Botrylloid

This colonial tunicate forms encrusting mats on hard substrates such as pier pilings, dock floats, rocky intertidal and subtidal surfaces, and the hulls of boats, often spreading in irregular lobes of orange, red, or yellowish coloration with visible star-shaped or elongated zooid systems embedded in a shared tunic. Look for the gelatinous, rubbery texture and the characteristic pattern of individual zooids arranged in sinuous or branching rows sharing common atrial openings, which distinguishes it from solitary ascidians nearby. It can be found year-round but colonies tend to be most conspicuous and actively growing in warmer months; low tide exposures in sheltered harbors and marinas offer the easiest close-up views without the need for diving equipment.