (10.9%), Astropartus mediterraneus (Risso) (8.2%) and Astropecten aranciacus (L.) (8.1%); Echinoderms (43.1%) particularly important. The highest and lowest discard ratios were found in autumn and winter, respectively. Discards generally decreased with depth, varied considerably in relation to soak time and were not related to mesh size combinations. Trammel nets seem to be the most important gear in terms of ecological impacts on benthic invertebrates compared with other coastal fishing gears and at the depths studied (15–60 m).     

Effects of an extreme flash flood on the native fish assemblages across a Mediterranean catchment

Abstract  The effects of an extreme flash flood on the native fish assemblages across a Mediterranean catchment in Southwest Portugal were investigated. The fish community structure and habitat were surveyed at 10 sites pre- and post-flood. Overall species richness and rank abundances changed little after the flood, despite there being a consistent decline in the abundance of small cyprinids. Pre- and post-flood habitat correlates of abundance changed for at least some species, and variability in assemblage structure was associated with flood, depth and pH. These results indicate that extreme floods occurring early in the wet season may have little disruptive effects on the overall structure of native fish assemblages in Mediterranean streams, although may at least partially influence population dynamics for some species. Habitat quality and complexity are likely to play a role in mediating species responses to flooding.     

Reduction of elasmobranch by-catch in the hake semipelagicnear-bottom longline fishery in the Algarve (Southern Portugal)

ABSTRACT:   Elasmobranch fish, particularly deep-sea sharks, are the mostimportant component of the by-catch of the hake semipelagic near-bottom 'pedra-e-bola' longlinefishery in the Algarve (South Portugal) and most of these fish arediscarded. The effects of the removal of the lower hooks were evaluated,in terms of target and by-catch reductions, by quantifying the catchesof each hook relative to the distance from the bottom. The analysisshowed that most European hake ( Merluccius merluccius ), thetarget species of this fishery, were caught in the middle rangeof the hooks, with very few individuals caught near the bottom,whereas for sharks the situation was the opposite, with most hookednear the bottom. The removal of the lower three pairs of hooks wouldresult in a small reduction in the catch of the target species,but a much more significant reduction in elasmobranch by-catch.In the specific case of the blackmouth catshark ( Galeus melastomus ),discard mortality would be further minimized due to the fact thatthe lower hooks capture significantly smaller animals that are alwaysdiscarded compared with hooks that are more distant from the bottom.     

Biliary excretion of technetium-99m-sestamibi in wild-type dogs and in dogs with intrinsic (ABCB1-1Δ mutation) and extrinsic (ketoconazole treated) P-glycoprotein deficiency

P-glycoprotein (P-gp), the product of ABCB1 gene, is thought to play a role in the biliary excretion of a variety of drugs, but specific studies in dogs have not been performed. Because a number of endogenous (ABCB1 polymorphisms) and exogenous (pharmacological P-gp inhibition) factors can interfere with normal P-gp function, a better understanding of P-gp's role in biliary drug excretion is crucial in preventing adverse drug reactions and drug–drug interactions in dogs. The objectives of this study were to compare biliary excretion of technetium-99m-sestamibi (^99mTc-MIBI), a radio-labelled P-gp substrate, in wild-type dogs (ABCB1 wild/wild), and dogs with intrinsic and extrinsic deficiencies in P-gp function. Dogs with intrinsic P-gp deficiency included ABCB1 mut/mut dogs, and dogs with presumed intermediate P-gp phenotype (ABCB1 mut/wild). Dogs with extrinsic P-gp deficiency were considered to be ABCB1 wild/wild dogs treated with the P-gp inhibitor ketoconazole (5 mg/kg PO q12h × 9 doses). Results from this study indicate that ABCB1 mut/mut dogs have significantly decreased biliary excretion of ^99mTc-MIBI compared with ABCB1 wild/wild dogs. Treatment with ketoconazole significantly decreased biliary excretion of ^99mTc-MIBI in ABCB1 wild/wild dogs. P-gp appears to play an important role in the biliary excretion of ^99mTc-MIBI in dogs. It is likely that concurrent administration of a P-gp inhibitor such as ketoconazole will decrease P-gp-mediated biliary excretion of other substrate drugs as well.     

Patterns of genetic divergence in Chondrostoma lusitanicum Collares-Pereira, in intermittent Portuguese rivers

Samples collected from throughout the range of Chondrostoma lusitanicum Collares-Pereira, were examined electrophoretically for patterns of variation at 24 presumptive gene loci. Thirteen loci were found to be polymorphic (frequency of the most common allele 0.95). There was high differentiation between rivers, especially in the southern populations of the Mira and the Arade catchments. This differentiation was associated with a low level of genetic variation and was thus interpreted in the light of past and present bottlenecks. The differentiation of C. lusitanicum is congruent with that already observed for another cyprinid species of the genus Leuciscus inhabiting the same catchments. This reinforces the hypothesis that the periodic drying-up of extensive sections of these rivers may lead to reduction in population sizes and subsequent differentiation. The level of genetic divergence of both the Mira and Arade populations of C. lusitanicum compared to all other populations sampled suggested a review of their conspecific status is necessary despite morphological similarity. The management implications in these rivers, and in the Tejo and Sado basins where C. lusitanicum is very rare, are discussed.     

Diet and feeding relationships of two Iberian cyprinids

The diet and feeding interactions of the Iberian roach, Rutilus alburnoides (Steindachner), and chub, Leuciscus pyrenaicus Günther, were studied in the Sorraia river system. Seasonal shifts in the diets were examined to determine trophic overlap between the two species. Dipteran larvae were the dominant item in the diet of roach with the exception of summer and early autumn when dipteran adults became important. Ephemeroptera nymphs and imagos were the two principal food categories in chub diet. Plant material and terrestrial insects were consumed by both species mostly in the summer and autumn, periods of low availability of aquatic invertebrates in temperate streams. A low dietary overlap was found, probably resulting from differences in their seasonal foraging activity, but also from a compromise between the consumption of highly abundant plant material and rare animal food items.     

PULMONARY ANGIOGRAPHY USING 16 SLICE MULTIDETECTOR COMPUTED TOMOGRAPHY IN NORMAL DOGS

We report a canine computed tomography (CT) pulmonary angiography technique using multidetector CT (MDCT). CT pulmonary angiography using a 16 slice MDCT was performed on five healthy, anesthetized beagles. A helical acquisition with pitch of 1.4 was used. The time delay for the angiographic study was determined using a bolus‐tracking program. A dose of 400 mg I/kg of nonionic contrast medium (Iohexol 300 mg I/ml) was administered to each dog via a cephalic catheter using an angiographic power injector at a rate of 5 ml/s. In two dogs a second study, using a contrast medium dose of 200 and 600 mg I/kg was performed. Arterial enhancement of transverse and reformatted images was classified subjectively as excellent, good, or poor, and assessed objectively by measuring Hounsfield units at the right main pulmonary artery. Angiographic studies were evaluated by two radiologists to determine the number of subsegmental arterial branches visualized. The median number of subsegmental arterial branches identified was five (range: 2–7). Based on the time attenuation curve obtained by the bolus‐tracking program, there was consistent enhancement of the right main pulmonary artery beginning at 6 s and peaking at 8 s in 4/5 dogs. The contrast medium dose of 400 mg I/kg produced good to excellent vascular enhancement in the same 4/5 dogs. A dose of 200 mg I/kg resulted in poor enhancement. CT pulmonary angiography using MDCT and an automated bolus‐tracking program allows rapid, consistent evaluation of the pulmonary vasculature using a single dose of 400 mg I/kg of contrast medium.     

万寿菊：铬植物修复的潜在价值

Environmental pollution with chromium(Cr) is harmful to humans, animals and plants, while in plants it causes diminished growth,anatomical alterations and death. In the present study, the potential value of marigold(Tagetes erecta) in the phytoremediation of Cr has been investigated. The randomized experimental design involved the exposure of plants to nutrient solutions containing 0.00,0.04, 0.08, 0.12, 0.16 or 0.24 mmol L~(-1)Cr(Ⅲ). Chromium toxicity was observed at Cr(Ⅲ) concentrations ≥ 0.12 mmol L~(-1) as demonstrated by diminished growth of the aerial parts and reduced density of the root system. Increasing Cr(Ⅲ) concentrations in the nutrient solution resulted in a higher bioaccumulation of total Cr in the tissues, although translocation from roots to aerial parts was not efficient(maximum value of 25% at 0.12 mmol L~(-1)Cr(Ⅲ)). The Cr bioaccumulation was up to 11-fold greater in roots than in the aerial parts. Tagetes erecta exhibited leaf plasticity when exposed to Cr, indicating the existence of a tolerance mechanism to Cr in this species. Chromium caused a reduction in xilem vases, resulting in a plastic effect in T. erecta leaves that increased the metal tolerance in culture solution. Tagetes spp. are potential Cr hyperaccumulators; at Cr(Ⅲ) concentrations up to 0.12 mmol L~(-1), the plants accumulated levels above that proposed for hyperaccumulators and still maintained a considerable growth and even flourished. However, this study was conducted in nutrient solution, and studies on species confirmation as Cr hyperaccumulator should be conducted in soils for further clarification.     

Amino sugars in fungal melanins and soil humic acids

Humic acids from six Brazilian topsoils (three Latosols and three Podzols) and five soil fungal melanins were hydrolysed and the released amino sugars qualitatively and quantitatively determined by capillary gas-liquid chromatography. Melanins were obtained from liquid culture media, synthesized with nitrate or asparagine as a source of N, of Stachybotrys atra, Aspergillus glaucus, Eurotium echinulatum and Hendersonula toruloidea. Glucosamine (48–60%), galactosamine (39–52%), and traces of mannosamine were detected in all humic acids. The total amino sugar content ranged from 1351 to 2287 mg kg^?1. In the fungal melanins analysed, mostly glucosamine (80–99%) and trace to small amounts of galactosamine and mannosamine (<10%) were found in amounts ranging from 192 to 635 mg kg^?1. The Occurrence of mannosamine in fungal melanins and fungal polysaccharides had not previously been found. The present study gives additional data to the theory that fungal melanins may play a role, as precursors, in the formation of soil organic matter.