Assertion: silver carp | /r/HasProperty | imported to north america
Facets:
value: to control algae growth
type: PURPOSE
value: in the 1970s
type: TEMPORAL
Source sentences:
text: Silver carp were imported to North America in the 1970s to control algae growth in aquaculture and municipal wastewater treatment facilities, but escaped from captivity soon after their importation and are now considered a highly invasive species.