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Species of Concern

Coaster Brook Trout:
Questions and Answers about the 90-Day Finding, Status Review, and 12-Month Finding


Coaster brook trout are a form of brook trout (Salvelinus fontinalis) that spend a portion of their life cycle in the Great Lakes. At one time, there were believed to be at least 100 runs, with more than 50 runs in the U.S. waters of Lake Superior.  They were also found in Lakes Huron and Michigan, where they are now extirpated.  Today, there are four known U.S. populations in Lake Superior, all in Michigan: one in the Salmon Trout River in the Upper Peninsula and three on Isle Royale.


Q: What is a petition?

A: A petition is a request that a species be listed on, delisted from, or reclassified on the Federal List of Endangered and Threatened Wildlife and Plants.

Q: Who petitioned the Service and what did they request?

A: On March 1, 2006, we received a petition from the Sierra Club Mackinac Chapter and the Huron Mountain Club to list the coaster brook trout under the Endangered Species Act (ESA).  The petitioners, later joined by Marvin J. Roberson Jr., submitted supplemental information for the petition on May 25, 2006. 

Q: Where can I get a copy of the petition? 

A: The petition and petition supplement are posted on our coaster brook trout website,

Q. What is a 90-day finding on a petition to list?

A. Section 4 of the ESA requires that the Fish and Wildlife Service make a finding on whether a petition to list, delist, or reclassify a species contains substantial information to indicate that the requested action may be warranted. That finding is to be made within 90 days, to the maximum extent practicable, after receipt of the petition and is to be published in the Federal Register. Findings are based on information contained in the petition, supporting information submitted with the petition, and other information available to the Service at the time.

Q. What is meant by substantial information?

A. When the Service evaluates a petition for substantiality, we consider the adequacy and reliability of the information supporting the action requested in the petition. A "substantial" finding indicates we have determined that adequate and reliable information has been presented or is available that would lead a reasonable person to believe the petitioned action may be warranted.

Q. What kinds of information are considered reliable?

A. Among the most reliable and credible sources are papers published in peer-reviewed scientific literature. Information provided by individuals with demonstrated expertise in the relevant subject area is also generally considered reliable. Anecdotal information or information from sources without established experience and expertise must be strongly corroborated to be considered substantial.

Q: Why was there a delay in the issuance of a 90-day finding for the coaster brook trout?

A: We were unable to evaluate the coaster petition until 2007 because limited funding required us  to devote resources to other higher ESA priorities. 

Q: What did the Service conclude in the 90-day finding for coaster brook trout?

A: The Service reviewed the petition and literature cited in the petition. After this review and evaluation, we found that petition was positive, meaning that it contained substantial information indicating that the species might be threatened or endangered.

Q. What happens now?

A. Once a positive 90-day finding is made, the Service conducts a status review of the species. Within 12 months of receipt of the petition, the Service decides whether the petitioned action is warranted, not warranted or warranted but precluded by proposals for other, higher-priority listing actions. This is called a 12-month finding. If a warranted finding is made, the Service must promptly publish a proposed rule to pursue the petitioned action.


If a warranted but precluded 12-month finding is made for a petition to list, the Service classifies the petitioned species as a candidate for listing. The Service must document that it is making progress in listing, reclassifying or delisting species, and that the Service's decisions follow its listing priority system. The Service annually reviews warranted but precluded species for possible listing action.

If a not-warranted 12-month finding is made for a petition to list, the species is not assigned to candidate status.

Q: Coaster brook trout populations are currently documented in Michigan and Canada, and other potential coaster sightings have been reported in Wisconsin and Minnesota.  In addition, historic populations were found in Lakes Michigan and Huron.  What geographic range will the Service consider in its status review?

A: We will consider all potential areas with current and/or historic coaster occurrences and our final conclusion may encompass all or a portion of the range, as guided by both scientific and policy considerations. 

Q: Coaster brook trout are not considered a species or subspecies.  How can they be considered for listing under the ESA? 

A: The authority to list a “species” as endangered or threatened under the ESA is not restricted to species as recognized in formal taxonomic terms, but also extends to subspecies, and for vertebrate taxa, to distinct population segments (DPSs).  As directed by the Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the ESA (61 FR 4722; February 7, 1996), we must consider three elements in determining whether vertebrate population may be considered a DPS:


(1) The discreteness of the population segment in relation to the remainder of the species to which it belongs;
(2) The significance of the population segment to the species to which it belongs; and
(3) The population segment's conservation status in relation to the ESA's standards for listing (that is, whether the population segment, when treated as if it were a species, is endangered or threatened).


Under the DPS Policy, a population segment of a vertebrate species may be considered discrete if it satisfies either one of the following two conditions:

(1) It is markedly separated from other populations of the same taxon as a consequence of physical, physiological, ecological, or behavioral factors; or
(2) It is delimited by international governmental boundaries within which significant differences in control of exploitation, management of habitat, conservation status, or regulatory mechanisms exist.


Under our DPS Policy, if we determine that a population segment is discrete, we consider its biological and ecological significance to the taxon to which it belongs (i.e., brook trout).  The DPS policy states that if a population segment is considered discrete under one or more of the discreteness criteria, its biological and ecological significance will then be considered in light of Congressional guidance that the authority to list DPSs be used “sparingly” while encouraging the conservation of genetic diversity.  Under the DPS policy, our consideration of significance may include, but is not limited to:


(1) Evidence of the persistence of the discrete population segment in an ecological setting that is unique or unusual for the taxon;

(2) Evidence that loss of the population segment would result in a significant gap in the range of the taxon;

(3) Evidence that the population segment represents the only surviving natural occurrence of a taxon that may be more abundant elsewhere as an introduced population outside its historical range; or

(4) Evidence that the discrete population segment differs markedly from other populations of the species in its genetic characteristics.


Conservation Status
To meet the third element of the DPS policy, we evaluate the level of a population segment’s conservation status in relation to the ESA’s standards for listing.  This involves an analysis, referred to as a threats analysis, pursuant to the five listing factors specified in Section 4 of the ESA.  Our consideration of conservation status may include, but is not limited to:


(1) The species’ historical and current population status, distribution, and trends; its biology and ecology; and habitat selection;

(2) The effects of potential threat factors that are the basis for a listing determination under section 4(a) of the ESA, which are:

(a) the present or threatened destruction, modification, or curtailment of the species’ habitat or range;
(b) overutilization for commercial, recreational, scientific, or educational purposes;
(c) disease or predation;
(d) the inadequacy of existing regulatory mechanisms; or
(e) other natural or manmade factors affecting its continued existence.

(3)  Management programs for the conservation of the coaster brook trout




Last updated: February 10, 2016