Metabolism, Consumption Rates, and Scope for Growth of Porcelain Crab (Petrolisthes galathinus)

Porcelain crabs Petrolisthes galathinus (Bosc, 1802) can be found at high densities in oyster reefs. To examine effects of diet on metabolism, crabs (N = 32) were fed Artemia salina nauplii, mixed microalgae, or algal biofilm extract, or left unfed. Oxygen consumption, ammonia excretion, food consumption rate, and absorption efficiency were determined and scope for growth (SFG) was calculated. Oxygen consumption and food consumption rates were highest in crabs fed Artemia. The energy gained from mixed microalgae (47 ± 143 J h-1) and algal biofilm (265 ± 203 J h-1) was less than the energy gained from Artemia (9,963 ± 658 J h-1). Energy expenditures (oxygen consumption and ammonia excretion) suggest that P. galathinus has a low cost of routine metabolism and is able to consume a broad range of food resources including microalgae, benthic algae, and zooplankton. Consumption rates and SFG suggest that zooplankton, when present, are an important and valuable food source for porcelain crabs

Effects of Black Mangrove (Avicennia germinans) Expansion on Saltmarsh (Spartina alterniflora) Benthic Communities of the South Texas Coast

This study examined the effects of mangrove expansion on benthic communities. This was accomplished by examining plant composition, benthic community composition, and belowground root biomass. Two sites were examined: Corpus Christi Pass, Corpus Christi, TX where mangroves have become more common in the last decade and the Lower Laguna Madre, South Padre Island, TX where mangroves are well established. This research seeks to provide preliminary results to provide direction for future studies examining the interplay of S. alterniflora and A. germinans habitat on benthic communities. We hypothesize that the more established site of South Padre Island will have greater numbers of species than the newer communities of Corpus Christi, and that A. germinans habitats will have lower diversity of infaunal organisms than S. alterniflora habitats