Physiological responses to salinity and temperature stress in northern Gulf of Mexico eastern oyster populations

Document Type

Article

Publication Date

1-1-2025

Abstract

In the northern Gulf of Mexico, eastern oysters Crassostrea virginica inhabit areas with mean annual salinities from ~5 to >40 psu. They differ in salinity tolerance in a pattern consistent with their local salinity range, but the mechanisms responsible are mostly unknown. The physiological rates of 4 F1 populations (from the highest to lowest salinity estuaries: Packery Channel [PC], Aransas Bay, Calcasieu Lake, Vermilion Bay [VB]) were compared under combinations of 4 salinities (6, 12, 24, and 36 psu) and 2 temperatures (25 and 32°C). Clearance rate (CR) and oxygen consumption rate (OCR) were first measured in all populations at all salinities at 25°C (Expt 1). CR, absorption efficiency %, OCR, ammonia excretion rate, and scope for growth (SFG) were then measured in populations from the highest (PC) and lowest (VB) salinity estuaries at 25°C (Expt 2) and 32°C (Expt 3). In Expt 1, CRs were greatest at 24 psu for the 3 populations from the higher–medium salinity estuaries but extended to 12 and 24 psu for the population from the lowest salinity estuary. In Expt 2, CR and SFG tended to be greater for VB at 6 psu, but were greater for PC at 24 and 36 psu. SFG became negative at 6 psu for PC and at 36 psu for VB. At 32°C, SFG was negative or low in both populations, overriding the effects of salinity on oyster physiology. At 25°C, salinity impacted all physiological rates, and oysters showed variations in their physiological profiles consistent with their local salinity range.

Publication Source (Journal or Book title)

Marine Ecology Progress Series

First Page

87

Last Page

104

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