Conn. Gen. Stat. § 26-308: Treatment of species not listed as endangered or threatened as endangered or threatened species.

(a) The commissioner may adopt regulations, in accordance with the provisions of chapter 54, to treat a species not listed as endangered or threatened pursuant to section 26-306 as an endangered or threatened species if he finds that: (1) Such species so closely resembles a species listed as endangered or threatened that enforcement personnel would have substantial difficulty in attempting to differentiate between it and the listed species; (2) the effect of such substantial difficulty is an additional threat to the endangered or threatened species; and (3) treatment of the unlisted species as an endangered or threatened species would substantially facilitate enforcement and further the policy state in section 26-303.

(b) The regulations may include a provision to allow a person to conduct an activity which affects a species that resembles an endangered or threatened species if the person can demonstrate to the commissioner that the activity does not affect the endangered or threatened species.