A marine mystery for the uninitiated

sea pork IMG_0159_1©Maria de Bruyn resFor my friends who know me as a staunch vegetarian, it might come as a surprise that I have become fascinated with sea pork (Aplidium stellatum). It is one of the most colorful yet odd forms of sea life I have personally encountered.

My introduction to this interesting creature occurred on Topsail Island in May 2013, where I found two specimens on the beach.

Sea pork IMG_7631© Maria de Bruynres sea pork IMG_7029© Maria de Bruyn

sea pork IMG_0136_1©Maria de Bruyn res

Then, on 19 January this year, I saw some sea pork again – oodles and oodles of it, actually, accompanied by sea liver as well!

So what is sea pork, you might ask? Each blob or globule is a tunicate: an invertebrate animal that can be one individual or a collection of individuals that reproduce to form colonies measuring an inch or more in height. The larvae look a bit like tadpoles until they join to create the colonies, living in water-filled sac-like structures that are rubbery or cartilaginous to the touch.

sea pork IMG_0152_1©Maria de Bruyn ressea pork IMG_0161_1©Maria de Bruyn resThese creatures are marine filter feeders. The sacs have two tubular siphons, through which water is drawn in and expelled during feeding and respiration. The zooids extract nutrients from the water.

What are zooids? These are the reddish-colored individuals that form a colony. You can see them in circular groups under the sac’s tunic, which varies in color, including creamy pinks, orange, green, red, lavender, deep purple and black. The colonies can become large, spreading 12 inches or more and weighing up to 10 pounds.

sea pork IMG_0153_1©Maria de Bruyn res sea pork IMG_0154_1©Maria de Bruyn res
Sea pork was given this name because the rubbery tunic bleaches to white, resembling salt pork or fatback, after the colony dies. While alive, sea pork is eaten by bottom-dwelling fish, sharks and skates.

sea pork IMG_0144_1©Maria de Bruyn res sea pork IMG_0190_1©Maria de Bruyn res
Apparently other creatures also find a home on sea pork, including barnacles and sea whips (Leptogorgia).

Sea pork with barnacle IMG_0141_1©Maria de Bruyn ressea pork and sea whip IMG_0126_1©Maria de Bruyn resSea liver (Eudistoma hepaticum) looks similar to sea pork, but the tunic is softer. It is said to feel slimy in comparison to sea pork but the consistency seemed the same to me.

sea liver IMG_0186_1©Maria de Bruyn ressea pork IMG_0147_1©Maria de Bruyn resHowever, the difference may be more apparent when they are in their natural habitat, fastened to the sea floor or some other substrate rather than torn loose from their underground homes and cast ashore.

I spent some time throwing live sea pork back into the ocean until I came on a stretch of beach that was covered with these blobs; I hoped the tide would come in and carry the creatures back to their watery homes where they might continue their colonial lives.

 

unknown alga IMG_0177_1©Maria de Bruyn resI now have a query in to a Smithsonian marine botanist for help in identifying this organism. A scientist at the North Carolina Museum of Natural Sciences ruled it out as a marine invertebrate and said he and colleagues surmised it is a marine alga. Suggested IDs are welcome!

 

5 thoughts on “A marine mystery for the uninitiated

  1. This is very interesting! I have never heard or known about the sea pork before. Do they live all over the world? When I go to the beach next time, I have to look for them.

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  2. Glad you enjoyed it, Malai – my faithful reader! My understanding is that they live in all the oceans of the world. I had not seen them until last year but perhaps I wasn’t paying sufficient attention before. At Huntington Beach, however, you couldn’t miss them. They had washed ashore with the tide by the dozens; one stretch of beach was completely “littered” with them!

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