I am wondering, do you have a means of taking underwater images? Doesn't have to be fancy, a Go Pro, one of the various housings for iphone or android phones. Also do you bring an underwater flashlight with you while diving? A good light is pretty much essential to anybody trying to expand there list of critters and fish while diving. I see some people have pointed you in the right direction in regards to books.
Have you heard of iNaturalist.org? inaturalist . It's free to join, and is an excellent resource for identifying flora and fauna worldwide. Members can upload their own observations for identification, or they can help others by making identifications. If members agree on identification of a specific observation, then the observation becomes "Research Grade". There are thousands of separate projects. For example I dive the "world famous" Blue Heron Bridge frequently, there is an inaturalist project started by somebody called the Blue Heron Bridge Project, where I contribute observations. It says you are in the Monterey/Carmel, Ca area. So you can take your own images and compare it in different projects, better yet upload your observations and add them to different projects. There are quite a few projects available for just that area these include but are not limited too:
Monterey Bay Subtidal Diversity Project
Monterey Bay Marine Biodiversity
Coastal Marine Fishes of Monterey Bay
Of course there are terrestrial projects as well:
Interesting Birds of Monterey/SF Bay Areas
And challenge projects:
Monterey County Bio-Blitz
I see somebody already recommended the REEF books, but you might want to check out REEF.org . You might do a data search by hitting the Program Tab, and then going down the list to "Explore Data- Create Reports". You would have to drill down a little further but you could find this Geographic Zones: S. Davenport - Point Lobos Reserve. It gives a list of fish and invertebrates and the sighting frequency of each from over 4000 surveys collected over 25 years for that specific area. Of course you can join both inaturalist and REEF for free and contribute your own observations and surveys. If you do a REEF survey on every dive it is a good alternative to keeping a logbook because, the length of dive, depth, current, date, temperature, underwater topography, and of course all the species you observe get recorded in the database.
If you really want to go down the identification Rabbit Hole, find a species on iNaturalist and click on the speices name in bold letters. For example Green Razorfish of course you will see the picture but scroll down and you see the following as below:
Map About Taxonomy Status Similar Species, below and to the right you will see links to various databases on that specific species. There is enough information here to keep anybody busy, pretty much forever if they are interested. Hope this all helps.
