Barbara Block is an American marine biologist and Charles & Elizabeth Prothro Professor of Biology in Marine Sciences at the Stanford University Hopkins Marine Station and a co-director of Stanford University's Tuna Research and Conservation Center, with the Monterey Bay Aquarium. She has published numerous bodies of work throughout her career in marine biology and chemistry, mainly focusing on the biology and chemistry of metabolism in different tuna and shark species. Additionally, she has helped develop two new types of electronic tags for large pelagic predators in order to track the migrations of large oceanic predator species.

Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists have pioneered the animal husbandry of jellyfish and it was the first to successfully care for and display a great white shark. The organization's research and conservation efforts also focus on sea otters, various birds, and tunas. Seafood Watch, a sustainable seafood advisory list published by the aquarium beginning in 1999, has influenced the discussion surrounding sustainable seafood. The aquarium is the home of the current oldest living sea otter, Rosa, and the birthplace of Otter 841.