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] Marco et al (2020) Sea turtle bycatch by different types of fisheries in southern Spain. Basic and Applied Herpetology
Average (0 Votes)

Latest News Latest News


Body size reduction in the wood mouse population of Doñana

Body size reduction in the wood mouse population of Doñana

Thermoregulation, metabolism and life history of species are affected by body size and shape. Based on specimens of the wood mouse Apodemus sylvaticus that were collected at Doñana National Park in 1978–81 and 2006–07, changes in body mass, body size, and allometry were tested between these periods. Furthermore, data from 1978–81, when more specimens were available, were used to evaluate the sexual dimorphism of adults. Between the two periods and regardless of age, the most striking reduction in size in both females and males concerned body mass (females ?29.5%, males ?36%) and ear length (?20% for both sexes). Although less pronounced (3–4%), also a significant reduction in the total cranial and the condyle-basal lengths of females but not of males was observed. No change was evident for the zygomatic width and the diastema length and for the head-body and hind foot lengths in either sex. The allometric relationships between the measured traits and the head-body length in adults did not change between the two periods. Males were larger than females in all the measured traits except the zygomatic width and the ear length. No sexual dimorphism was evident relative to the static allometry of adults. A major determinant of this reduction may have been a shortage in suitable resources. Overall, this study confirms and extends previous findings on male-biased sexual size dimorphism and reveals a dramatic decline in body mass, which is likely linked to the observed reduction in species abundance at Doñana. The extent and rapidity of the observed morphological changes raise concerns about the conservation of Doñana ecosystems and pose questions for future research on the ecological processes that caused these changes. informacion[at] Docampo et al (2019) Marked reduction in body size of a wood mouse population in less than 30 years. Mammalian Biol