Monday June 22, 2026
The conservation statuses of fish species flash through our news feeds more often than desired—Threatened, Vulnerable, Endangered, or the dreaded Extinct. It may feel like an uphill battle with more and more species ending up on endangered species lists in the face of environmental degradation, habitat loss, nonnative species invasions, and many other factors. But just because a species is placed on a list, that does not mean that it is there to stay. Delisting a species, however, is much easier said than done, and it does not always happen with the species’ best interests in mind.
When a species is classified as Endangered, it means that species is likely to go extinct. Endangered species lists can exist at both the state and the federal level. Between these lists, a species can have multiple statuses and receive varying levels of protection. At the federal level, the 1973 Endangered Species Act (ESA) is the primary piece of legislation that prevents listed species from being “taken,” or harassed in any way. State ESAs can fill gaps left by the federal act, tailoring protections to local and regional needs. Today, 46 states implement some form of an ESA. Endangered Species Acts protect species after they meet the definition of a Threatened (meaning they are likely to become Endangered) or Endangered species and undergo a thorough review. Intuitively, species are delisted when they are no longer Endangered or Threatened and no longer require the same level of protection.
A species can follow several different paths to delisting. The best-case scenario is that management efforts have been successful, and the population size has grown to the point that it is no longer Endangered or Threatened. On the other hand, if management is unsuccessful and a species goes extinct, this will also result in its delisting. Another more contentious path to delisting can occur if the original listing was based on incorrect or limited data and new information is supplied which can lead to a status revision. Sometimes, this means that a species’ protections may be removed before it is fully recovered, especially if new information is used in a way to further economic or political agendas.
One success story is the Okaloosa darter, which managers placed on the Endangered Species List in 1973 following a drastic population decline due to habitat loss and destruction. In the 1990s, the Okaloosa Darter Recovery Plan was implemented, including conservation measures such as monitoring, erosion control, and wildfire management. The delisting process for the Okaloosa darter began after the population surged in 2021. The species was officially removed from the list in 2023. Similarly, Arizona’s state fish, the Apache trout, was listed in 1973 because of habitat loss and invasive species. Managers delisted the species in 2024 following a successful recovery plan. While the Okaloosa darter and the Apache trout represent success stories, other species have been delisted—but not for the same happy reasons. The San Marcos gambusia and the Scioto madtom were both removed from the Endangered Species List in 2023 after their extinctions.
In other cases, delisting can result from new scientific information or reclassification. The Umpqua River cutthroat trout was removed from the Endangered Species List in 2000 because a taxonomic revision determined that it was part of a larger population that was not considered Threatened or Endangered. More recently, the San Francisco Bay-Delta population of longfin smelt was listed as federally Endangered in 2024. In 2025, California House Republicans proposed delisting the population citing its original listing as “unscientific.” Representatives argued that the smelt’s current placement on the Endangered Species List makes it more difficult to deliver water to the area’s farmers. Many other politicians argued that this decision undermined years of scientific research and would weaken necessary protections for an imperiled species.
The process of listing and delisting species shows just how complex species conservation can be. While recovery and delisting are victories for some fish, other removals highlight the political and economic tensions that can shape environmental decisions. The stories of the Okaloosa darter and Apache trout show what dedicated recovery efforts can achieve, while cases like that of the longfin smelt serve as reminders that data, science, and policy do not always align. As more fish species face mounting pressures from habitat loss, climate change, and water scarcity, ensuring that delisting reflects accurate information will be essential for the long-term health of aquatic ecosystems.
This post was featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.
Header Image Caption: Successful habitat restoration efforts can lead to the recovery of species and their removal from an endangered species list.