Tide Pool Census 2009

Pacific Science Center’s Puget Sound Saltwater Tide Pool is home to animals collected under a Scientific Collection permit, issued by the Washington State Department of Fish and Wildlife (WSDFW). Without a permit, it is illegal to gather animals from beaches. With a permit, it is still Pacific Science Center’s responsibility to take animals correctly, gathering only what will be used and leaving the environment as intact as possible.



Each year we submit a list of all the animals we have collected in the last 12 months. In addition to being a requirement, this is a tool for us to assess how well different species do in the exhibit.

Below is a list of the animals collected in 2009 and the census of animals present at year’s end. This is a shorter version of the list we give the WSDFW, which gives details to genus or species level.

In some cases, there are more animals listed than we collected in 2009. The extras are animals collected in previous years – a sign that they are doing well in husbandry for that group.


Other animals are collected in substantial numbers and yet none are present at year’s end. In the case of shellfish, this is planned. Clams, barnacles and mussels are collected as food items for the sea stars. In other cases, such as “small assorted animals” we may still have the animals but cannot find them. Isopods, tiny anemones and small shrimp routinely work their way into our filter beds, where they live free from predators, and well nourished by the remnants of food left by other animals.



In some cases, though, the species is simply not doing well in our environment. Sand dollars, for example, have very specific habitat needs that are not met in our enclosure. This is an animal we are unlikely to collect in the future.


We had a very marked change in survival rates for anemones, urchins, and sea stars when we installed a hand rinse sink in 2003. Previously these animals could not be touched without rapid loss of health. Now they are highly resilient to touching. Contaminants on people’s hands were more harmful than the physical fact of being touched.


Hermit crabs are a special case because guests are allowed to handle them. Sadly, they did not experience the same jump in survival rates when we got the sink, and we are still working on ways to increase their longevity. The biggest risks to our hermit crabs seem to be, in order from highest to lowest: wandering into unsafe areas, fighting with each other, and rough handling by people. One way we have found to keep them healthy is to keep the population relatively low. An enclosure with twelve to 15 hermit crabs will remain stable, but one with twenty or more will experience losses until the number drops below 15.


Keeping these statistics is the best way for Animal Caretakers to track and assess our tidepool husbandry procedures.

-Sarah Moore, Life Sciences Manager