Upper thermal tolerances of early life stages of freshwater mussels

Journal of the North American Benthological Society
By: , and 

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Abstract

Freshwater mussels (order Unioniformes) fulfill an essential role in benthic aquatic communities, but also are among the most sensitive and rapidly declining faunal groups in North America. Rising water temperatures, caused by global climate change, industrial discharges, drought, or land development, could further challenge imperiled unionid communities. The aim of our study was to determine the upper thermal tolerances of the larval (glochidia) and juvenile life stages of freshwater mussels. Glochidia of 8 species of mussels were tested: Lampsilis siliquoideaPotamilus alatusLigumia rectaEllipsaria lineolata,Lasmigona complanataMegalonaias nervosaAlasmidonta varicosa, and Villosa delumbis. Seven of these species also were tested as juveniles. Survival trends were monitored while mussels held at 3 acclimation temperatures (17, 22, and 27°C) were exposed to a range of common and extreme water temperatures (20–42°C) in standard acute laboratory tests. The average median lethal temperature (LT50) among species in 24-h tests with glochidia was 31.6°C and ranged from 21.4 to 42.7°C. The mean LT50 in 96-h juvenile tests was 34.7°C and ranged from 32.5 to 38.8°C. Based on comparisons of LT50s, thermal tolerances differed among species for glochidia, but not for juveniles. Acclimation temperature did not affect thermal tolerance for either life stage. Our results indicate that freshwater mussels already might be living close to their upper thermal tolerances in some systems and, thus, might be at risk from rising environmental temperatures.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Upper thermal tolerances of early life stages of freshwater mussels
Series title Journal of the North American Benthological Society
DOI 10.1899/09-128.1
Volume 29
Issue 3
Year Published 2010
Language English
Publisher North American Benthological Society
Publisher location Schaumberg, IL
Contributing office(s) Coop Res Unit Atlanta
Description 11 p.
First page 959
Last page 969
Online Only (Y/N) N
Additional Online Files (Y/N) N