Between the sand and a wet place
Jetties are built to last
Jetties are built to prevent shipping channels from filling with sand and silt. The jetty stones also provide food and shelter for a variety of sea life such as algae, anemones, urchins, crabs and fish.
On the Texas coast, nearly the only rocky shores you'll find are man-made jetties. These structures, usually built in pairs, extend side-by-side into the water to form a channel and to keep the channel clear of sand bars and cross-currents.
Texas jetties are broadly triangular in shape. They're built on a base of 15- to 200-pound stones. Large stones-up to three tons each-make up the core and even larger cover stones weighing as much as 10 tons from a wide walkway on top.
It's all the same to the animals
Cracks and crevices between the jetty stones are home to seaweeds, crabs, sea anemones and the like. Most were swept in as larvae by the Gulf currents or came from oyster reefs in a bay. Some were transported from distant seas on ocean-going vessels.
Organisms on Texas jetties live in zones just as they do on natural rocky shores. Some stay above the high tide mark with the periwinkles, some thrive with the barnacles between the tide lines and some remain with the seaweeds below the lowest tides.