The Commissioner of Energy and Environmental Protection shall appoint such number of conservation officers as may be necessary for the efficient execution of the duties of the department under § 26-6. The commissioner may supplement the regular conservation officer force by appointing as special conservation officer any employee of the department or any sworn federal law enforcement officer of the United States Fish and Wildlife Service or National Marine Fisheries Service, provided such federal officer shall not be considered an employee of the state and may only exercise such officer’s authority pursuant to § 26-6 when working with a full-time conservation officer. The commissioner may also appoint any lake patrolman as a special conservation officer solely for the purpose of enforcing boating laws within such patrolman’s jurisdiction, provided such patrolman shall not be considered an employee of the state, and further provided that such patrolman has completed a police training course at the state police training school or an equivalent course approved by the Commissioner of Emergency Services and Public Protection. Notwithstanding the provisions of this section, no such lake patrolman shall carry a firearm while in the performance of his or her duties as a special conservation officer unless the board of selectmen of the town or towns in which the lake on which the lake patrolman serves is located approves such carrying of a firearm, or in the case of any town having no board of selectmen, the lake patrolman obtains the approval of the legislative body of such town or towns in which the lake is located. Each conservation officer or special conservation officer shall complete a police training course at the state police training school or an equivalent course approved by the Commissioner of Emergency Services and Public Protection. Special conservation officers who are employees of the department shall be entitled to the same benefits to which conservation officers are entitled under the provisions of § 5-142, and such an appointment shall be deemed not to be in conflict with any of the provisions of chapter 67. In addition to their salaries, conservation officers and special conservation officers who are employees of the department shall be reimbursed for all expenses incurred in performance of official duty.