rgv reef spi

Fixing Marine Harm

The marine environment, and hence the food chain on the continental shelf is negatively impacted by multiple stressors. Round up the usual suspects; habitat loss from bottom trawl fishing, chemicals, including the reproductive hormone disruptor BPA from plastics as they degrade concentrating in fish tissue up the food chain, mercury from dirty coal burned in foreign countries concentrating in apex predators, introduced exotics like Lionfish, new species moving north like mangroves trees and mangrove snapper as waters warm, over fishing, occasionally poor fisheries management by State and Federal fisheries management, and intense overfishing of the highly migratory species particularly the tunas, inside and outside US waters. We see this in greatly reduced fish numbers. Ask any Old Salt or fisheries biologist; fish populations are small fractions seen in earlier days.

 

Some of these things we can’t change, particularly on just a few years timeframe.  The good news is that Marine Biologists are coming to understand what terrestrial biologists have known for a long time. Habitat is the key building block for any wild population.  And that many of our species, particularly juveniles are habitat limited.  The primary habitat degradation on the Gulf bottom is the loss of low relief reef, small softball to basketball sized scattered patchy materials. These small diffuse caliche clumps, dirt clods, clay balls, and loosely cemented sand clods formed on land, beach and lagoon and were drowned as the coastal plain flooded after the end of the last ice age around 40,000 years ago.  The remnants can still be found near high relief reef where nets and chains can’t sweep.  The destruction of low relief reef severly impacts the productivity of the foundation of the food chain and denudes the bottom of the cover that a myriad of small or juvenile fish must have to survive.  For 40 years the Texas shrimp fleet drug a tickler chain strung between net opening doors (planning surfaces) across over 1,000,000 acres of the bottom every night. According to the State of Texas’ Wildlife Management Plan, if a portion of bottom is trawled one time it’s productivity may come back in 6 months to a few years, if it is trawled multiple times, it’s productivity may come back in years, decades or never. This is the loss of the low relief reef, the nursery reef, the bottom of the food chain. No house, no groceries, no fish.

 

This, we can do something about. Build low relief reef.  RGV Reef contains the first industrial scale low relief reef in the world; 20,000,000 pounds of concrete railroad ties, broken concrete and 90,000 cinderblocks in the low relief portions of the reef, the remaining 26,000,000 pounds comprise mid and high relief reef, mostly deployed on the boundaries.  It’s a de-facto marine protected area. The large concrete structures deployed around it’s 6 mile perimeter exclude bottom trawls. Multitudes of fish have a small rock or complex crevice to dodge around or hide within. There is a place to get out of the unceasing current and convert food into body mass.  Ambush cover for feeding. These small structures generate current vortices, disorienting prey and pulling organic matter out of the passing water column, generating just enough food that microbe colonies can form, feeding marine worms, crabs, crustaceans and mud sifting fish.  Hard substrate provides anchorage for algae and hard-shelled filter feeders.

 

Most of the fish using low relief reef stay small all their life, but some snappers and groupers grow larger, and they need a new homes that fit their size as they grow and mature, and RGV reef also contains mid and high relief reef (up to 32 feet tall) to provide habitat for a multitude of fish specie through their life stages.

This is how friends of RGB reef is ameliorating past and anticipating future harm to the marine environment. This is how to put fish back in the Gulf.

Learn how to Get Involved.

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