Mussels? Not like the ones in your arms!!!!
Like barnacles, mussels like to gather in dense clusters in the middle intertidal zone. They have blue-gray bodies that contrast against the sea star (starfish),their predators. Mussels filter plankton from the water they suck into their bodies. An average-sized mussel can filter up to three whole quarts of water in an hour!!!!! As they mature, they begin to secrete a string-like substance. It is called a byssal thread. Byssal threads hold the mussels firmly to rocks and other mussels. Once they are matured, the mussels are unable to regenerate their byssal thread. Some mussels can be quite beautiful!!!!
The California sea mussel, is found in the middle intertidal zone, usually in densely populated beds. All the mussels are either attached to the rock or to each other by byssal threads. If the mussels grow on top of each other, and are not directly attached to the rock, chunks of the mussels may be ripped from the beds by strong waves. Mussel beds are often large enough to be a home to many other creatures, like snails and worms. The scientific name for the California mussel is Mytilus californianus. The length is tops 7 inches. Mostly, in the intertidal zone, they are less than 5 in long. The outer covering of the shell is dark brown. It has a blue-gray layer beneath. The shell usually shows radiating ribs, especially around the outer edges. MacGinitie and MacGinitie (1968) once counted 625 California mussels in an area of about 20 cm (10 in.) square, and among then they found 4096 other creatures of 22 different species. A large mussel may process as much as 60 liters (16 gallons) of sea water in a full day of feeding.