No one knows exactly how many species live in the ocean. Scientists have formally described more than 250,000 living marine species, while broad estimates often place the total number of animal and other eukaryotic species between about 700,000 and one million. Microbes make the question much larger and harder to define. The range changes with…
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Asian tiger shrimp are a coastal concern because they grow larger than native U.S. shrimp, eat other invertebrates and can carry pathogens that affect crustaceans. Their presence does not prove that they have caused ecological damage in every location. It creates a credible risk that agencies monitor before impacts become difficult to reverse. The species,…
For sea turtles, the temperature surrounding an embryo helps determine whether it develops as male or female. Cooler incubation generally produces more males, while warmer incubation produces more females. Genes still direct development, but unlike humans and many other vertebrates, sea turtles do not use sex chromosomes as the primary switch. The effect is strongest…
Sharks do not normally hunt people as prey. Humans are absent from the natural diets of nearly every shark species and encounters that end in a bite are rare relative to the number of people who enter coastal water. A bite can still cause devastating injury, so low probability should not be confused with no…
