My cousin and his better half went driving down to Padre Island National Seashore near Corpus Christi to do some beach combing and they spotted a four foot alligator on the shore. Interesting since alligator gar normally reside in freshwater lakes, bayous, canals and rivers.
I have heard of folks running into some in brackish or salt water. It is possible that when there is a good amount of rain (as was had recently in the area) that they may move out into the ocean and bays when the salinity levels drop. However, they can't survive there very long.
My cousin indicated the gar was freshly dead. On a side note, for those that haven't eaten gar before, the flesh is white and firm and when fried tastes a lot like chicken breast. The hard part is cutting through the armor plating hide. By the way, my cousin left the fish on the beach.