Checking out the anchor is not usually a pretty dive, but it is a good place to start learning to see ocean life because anchorage areas generally don’t have the overwhelming diversity of the reef. Look closely and take nothing for granted. If the water is clear you can spot things from the surface. Amazing things are right under your boat!
Pumpkin Key, Florida Keys 7/25/2016 — N25° 19.468′ W80° 18.022′ Water depth-12′
The water here was green and visibility 10 ft or less with a lot of suspended sediment. The muddy bottom was covered with Sea Grasses and Algae. Sea Grasses are flowering vascular plants similar to what you see on land. They have developed distinct roots, stems, and leaves, and possess an internal transport system (vascular system) to distribute nutrients and fluids.
Most marine plants, what you call Seaweeds, are algaes, simple plants that can have distinctive looking parts but less cellular diversity and no vascular system. Marine algae are much more complex than the green or brownish coating you might have had on your dirty aquarium.
As I scanned the bottom from the surface, I was able to pick out some clumps that were inconsistent with the Sea Grass bed. I dove down to investigate. These were sponges—I could identify the Rope Sponges and Fire Sponges but there were others here and there draped with sediment. Sponges fascinate me with their myriad colors and textures—fun macrophotography subjects because they so cooperative. Sponges are often confused with corals—sponges generally have openings scattered all over of different sizes while coral appears more uniform.
Another reason to look carefully at sponges is that they often harbor other forms of life. I inspected this small black sponge and found an inch long Lancer Dragonet (Paradiplogrammus bairdi). I had never seen this species of fish before. What I thought, at first, was an unusual fringe on its dorsal (top) fin, was actually a row of parasitic copepods (a small crustacean).
There were not many fish here and the conditions were not good for photographing fish. I saw a couple of these guys near holes. I am not sure what kind of fish it is. The holes could be made by worms, shrimp, or crabs. A Barracuda also passed by me and some small Jacks.
On the way up I caught sight of a Moon Jellyfish (Aurelia aurita). The tentacles are very short but, like all jellyfish, contain stinging cells (cnidoblasts). The cnidoblasts eject a harpoon-like structure on contact which delivers a venom. They are used for subduing prey or defense.
Oh–I did check out the anchor. It was well buried. Just forgot to take a picture of it.