Hooded Nudibranch Mating Season Begins

Late summer each year is the time Hooded nudibranch (Melibe leonina) migrate from deep water to the shallow eelgrass beds of Puget Sound to mate and lay eggs. During peak times, they can be seen by the thousands at dive sites such as Edmonds Underwater park and Redondo Beach. They can also be found as far north as Alaska and south to California.

Hooded nudibranch by David Sisson

Hooded nudibranch by David Sisson

Hooded nudibranch can reach up to 4” long with a round oral hood that is used to catch prey.  Their bodies are translucent, with a pale white, yellow, orange, or greenish tint and give off a sweet smell when taken out of water. During reproductive season in the late summer, they congregate in shallow eelgrass (genus Zostera) habitat, clinging to eelgrass blades. They are carnivorous, eating small fish & invertribrates such as copepods and zooplankton. Hooded nudibranch are in turn preyed upon by larger fish, Northern kelp crabs, and sea stars.

Hooded nudibranch are hermaphrodites, meaning they have both male and female reproductive organs. To reproduce, two Hooded nudibranch simply fertilize each others eggs. After laying their eggs, the Hooded nudibranch die off, leaving behind a new generation.

The best time for divers to see Hooded nudibranch is at the end of the dive, during a safety stop. Hover over the eelgrass bed at around 15’ and look down, inspecting the eelgrass for Hooded nudibranch clinging to the blades.

Spring in Puget Sound

Puget Sound in the Spring… from Laura James on Vimeo.

Seattle videographer Laura James has put together this very fun video of life in Puget Sound over at one of our favorite dive sites, Alki Beach Junk Yard. So many fish and invertebrates in the video, my favorites were Striped nudibranch, Grunt sculpin, and a juvenile Wolf eel.

Are you ready to go diving and see all the amazing sea life here in Seattle?

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Hooded Nudibranch Season

Early fall brings the arrival of an unusual Pacific Northwest creature, Hooded nudibranch, (Melibe leonina).

Hooded nudibranch (Melibe leonina) by Eva Funderburgh Hollis

Hooded nudibranch (Melibe leonina) by Eva Funderburgh Hollis

Hooded nudibranch arrive for a few weeks in September/October in large numbers, clinging to eel grass and kelp, and feeding on small larva and small invertebrates. They catch their prey by extending their hood out and down, wrapping it around the prey, then eat eating it whole. When in danger, Hooded nudibranch can swim long distances by lateral-twisting movements.

During fall, we can sometimes see hundreds of Hooded nudibranch on a single dive. Good bets for dive sites include Redondo Beach and Seacrest Park. At the end of the dive, divers can use their safety stop to observe the Hooded nudibranch in the shallows. Ready to see the many Hooded nudibranch for yourself? Book your guided dive tour today.