Saturday, May 8, 2010

Yaquina Bay Invasive Tunicate Survey - May 7, 2010

A scientific diving team from the Oregon Coast Aquarium conducted a survey for invasive tunicates at Yaquina Bay, Oregon on May 7th, 2010. The target for the day: South Beach Marina. Five divers examined the west breakwater, the brewery dock and docks A, D, and G.

Botrylloides violaceus was found to be pervasive. An invasive sponge, Halichondria or Haliclona, was also noted. The two invasives were more abundant at A dock than the other locations.

Report from the team of two
Galen and Lorne surveyed the side of the breakwater facing the marina from the brewery dock to the point opposite the boat launch. Rock typically terminated at a six foot depth measured from high tide, so we primarily inspected the intertidal zone. B violaceus was evident in small 10 cm square colonies. Natives included Monkeyface Prickleback, Blackeye Goby, and Copper Rockfish. The bivalve Pododesmus macrochisma (Green False-Jingle) and chitons were noted after cleaning off their overgrowth of algae.

Proceeding along bottom to G Dock, we passed Spiny Pink and Sunflower Stars. Inspecting two powerboats and a sailboat long moored at end of dock, we found larger colonies on pilings and abundant but small B violaceus colonies on the sailboat. The hull of said sailboat supported luxuriant macro-algae, and young of year rockfish benefited from the habitat created.

Surface-swimming from G dock to D, we inspected the sailboat moored at the end to find little but filamentous algae growing on the hull but mussels and some Bv clustered on the propeller. A Padded Sculpin also rested there. Undersides of docks generally showed a sparser fouling community than that of the Embarcadero with a representation of mussels and the invasive sponge also noted by the other team. One piling had a collection of the nudibranch Janolus fuscus.

Report from the team Of three
Three dropped in at the west end of the dock along the brewery. Small spots (2 inch and less) of violaceus were on the concrete wall and pilings, 1 to 3 foot spacing. Around 10 (shellfish) (around 5" long ovals) were seen on the concrete wall and a metal piling, many with violaceus growing on the shells. Chitons were also in the same area.

The three examined a small portion (50 feet) of the west jetty wall of the marina. They observed violaceus in small to medium patches (2 to 8 inches) on any exposed rock. They often saw larger patches underneath larger rocks.

They cut across to A dock and examined the west half of it. Immediately they noted well distributed violaceus growing on top of mussels, algae and what looked like oar weed kelp. The violaceus, growing on such fragile structure, easily detached with disturbance such as exhaled bubbles. They opted to observe the dock from the edge so as not to dislodge / spread the violaceus. The west half of A dock was examined, violaceus noted constantly. They descended along a piling and found violaceus in sparse (every 1 - 3 feet) medium patches (2 - 4 inch) down to the silty bottom. It favored the east side of the piling.

They observed a small, soft tube sponge that is also very established under A dock. It tends to grow in clusters of maybe 6 to 8 individuals with 1.5" horn-like tube (cream white color) extending outward. Same invasive sponge noted in other Oregon locations.

Dive team present: Aquarium staff members Vallorie Hodges, Brittany, and Roy Hildenbrand. Aquarium volunteers Lorne Curran, Dylan Curran, Galen Gard and John Estabrook.

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