South Walney lagoons: species composition monitoring: final report.
Abstract
In this work, the Institute of Estuarine and Coastal Studies (IECS) was commissioned by Natural England to undertake a condition monitoring study to establish the current species composition of the South Walney lagoons near Morecambe Bay in the United Kingdom and, where possible, to comparatively analyze the condition of the communities against those identified in previous studies. Monitoring surveys at South Walney Lagoons were undertaken between the 6th and 10th of August 2013. Twenty-seven stations overall were sampled in the pools for biological assemblages, with quantitative sampling of sediments collected by corer in shallow marginal stations (where the sediment type allowed coring) and grab in deeper stations. Nekton fauna was also sampled semi-quantitatively by means of a push net swept in marginal stations and, where aquatic vegetation was present, vegetation coverage was estimated by using 1m2 quadrats and samples of epifauna were collected from the submerged vegetation (by washing 0.5L of seaweed). In general, lagoon habitats are variable and fragile, with this variation occurring spatially and temporally in extremes of both. Although the South Walney lagoon feature is assessed as a whole, variability within the system has been observed, mostly associated with the salinity gradient among pools reflecting water circulation and inputs and different degrees of isolation from water exchanges.