One of the largest local barnacles; to 11 cm diameter with a broad aperture relative to its base; opercular plates with distinct beaks. 

Common but patchy, usually occurring in clusters; on rocks especially in deeper water & on isolated rocky pinnacles; also on wharf pilings where they haven't been eaten by sea otters.

| back to spp. list | more info | refs. | kelp forest index |

Large barnacle to 13 cm diameter; aperture small relative to basal diameter; opercular plates with distinct beaks. 

Infrequent and patchy, sometimes occurring in clusters; on rocks at all depths; also on wharf pilings.

| back to spp. list | more info | refs. | kelp forest index |

Acorn barnacle to 10 mm, white with smooth shell plates. 

Abundant but inconspicuous, especially on vertical rock faces in kelp forests.

| back to spp. list | more info | refs. | kelp forest index |

Acorn barnacle to 30 mm diameter, shell plates with longitudinal red and white stripes; mantle margin with orange, blue, yellow, & red - most colorful local barnacle.

Common but patchy; low intertidal zone and subtidal on rocky substrate; most frequently seen in clusters on buoys & pilings.

Large crab 15-18 cm across; reddish-brown; large claws tipped with black; teeth on anterior edge of carapace taper to a sharp point; underside of body with conspicuous red spots; juveniles' carapace usually covered with hair-like setae.

Common, but cryptic; under rocks and in crevices on rocky substrate in kelp forests.  Predator on hard-shelled prey (snails, clams, etc).

Medium-size crab 6-9 cm across; carapace more oval than other Cancer & widest at 9th tooth; legs slender & graceful; teeth of carapace edged with white; tips of claws white, legs purple.

Can be common on sand & mudflats; feeds on barnacles & small bivalves.  Late stage larvae & young juveniles commonly found living on large jellyfish (Chrysaora spp.)

Small, hairy Cancer crab to 3.9 cm across; mottled brown or red with black tips on claws; teeth on carapace strongly curved; legs & carapace with many fine hair-like setae.

Uncommon & cryptic; under rocks and nestled in kelp holdfasts.

Decorator crab; large triangular carapace 8-12 cm across; decorates heavily when young, but less so with increased size (inset); rostrum a pair of short, flattened, straight- sided horns; males with larger claws than females.

Common, in rocky habitat with good algal & invertebrate cover.

Sheep crab; large, rounded carapace 11-16 cm across with wart-like tubercles; rostrum angles sharply downward; grayish- brown with blue on tips of tubercles; young crabs usually decorate carapace, but decreases with age/size.

Uncommon in Monterey, in rocky areas with kelp or on adjacent nearby sandy areas.

Triangular carapace 4-5 cm across; rostrum a pair of flat, leaf-shaped horns; carapace brown or tan, but usually overgrown with encrusting invertebrates. Males with larger claws than females.

Abundant, among algae & sessile invertebrates on rocky substrate. 

Carapace wider than long, 3-4 cm across; 2 flattened carapace teeth form pointed flanges on either side of rostrum; lateral margins of carapace with pair of wide triangular flanges; color pattern variable, often forming disruptive patterns between carapace, legs, and claws.

Abundant, but cryptic; on rocky substrate nestled among algae & sessile invertebrate cover. Decorates relatively little compared to other spider crabs.

Carapace 3-4 cm across, somewhat diamond-shaped with several prominent lateral spines; brownish to scarlet; lateral carapace with curved horn-like teeth; tips of claws white. Decorates rostrum (but not rest of carapace) with red algae.

Abundant, but well camouflaged among red algae & sessile invertebrates; at night, climbs kelp fronds and reproductive fronds of Cystoseira.

Kelp crab; carapace smooth & broad 8-9 cm across; pointed lateral teeth curve forward; edge of carapace between teeth straight; kelp brown to dark maroon. Juveniles may occasionally decorate rostrum, but adults devoid of decoration.

Common, in canopy of giant kelp, also wharf pilings. Juveniles in low intertidal on rocky shores.

Elbow crab; wing-shaped carapace with straight posterior edge, much broader than long, 2 cm across; rostrum shaped like an arrowhead; propodus & carpus of claws very elongate, tipped with small, angled pincers. 

Moderately common, but very cryptic, remaining buried in sand or shell rubble during daylight hours. Captures small prey in the elbow of claw between propodus & carpus, not with pinchers.

Coonstripe shrimp; brown to red irregular stripes with blue spots and white & yellow markings; antennae and legs banded. To 14 cm but usually much smaller in kelp forest habitats.

Common, in crevices on rock outcrops; maybe be a facultative fish cleaner.

Hermit crab; red with small white or blue markings; distinctive yellow rings on compound eyes. 

Very abundant, throughout kelp forest habitats on and around rocky substrate. Usually in Chlorostoma shells. Scavengers & micro-predators.

Large hermit crab with distinctive black oblong compound eyes; claws with numerous spines; legs and claws with orange-red & white bands.

Common, in sandy areas adjacent to rocky kelp forest habitats. Often in shell of the moon snail Euspira.

Medium large hermit crab; with orange to brown legs & claws covered with golden hairs; eye stalks long and slender; short stout antennae with obvious fringe of long hairs used for suspension feeding. 

Moderately common in Monterey kelp forests, on rocks, sandy areas near bases of rocky outcrops.

Helmet crab; carapace to 8 cm across, expanded to cover legs & claws; width of rostrum expands from base to tip; bright red, orange to white with spots of various colors. 

Common, on rocky substrate or sand near rocks.

Triangular carapace to 9 cm across (usually less) with obvious heart-shaped raised ridge; legs and claws with thick spine-like projections.

Uncommon, in rocky areas.

Elongate body, dorso-ventrally flattened; posterior edge of telson distinctly concave. Kelp colored. 

Abundant on fronds of giant kelp; also occurs on sea grasses and smaller red algae.  Major prey of many fishes.

Beach hoppers; bodies laterally compressed. Most amphipods in kelp forests are tiny; some species build spongy proteinaceous tube masses (photo) in which many individuals live.

Very abundant; ubiquitous. Important prey for a variety of fishes.

Skeleton shrimp.  Tiny elongate amphipods; grasp substrate with posterior legs and wave upper body in the water to capture food particles drifting by.

Very abundant, on algae, hydroids, and other bushy invertebrate colonies.