Orca

Orca

Friday, October 22, 2010

The Eccentric Sand Dollar – Dendraster excentricus

Before moving to South Puget Sound, I had never seen a living sand dollar. Sure, I saw the bleached-white sand dollar with the “star” on its shell lying on the beach, but it never occurred to me that the animal lived somewhere.

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It turns out that on some of the sandy beaches in South Puget Sound, there are areas of living sand dollars packed in very high densities. They generally embed a part of their shell in the sand (to keep them from being swept away by waves and action of the currents ).

Sand dollars feed on diatoms (phytoplankton) and detritus (organic debris). They can live to be 13 years old. They are also part of the food web and may become the meal of the starry flounder or the pink short-spined sea star.

As part of the marine habitat, these beds of sand dollars provide effective shelter for other creatures. For example, small juvenile Dungeness crabs find protection from predators by hiding between and under sand dollars.

So why are we talking about sand dollars? Remember that they are found on sandy beaches in the lower part of the inter-tidal zone. This is the same area where geoduck aquaculture takes place and shellfish people do not like sand dollars. Why? Well, they get in the way of all those PVC tubes that are stomped into the ground.

The shellfish industry has classified the sand dollar as a “pest”. Here is what industry has to say:

Sand dollars encroach upon geoduck growing ground such that the ground becomes nearly impenetrable … Sand dollars can prohibit insertion of geoduck protection devices, such as tubes. In addition, if planted areas become covered with sand dollars, it can be difficult for geoduck siphons to reach the surface of the sand (to feed), and it can also impact geoduck harvest activities.

Note that the shellfish farmer, being a superior species, characterizes the sand dollar as the encroacher. The sand dollar has been around for centuries while geoduck aquaculture has been around for maybe 15 years. Such arrogance is so sad.

How does geoduck aquaculture deal with the sand dollar “pest”? Well, they “relocate” them. Recently a resident living on the shoreline experienced this process first-hand. This person observed shellfish workers with shovels and wheelbarrows, digging up sand dollars and dumping them high on the beach (generally above the high-tide mark).

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The resident was concerned by this activity and asked several state and county agencies if it was legal. After much bureaucratic runaround, and the all-too typical excuse that “it’s not our problem”, it was finally decided that shellfish farmers could do whatever they pleased, that “they police themselves.”

Questions were sent to UW scientists about the efficacy of “relocating” sand dollars. The scientists responded that to their knowledge no research has ever been published that addressed the issue. They went further and stated that is was unlikely that relocation would work, especially when the animals were placed high on the shoreline on gravel, not sand.

The Washington State Department of Fish and Wildlife, the agency that is tasked with enforcing “take limits” on fish, shellfish, and other creatures from State waters and shorelines did react however. They changed the rule so that the “take limit” for sand dollars would be changed to zero (see WAC 220-56-130). That’s right; no one is allowed to remove a single living sand dollar from any beach in the State of Washington. When asked if that applied to the shellfish farmer too, their response was they had no jurisdiction regarding the aquaculture industry (see RCW 77.12.047(3))and therefore the limit did not apply to them.

So neither you nor I can remove a single living sand dollar (a good thing by the way) while the shellfish industry can remove all they want without limits – such a sad state of affairs.

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