Establishing survey and monitoring protocols for the assessment of conservation status of fish populations in river Special Areas of Conservation in the UK

Abstract

ABSTRACT1. Under the EC Habitats Directive (92/43/EEC), several rivers in the UK have been designated Special Areas of Conservation (SACs) because they support important populations of fish species. Several factors need to be considered when establishing survey protocols to assess the conservation status of fish species in these rivers.2. It is important to understand the biology and habitat requirements of fish species and to design appropriate monitoring surveys that adequately assess the status of the fish populations. This information can, in turn, provide the basis for establishing sustainable conservation targets for specific stocks, a process known as condition assessment.3. Favourable condition of fish species in SAC rivers is assessed using three criteria. The first relates to density of fish in various life stages against pre-set targets, assuming that an appropriate number of sites is surveyed to account for natural spatial and temporal variations in fish populations. The second is evaluation of the demographic structure to demonstrate continued recruitment success. Third, by mapping the distribution of the target species in individual rivers and where favourable condition is only achieved where there has been no reduction in the distribution range river between surveys. 4. The framework described was developed from limited survey data. As more monitoring and assessment data become available, the threshold criteria for favourable condition for each species should be improved, and uncertainty in the procedures reduced.

Assessment of the conservation status of endemic sculpinCottus haemusi(Cottidae) in the river Vit (Danube Tributary), northwest Bulgaria

“…Appreciable differences in bullhead abundance from site to site were also found in the Garonne stream system (Legalle et al, 2005). In those parts of northern Europe in which bullhead populations are not threatened and the species is quite common or even abundant, abundances of less than 0.2 individuals·m -2 and 0.5 individuals·m -2 for upland rivers and lowland rivers respectively indicate sites with unfavourable conditions (Copp et al, 1994;Carter et al, 2004;Cowx and Harvey, 2003;Cowx et al, 2009). There are several possible reasons for the relatively low abundance of C. haemusi in the river Vit tributaries.…”

“…The present assessment of the population status of C. haemusi was based on three main criteria: population demographic structure, abundance and species distribution as recommended by Cowx and Harvey (2003) and Cowx et al (2009). The data from the length frequency analysis suggested that the investigated Vit sculpin populations contained more than three age classes.…”

“…The uppermost parts of some of the tributaries are located in reserves within the Central Balkan National Park, in which fishing is prohibited. According to Cowx et al (2009), adequate assessment of the status of the fish population should include three criteria: fish density, population structure and the distribution of the target species in individual rivers. Assessment of these criteria is practical and cost-effective (Cowx et al, 2009).…”

“…According to Cowx et al (2009), adequate assessment of the status of the fish population should include three criteria: fish density, population structure and the distribution of the target species in individual rivers. Assessment of these criteria is practical and cost-effective (Cowx et al, 2009). The aim of this study was to assess the current status of C. haemusi in the river Vit basin on the basis of its distribution, abundance and size structure and to describe the habitat characteristics of the sites at which bullheads exist.…”

Restoring River Connectivity: Prioritizing Passage Improvements for Diadromous Fishes and Lampreys

“…As such, populations in many areas are likely to have been underestimated. Specific surveys may therefore be required to quantify the status of target populations before passage improvements are undertaken (Cowx et al 2009;Moser et al 2007), and surveys of passage efficiency and habitat quality will also reduce the subjectivity of the assessment (Kemp and O'Hanley 2010;Raven et al 1998). Indeed, the greatest sources of between-assessor differences in B were generally the estimates of F and P. It may also be possible to incorporate confidence rankings for estimates based upon expert judgement, as is being developed for risk assessment of non-native species (e.g.…”