STEELHEAD - Oncorhynchus mykiss irideus

Although the San Pedro Creek Watershed is home to a disparate variety of flora and fauna, the Creek itself provides habitat for a majestic, elusive and disappearing species - a distinct population of the Central Coast Steelhead. Reaching as much as 40lbs, the Steelhead shares the genetic profile with California’s Rainbow Trout but unlike the trout of the Sierra Streams, the coastal populations of trout live the majority of their lives in Pacific Ocean. High in the watershed, the fish start their life in the Spring, maturing 1-2 years in the Creek, migrating out on high water to the Pacific Ocean. Here they feed in the nutrient-rich waters of the Eastern Pacific, growing in size until triggered to come home, and spawn (reproduce). The Steelehead then finds the signature of its home waters and at a time of a high tide and high winter flows, slips over the sands of Linda Mar Beach, swims into the estuary beneath Highway 1 and re-acclimates to its freshhwater environment. It then migrates up the creek, through backyards and beneath roads to find a like-minded mate, where they lay eggs and fertilize them in gravel of San Pedro Valley Park. This life cycle is known as anadromy, a cycle shared with other anadromous fish such as the Pacific Salmon. But unlike the Pacific Salmon who die after the exhasting journey to spawn, Steelhead somehow recharge and return to the Pacific Ocean to do it again!

It was listed as threatened under the Endangered Species Act on January 5, 2006. We need to do everything we can to ensure this beautiful species can continue to use San Pedro Creek, thus helping to perpetuate the Central Coast population. According the the National Marine Fisheries Service, “this distinct population segment, or DPS, includes naturally spawned anadromous O. mykiss (steelhead) originating below natural and manmade impassable barriers from the Russian River to and including Aptos Creek, and all drainages of San Francisco and San Pablo Bays eastward to Chipps Island at the confluence of the Sacramento and San Joaquin Rivers.”

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PACIFIC LAMPREY - Lampetra tridentata 

Like steelhead, Paficic lampreys are also anadromous - they spawn in fresh water but migrate to sea, returning to fresh water to spawn.  They aren’t quite as charismatic as steelhead, but they have their role in nature, too.  Lampreys are the last living descendants of a very ancient and primitive group of fish – a group that doesn’t even have jaws.  Adult lampreys live at sea, and make their living by attaching to the side of a larger fish like a halibut or salmon with their disk-like mouth, drilling a hole in the side of the fish and feeding on blood or body fluids before dropping off.  Most of the fish attacked by lampreys seem to survive, because many salmon show lamprey marks.  This kind of gruesome adult stage is really just one portion of the life of a lamprey, though.  The young stage living in fresh water is called an ammocoetes.  It burrows into the mud, and makes its living mucking algae and organic matter from the floor of the stream – they act like little garbage recyclers.  These ammocoetes spend several years in the stream, growing to several inches in length. 

Lampreys are elongated and kind of eel-shaped, and can occur in large numbers as they migrate.  The Eel River in northern California is named for them.  Native Americans prize lampreys as food, and use specials tools for catching them as they migrate upstream.

THREE SPINED STICKLEBACK - Gasterosteus aculeatus

These little fish (up to a few inches long) are most common in the lower parts of the stream, where they often form large schools.  Related to sea horses and pipefish, they may have bony plates on their sides, and they have a small mouth through which they suck in prey.  Sticklebacks are tolerant of seawater, and colonize streams from the sea.


Sculpins are stocky-bodied bottom dwellers, and include common tide-pool dwellers.  Some kinds of sculpins, like the prickly sculpin, have become adapted to fresh water, and inhabit streams all along the west coast.  Like sticklebacks, they also tend to be more common in the lower reaches of the stream, and they tolerate salt water as well.  They may reach up to eight inches in length.