The sandy sea floor harbors a diverse and uniquely adapted array of organisms that are part of an ecologically important community.  The fish and invertebrates living on the shallow sandy sea floor within the Los Angeles Harbor (9-18 m/5-10 fathoms/30-60 ft deep) will be sampled using a net called an otter trawl.  Organisms living at different depths can differ radically from shallow water species in terms of both biology and behavior.  To compare animals from two sandy bottom habitats of very different depths, the otter trawl is used to collect organisms from about 90 m (50 fathoms/ 300 ft) deep near the White Point outfall (an outfall from a sewage plant in Carson).