marine invasives of kachemak bay, alaska

Kachemak BayResearch ReserveNational Estuarine Research Reserve System

Fostering stewardship through integrated research & education

KACHEMAK BAY RESEARCH RESERVEa unit of the

National Estuarine Research Reserve System

Marine Invasives of Concern for Kachemak Bay

-Escape from co-evolved diseases, parasites, predators, and competitors.

Characteristics of successful invaders:- Aggressive

- Broad ecological tolerances

- Generalist diet

- Mature quickly

Why Do Exotics Cause Problems?

#2 cause of extinction in the U.S.

GREEN CRAB• Mature very quickly

– Female can lay 200,000 eggs.

• Aggressive– Eat other crabs as large as themselves

• Voracious– Eat young crab– Very good at opening mussels and clams– Can eat 40 ½” clams per day

• Broad ecological tolerances– Wide range of salinities– Wide range of temperatures

What is a tunicate?• Tunicates named for their tunic, a tough fleshy shield that surrounds the barrel-shaped body

of the animal. • Closely related to vertebrates. This is evidenced by their larvae bilateral tadpole-like larvae w/

simple nerve cord. Larvae is free swimming with several vertebrate characteristics including; notochord, gill slits, dorsal nerve cord post anal tail Phylum chordata, subphylum Urochordata.

• Adult tunicates are sessile, larval tunicates float/swim in the water column.

solitary or colonial

Tunicates native to Alaska

Invasive Tunicates

-Fouling organisms (tunicates) -many originate in Asia

-Cause problems for marine infrastructure including boats and aquaculture

-Out-compete native benthic organisms-Difficult to remove

Botryllid Tunicates

Club Tunicates (Styela clava)

Club Tunicates (Styela clava)

Solitary Tunicates (Ciona savigney)

Colonial Tunicates (Didemnum sp.)

Colonial Tunicates (Didemnum sp.)

Shipping has contributedto ~80% of over 300 non-native species ofinvertebrates and algae introduced to North America

How are invasives getting here: Vectors

What do tunicates and green crab have in common?

• Planktonic stage in life history-Free floating in the water column and at the mercy

of tides and currents for at least part of their lives.

Ballast water discharge

-12 billion metric tons of ballast discharged annually

Volumes of ballast water discharged from ships in Alaska by country or sea of origin of the ballast water and exchange status of the ballast at discharge (NBIC data, July 1999 to December 2003).

Volumes of ballast water discharged by arrival port in Alaska (NBIC data, July 1999 to December 2003). Discharge for Valdez is segregated ballast data from ADEC.

But…Heavy shipping only began in AK began w/ start-up of Valdez terminal.

In Kachemak Bay…

Caprella mutica (2000, 2007) Botrylloides violaceus (2000)

E. GrayG. Ashton

What can we do?

• Top-down (prevention)– Regulation

-mid-ocean ballast exchange (currently coastwise, and tanker traffic exempt)

-ballast treatment (engineering challenges)

• Bottom-up (response)- Monitoring aimed at early detection/rapid response

Regulation: mid-ocean exchange

• Exchange coastal water with open ocean water 200 miles off shore– Coast wise traffic exempt– Oil tankers exempt– Safety exemption

Ballast water treatment

Ship-based treatment

Shore-based treatment

Early Detection Rapid Response

K-Bay Aquatic Invasive Monitoring

European green crab

Tunicates/fouling organisms

Green Crab Monitoring

Tunicates/fouling organisms

Settling platesPVC square, brick, line, tag

Deploy/retrieve/re-deploy quarterly: 1m from surface

Take Home Message:

1) Ballast water is a major vector for marine invasives, Alaska receives large quantities of untreated ballast water

2) Community monitoring aimed at early detection and rapid response is a the most immediate and valuable tool we have for combating marine invasives.