Atlantic sturgeon
Can an Atlantic sturgeon grow to the length of an ordinary car? These fish live in river and ocean habitats on the east coast.
In the 1800s, Atlantic sturgeon was revered for its eggs, and they were considered premium caviar. People flock to the eastern United States to hunt sturgeon and harvest precious eggs. This period was known as the "Black Gold Rush" and led to a sharp decline in Atlantic sturgeon populations.
Since Atlantic sturgeon were listed under the Endangered Species Act in 2012, they are no longer threatened by direct fishing. However, accidental catch-up in gillnet and trawler commercial fisheries still poses a significant risk to the species. Water pollution, dams, dredging and ship impacts also threaten this species.
Pseudo-killer whales
Fake killer whales are actually dolphins, although their names suggest them. They are found in tropical and subtropical oceans around the world. Fake killer whales are known for their sociability, they have strong social bonds, and form groups that hunt and share food together.
Like all marine mammals, fake killer whales are protected by the Marine Mammal Protection Act. Specific populations of false killer whales, known as the main island-like false killer whales of the Hawaiian Islands, are also protected by the Endangered Species Act.
Since the late 1980s, their numbers have decreased dramatically and it is estimated that fewer than 200 remain. Interactions with longline fisheries have led to this decline. Fake killer whales are known to remove fish and bait from fishing lines, which can lead to accidental hooks or entanglements.
Olive Ridley turtle
As one of the smallest sea turtles in the world, the olive sea turtle takes its name from its olive gray-green heart shell.
Like all turtles, female olive turtles return to land to lay their eggs in the sand. They are excellent navigators and usually return to the beaches of the general area where they hatch. Most olive Ridley females come ashore during a massive nesting campaign known as arribada, which means "arrive" in Spanish. Only ridley turtle species (olive and camp) are so large and synchronized to nest.
Unfortunately, the nesting practices of Alibad make it easy for people to obtain large numbers of eggs and kill large numbers of adult females (for food). This is the main reason for the global decline of the Olive Ridley Sea Turtle.
Many national bans on killing turtles and collecting eggs have reduced the threat. However, bycatch in commercial trawling, longline and gillnet fisheries remains a global threat to the species, with some countries continuing to collect turtle eggs and kill sea turtles.
Small-toothed sawfish
Although their bodies resemble sharks, the small-toothed sawfish are actually rays, and their bones are made up entirely of hard but flexible cartilage, not bones. This species looks like creatures from prehistoric times and can be found off the coast of Florida, USA.
Sawfish pierce schools of fish with their long spikes, swinging back and forth to stab and stun prey. Their saws also contain electrically sensitive organs that can sense the weak electricity emitted by other animals, allowing sawfish to sense nearby prey.
Young sawfish rely on shallow estuarine habitats such as mangroves as nursery areas. However, coastal developments in Florida and other southern states have altered or destroyed much of the habitat. Habitat loss and accidental catch of fishing nets are major threats to sawfish.
Bay grouper
Gulf grouper is one of the top predators found in the Gulf of California and the Eastern Pacific Ocean. Once these larger fish eat a variety of prey, bay groupers gather on underwater coral reefs once a year to breed. Gulf groupers are likely to mature in females and then transition to males as they age, with a lifespan of more than 48 years.
Bay grouper was once a common catch for fishermen on the West Coast. But due to overfishing, in 1970 the amount of landfall in the fishery was almost zero.
Bowhead whale
Of all the large whales, bowhead whales are best suited to live in icy water. Their fat layer may be 4 cm thick, which can help them live in seasonal ice-covered waters. The thick skulls of bowhead whales help them break through 20 cm thick sea ice. This behavior, combined with killer whale encounters, boat strikes and entanglement with fishing gear, causes bowhead whales to accumulate scars on their bodies. NOAA fisheries scientists use these scars to identify individual whales.
Since the end of commercial whaling in the early 1900s, the western Arctic bowhead whales off Alaska's north coast have recovered significantly. However, bowhead whales still face many threats. About 12% of bowhead fish are scarred by being entangled in fishing gear, mainly from commercial tank gear. Pollutants such as oil spills can damage bowheads' immune and reproductive systems. Ocean noise, boat crashes and killer whale predation are other factors that threaten the survival of bowhead whales.