Like a lot of divers I participate in the diving community in several ways. One way is by serving on the Board of Trustees of the Reef Environmental and Educational Foundation (REEF). REEF’s membership is free, and we welcome anyone who cares to join. 

Shearwater TERN
REEF volunteers survey fish populations around the world, including many sites in California. The results are available to anyone that wants to use them, and a lot of scientists put REEF’s data to good use in a variety of ways. 
Surveyors attain graduated levels of proficiency as REEF offers free courses that help volunteers learn to identify various fishes. But to get started all you have to do is be able to identify one species of fish. For most divers things don’t get much easier than that!
Just recently I took part in a weeklong survey expedition, and I really had a lot of fun. Despite having made well over 10,000 dives in my life, I found the experience to be surprisingly educational as my ability to quickly and positively identify a number of fish species increased significantly in just a few days of focused diving.
My participation in the surveying trip also served to remind me of how many different activities there are for all California divers to participate in. Personally, I almost always have a camera in my hands when I dive. Other divers find their primary source of diving enjoyment in exploring shipwrecks, spearfishing or otherwise collecting game. Still others find technical diving and the opportunity to expand their horizons by using mixed gases and rebreathers to be their thing. Perhaps your thing will be to increase your diving skills by becoming a divemaster or mastering the entire skill set needed to become an instructor. Or perhaps you will want to work with another organization that enables volunteer divers to help protect and conserve our waters. 
A lot of studies have shown that divers that participate in some activity during their dives go diving more often and stay active far longer than divers that only suit up and go for a swim. Well, lucky us! We have a lot of choices that can be easily fulfilled.
When new divers get certified, instructors usually remind them that their initial scuba course is just the beginning — a license to learn. My recent REEF trip reminded me of the truth in that statement. 
Shearwater TERN