UKTAG – Biological Status Methods Transitional Waters – Macroalgae (Fucoid Extent) What do we use as an Indicator? almost to the freshwater limit (0 to <6 mean salinity). In poor status estuaries fucoids would be present in Macroalgae (Seaweeds belonging to the group the lower estuary but either they do not extend known as ‘wracks’ of the genus ‘Fucus’) upstream or there is a significant interruption in the continuity of the fucoid zone. If algae are present in Why do we use macroalgae? poor status conditions they are likely to be mat and slime producing species. This method has been designed primarily to detect the impact of toxic substances on the distribution of The mean annual salinity at the upstream fucoid certain species of macroalgae. This method monitors site the upstream limit of three brown seaweed species; This is simply the salinity measurement of where the horned wrack, Fucus ceranoides, spiral wrack, Fucus indicator species are found at the upstream extent spiralis and bladderwrack, Fucus vesiculosus. It works and should cover both wet and dry seasons and on the basis that man-made disturbances can limit the spring and neap tides. upstream colonisation of estuarine habitats by these species of seaweed. It also takes into account variations of fucoid penetration of the estuary owing to natural factors such as the ranges of salinity and turbidity. With little toxic stress they can penetrate almost to the freshwater inflows. Fucoids on sand and mud flat of a small, completely flushed lower estuary showing a mixed fucoid community, further upstream only F.ceranoides is present, Ffraw estuary. How do we decide the Biological Status? For the 2 measures figures were calculated to A typical upper estuarine shore with an upper green determine what these would be for undisturbed band and a lower fucoid band (Fucus spiralis) with a waters. The observed results are then compared with very sparse understory of other species, Tees estuary. these results to calculate the Ecological Quality Ratio Sampling (EQR). EQR values close to one indicate macroalgae communities are close to their natural state; those A survey along the estuary is carried out to identify near to zero indicate a high level of pollution or the most up-stream (nearest the freshwater) location disturbance. To decide the Biological Status the two of Fucus; the average salinity of the water covering measures are combined and the range from 1 to 0 these plants is measured and the presence of any divided into the five bands required by the Water other species of macroalgae is noted. This type Framework Directive see the table below: intertidal survey can take place at any time of year. What do we measure? Biological Status Boundary Values We measure 2 things: Status EQR Values High 0.80 Presence of any of the 3 species of fucoids Good 0.60 This is a measure of the presence or absence of the Moderate 0.40 three indicator fucoid species or, if those species are Poor 0.20 absent from the survey, the presence or absence of Bad <0.20 any other macroalgal species. In high status waters the lower estuary may be dominated by fucoid For more details see – (UKTAG TRANSITIONAL communities (where habitat allows) while the upper WATER ASSESSMENT METHODS, FUCOID estuary will have 1 species of fucoid which will extend EXTENT) ISBN 978-1-906934-11-8 .