How Stable the Starfish?

In response to The Daily Post’s writing prompt: “Finite Creatures.”

This post is the Day 11 assignment for my Blogging 101 class.

Sea stars, Pisaster ochraceus
Sea stars, Pisaster ochraceus, a keystone species

For decades we have known that starfish, like Pisaster ochraceus, are potent predators that play a big role, directly or indirectly, in maintaining the familiar communities of plants and animals in the intertidal zones. In Sea Stars and Sand Dollars I said it like this:  

“The P. ochraceus association with mussels, barnacles and gastropods is well known and well studied.  P. ochraceus is an effective predator that can shape the distributional patterns of it’s prey and other species. Species with this kind of profound effect have been called keystone species. If you want to learn about this concept a good place to start is Paine 1966. A good review and experimental test of Paine’s ideas almost 30 years later is given by Menge et al., 1994. The star of the show is P. ochraceus…”

It’s been this way as far as anyone can remember, and the predictable intertidal zones and regular occurrence of their inhabitants, have seemed more or less immutable, but that’s naive, and neither the starfish nor Paine’s wonderful system is infinite.

June 14, 2014
Wasting syndrome, P. ochraceus

In early 2013 we started to hear a lot about sea star wasting syndrome, a disease that has significantly reduced starfish of all along the Pacific coast, USA, and beyond. I described the progression of Pisaster ochraceus decline at a site in northern Oregon in A Peek at Pisaster After Two Years of Sea Star Wasting Syndrome. Here, there has been little Pisaster activity for well over a year. Pisaster seems to be slowly bouncing back, but it’s going to be a while before we see them at abundances we are used to. Losing a keystone predator in any ecosystem is a big deal. What changes are in store for the rocky intertidal?