Species Focus Area
Coastal and ocean species carry pressures that begin far inland, arriving through rivers, bays, and the debris that travels with them.
Marine species cross national boundaries, so their protection depends on cooperation between fisheries, shipping, and coastal management at once.
Common threats
How people can help
These ten are not a scientific ranking. They were selected for conservation urgency, teaching value, and regional relevance, and each one has a complete, sourced profile.
Critically Endangered (IUCN)
Phocoena sinus
The world's most endangered marine mammal, reduced to about ten individuals by gillnets set for a different endangered species.
Critically Endangered (IUCN) / Endangered (ESA)
Eubalaena glacialis
A large baleen whale whose entire population is individually catalogued by photograph, and which is dying faster from ship strikes and rope entanglement than it can reproduce.
Critically Endangered (IUCN) / Endangered (ESA)
Lepidochelys kempii
The world's smallest and most endangered sea turtle, nesting almost entirely on a short stretch of Gulf coastline in Mexico and Texas.
Critically Endangered (IUCN) / Endangered (ESA)
Eretmochelys imbricata
A coral reef turtle hunted for centuries for its patterned shell, sold as tortoiseshell, and still critically endangered worldwide.
Endangered (IUCN); Threatened or Endangered by population (ESA)
Chelonia mydas
A large sea turtle that grazes seagrass meadows, protected under the ESA as eleven separate populations with markedly different trajectories.
Endangered (IUCN and ESA)
Neomonachus schauinslandi
One of the most endangered seals on earth, found only in Hawaii, and slowly increasing after decades of intensive individual care.
Critically Endangered (IUCN) / Threatened (ESA)
Acropora palmata
Once the dominant reef-building coral of the shallow Caribbean, reduced by disease and bleaching to a fraction of its former cover.
Critically Endangered (IUCN) / Endangered (ESA)
Pristis pectinata
A shark-like ray with a toothed rostrum, the first marine fish ever listed under the U.S. Endangered Species Act.
Critically Endangered (IUCN) / Threatened (ESA)
Carcharhinus longimanus
Once among the most abundant large animals on earth, this open-ocean shark has declined by an estimated 95 percent or more, largely as fishery bycatch driven by the fin trade.
Critically Endangered (IUCN) / Endangered (ESA)
Balaenoptera ricei
A baleen whale recognized as a distinct species only in 2021, found solely in the Gulf of Mexico, with fewer than 100 individuals believed to remain.