(a) The term experimental population means any introduced and/or designated population (including any off-spring arising solely therefrom) that has been so designated in accordance with the procedures of this subpart but only when, and at such times as, the population is wholly separate geographically from nonexperimental populations of the same species. Where part of an experimental population overlaps with nonexperimental populations of the same species on a particular occasion, but is wholly separate at other times, specimens of the experimental population will not be recognized as such while in the area of overlap. That is, experimental status will only be recognized outside the areas of overlap. Thus, such a population shall be treated as experimental only when the times of geographic separation are reasonably predictable; e.g., fixed migration patterns, natural or man-made barriers. A population is not treated as experimental if total separation will occur solely as a result of random and unpredictable events.

(b) The term essential experimental population means an experimental population whose loss would be likely to appreciably reduce the likelihood of the survival of the species in the wild. All other experimental populations are to be classified as nonessential.

(a) The Secretary may designate as an experimental population a population of endangered or threatened species that has been or will be released into suitable habitat outside the species' current range, subject to the further conditions specified in this section; provided, that all designations of experimental populations must proceed by regulation adopted in accordance with 5 U.S.C. 553 and the requirements of this subpart.

(b) Before authorizing the release as an experimental population of any population (including eggs, propagules, or individuals) of an endangered or threatened species, and before authorizing any necessary transportation to conduct the release, the Secretary must find by regulation that such release will further the conservation of the species. In making such a finding, the Secretary shall utilize the best scientific and commercial data available to consider:

(1) Any possible adverse effects on extant populations of a species as a result of removal of individuals, eggs, or propagules for introduction elsewhere;

(2) The likelihood that any such experimental population will become established and survive in the foreseeable future;

(3) The effects that establishment of an experimental population will have on the recovery of the species; and

(4) The extent to which the introduced population may be affected by existing or anticipated Federal or State actions or private activities within or adjacent to the experimental population area.

(c) Any regulation promulgated under paragraph (a) of this section shall provide:

(1) Appropriate means to identify the experimental population, including, but not limited to, its actual or proposed location; actual or anticipated migration; number of specimens released or to be released; and other criteria appropriate to identify the experimental population(s);

(2) A finding, based solely on the best scientific and commercial data available, and the supporting factual basis, on whether the experimental population is, or is not, essential to the continued existence of the species in the wild;

(3) Management restrictions, protective measures, or other special management concerns of that population, as appropriate, which may include, but are not limited to, measures to isolate and/or contain the experimental population designated in the regulation from nonexperimental populations and protective regulations established pursuant to section 4(d) of the Act; and

(4) A process for periodic review and evaluation of the success or failure of the release and the effect of the release on the conservation and recovery of the species.

(d) The Secretary may issue a permit under section 10(a)(1)(A) of the Act, if appropriate, to allow acts necessary for the establishment and maintenance of an experimental population.

(e) The National Marine Fisheries Service shall consult with appropriate State fish and wildlife agencies, affected tribal governments, local governmental entities, affected Federal agencies, and affected private landowners in developing and implementing experimental population rules. When appropriate, a public meeting will be conducted with interested members of the public. Any regulation promulgated pursuant to this section shall, to the maximum extent practicable, represent an agreement between the National Marine Fisheries Service, the affected State and Federal agencies, tribal governments, local government entities, and persons holding any interest in land or water which may be affected by the establishment of an experimental population.

(f) Any population of an endangered species or a threatened species determined by the Secretary to be an experimental population in accordance with this subpart shall be identified by special rule in part 223 as appropriate and separately listed in 50 CFR 17.11(h) (wildlife) or 17.12(h) (plants) as appropriate.

(g) The Secretary may designate critical habitat as defined in section (3)(5)(A) of the Act for an essential experimental population as determined pursuant to paragraph (c)(2) of this section. Any designation of critical habitat for an essential experimental population will be made in accordance with section 4 of the Act. No designation of critical habitat will be made for nonessential experimental populations.

(a) Any population determined by the Secretary to be an experimental population shall be treated as if it were listed as a threatened species for purposes of establishing protective regulations under section 4(d) of the Act with respect to such population.

(b) Accordingly, when designating, or revising, an experimental population under section 10(j) of the Act, the Secretary may also exercise his or her authority under section 4(d) of the Act to include protective regulations necessary and advisable to provide for the conservation of such species as part of the special rule for the experimental population. Any protective regulations applicable to the species from which the experimental population was sourced do not apply to the experimental population unless specifically included in the special rule for the experimental population.

(a) Any experimental population determined pursuant to paragraph (c) of this section not to be essential to the survival of that species and not occurring within the National Park System or the National Wildlife Refuge System, shall be treated for purposes of section 7 of the Act (other than subsection (a)(1) thereof) as a species proposed to be listed under the Act as a threatened species, and the provisions of section 7(a)(4) of the Act shall apply.

(b) Any experimental population that either has been determined pursuant to paragraph (c) of this section to be essential to the survival of that species, or occurs within the National Park System or the National Wildlife Refuge System as now or hereafter constituted, shall be treated for purposes of section 7 of the Act as a threatened species, and the provisions of section 7(a)(2) of the Act shall apply.

(c) For purposes of section 7 of the Act, any consultation on a proposed Federal action that may affect both an experimental and a nonexperimental population of the same species should consider that species' experimental and nonexperimental populations to constitute a single listed species for the purposes of conducting the analyses under section 7 of the Act.