Golden Sea Squirt

Overview

The Golden Sea Squirt (Polycarpa aurata) is a solitary, sessile tunicate frequently encountered on tropical coral reefs. Often referred to as the "ink-spot sea squirt" or "ox heart ascidian," this marine invertebrate is recognized for its vibrant, patterned appearance and its role as an efficient filter feeder within reef ecosystems.

Appearance

This species typically grows to a height of 5 to 15 cm and features a distinct, urn-shaped body. Its tough outer tunic is often marked with a striking combination of white, purple, and orange patches or lines. The interior, visible around the rim of its two siphons, is a vivid yellow or orange. The oral siphon, located at the top, is generally larger and more prominent than the atrial siphon found on the side.

Distribution & Habitat

Polycarpa aurata is native to the tropical Indo-West Pacific, with a range extending from the eastern Indian Ocean through the Coral Triangle to the western Pacific. It is commonly found attached to hard substrates in coral reef environments, often thriving in areas with moderate water movement.

Biology & Behavior

As a solitary filter feeder, it draws water through its branchial siphon to capture phytoplankton, bacteria, and other small organic particles. It is a simultaneous hermaphrodite that reproduces via broadcast spawning, releasing gametes into the water column. The resulting larvae are tadpole-like and free-swimming for a short duration before settling onto a substrate to undergo metamorphosis into their sessile adult form. While generally indifferent to divers, this species is sometimes preyed upon by specific nudibranchs.