Good news for sea turtles, once listed as endangered

Written by on January 17, 2019 in Rare Critters - No comments

The population of sea turtles and some other endangered or threatened marine mammals have grown after some species were listed as endangered, a new study shows.

The Center for Biological Diversity published a study in the journal PLOS ONE analyzing annual population data for the 62 marine mammal species and sea turtle species listed under the Endangered Species Act.

The researchers then focused on 23 representative populations — 14 marine mammal species and five sea turtle species — to study population trends, the magnitude of population change and recovery status.

What they found was that 78 percent of marine mammal populations and 75 percent of sea turtle populations increased significantly after being listed for federal protection.

Conservation measures triggered by ESA listing such as ending exploitation, tailored species management, and fishery regulations, and other national and international measures, appear to have been largely successful in promoting species recovery, leading to the delisting of some species and to increases in most populations,” the study abstract states, using an abbreviation for the 1973 law.

These findings underscore the capacity of marine mammal and sea turtle species to recover from substantial geographical population declines when conservation actions are implemented in a timely and effective manner.”

Wednesday’s study comes at a time when human activity — including large-scale fishing operations, offshore oil drilling, sonar waves and underwater bomb detonations — have caused significant population declines in a large numbers of marine life.

Just last month, the group, led by Abel Valdivia called it “shocking” that the Trump administration denied protections to 13 rare species of wildlife.

The researchers say their findings underscore the capacity of conservation efforts to bring marine life back from the brink of extinction.

“Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles),” the study abstract said.

The study did find population declines in two species of marine mammal that were listed, as well nonsignificant changes in three marine mammal populations and two sea turtle populations.

Abstract

The U.S. Endangered Species Act (ESA) is a powerful environmental law protecting imperiled plants and animals, and a growing number of marine species have been protected under this law as extinction risk in the oceans has increased. Marine mammals and sea turtles comprise 38% of the 163 ESA-listed marine “species”, which includes subspecies and distinct population segments, yet analyses of recovery trends after listing are lacking. Here we gathered the best available annual abundance estimates for geographically delimited populations of all 62 marine mammal and sea turtle species listed under the ESA. Of these, we chose representative populations of species that were listed before 2012, occur and reproduce in U.S. waters, and have data of sufficient quality and timespan for trend analyses. Thus, we quantitatively analyzed population trends, magnitude of population change, and recovery status for 23 and 8 representative populations of 14 marine mammal and 5 sea turtle species, respectively. Using generalized linear and non-linear models, we found that 18 marine mammal (78%) and 6 sea turtle (75%) populations significantly increased after listing; 3 marine mammal (13%) and 2 sea turtle (25%) populations showed non-significant changes; while 2 marine mammal (9%), but no sea turtle populations declined after ESA protection. Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles). Conservation measures triggered by ESA listing such as ending exploitation, tailored species management, and fishery regulations, and other national and international measures, appear to have been largely successful in promoting species recovery, leading to the delisting of some species and to increases in most populations. These findings underscore the capacity of marine mammal and sea turtle species to recover from substantial geographical population declines when conservation actions are implemented in a timely and effective manner.

 

 

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0210164

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Peg Fong

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