Aquatic invasive species

INVASIVE TUNICATES

Tunicates, or sea squirts, are small marine animals that spend most of their lives attached to an underwater substrate. They are named "tunicate" for their thick skin resembling a tunic. They feed by filtering seawater through their siphons.

Several invasive species of tunicates threaten our waters. They are found on the Atlantic and Pacific coasts and can be spread by ocean currents as well as by human activities.

 

HABITAT

Didemnum - G. King
Didemnum
G. King
Tunicates are typically found in sheltered areas, attached to rocks, eelgrass, seaweeds, other animals or on man-made structures such as boat hulls, buoys, ropes, anchors, floating docks, aquaculture gear and wharf pilings.
Golden Star - R.Gidney; Didemnum - D. Blackwood
   UP : Golden Star - R.Gidney
Down : Didemnum - D. Blackwood

SOLITARY OR COLONIAL

Solitary and colonial tunicates - A. Epelbaum
Solitary and colonial tunicates
A. Epelbaum

Tunicates can be either solitary or colonial. Several colonial species form gelatinous mats that may cover almost anything underwater.

The colonies are made up of many individual organisms, called zooids, embedded in a common matrix.

For certain species, colonies can form folds and lobes that hang down in the water.

ECOLOGICAL AND ECONOMIC IMPACTS

  • May outcompete other organisms for food and space, thereby altering the natural community dynamics;
  • Threaten aquaculture, fishing and other coastal and offshore activities;
  • Increase the weight of the aquaculture cultivation gear, causing work to be more demanding;
  • Increase the operating costs for shellfish producers and processors.
Clubbed tunicate  - DFO  C. McKindsey
Clubbed tunicate
DFO C. McKindsey

WHAT YOU CAN DO