Most divers never see this huge, 15-inch-long marine snail except in the roadside shell stands. Hawai‘i has the largest helmet shells in the world, and I have seen divers swim right over them only two feet away and not know they are there. When pu puhi is crawling on the sandy sea floor the top side of its shell looks just like a rock covered in a thin layer of sand. The top of the shell is brown and knobby and perfectly camouflages to its sea floor surroundings. This is good because this important reef creature is often collected and sold in shell shops where people break off the tip of the shell and use it as a blowing horn.
Pu puhi feeds on sea urchins that are buried in the sand. The brightly polished base of the shell acts as a platform resting on the sand and the inside foot of the shell comes out and drills into the sand finding buried urchins to feed on. The horned helmet shell helps keep the urchin populations in balance which keeps the entire reef in balance. If the urchin population explodes they can wipe out certain species of limu that are important for the sea turtles and other marine creatures to feed on. Like most things in the sea they evolved to live in harmony with the other sea creatures which creates a healthy balance between predators and prey.
If one removes one of these beautiful giant shells they may be upsetting the balance of the entire reef system in that area and that is why it is so important to never take live shells out of the sea. Back in old times here in Hawai‘i there were a lot of pu puhi out on the reef and very few people so taking a shell or two to use as a blowing horn was fine but nowadays removing hundreds of these amazing creatures from the reef to sell in shell stores is extremely harmful to the entire marine ecosystem.
In places like the Bahamas where they remove and eat helmet shells and similar conch shells the entire reef ecosystem has been changed which affects everyone who enjoys the sea or lives off of the ocean for food. The good thing is these giant marine snails grow well in a captive breeding setting in calm bays and are now being farmed instead of being removed off of the reef and the wild shells are starting to return. If you choose to purchase a shell from a store make sure it has been captive produced and not wild caught!
You can see pu puhi in action in my underwater educational movie “The World’s Guide To Hawaiian Reef Creatures” up on my web at www.underwater2web.com. We have a whole series of online marine life educational movies now to be used in Hawaiian schools and also to educate tourists that visit Hawai‘i. You can follow my weekly marine life educational post up on my Instagram that is under my name.
Terry Lilley is a marine biologist living in Hanalei and co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to www.reefguardianshawaii.org.
Source: The Garden Island