Search

Throughout the European Union, the EC Habitats Directive requires that member states undertake national surveillance of designated species. Despite biological connections between-populations across-borders, national assessments need not be co-ordinated in any way. We conducted a trans-boundary assessment of the status of Eurasian otters (Lutra lutra) aimed at providing consistency across a single biogeographical unit, i.e. the island of Ireland, comprising two states, i.e. the Republic of Ireland and the United Kingdom (Northern Ireland). Our aim was to ensure consistency with previous assessments conducted separately in each state, and permit each Government to fulfil their separate statutory reporting commitments. The species range increased by 23% from 1996-2006 and 2007-11. The population estimate of 9400 [95%CI 8700-12,200] breeding females during 2010/11 was not significantly different from 8300 [95%CI 7600-9800] breeding females established as a baseline during 1981-82. Modelling of species-habitat associations suggested that available habitat was not limiting and no putative pressures recorded at sites surveyed negatively affected species occurrence. Thus, under the statutory parameters for assessing a species' conservation status, i.e. range, population, habitat and future prospects, the otter was judged to be in 'Favourable' status throughout Ireland and in both discrete political jurisdictions. Thus, we provide a trans-boundary test case for EU member states that share habitats and species across ecoregions, ensuring conservation assessment data are standardised, synchronised, spatially consistent and, therefore, biologically relevant without compromising legal and administrative autonomy within separate jurisdictions. [ABSTRACT FROM AUTHOR]

In this study, the growth pattern of juvenile European hake (Merluccius merluccius) was analyzed in relation to oceanographic and ecological factors in the Ligurian Sea and northern Tyrrhenian Sea, both part of the Mediterranean Sea. The ages of juvenile European hake, collected during a trawl survey in June 2011, were estimated by reading otolith daily growth rings. The growth pattern (length-age relationship) of juvenile European hake recruited to the population (<1 year old) was analyzed by fitting a multivariate generalized additive model with explanatory variables: depth, bottom temperature, sea-surface temperature, scalar wind speed, chlorophyll-α concentration, and fish density (number of individuals per square kilometer). A significant effect of density on the length-age relationship was found, and an increased growth rate at densities >3000 individuals km-2. This observed positive effect of density on growth could be argued to be a consequence of favorable environmental conditions, such as food availability and temperature, where both fish density and growth are maximized. Conversely, areas of lower density correspond to habitats of low suitability, where growth is impaired. [ABSTRACT FROM AUTHOR]