Gulf waters reach clear to the tropics
The Gulf of Mexico stretches from the barrier islands of Texas across the continental shelf to the horizon and beyond. Under this expanse of water, the bottom is mostly sandy mud, washed into the Gulf by coastal rives such as the Mississippi and Rio Grande.
The rivers also carry nutrients which settle to the bottom of the Gulf. These nutrients feed both the animals that live buried in the mud and those that live on the few rockly outcrops and submerged banks that are the only hard bottoms off the coast of Texas.
On the borderline
The Gulf of Mexico is bordered by temperate Texas on one side and tropical Mexico on another. These two climates meet each other and overlap somewhere in the offshore waters of the Gulf.
From time to time when the currents are right and the winters mild, parrotfish, angelfish, spiny lobsters and other usually tropical animals are found in the Gulf off the Texas coast.