Taxonomy

Rarity

The California golden gorgonian is the orange sea fan in almost every Southern California dive photograph, and until now this site had no page for it. It is common on rocky reef through the southern half of the state, in the exact depth band divers work, and a diver who has been on a Southern California reef has swum past one whether or not they knew what to call it.

Nobody harvests it. There is no food fishery, no curio trade and no California rule written specifically for the species, so it sits under the general invertebrate limit of 35 of any one species per day. Take of all invertebrates is prohibited inside state marine reserves, with further restrictions in state marine parks and conservation areas, and that is the rule that actually matters for an animal like this. The International Union for Conservation of Nature has never assessed it, which is a statement about attention rather than about condition.

Seasonality

Location

The golden gorgonian ranges from Point Conception, Santa Barbara south to Panama. Point Conception is the northern wall, the same headland that stops the diamond stingray and the California butterfly ray, and it separates the cold water of the north coast from the warmer Southern California Bight. This is a warm-temperate animal at the cold edge of its range in California.

Depth runs from about 16 feet to 98 feet, with most colonies between 39 and 98. The habitat is rock with water moving over it. Colonies grow on rocky reef in moderate to high flow, on exposed and protected rocky shore alike, and on the reef under kelp forests.

A colony reaches about 3 feet tall. The branches are thick, reddish brown, and they all lie in a single plane, so the whole animal is a flat fan rather than a bush. The polyps that cover it are yellow, and when they are open the colony reads bright yellow to almost orange. That plane is not decoration and it is not random, which is the most useful thing a diver can know about this species.

Deep Dive

The fan is aimed. Golden gorgonian colonies orient themselves perpendicular to the prevailing current, which puts the maximum surface area across the flow of water, and every polyp on that surface is a mouth waiting for what the current carries. A diver who looks at a stand of these fans is reading a record of which way the water usually moves at that spot, written by an animal that has been standing in it for years.

The thing being aimed is not 1 animal. A golden gorgonian colony is thousands of individual polyps, each a tiny cnidarian with its own tentacles and its own gut, all sharing a common skeleton that they build themselves by secreting calcium. What looks like a plant is a colony of animals arranged into the shape of a filter. They feed on plankton and on whatever else drifts past, including the eggs and larvae of other animals, and they do it without moving, without hunting and without any of the machinery a fish needs to make a living.

The skeleton keeps a record. As the colony grows it lays down rings inside the skeleton, in the same way and for the same reason a tree does, so a cross-section of a branch carries the colony's history. That is where the honest limit of this page sits. The rings are described in the literature and the growth rate is not, so how old a 3-foot fan actually is remains unknown. Given that these are slow-building colonial animals, the answer is probably a long time, but this page will not put a number on something nobody has published.

Reproduction is a temperature switch. Golden gorgonians spawn during the months when mean water temperature runs above about 57 degrees, releasing eggs and sperm into the water at the same time so fertilization happens in open water rather than inside the colony. The larvae drift, and the ones that survive settle onto rock and become the founding polyp of a colony that may stand there for decades. Everything about that strategy depends on there being bare rock available and current to deliver the larvae to it.

Two animals are recorded eating them, and 1 of them is already on this site. A small snail lives on the colonies and feeds on them, camouflaged against the branches well enough that divers rarely notice it. The other is the garibaldi, the bright orange fish that is California's state marine fish and a fixture of every kelp reef in the southern part of the state. A fish famous for aggressively defending a patch of reef turns out to be feeding on the sea fans growing in it.

The reason this entry exists at all is worth stating plainly. Before it, this Ichthyopedia had 139 species and not 1 cnidarian: no anemone, no jellyfish, no coral and no sea fan, on a coast where those animals cover the rock. Cnidarians are the group that includes corals, anemones, jellyfish and hydroids, all built on the same basic plan of a soft body ringed with stinging tentacles, and they are among the most abundant things a Southern California diver looks at. The golden gorgonian is where that gap starts closing.

Where to Find Them

Beaches whose habitats match this species

Matched by habitat: a beach is listed when its biome tags overlap this species' biomes.