Friday, August 22, 2014

Return of the Sea Grasses

Guides and frequent anglers on the lower Laguna Madre often comment on macro-level changes that they have observed over the years. And what I find is that we are often like the 10 blind men and the elephant. That is, each of us is "touching" one facet of the whole, and describing the whole in terms of their narrow experience. It's human nature to extrapolate on what we see and experience, thereby projecting a highly subjective view upon a rather complex and multifaceted whole.

There are several observations that are factual, however. The seagrasses took a huge hit from the fresh water inflows about five seasons ago. Over 30 inches of rain fell in the Mexican mountains to the south of us, and the water poured into the Rio Grande River watershed over the course about six weeks. The Arroyo Colorado is part of the flood diversion system in the Rio Grande Valley, which is designed to protect riverside communities on both sides of the border. But we will all remember the sights and sounds of the smelly and turbid water that literally raced overland into Payton's bay and created 5-foot troughs in the Arroyo Colorado. Interestingly, we were still able to find clear water to the south of the mouth of the Arroyo that summer, and did fairly well.

The impact on the bay was immediate and long-lasting, especially in areas north of the mouth of the Arroyo. Between the mouth and Port Mansfield, huge amounts of rainwater flooded the bay, and brought carp and gar and alligator into otherwise hypersaline areas. It was a strange and disturbing experience, but the clear water returned after a few weeks of runoff. Unfortunately, perhaps, the seagrasses were decimated in those areas, and didn't recover until…well, really, not until this year, by my estimation (keep in mind that I am a blind man, too!). The odd thing was that some areas that were normally devoid of seagrass--like the sand, and areas south of the mouth--became seagrass nurseries, and still have more grass than they ever did. And now, finally, Payton's Bay looks like a manicured lawn beneath a few inches of clear water. The shoal grass, especially, is thick and unbroken except for prop cuts. The ducks will take their toll on the grasses this fall and winter, as they pluck the grass from the bottom in their search for food, but next year should feature an even thicker seagrass recovery.

Before the flood, turtle grass was replacing the shoal grass as the dominant grass in the lower Laguna. Biologists referred to this phenomenon as a the end point of a long process, much like a "climax woodland." However, the turtle grass has become scarce in the aftermath of the flood. It's as if the flood reset the clock on seagrass development, and created a new opening for shoal grass, which is wonderful habitat for juvenile crabs and shrimp. So perhaps the flood was a good thing, similar to the fires in Yellowstone Park--immediately disturbing and unsightly, but purposeful from the standpoint the big picture.

Another observation, which apparently is false, is that the redfish have declined. Not so, say the Texas Parks and Wildlife biologists. I have to agree that I've not noticed any decline in redfish in the back lagoons. If the reds are not in decline, then why do reputable guides and veteran anglers say that they are diminished in number? It's probably because these observations are based on "sampling" in the same areas year after year. And the fact of the matter is that the reds will move from place to place in search of food. Some areas, such as the lagoon just north of the mouth of the Arroyo (the Mud Hole) can wax and wane like the moon from season to season. Indeed, the Mud Hole can be the highest producing venue one year, and yet be a consistent disappointment the next, probably because of the movements of the shrimp hatch from back lagoons into the Intracoastal on their way to the Gulf. I have waded in the Mud Hole on occasion, to find so many shrimp jumping ahead of me that I could feed my family with a dip net. But that phenomenon isn't reliable. Anglers typically base their conclusions on comparing the fish population in the same area from visit to visit without taking into account changes in food availability, tide, etc. T'is human to deny the larger truth.

Another observation, which is undeniably true is that the big trout population has exploded. This is in spite of the tendency of anglers to hammer them with live croaker--a method that biologists say they cannot resist because croaker are natural enemies that eat trout eggs. Even guides who would fly fish all the time if their client population would support it, will turn to croaker for the purposes of providing "instant success" to anglers who don't know the first thing about these great predators and their rythmns. I may sound cynical, and I am. Still, the trout populations have resisted over-predation from opportunistic anglers, and with the help of the Texas Parks and Wildlife, I have hopes that this greatest fish of the mother lagoon will continue to thrive.

What do you think has changed about the bay? Do you think your observations are objective, or based on "touching one part of the elephant?" Let us know.

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