Halimeda

Common Name: Unknown - Cactus Alga? Coin Green?
Scientific Name: Genus Halimeda - Halimeda discoidea?

Family: Halimedaceae - Halimeda is the only genus
Class: Bryopsidophyceae - macroscopic green alga

Conservation status: Not yet assessed
Sighting: Ocasional

Identifying this species is very difficult for the amateur, as seems common with alga and seaweed. We think this beautiful alga is part of the genus Halimeda, but we can not narrow down to which species it really belongs. Lacking a good alga identification site, we have found pictures of Halimeda discoidea looking very similar, but then, some other H. discoidea pictures looked completely different, showing branches or segments of discs, which do not seem apparent in our pictures. It may well be some of the pictures are misidentified themselves, making the whole search even more challenging. 

In any case, Halimeda, described as a "green macroalgae, with a body (thallus) composed of calcified green segments", and the pictures of some of its species (it has more than 40 species listed, we didn't found examples of all), seem close enough to give us confidence we have the right genus.

Of the various common names we have found for species of this genus, green coin seem to be the most appropriate to this particular specimen. At least that is how we would describe it, they are the size of a US dollar quarter, but thicker, with a characteristic bright green rim. They do look like some Crassulacean plants (cactus without spines, if you want), therefore the "cactus alga" name, which also seem suited to this particular example.

FInally, in this -poor- video you can take a look how the colonies are interspersed within the turtle grass. You can also see a starfish featured in Cushion Starfish post, and the location of the area near Bill Baggs Cape lighthouse where you can find this species.

Look for an update on this page with better video, and hopefully full identification of the species. We will try to carefully analyze the stem structure, to see if it matches the descriptions.

Yellow Ray

Common Name: Yellow Ray, or Yellow Stingray.
Scientific Name: Urobatis jamaicensis or Urolophus jamaicensis

Familiy: Urotrygonidae - Round rays
Class: Chondrichthyes - Cartilaginous fishes (sharks & rays)

Conservation status: Least concern
Sighting: Infrequent


Not really yellow, but brown with lighter and darker spots. We have seen this amazing fish a few times, always in the same are of the Virginia beach in Key Biscayne. It usually lays down on sand, motionless, in what seems cryptic behavior. We have also seen this behavior when it lays on top of turtle grass.

When it feels threatened, it swims away very quickly. We capture this in the video, below. In most cases, it first tries to "hide" in the environment, then starts swimming  as it notices our focus, and finally, it disappears in a fast swim. 

On another occasion we captured two of them together. In the camera. They are sting rays, so you want to stay a bit apart from them.

According to the Marine Species identification portal, it could be 1.2 to 1.8 meter wide. The ones we have seen are much smaller than that. Wikipedia mentions 70 cm (28 in) long. All the specimens we have seen are more about a foot (30 cm). Probably juveniles, that close to the shore.

We are still trying to see if it changes color, like cuttlefish, or not. Wikipedia mentions they could change coloration in response to the environment, but we have not been able to see that in the videos. So far.

All in all a very exciting sight!.