The SMP data originates from the Strandaanspoelsel (beach washup) Monitoring Project (SMP), a citizen science project executed by Stichting ANEMOON. Data dates back to 1977 and new data will keep on being added as long as there are sufficient citizen scientists. The data is from eight locations scattered along the Dutch coastline. On these locations, all washed-up marine organisms and remains are determined and counted on a biweekly or monthly basis. Macroalgae, Cnidarians, Gastropods, Cephalopods, Bivalves, Crustaceans, Echinoderms, Shark and Ray egg capsules and Bryozoans are noted at species level.