Volunteer Divers tackle invasive tunicate in Hood Canal

[nwscubamom]

Volunteer divers with Washington Scuba Alliance have been monitoring an ever-spreading patch of the invasive tunicate, Ciona savignyi, at a popular dive site on Hood Canal since April of 2006. (wylerbear is one of 'em!) A few individuals of the unwanted invertebrate appeared first in cracks at Sund Rock North Wall, and began spreading and thickening in population over the summer months. It’s found on rocks and boulders 40 feet below the surface of the water and extend down to about 70 feet.

With the recent low dissolved oxygen event in mid-September, much of the fish and invertebrate life died below 20 feet under the water’s surface. However, the large patches of the clear, cylindrical-shaped tunicate seem to be unaffected by the low dissolved oxygen and appear healthy and growing.



The invasive tunicate is taking over large expanses of South Hood Canal and was likely introduced by imported shellfish stock. Much attention and government funding has been spent in efforts to control another invasive tunicate, Styela clava (found at Pleasant Harbor Marina on Hood Canal), but nothing has been done yet about Ciona savignyi.

Volunteer divers are about to change that.

After consulting with Washington Dept of Fish and Wildlife Asst. Aquatic Nuisance Species Coordinator Pam Meacham, and UW Tunicate expert Gretchen Lambert, a team of volunteer divers was put together by Washington Scuba Alliance Board member Janna Nichols. The removal effort will take place Wednesday, Oct 25th, 2006.



More information on three invasive tunicates found in Washington can be found here:
http://www.pnwscuba.com/critterwatchers/invasive.htm

- Janna

[Sounder]

Yeehaw! It's a round-up!

[CaptnJack]

Are you just going to shovel them off the rocks? How is this going to proceed?

Really curious
Richard

[lamont]

i think i've been seeing more of these in cove 2.

there's some isolated ones growing on the pilings at about 30-40 fsw which are directly shallower from the buoy and north from the honey bear (the one big cluster of pilings which are not downslope from the honey bear)...

( i brought my camera last time but got distracted by a moonsnail and diving with a newbie diver and forgot to look for them to take pics... )

[nwscubamom]

Our first dive is going to be a survey/photo/video dive to scope out the patches that are there, and mark them.

The second dive we'll take down little putty knives and spatulas, and you just sort of scrape them off the rock and plop them in a goody bag.

I did an extensive marine life survey in Hood Canal on Monday (from Pulali Point down to Jorsted Creek) and found several spots where there were small clumps of the tunicate growing. We removed them and put them in the goody bag, and they stayed there just fine.

I thought they'd perhaps disintegrate and smooosh through the mesh, but no probs. Pretty sturdy things I guess.

Will keep you posted, about to head out the door up to Sund! KOMO TV said they may be coming to cover it!

- Janna

[Old Crab]

Well, it's Thursday...please let us know how things went! We would love to hear your report.

Thanks,

Eric

[nwscubamom]

Sorry, it's been a busy day!!! Both of the photos here were taken by JD Rowe.



A wolfie has its den overtaken by Ciona savignyi.

We were able to get about 80% of the Ciona at the North Wall. It took two dives, 6 people, and a lot of work. The funny part is, all we had to show for it when we were done, was a teeeny bit inside ONE goody bag. The tunicates compress dramatically when out of water.

Here's Trevor on the left and me on the right, removing the tunicates from the rock wall.



All photos, complete with captions, here:
http://nwgeogirl.smugmug.com/gallery/2052016

We'll round up another batch of divers in a while to go back and continue the clean-up effort.

- Janna

[Old Crab]

Is scraping the tunicate off with the putty knife sufficient to remove the animal completely? No chance of regrowth? I'm just wondering if on subsequent visits to Sund Rock or other places if I should try removing this particular tunicate myself if it is spotted during a dive?

Since these things appear to be in dense communities, what is it's mode of reproduction?

I don't know if you can answer these questions, but if you can, please help us all to understand what if anything we can do to help?

Thanks,

Eric

[nwscubamom]

First off, it's illegal for you to remove, kill or take anything without specific permission from WDFW. We were asked to do this project by them, and given the proper clearance to do so.

We are working on a way to allow recreational divers the proper permitting to be able to remove them as they crop up - perhaps with training and passing of a test or something.

There are other tunicates that appear similar, and we can't just go around maiming or removing the wrong thing! Even some of the advanced fishwatchers are having problems ID'ing it.

Now, with that being said, the only tunicate that's clear and long and tubular at Sund Rock north wall, is the invasive tunicate.

Scraping it off is NOT sufficient to kill it. You must remove and collect the entire animal, or destroy it by squishing it.

It is a broadcast spawner. But since there's not much current in south hood canal, it would appear it can't broadcast too terribly far.

We'd really like to enlist the help of other divers for this - but we better make sure we do it properly so as to not make a bad reputation for the recreational diving community when working with WDFW and other agencies.

I'll keep you posted - and keep reminding me if you don't hear anything!

Best thing for now is if you see it, let me know - take a photo if possible.

- Janna

[Old Crab]

If it's capabilities to broadcast are not very good, the question arises, how did it get there in the first place?

Obviously there are a lot of good questions without any really good answers.

As far as removal, I meant removal and collection, but some animals are able to replicate themselves from very little organic material, and I was asking if the material left on the rock or whatever the tunicate attached itself to would be a danger regarding replication.

I am glad that you made me aware of the legalities of removal. I would rather do things correctly and legally.

Thanks you for your work. Please keep us posted if there is something we can do.

Thanks again,

Eric

[Sounder]

Janna,

What is the best method of "squishing" them you came up and how can one be sure to get the whole body? Do you have a clear picture of one that shows the "whole body?" Was the putty knife the best tool? If one was to scrape them off and leave them there (not bring them to the surface), would they re-attach somewhere else or continue "broadcasting?"

This is all hypothetical of course - but please do let us know when the "license to kill" is granted to divers and how to ensure the divers know exactly what needs to be taken and what should be left alone.

[nwscubamom]

I don't have time right this second to answer everything, but DO want to say I just got a call from the Puget Sound Action Team, and they are going to issue a permit or license to members of the REEF Advanced Assessment Team for now. Which is very exciting news indeed!!!

More later, sorry, got family coming for the weekend and they're HERE!

- Janna