Habitat: Pilings
The Mediterranean mussel (Mytilus galloprovincialis, pictured here in the outer harbor) is a non-native species that has been introduced into coastal habitats worldwide both unintentionally through shipping and purposefully through aquaculture. Common and often abundant in intertidal habitats throughout the harbor, mussels feed by filtering plankton and organic material out of the water.

Habitat: Pilings
There are two species of oysters common in the harbor, the native Olympia oyster (Ostrea lurida) and the non-native Pacific oyster (Crassotrea gigas; pictured here in the inner harbor). Olympia oysters grow to a size of only 2-3 inches and were about 20 times more abundant in the harbor than the non-native species, which is conspicuous when growing on pilings as it can reach sizes of 10 inches. Oysters feed by filtering plankton and organic material out of the water.

Habitat: Seafloor
The California halibut (Paralichthys californicus) is a commercially valuable species commonly found in the harbor. These fish partially bury themselves to blend into the seafloor in order to ambush prey such as shrimps, crabs, anchovies, and other fishes. They use shallow bays, especially where eelgrass is present, as nursery habitat before moving into offshore habitats as they become adults.

Habitat: Riprap and Seafloor
The California scorpionfish (Scorpaena guttata), often mistakenly referred to as “sculpin”, can be found hiding in crevices in riprap as well as settled on the seafloor throughout the harbor. The venomous spines help protect it from predators and unknowing fishermen, as these fish are popular sportfish commonly caught on hook and line when targeting rockfish. California scorpionfish are a federally managed fishery, relying on healthy habitat to find food such as crabs, shrimp, octopus, and small fishes.

Habitat: Pilings, Seafloor
Tunicates, or ‘sea squirts’, are commonly found in the harbor on the seafloor , and can be highly abundant on pilings. More than half of the tunicate species that are present in the harbor are non-native, with Ciona (pictured here in the inner harbor) one of the most abundant. Tunicates can be solitary or colonial, and feed by filtering plankton and organic material out of the water.

Habitat: Pelagic
The common dolphin (Delphinus sp., pictured here in the inner harbor), is one of the most abundant dolphins found in the harbor, followed by the larger bottlenose dolphin (Tursiops truncatus). Dolphins can be spotted throughout the harbor feeding on small schooling fish (e.g. anchovies and sardines), cephalopods (e.g. squid and octopus), and crustaceans (e.g. shrimp and crabs).

Habitat: Seafloor
California round stingrays (Urolophus halleri) are common in the harbor, where they prefer shallow, sandy environments. They find food by digging into the seafloor, hunting for worms, crabs, snails, clams, and small fishes. Their primary predators include marine mammals and sharks, especially leopard sharks.

Habitat: Seafloor
Swimming crabs (Portunus xantusii) are common in the harbor, ranking as one of the top 10 most abundant invertebrate species found on the seafloor. These crabs are most active at night hunting small prey such as shrimps and worms and can use their flattened rear legs to rapidly swim away to avoid predators or to burrow backwards into the seafloor.

Habitat: Pilings and Seafloor
The large number of pilings in the inner harbor creates favorable habitat for predators such as barred sand bass (Paralabrax nebulifer). As juveniles, these fish eat crabs and small shrimp while adults hunt other fishes such as anchovies, which are common in the area.