False Bay Species

False Bay: Species Descriptions

Annelida: Polychaeta

Arenicolidae (Lugworms)

As a subsurface deposit feeder, the lugworm Abarenicola lives in a J-shaped tube with its posterior end close to the surface. It produces distinctive coiled fecal castings at the mouth of the burrow. Try the following trick: poke a finger into a burrow hole, and see if water springs up out of another hole, showing that the two holes are connected by a common burrow. Digging under a few fecal castings will surely turn up a lugworm. The bright red gills along the sides of this worm are in contrast to its dull brown body. Chaetopteridae

The tube of this worm can be seen throughout the sandy areas of False Bay, but it is rare to find a complete specimen. Chaetopterid tubes may reach as deep as 2 m, making it difficult to dig one out, although a quick shovel full may turn up a portion of the anterior end. The body of the chaetopterid is divided into three main sections. These animals are filter feeders, using a unique mucous bag to capture food particles. Glyceridae (Bloodworms) Named for its deep red color, glycerid worms are found in most parts of False Bay. Glycerids are long slender worms with what seem to be featureless heads. When disturbed, however, you may notice it evert its long pharynx, which it uses for burrowing and feeding. The jaws on the surface of the pharynx can sometimes be seen as dark spots underneath the skin when the pharynx is not everted. Blood can also be seen through the skin pulsing through the circulatory system. Hesionidae This is a crawling polychaete with well-developed parapodia, which are the small paddle-like appendages associated with each body segment. Hesionids are carnivores, feeding on a variety of small invertebrates. Lumbrineridae This common worm is found throughout False Bay. It resembles an earthworm as it has few obvious appendages and is similar in shape. Generally a pinkish color, when observed under bright light the lumbrinerid shows a shining irridescence as it moves. Lumbrinereids have eversible jaws which they use for tearing pieces of algae. Maldanidae (Bamboo Worms)

With segments that are longer than they are wide and distinctive red bandings, the bamboo worm is easily identifiable. The sand and mucous tubes can be seen in many areas, rising 1-2 cm above the sand. The tubes are narrower and more brittle than those of the chaetopterids. The rear end has an odd frilly appearance. Nephtyidae Nephtyids are well-adapted to both burrowing and crawling on the surface. They are called shimmy worms, as they make rapid undulations of the body. Nephtyidae are omnivorous worms, consuming both other animals and plant material. Nereididae

An active worm, the nereid can often be seen crawling on the surface of the sand, although they burrow as well. Individuals as long as 30 cm are commonly observed. Large epitokes (the reproductive form of the worm) can be found swarming in the plankton during reproductive season. Onuphidae Onuphids form sand and mucous tubes, but unlike most tube-dwelling polychaetes, they often leave their tubes to forage. They are omnivorous and may also reach from their tube to capture passing prey. Orbiniidae This is a burrowing polychaete, common in muddy areas. It is a non-selective deposit feeder. Phyllodocidae This is a carnivorous worm that uses its long pharynx to catch prey. The parapodia of this worm are flattened and paddle-like. Terebellidae (Spaghetti Worm)

The terebellids are surface deposit feeders, using their long tentacles to reach for food particles on the sediment. The extensive tentacles on the anterior end give this worm its name, and when the tentacles are seen snaking out over the surface of mud, they are unmistakable. Their tubes are made of mud and mucous, but are generally not as obvious as tubes from other worms such as Arenicolidae or Chaetopteridae. The body is usually green to brown.
Cnidaria (sea anemones)

Anthopleura

This sea anemone may be found in muddy areas, usually attached to a buried rock, cobble, or other hard substrate. Epiactus This is a greenish brown anemone commonly found on eelgrass blades and also seen in the Ulva Area, attached to pieces of ulva. This is a unique anemone in the way that it broods its young. Nemertea (ribbon worms)

Paranemertes peregrina

This long worm, purplish-brown in color with a light underside, is the most common nemertine in False Bay. It can often be seen at the sand surface on cool days. It obtains much of its food by preying on polychaetes. It kills the polychaetes by everting its proboscis and injecting the prey with a toxin. It is also known to feed on Ulva (Kozloff, 1996). Amphiporus sp. This is another predatory nemertine worm. Tubulanus polymorphus This nemertine is recognizable by its bright orange coloring. It may reach up to 1 m in length, and can be found with the Ulva at False Bay. It also preys upon polychaetes and other small invertebrates. None of these ribbon worms is dangerous to humans. Arthropoda

Amphipods:

Grandifoxus grandis

This small beach hopper occurs on sandy beaches throughout Puget Sound. It is a typical amphipod in having a body that is taller than it is wide. Brachyura:

Hemigrapsus

This common brachyuran crab is found in false bay primarily in the rocky area closest to shore. It is found under rocks in sandy or muddy areas and prefers quiet water. It is an omnivore, eating such things as algae, small invertebrates, scavenging, and even filter-feeding. Pinnixa tubicola This small crab (<2 cm) is much wider than it is long, and is found generally in the tubes of Chaetopterus and terebellid worms (Jensen, 1995). In False Bay, we observed this crab living in terebellid worm tubes. The unusual body form is probably an adaptation for living as a commensal organism inside of long tubes. Anomura:

Pagurus spp.

Many hermit crabs occur in False Bay. They inhabit gastropod shells of varying sizes. This is notable in False Bay because gastropods in general, and loose shells in particular, are not especially common. Thalassinids:

Neotrypaea spp.

Known as the ghost shrimp, this crustacean lives exclusively in muddy habitats, and feeds off of organic matter in the mud. It lives in burrows, and is noticeably helpless when brought to the surface. It is estimated, however, that larger individuals (up to 10 cm in body length) may be as much as ten years old (Kozloff, 1996). Upogebia pugettensis

Commonly called the mud shrimp, this crustacean also lives in burrows in muddy environments. Like the ghost shrimp, it moves remarkably slowly when brought to the surface. It is at times found with a commensal clam, Orobitella rugifera, living attached to the underside of its abdomen.

Echinodermata

Holothuroidea:

Leptosynapta clarki

This burrowing sea cucumber lives in sand and feeds by digesting organic material from sand grains that it ingests. This cucumber is unusual in lacking tube feet, except for the tentacles associated with the mouth. It is often mistaken for an annelid worm, and lives in the top 10 cm of sand. Where it occurs in False Bay, in some years it is very abundant. Echinoidea:

Dendraster excentricus

This sand dollar usually occurs in sandy environments, and feeds on organic matter in the sediment. In False Bay it was nearly always found buried a few centimeters into the sediment, often with a distinctive circular depression above an individual. The animal is a distinct dark purplish brown. Commonly found is just the inner shell, or test, of a dead individual--the test is white.
Mollusca

Bivalvia:

Macoma nasuta

Commonly known as the bent-nosed clam, this bivalve usually lives in muddy environments, and is distinguished by the bend in both valves on the posterior end. It lives buried 10 - 15 cm in the sediment, and is a filter feeder. Macoma inquinata This species of bivalve is extremely similar to the bent-nosed clam, except that its valves lack the distinctive bend in the posterior region. It is also found in muddy habitats, and is a filter feeder. Clinocardium nuttali The heart cockle, as it is commonly known, lives on sandy beaches, just below the surface of the sediment and is a filter feeder. If you are lucky enough to expose a heart cockle to the sea star Pycnopodia, the cockle will thrust out its large foot and move it violently in an effort to escape. Orobitella rugifera

This clam lives commensally on the underside of the mud shrimp, Upogebia. It attaches itself using a byssus thread (commonly seen attaching mussels to hard surfaces) to the underside of the shrimp, and lives in the burrow with the shrimp, filtering food out of the water that flows through the burrow.

Tresus capax (Gaper Clam)

The gaper clam was the largest clam encountered in False Bay, over 10 cm in its largest shell dimension. It was remarkable for its burrowing speed and power using a large, muscular foot. It earns its name from the gape left for the siphon, even when the valves are pulled tightly together. Transennella tantilla

This tiny bivalve does not exceed 5 mm in length, and lives on the surface of the sand. It is rather common in False Bay (if you look carefully), and is notable because the females actually brood their even tinier offspring (Kozloff, 1996).

Gastropoda:

Lacuna variegata

This small snail (<1 cm) is found in eelgrass and ulva beds. Commonly known as the chink shell, it leaves distinctive doughnut-shaped, slightly yellow egg masses on the leaves of algae and plants.

Haminoea (Bubble Snail)

Found mainly in the pools of standing water, these are small gastropods, approximately 2 cm long. Only a small portion of its internal shell can be seen in the middle of its body. The body is grey to light brown in color. The bright yellow egg masses, commonly found in the spring and early summer, are typically deposited as ribbons attached to some hard surface (bit of shell, eelgrass, log).