Near the top of the Estuarine food web are various carnivores and omnivores. At the top of the food web are animals such as seals, sea lions, and even humans. Seals and sea lions are preyed upon by killer whales and the larger sharks, which sometimes enter estuaries and frequent the larger ones. Near the bottom of the food web you have animals such as shrimp, crabs, and fish such as Flounders. Some animals in this type of area graze on the larger plants within this area. Benik, or bottom-dwelling, and bottom-oriented organisms are other important links in Estuariene food chains and webs. Clams, for example, reside in the bottom sediments and feed on plankton and other organic matter by filtering it from the water. Oysters and mussels are other filter feeders.Deposit feeders, such as the various kinds of worms found in the estuary, move over and through bottom sediments where they find food deposited in or on the sediments. Shrimps, crabs, and other invertebrates are well adapted to bottom feeding, as are many of the estuarine fishes, such as Sculpin, flounder, sole, and sturgeon.