Initial effects of opening Packery Channel on estuarine macrofauna in Corpus Christi Bay, Texas

Packery Channel is part of a complex of storm washover channels which in the past have opened intermittently during the passage of large storms and strong north fronts. However since dredging of the Aransas Pass inlet began in 1912, water diversion to Aransas Pass has in part caused Packery Channel to remain closed. A before versus after, control versus impact (BACI) design has been implemented to assess the effects of reopening Packery Channel on water quality and estuarine macrofauna in Mollie Beattie Coastal Habitat Community (MBCHC), Corpus Christi Bay. Two deep (approx. 1 m below m.s.l.) and two shallow (approx. 0.2 m below m.s.l.) stations were sampled monthly for physical and biological characteristics at both control and impact sites. Sampling occurred between November 2003 and December 2005. There has been little impact on the macrofaunal community composition from the permanent opening of Packery Channel in July 2005. There is more difference in community composition between deep and shallow stations than between either before and after, or control and impact sites. ANOVA tests show that there have been no significant changes in abundance, biomass, N1 diversity or average taxonomic distinctness from the opening of Packery Channel. Salinity was reduced at MBCHC and fluctuated in a diurnal pattern after the opening of Packery Channel, which is related to increased tidal exchange with the Gulf of Mexico. Apart from salinity, Packery Channel has caused little hydrographic change in MBCHC since opening in July 2005. Future macrofaunal changes may be seen at times of the year when salinity is normally lower at MBCHC or after seasonal recruitment events in months not observed in this study.