Effects of Temperature on the Oxygen Consumption and Heart Rate in the Inter-Tidal Wedge Clam, Donaxfaba (Gmelin)

Abstract

The effect of temperature on the rate of oxygen consumption and heart rate has been investigated in the Red Sea, inter-tidal wedge clam Donax faba. The 010 values for both oxygen consumption and heart rate were often < 2.5 and were relatively constant over a wide range of temperature. This suggests that wedge clam is well adapted for life in high temperature environment. It was noted, however, that behavioural mechanisms were important in reducing the degree of temperature stress that could be experienced in the field.

Ecological Behaviour and Biology of the Beach Clam Donax faba (Gmelin) from the Red Sea

“…However, in the present study, Donax faba nei ther exhibited tidal pattern nor a semilunar migratory pattern but rather a seasonal mi gratory pattern related to the seasonal variation in the mean sea level. Similar patterns of behavior were observed for semi-terrestrial crabs [6][7][8]10] .…”

“…There is a remarkable seasonal variation, in the mean sea level in the Red Sea due to the monsoon effect [5][6][7][8]12,13,38] . Patzert [12] suggested that the monsoon wind reversal is the major factor controlling sea level.…”

“…Whatever the factors controlling circulation are, the resulting sea level changes were clearly observed by Eshky [6][7][8] who recorded the seasonal variation from Jizan city, 750 km south of Jeddah and from the same area where Morley [5] recorded his data. The present study clearly illustrates the seasonal change in the level (Fig.6) and is in full agreement with all previous studies.…”

“…Smith [13] and Alagarswami [4], however, noted its occurrence on exposed sandy beaches of Africa and India re spectively. The littoral environment of the Red Sea is characterized by wide diel temperatures [5][6][7][8] . Salinity is also high in the Red Sea and may reach 41% in the reef pools in the Jeddah region in July and August [5] .…”

“…In the Jeddah region the maximum spring tide range is about 36 cm [5,6,11,12] , but de spite its small magnitude it plays an essential role in the behavior of littoral fauna par ticularly on the feeding behavior [6][7][8][9][10] .…”