The Reef Environmental Education Foundation (REEF) - REEF's mission is "to educate and enlist divers in the conservation of marine habitats". The REEF Fish Survey Project enlists the volunteer efforts of divers to collect data on ocean fish and invertebrate populations. See our Fish ID and Invertebrate ID classes for more information on how to participate. 
Oceana - A group composed of scientists, economists, lawyers and advocates for specific and concrete policy changes to reduce pollution and to prevent the irreversible collapse of fish populations, marine mammals and other sea life.
The Ocean Conservancy - Promotes healthy and diverse ocean ecosystems and opposes practices that threaten ocean life and human life. Through research, education, and science-based advocacy, The Ocean Conservancy informs, inspires, and empowers people to speak and act on behalf of the oceans.
The Nature Conservancy - Their mission is to preserve the plants, animals, and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive.
The Ocean Legacy - A non-profit, non-partisan campaign to build support for ocean and fish protection. Aimed at raising awareness about the threats of over-fishing, bycatch, and habitat destruction.
Oceans Alive - environmental defense - With over 400,000 members, this organization finds innovative ways to solve the most urgent environmental problems.
seaturtle.org - Founded out of a desire to support research and conservation efforts in the sea turtle community. Dedicated to providing online resources and solutions in support of sea turtle conservation and research. 
NOAA Marine Sanctuaries – The mission of NOAA's National Marine Sanctuaries is to serve as the trustee for the nation's system of marine protected areas, to conserve, protect, and enhance their biodiversity, ecological integrity and cultural legacy.
Seafood Choices Alliance - A global trade association for the issue of ocean-friendly seafood. The Alliance helps the seafood industry—from fishermen and fish farmers to distributors, wholesalers, retailers and restaurants—to make the seafood marketplace environmentally and economically sustainable.
SeaWeb - A communications-based nonprofit organization that uses social marketing to advance ocean conservation. Programs combine science, communications and policy expertise.
NOAA’s National Ocean Service - Works to observe, understand, and manage our nation's coastal and marine resources. NOS measures and predicts coastal and ocean phenomena and provides tools and information to protect and restore coastal and marine resources.
The Census of Marine Life - a growing global network of researchers in more than 70 nations engaged in a ten-year initiative to assess and explain the diversity, distribution and abundance of marine life in the world’s oceans - past, present and future.