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Impact of fisheries on sea turtles

The bycatch of sea turtles by industrial fisheries is receiving an increasing attention in recent years due to the high impact it causes on these endangered species. This issue was evaluated in southern Spain waters that harbors an important feeding ground of loggerhead and leatherback turtles, including the endangered Eastern Atlantic loggerhead population. To quantify the impact that different fisheries represents to sea turtles, 272 fishermen answered to detailed illustrated questionnaires in all the main ports of Andalusia and Murcia (Spain) during 2014. This study has updated the knowledge of turtle bycatch in the southwestern Mediterranean revealing a widespread impact of fisheries on sea turtles. Fishermen recognized an annual catch of 2.3 turtles per boat. Considering the census of industrial fishing boats in the study area (1182), more than 2840 sea turtles could be bycaught per year in the study area. Most of captures (96.2%) were produced during the summer. These results suggest a severe impact of most of legal fisheries (surface longline, pursue seine, trawling and small scale fisheries) on loggerhead feeding grounds in the southwestern Mediterranean. Fishermen suggests that drift fishing conducted by foreign or illegal fishermen and almadrabas are also causing a significant bycatch of turtles. Several measures such as reviewing compliance of current fishing and environmental regulations, modifying turtle technics to reduce turtle bycatch (e.g. reduction of the use of squid as bait and disposal of hooks deeper in the water column), facilitating the rescue and handle of wound turtles and their transport to the port for recovery, and recognizing the efforts of anglers to perform a more sustainable fishing, are recommended to mitigate this impact. informacion[at] Marco et al (2020) Sea turtle bycatch by different types of fisheries in southern Spain. Basic and Applied Herpetology
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Mirror, mirror! Where should I settle?

Mirror, mirror! Where should I settle?

The matching habitat choice hypothesis holds that individuals with different phenotypes select the habitats to which they are best adapted to maximize fitness. Despite the potential implications of matching habitat choice for many ecological and evolutionary processes, very few studies have tested its predictions. Here, a 26-year dataset on a spatially structured population of pied flycatchers is used to test whether phenotype-dependent dispersal and habitat selection translate into increased fitness (recruitment success). In this study system, males at the extremes of the body size range segregate into deciduous and coniferous forests through nonrandom dispersal. According to the matching habitat choice hypothesis, fitness of large males is expected to be higher in the deciduous habitat, where they preferentially settle to breed, while the reverse would be true for small males, which are more frequent in the coniferous forest. In the coniferous forest, males at the middle of the size range had higher fitness than both large and small-sized males. However, no clear trend was observed in the deciduous forest, where males of either size had similar fitness. These results do not provide positive support for the hypothesis' predictions and, therefore, a conclusive demonstration of its operation and occurrence in nature remains to be done. informacion[at] Camacho et al (2015) Testing the matching habitat choice hypothesis in nature: phenotype-environment correlation and fitness in a songbird population. Evol Ecol 29: 873–886; DOI 10.1007/s10682-015-9793-4