single-celled organisms that live in the tissue of corals and provide energy to the corals (M2)


the distribution of plants and animals according to environmental conditions, generally in a pattern of vertical banding (M3)


in traditional Polynesian voyaging, the person who navigates the canoe using no instruments (M1)

Visual strip-transect search

a research method for studying fish in which two divers swim side-by-side down either side of a transect, counting all fishes seen within a specified corridor (M4)

Trophic levels

pathways and levels through which nutrients and energy flow between organisms (M2)


a sample area, usually in the form of a long, continuous strip; in coral reef monitoring, often a marked line across the reef (M4, M5)

Tertiary consumers

predators that feed on secondary consumers and comprise the fourth trophic level of marine food webs (M2)

Target screen

a destination area set in charting a navigational course in which the highest points of the destination islands will be visible (M1)