Invasive Tunicates

Report it

If you think you have found an aquatic invasive species:

do not return the species to the water
take photos
note:
- the exact location (GPS coordinates)
- the observation date
- identifying features
contact us to report it

Learn about invasive tunicates, including types of tunicates, location, habitat, impacts and our response.

Types of invasive tunicates

Tunicates are small marine invertebrates that spend most of their lives attached to an underwater surface. They are named “tunicate” for their thick outer layer resembling a tunic. They are water-filled sacs that filter feed by drawing in and expelling water through tubular siphons. Several invasive species of tunicates threaten our waters. They can be spread by ocean currents but are mainly moved from place to place by human activities.

Tunicates can be either solitary or colonial. Both can reproduce sexually, producing free swimming larvae. Colonial tunicates can also form new colonies when pieces break off and drift to a new area and become attached there. Colonial tunicates form gelatinous mats or hanging lobes that may cover almost anything underwater. The colonies are made up of many individual organisms, called zooids, embedded in a common matrix, whereas, solitary tunicates operate as separate individuals. Though solitary tunicates grow individually they can form very dense groups.

Invasive solitary tunicates in Canada include:

Species of colonial invasive tunicates include:

If you think you have seen an invasive tunicate, report it.

Where is the group invasive?

Invasive tunicates have been found in coastal waters of the Canadian Pacific and Atlantic Oceans.

Distribution

More information on the distribution ranges of each invasive tunicate species can be found following the links to their individual pages above.

Habitat

Tunicates are typically found:

in sheltered areas and attached to:

rocks
other animals
eelgrass or seaweeds

on man-made structures, such as:

ropes
buoys
anchors
boats
wharf pilings
floating docks
fishing gear
aquaculture gear

Impacts

The presence of invasive tunicates can lead to several negative impacts on indigenous aquatic communities, the aquaculture industry and many other users of aquatic resources. The following are examples of potential impacts:

may outcompete native organisms for food and space
threatens aquaculture, fishing, and other coastal activities
can increase drag on vessels, slowing them down and increasing fuel costs
increases the weight of gear, causing work to be more demanding
increases the operating costs for shellfish producers and processors
may reduce size and condition of commercially raised species (e.g. mussels)

Response

We collaborate in on-going efforts to detect and control invasive tunicates with groups including academia, Indigenous Groups, and industry. Monitoring efforts allow for early detection of new invasive species and to determine the spread, establishment and spatial distribution of existing ones.