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).     

Diplodus spp. assemblages on artificial reefs: importance for near shore fisheries

Abstract  Artificial reefs have been deployed along the southern coast of Portugal (Algarve) since 1990 to enhance artisanal fisheries. The objectives of this study were to: (1) describe the colonisation process; (2) assess the role of the artificial reefs in terms of juvenile recruitment and growth and as mating/spawning areas and (3) evaluate the potential of artificial reefs as near shore artisanal fishing grounds for three economically important fish species, Diplodus bellottii (Steindachner), Diplodus sargus (L.) and Diplodus vulgaris (Geoffroy Saint-Hilaire). The fish assemblages were monitored after the deployment of a large artificial reef (Faro/Ancão) in 2002. Colonisation rates for the three species were fast. Artificial reefs play a multiple role for Diplodus spp., acting as recruitment, growth and nursery areas for juveniles, and spawning/mating areas for adults, and can thus be considered essential fish habitat. Three months after deployment of the artificial reefs, exploitable biomass was 16, 29 and 8 kg per reef group, respectively, for D. bellotti , D. sargus and D. vulgaris . These results indicate that artificial reefs quickly become good fishing grounds, where suitable financial yields may be obtained by fisher. Moreover, the artificial reefs became new and alternative fishing grounds, allowing reduction of fishing effort over traditional rocky areas that are scarce along the Algarve coast. Management measures for artificial reefs, in terms of fishing strategies, are discussed.     

Management of the invasive species Opuntia stricta in a Botanical Reserve in Portugal

Opuntia stricta is an invasive species in the Dom António Xavier Pereira Coutinho Nature Reserve (Portugal). Different chemical approaches were assessed to simultaneously manage it and preserve the natural flora of the Botanical Reserve. Glyphosate was applied at different concentrations (2.8–180 g a.e. L⁻¹) and times of application (April, July and October) by injection into cladophyll and direct application onto areas in which the cladophyll had been cut (90 and 180 g a.e. L⁻¹). The efficacy of the herbicide applied on the cut areas was good, but the pieces of the cladophyll that had been cut were difficult to remove and destroy. Herbicide injection of a 2 mL of solution containing 45 g a.e. L⁻¹ glyphosate in the summer proved to be the easiest and most effective way of controlling the weed. Germination studies were carried out in order to understand the importance of seeds in the dissemination of O. stricta. The optimum constant temperature for germination was generally 20–25°C, there was a tendency towards increased germination following leaching in water for 24 h (7% germination at 20°C 12-h light) and 60-min scarification in sulphuric acid (15% at 20°C 12-h light). Although germination rates may be considered low, they do indicate that the emergence of O. stricta seedlings is possible.     

Flight performance and wing morphology in the bat Carollia perspicillata: biophysical models and energetics

Studies on functional performance are important to understand the processes responsible for the evolution of diversity. Morphological trait variation within species influences the energetic cost of locomotion and impacts life history traits, with ecological and evolutionary consequences. This study examined wing morphology correlates of flight performance measured by energetic expenditure in the Seba's short-tailed bat, Carollia perspicillata. In the flight experiments, nature caught bats (59 females, 57 males) were allowed to fly for 3 min in a room. After each flight, thermographic images were taken to measure body temperature, and biophysical models were used to calculate sensible heat loss as a measure of energetic expenditure. Wing morphological traits were measured for each individual and associated with heat loss and power required to fly on performance surfaces. Wing morphological traits explained 7–10% of flight energetic cost, and morphologies with the best performance would save the energy equivalent to 9–30% of total daily requirements. The optimal performance areas within the C. perspicillata morphospace were consistent with predicted selection trends from the literature. A trade-off between demands for flight speed and maneuverability was observed. Wing loading and camber presented sexual dimorphism. These morphological differences are likely associated with more economical but less maneuverable flight in females, leading them to fly more often in open areas along the forest edge. Our findings demonstrate how small scale changes in wing morphology can affect life history strategies and fitness.     

Topographic laparoscopy for buffaloes in the quadruped position

This study aimed to describe the anatomical topography of the abdominal cavity of buffaloes in the quadruped position to establish the best endosurgical access and vantage points and identify possible limitations. Laparoscopies were performed on 10 healthy female buffaloes obtained from the Universidade Federal Rural da Amazônia to explore possible access points to the abdomen. Techniques for assessing and possibly observing certain organs and structures through the left and right flanks of 10 animals have been described. In five animals, access was created through the right side of the last intercostal space to allow more cranial access to the abdominal cavity. Despite the presence of the rumen, access through the left flank allowed the visualization of the structures of the gastrointestinal tract and the genitourinary system. With access through the right flank, however, imaging was hampered by the presence of the greater omentum and its deep and superficial walls, which prevented the progression of the endoscope. Access through the last right intercostal space allowed the visualization of the cranial structures of the abdominal cavity, such as the caudate process, right lobe of the liver, right kidney, and pancreas. Laparoscopic access through the left flank and the last intercostal space in healthy buffaloes in the quadruped position is feasible, and it is promising for the exploration, diagnosis, and treatment of various disorders in buffaloes.