Wildlife of the Month - Yaldwyns triplefin
Anna Clague Jan 29, 2025
Notoclinops yaldwyni
Habitat - found around the North Island of New Zealand from subtidal areas to depths of about 20m most common in reef areas of broken rock, but nowhere common. Most triplefins live on or very close to the seabed, often in crevices or under cobbles or boulders, overhangs and walls among encrusting organisms.
Feeding – Mostly carnivorous.
Size - Its length is between 4 - 8cm.
Breeding habits - Spawning males become entirely orange with darker heads. Males establish territories of a few square metres and stay there for life. These contain nesting sites, which the male attracts females to. A female deposits her sticky eggs on a rock or in a shell, and the male immediately fertilises them with his sperm. Eggs are hemispherical and covered with numerous sticky threads that anchor them in the algae on the nesting sites. He then guards the eggs, defending them from predators and aerating them by wafting them with his fins. They hatch out 1–2 weeks later as well-developed larvae and join the plankton in the open sea. Triplefins only produce small numbers of young, but by protecting them through the vulnerable egg and early larval stages, their survival chances are greatly enhanced.
Defence – Camouflage plays the biggest role in their defence. Their habitat is covered with encrusting sponges, ascidians, bryozoans and sea anemones which provide a colourful background for the triplefins to blend into without difficulty.
Description - pale yellow-brown with a faint orange tinge to the head, and two or three rows of small black dots on the flanks. Scientists have found that each one has a unique colour pattern that lasts for years, perhaps for its lifetime, so individuals can be recognised by each other, and by us if we take the time to look for the subtle differences.
