ANIMAL DIET IN TEXAS SEAGRASS MEADOWS - DELTA-C-13 EVIDENCE FOR THE IMPORTANCE OF BENTHIC PLANTS

Over 340 animals from Texas estuarine seagrass meadows and the nearshore Gulf of Mexico were analysed for their stable carbon isotope ratios (δ13C values). Fish and shrimp collected in seagrass beds were significantly enriched in 13C by an average of 3.3 to 5.1‰ relative to comparable animals collected offshore. For one polychaete worm species, Diopatra cuprea, specimens collected in seagrass meadows were as much as 8.3‰ enriched in 13C relative to specimens collected in areas where phytoplankton were the major primary producers. The differences found in δ13C values are attributed to differences in diet. The data support the notion that in Texas bays, seagrasses and other benthic plants are significant sources of nutrition for juvenile shrimp and fish which inhabit these areas. © 1979.