Category: Ecology

An often-overlooked environment, the cliffs and their sloping bases provide safe harbor for many marine species to rest and raise their offspring. The vertical cliffs create safe nesting areas for Brandt’s Cormorants, sea gulls, and falcons. Their sloping bases provide critical haul-outs for sea lions and perches for pelicans and other birds. In the spring, look for cormorant and sea gull chicks. Sea lions give birth on the rocky beaches and coves in late June and early July. These 75-million-year-old sandstone cliffs host the sea caves that draw many visitors to their beauty every year. The cliffs have been fractured by faulting activity along the Rose Canyon Fault System. The fractures are weak and susceptible to wave action and the cracks grow larger over time. The seven major sea caves that have eroded as a result of these fractures are named as follows, from east to west: White Lady (named for its ladylike silhouette), Little Sister, Shopping Cart (named for the lone shopping cart abandoned inside by local high school students, which now supports marine life), Sea Surprise (named for the accumulation of items that wash up regularly here), Arch Cave, Sunny Jim’s Cave (accessible by land through a tunnel dug in the early 1900’s and used to smuggle alcohol and Chinese immigrants), and The Clam Cave (the largest and oldest cave).

Just beyond the kelp forest at the edges of the ecological reserve, we can imagine a hidden environment – the deep marine canyon. Dropping to 600ft within the reserve and even deeper further seaward, the waters in this canyon are cold and nutrient rich. They support abundant marine life and market squid spawn here by the millions annually drawing in halibut, pinnipeds, sharks and other predators to feed. The canyon branches in two arms close to shore which refract Pacific swell and create “dead” zones like the small boat launch at the end of Avenida de la Playa, as well as big surf zones like Black’s Beach.

Kelp forests grow just offshore. In order to reach them, remember not to cross the swim lane. Instead, paddle north from the caves to the 1/2 mile buoy marking the swim lane. You can cross here after scanning for swimmers. Kelp can reach 100ft tall and grows at an astounding rate of 2ft/day. They are not true plants, but brown algae. Kelp attaches itself to the bottom with root-like structures called “holdfasts”. Kelp is vitally important to our oceans because it provides food and shelter for an entire ecosystem. Microscopic organisms and invertebrates grow on kelp leaves, small fish feed on them and hide among the kelp strands. Harbor seals, bigger fish, and California sea lions hunt for food among the kelp. An area with kelp supports 1000 times more life than an area without kelp. The balance is easily upset – over-fishing of sheepshead fish (which eat sea urchins), leads to an overabundance of urchins (which eat kelp holdfasts), and the entire kelp forest community collapses.

San Diego’s water is too cold to support coral growth, but our rocky reefs serve a similar function by providing a solid substrate for plants and animals to attach, as well as abundant hiding places. Eel grass and algae grow abundantly here, providing cover for many organisms and serving as the favorite food of visiting sea turtles. Organisms such as the sea hare have evolved to mimic both the color and the motion of brown algae awash in gentle waves and are well camouflaged. The nooks and crannies and tide pools are an important nursery for juveniles of many species. The most obvious resident, the bright orange garibaldi, stakes out a little piece of real estate and defends it ferociously.

Otherwise known as the “beach”, this is the desert of the ocean. Because the sand is in constant motion due to wave action, animals living here must be specially adapted. Buried safe in the sand are clams, worms, sand dollars and crabs. Predators like stingrays, guitar fish, leopard sharks, and surf perch cruise the surface hunting for them. This, in turn, draws in bigger predators like seals, sea lions, and dolphins. When you paddle along the sandy flats, especially when the bright sun is shining, look all the way to the bottom to see beautiful ripple marks and catch glimpses of sea life.