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- Spatial and temporal characteristics of benthic invertebrate communities at Culbin Sands lagoon, Moray Firth, NE Scotland, and impacts of the disturbance of cockle harvestingPublication . Mariyam Mendonca, Vanda; Raffaelli, David George; Boyle, Peter; Hoskins, SteveIn the present study, Culbin Sands lagoon, a protected site in NE Scotland, was surveyed every 2 to 4 weeks during a three-year period (1994-1996) to study benthic invertebrate communities. Beds of Mytilus edulis covered 18000 m(2). 53 macroinfaunal species were identified outside these areas. The most conspicuous were: the lugworm Arenicola marina (mean up to 55 casts m(-2)); and bivalves Cerastoderma edule (mean up to 158 ind. m(-2)) and Macoma balthica (mean up to 79 ind. m(-2)) after settlement. The standing stock ranged from 20 to 32 g AFDW m(-2) yr(-1) respectively from more exposed to more sheltered areas. Most species showed a clear recruitment peak in autumn, but others (e.g. Capitella capitata, and Spionidae) displayed several peaks in a year. Communities were also compared between the Sampling sites before and after an incidental disturbance caused by cockle Cerastoderma edule harvesting, which took place in June 1995. One site showed -0.7% variation in the total standing stock, but +22% for smaller-cockles, as larger filter-feeding cockles were removed therefore enhancing their own larval settlement. Polychaete Spionidae Populations also increased after larger cockles were removed. The polychaete Arenicola marina population returned to its normal activities just after the dramatic disturbance of the sediment.
- The ecological role of overwintering fish in the food web of the Culbin Sands lagoon ecosystem, NE Scotland: identifying major trophic links and testing effects of the fish Pomatoschistus microps (Pallas) on benthic invertebratesPublication . Mendonca, Vanda; Raffaelli, David; Boyle, Peter; Emes, ChasThe Culbin Sands lagoon ecosystem in NE Scotland was studied during a three-year period (1994-1996) to identify the major trophic links from benthic invertebrates to epibenthic predators, and to assess impacts of overwintering fish on their prey communities. Every 2-4 weeks, samples of mobile fauna were collected to study their diets. The major trophic links identified between benthic invertebrates and epibenthic predators were from benthic invertebrates to the shrimp Crangon crangon, and to the common goby Pomatoschistus microps and the plaice Pleuronectes platessa. The energy flow from benthic invertebrates to overwintering fish was estimated at 133 kJ m(-2)yr(-1). A flow of 10 kJ m(-2)yr(-1) was also observed from eggs and larval stages of the overwintering shrimp Crangon crangon to the overwintering fish. Nevertheless, manipulative field experiments showed no significant impacts of the most abundant overwintering fish Pomatoschistus microps on prey community densities, despite an overall individual ingestion rate of 89 J day(-1).