Texas built 1,650-acre underwater reef; sonar later found 24.4 tonnes of fish

A collection of old boats, concrete blocks and railroad ties may not sound like the beginning of a thriving marine habitat. But off the Texas coast, these man-made structures have become part of a sprawling underwater reef where researchers have now estimated nearly 24.4 tonnes of fish biomass. A study published in PLOS One examined the 1,650-acre Rio Grande Valley Reef using sonar surveys and found that fish were not spread evenly across the site. Instead, some structures attracted considerably more biomass than others, with sunken boats recording the highest average biomass among the structure types studied.How the artificial reef took shapeThe Rio Grande Valley Reef lies roughly 10 nautical miles offshore from South Padre Island. It is part of Texas' artificial reef programme, which uses suitable materials to create hard-bottom habitat in areas where the seafloor is otherwise dominated by soft sediment.