BS/EN 16859-2017 pdf download.Water quality Guidance standard on monitoring freshwater pearl mussel (Margaritifera margaritifera) populations and their environment.
Geographical Information Systems (GIS). Suitable quality assurance methods should be used, such as double entry of data into databases by two different operators followed by tests to ensure the results are identical. Data corruption can occur when systems are updated or during information transfer some form of checking procedure Is required following such changes. Sensitive data on Margaritifera populations should only be released according to national protocols on endangered species.
4.2.4 Licences
Margaritifera surveys are carried out under licence, and the methods used should be fully compliant with any conditions imposed. It is essential to maintain accurate information on the distribution and status of Margaritifera. A survey licence is normally provided on the understanding that data gathered are provided to the competent authority.
5 Monitoring the environmental conditions needed to support Margaritifera margaritifera populations
5.1 General
The assessment of water quality, hydromorphology, fish and macroinvertebrate features in pearl mussel rivers should be carried out by trained personnel. National protocols should always be used, and surveyors shall ensure that they obtain the appropriate licences before starting work
High water quality is vitally important in maintaining sustainable Margaritifera populations 161. Together with direct damage. how changes and sedimentation, a decline in water quality is often responsible for the loss of Margaritifera recruitment and ultimately for the extinction of populations. To assist clarity in presentation, this standard describes the ecological requirements of Margaritifera in three separate sections: fish hosts, water quality, and hydromorphology (including flow and habitat structure). However, these factors do not act In isolation from each other and their combined effects need to be taken into account when determining the requirements of a specific pearl mussel population. In addition, it is important to assess the requirements of Margaritifera populations in a way that takes account of the differences between rivers.
Given the wide-ranging applications of the standard, it is not necessary to monitor all the following aspects for every investigation; the purpose of the monitoring should determine which aspects need to be considered. For those parameters that can be measured in situ, automated continuous samplers are highly recommended, particularly in rivers showing inadequate juvenile recruitment. Where water quality is consistently high, standard monitoring carried out under the EC Water Framework Directive (WFD) may be sufficient, However, it is advised that these rivers should be included in the WFD sampling programme.
Table 2, Table 3. and Table 5 provide an inventory of methods that are useful for monitoring a range of environmental parameters that can influence the condition of a Margaritifera population. Informative Annex B explains the rationale for monitoring the environmental features set out in Clause 4 of the standard. Informative Annex C describes the conditions under which sustainable populations of Margaritifera have been found to occur.
Over the years national standards bodies, as well as CEN and ISO. have produced many water quality standard methods in areas relevant to pearl mussel work. Most of these standards are specific methods of analysis in chemistry, ecology or hydrology that enable national and International comparisons to be made between different pearl mussel rivers. Such comparisons will help to increase understanding of the requirements needed for maintaining or restoring pearl mussel populations. However, because the parameters of greatest importance for individual populations may vary, relevant experts (with knowledge of water quality standards) should be consulted on the most appropriate methods to use before planning an environmental survey programme in pearl mussel rivers. In many cases such experts will be employees of the statutory environmental regulators or the nature conservation bodies responsible for implementing the WFD and the Habitats Directive.
5.2 Fish hosts
5.2.1 Fish host species
It is desirable to determine the species and density of host fish that a mussel population needs, and whether encystment is occurring. Where there are no data or the data are inadequate, electrofishing should be carried out twice using standard methods (EN 14011:2003), once in early autumn to establish the presence and density of suitable fish hosts as a proportion of the fish population just downstream of mussel beds, and again in late spring to establish the presence of yearling fish in the vicinity of permanent mussel habitat. The fish in the second survey should be checked for encystment of glochidia on the gills, which are visible on the live fish. More detailed studies of fish numbers and glochidial encystment (e.g. number of glochidia per fish) can be undertaken but the above should be considered as a minimum requirement.
Fish species composition and densities should be derived from electroflshing (catch per unit effort or efficiency) in sites where glochidial attachment is likely (i.e. downstream of the sites with pearl mussels) (Table 2). Depending on the size of the river, the current velocity, and the technical feasibility, stream sections at least 50 m long, and in areas where glochidial encystment is likely to occur should be investigated. Where blocking with nets and multiple electrofishing runs are not possible, values of minimum densities should be reported. If a valid correction factor for catch efficiency can be applied, this should also be reported.
Although the priority is to obtain data on pearl mussel host species, information on other fish species and their habitat preferences may help to identify and resolve problems when fish hosts are absent.BS/EN 16859-2017 pdf download.
BS/EN 16859-2017 pdf download
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