Abstract

Rangia cuneata, are brackish water clams that act as key indicator species of freshwater inflow in Texas coastal watersheds. They are more abundant at the mouth of rivers where they enter into bays. The Mission-Aransas Na-tional Estuarine Research Reserve (MANERR), established in 2006, is one of the newest in the National Estuarine Research Reserve (NERRS) system. Located about 30 miles north of Corpus Christi, TX, its main purpose is to provide relatively natural settings for long term research. It is important to know abundance and distribution of R. cuneata to determine habitat quality in coastal watersheds. The objectives of this project were to determine whether the clams are present in the MANERR, and, if present, determine preliminary distribution and abundance. This study was conduct-ed throughout June and July of 2013. The Aransas and Mission River systems were surveyed. A dredge was used every mile up the river from the mouth, and live and dead R. cuneata were enumerated, when found. Once a bed of live clams was located, quadrat sampling was used. There were no beds found in the Mission system. In Aransas River, howev-er, 3 beds were found and surveyed. At each site, 5 quadrats were taken, and any extra clams found were measured and collected. The data collected did not yield a clear picture of abundance and distribution, however, R. cuneata are present in small refuge populations during the current extended drought. Future research should be conducted to de-termine more detailed abundance and distribution.

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