On Or In the Bottom by Herb Gruenhagen

Sandy beaches and mudflats shift with the waves and currents along our coastlines. It takes practice to find and photograph these animals that call sand and mud their home. Large plants find the shifting sand difficult to cope with so you will find only a few plants. The sand is composed of quartz grains, black volcanic sand and animal skeletons. Long-shore currents slowly move beach sands parallel to the shore. This is why you will sometimes find large populations of tiny clams one day, the next month, nothing.

The beach sand animal populations are also influenced by the water temperature so you will see seasonal blooms. Nudibranchs are good examples since they are an annual species, meaning that they only have a one year life-span. Some days we can find many examples and many different kinds, other days, only a few. Mud and sand grain size also influence the kinds of animals that you will find. Certain types of polychaete worms only use certain size sand grains to build their tubes, for example. In the few places were there are algae you will find the bay pipefishes and other juvenile kelp fishes.

In the near shore, beach hoppers prefer to burrow in the sand during the day, but come out at night. The sand and mud can be a very different place at night. Many crabs and shrimps only come out at night to feed. The octopus also comes out at night to feed on the now unprotected crabs.

In the middle beach area you will find evidence of lugworms. In the early spring we found big baggy brown sacs in the sand. These sacs are related to lugworms and their reproduction cycle. It is too bad we don't have x-ray vision sometimes. There are many burrows housing worms, crabs and shrimp under the sand forming huge thriving communities. 

In the sand there are the sand dollar communities. Sand dollars and heart urchins ingest the sand and filter out the organic detritus. Other filer feeders consist of the lovely sea pansy and sea pens.

On the beach, children pick up some colorful clams. These clams form large communities in the sand and exhibit a rhythmic behavior that corresponds to the tidal cycle. This innate sense of time is called a biological clock. The leopard shark comes in very close to the warm summer-time water of the shallow sandy shoreline to mate. The round stingray and butterfly ray can also be found in large areas of sand and often very close to shore.

The clean sandy shore line will often degrade into mud where you will find large clam siphons, larger crabs such as the sheep crab, sea stars, juvenile rockfishes fishes, and borrowing fishes such as the famous sarcastic fringehead. Now we are entering the deeper areas of the canyon and there are more surprises at every corner. At the deeper deeps, there are large tube anemones, gorgonian corals and the larger rockfishes and big halibut. In the valleys you will find cabezon fishes sometimes with their fluorescent green egg masses. Painted greenlings are on the muddy walls along with the brown rockfish and even an occasional wolf eel.

Beach sand and mud marine animal communities are composed of a very diverse collection of animals, as you can now understand. You just have to get out there and look and see for yourself to enjoy all the varied forms. Photographing sandy animals requires great skill with the strobe light so as not to get any backscatter in your image. Just remember to get close to your subject and do not light the water between the camera lens and your subject.