Oyster Drills as introduced species

While aquaculture species such as the Japanese oyster, Crassostrea gigas, were introduced intentionally, they also brought with them many undesirable hitchhikers, including oyster drills. Oyster drills are small predatory snails that use there drill to bore in small shellfish. These shelfsih are then destroyed, and Oyster drills are most prevelently taking out the american oyster. Not only does this hurt the food web, but also the local economy.

Predators of Estuaries

Bull Sharks are a common predator of hardhead (Arius felis) and gafftopsail (Barge marinus) catfish.



The Bonnethead Shark is a common predator of Swimming crabs, octopuses, squid, fishes, and shrimp



The Great Blue Heron is a common predator of estuaries, eating mostly small fish and amphibians like frogs.

Competitive

Many types of snails and oysters are only able to survive on hard surfaces like rocks. This is a stable area where they can be safe and have available food. The snails and oysters compete food available space, and when one dies many others compete for the new area. 

Parasitism

oysters are very common in Estuaries. Boring spongers, a type of sponges found in estuaries, are a parasite. They will drill trough the shell of the oyster, but will not actually eat the oyster. However, this process is known to kill the oyster.

Commensalism

Sharks are very fast swimming creatures. Sometimes, small fish are able to attach to the otter for a short period of time. This doesn't affect the shark, however the fish is able to get a quick ride to somewhere whereas normally it would take longer and it would have no protection.

Mutualism

In estuaries, sea anemones and clown fish are able to help each other. The sea anemones providers shelter for the clown fish, as most fish are prone the the sting of sea anemones. When the sea anemone stings a fish, the clown fish is able to eat the remains, providing food for the clown fish and cleaning the area of the sea anemone. Clown fish can even attract food to the sea anemone by having other fish notices its bright coloration. 

Biotic and Abiotic Features

Some biotic features would be Bristle Grass (Setaria megaphylla) or Irrawaddy Dolphins (Orcaella brevirostris).  Abiotic Features would be the Precipitation, that can vary between 100mm and 1000m. Another abiotic feature is temperature. Like precipitation, estuaries are incredibly varied in temperatures. The Amazon estuary in the summer can reach 100 degrees Fahrenheit while an Alaskan estuary in the winter may be -30 degrees Fahrenheit.