Habitats regulations for stage 3 assessments radioactive substance authorisations

This is the Habitats regulations for stage 3 assessments: radioactive substances authorisations report from the Environment Agency, published on October 2003. The report focuses on the stage 3 assessments of radioactive substances authorisations in UK (to take place over the next five years, starting in 2003), which may have a potential impact on European designated Natura 2000 sites such Special Protection Areas (SPA), Special Areas of Conservation (SAC); and thus require further detailed assessment. This Environment Agency R&D project was commissioned to ERC, University o f Liverpool, in conjunction with Westlakes Scientific Consulting and the Centre for Ecology and Hydrology, as part o f the agency's preparation for the Stage 3 Assessments o f radioactive substances authorisations. The aim was to prepare site information sheets containing all data relevant for individual Natura 2000 sites needing Stage 3 Assessment and to stylise and represent species that require protection under the Habitats Regulations by the reference organism geometries listed in R&D Publication 128 (Copplestone et al., 2001).

Estimates of survival probabilities for oceanic-stage loggerhead sea turtles (Caretta caretta) in the North Atlantic

Estimates of instantaneous mortality rates (Z) and annual apparent survival probabilities (Φ) were generated from catch-curve analyses for oceanic-stage juvenile loggerheads (Caretta caretta) in the waters of the Azores. Two age distributions were analyzed: the “total sample” of 1600 loggerheads primarily captured by sighting and dipnetting from a variety of vessels in the Azores between 1984 and 1995 and the “tuna sample” of 733 loggerheads (a subset of the total sample) captured by sighting and dipnetting from vessels in the commercial tuna fleet in the Azores between 1990 and 1992. Because loggerhead sea turtles begin to emigrate from oceanic to neritic habitats at age 7, the best estimates of instantaneous mortality rate (0.094) and annual survival probability (0.911) not confounded with permanent emigration were generated for age classes 2 through 6. These estimates must be interpreted with caution because of the assumptions upon which catch-curve analyses are based. However, these are the first directly derived estimates of mortality and survival probabilities for oceanic-stage sea turtles. Estimation of survival probabilities was identified as “an immediate and critical requirement” in 2000 by the Turtle Expert Working Group of the U.S. National Marine Fisheries Service.