News News

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]ebd.csic.es: Marco et al (2020) Sea turtle bycatch by different types of fisheries in southern Spain. Basic and Applied Herpetology https://doi.org/10.11160/bah.187


http://ojs.herpetologica.org/index.php/bah/article/view/187
Average (0 Votes)

Latest News Latest News

Back

Rapid assessment of ecological integrity for LTER wetland sites by using UAV multispectral mapping

Rapid assessment of ecological integrity for LTER wetland sites by using UAV multispectral mapping

Long-term ecological research (LTER) sites need a periodic assessment of the state of their ecosystems and services in order to monitor trends and prevent irreversible changes. The ecological integrity (EI) framework opens the door to evaluate any ecosystem in a comparable way, by measuring indicators on ecosystem structure and processes. Such an approach also allows to gauge the sustainability of conservation management actions in the case of protected areas. Remote sensing (RS), provided by satellite, airborne, or drone-borne sensors becomes a very synoptic and valuable tool to quickly map isolated and inaccessible areas such as wetlands. However, few RS practical indicators have been proposed to relate to EI indicators for wetlands. This work suggests several RS wetlands indicators to be used for EI assessment in wetlands and specially to be applied with unmanned aerial vehicles (UAVs). The applicability of multispectral images captured by UAVs over two long-term socio-ecological research (LTSER) wetland sites are also assessed to provide detailed mapping of inundation levels, water turbidity and depth as well as aquatic plant cover. An empirical approach is followed to find linear relationships between UAVs spectral reflectance and the RS indicators over the Doñana LTSER platform in SW Spain. The method assessment was carried out using ground-truth data collected in transects. The resulting empirical models were implemented for Doñana marshes and can be applied for the Braila LTSER platform in Romania. The resulting maps are a very valuable input to assess habitat diversity, wetlands dynamics, and ecosystem productivity as frequently as desired by managers or scientists. Finally, authors also examined the feasibility to upscale the information obtained from the collected ground-truth data to satellite images from Sentinel-2 MSI using segments from the UAV multispectral orthomosaic. A close multispectral relationship between Parrot Sequoia and Sentinel-2 bands was found, which made it possible to extend ground-truth to map inundation in satellite images. informacion[at]ebd.csic.es: Díaz-Delgado et al (2019) Rapid assessment of ecological integrity for LTER wetland sites by using UAV multispectral mapping. Drones https://doi.org/10.3390/drones3010003


https://www.mdpi.com/2504-446X/3/1/3