Journal Molluscan Studies Advance Access originally published online on August 5, 2005
Journal of Molluscan Studies 2005 71(4):401-408; doi:10.1093/mollus/eyi042
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EFFECTS OF TEMPERATURE ON CHRONIC HYPOXIA TOLERANCE IN THE NON-INDIGENOUS BROWN MUSSEL, PERNA PERNA (BIVALVIA: MYTILIDAE) FROM THE TEXAS GULF OF MEXICO
1Department of Biological Sciences, The University of Texas at Brownsville, 80 Fort Brown, Brownsville, Texas 78520, USA; and 2Department of Biology/Honors College, Box 19222, The University of Texas at Arlington, Arlington, Texas 76019, USA
Correspondence: D. W. Hicks; e-mail: davidhicks{at}utb.edu
Effects of temperature (15°, 20° and 25°C), O2 partial pressure (PO2=0, 1, 2, 4, and 6 kPa), and individual size (12–79 mm shell length; SL) on survivorship of specimens of the non-indigenous, marine, brown mussel, Perna perna, from Texas were investigated to assess its potential distribution in North America. Its hypoxia tolerance was temperature-dependent, survivorship being significantly extended at lower temperatures under all tested lethal PO2. Incipient tolerated PO2 was 
4 and 6 kPa at 15 and 20°C, respectively, with >50% mortality occurring at 25°C at all tested levels of hypoxia. PO2 had less of an effect on survival of hypoxia than temperature. At 25°C, survivorship was not different over a PO2 range of 0–2 kPa and increased only at 4 and 6 kPa. Survivorship was size-dependent. Median survival times increased with increasing SL in anoxia and PO2=1 kPa, but at 2, 4 and 6 kPa, smaller individuals survived longer than larger individuals. With tolerance levels similar to other estuarine bivalve species, P. perna should withstand hypoxia encountered in estuarine environments. Thus, its restriction to intertidal rocky shores may be due to other parameters, particularly its relatively low temperature tolerance.
(Received 26 January 2004; accepted 31 March 2005)