7357
Other exploitation such as the dredging of the mussel beds of the Firth of Thames , reaching its height in 1961 with an estimated 15 million mussels taken ( shortly before collapse of the industry ) have led to damages which have not been recovered forty years later , possibly due to the dredging having destroyed the underwater surfaces , and sediment drainage from the agriculture in the Firth of Thames affecting the mussel 's viability .
 location: Firth of Thames; location: Firth of Thames
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 location: Firth of Thames; location: Firth of Thames