Thermal maxima for juvenile shortnose sturgeon acclimated to different temperatures

Abstract

Many populations of shortnose sturgeon, Acipenser brevirostrum, in the southeastern United States continue to suffer from poor juvenile recruitment. High summer water temperatures, which may be exacerbated by anthropogenic activities, are thought to affect recruitment by limiting available summer habitat. However, information regarding temperature thresholds of shortnose sturgeon is limited. In this study, the thermal maximum method and a heating rate of 0.1°C min −1 was used to determine critical and lethal thermal maxima for young-of-the-year (YOY) shortnose sturgeon acclimated to temperatures of 19.5 and 24.1°C. Fish used in the experiment were 0.6 to 35.0 g in weight and 64 to 140 days post hatch (dph) in age. Critical thermal maxima were 33.7°C (±0.3) and 35.1°C (±0.2) for fish acclimated to 19.5 and 24.1°C, respectively. Critical thermal maxima significantly increased with an increase in acclimation temperature (p<0.0001).Lethal thermal maxima were 34.8°C (±0.1) and 36.1°C (±0.1) for fish acclimated to 19.5 and 24.1°C, respectively. Lethal thermal maxima were significantly affected by acclimation temperature, the log 10 (fish weight), and the interaction between log 10 (fish weight) and acclimation temperature (p<0.0001). Thermal maxima were used to estimate upper limits of safe temperature, thermal preferences, and optimal growth temperatures of YOY shortnose sturgeon. Upper limits of safe temperature were similar to previous temperature tolerance information and indicate that summer temperatures in southeastern rivers may be lethal to YOY shortnose sturgeon if suitable thermal refuge cannot be found.

Hematocrit and plasma osmolality values of young-of-year shortnose sturgeon following acute exposures to combinations of salinity and temperature

“…However, at 31°C, low hematocrit levels and dark plasma indicated that hemolysis was occurring in the blood of surviving fish, demonstrating substantial physiological stress at this temperature. In thermal maxima tests with shortnose sturgeon, Ziegeweid et al (2008a) estimated upper limits of safe temperature ranging from 28.7 to 31.1°C. In addition, Ziegeweid et al (2008b) estimated temperature LC 50 values ranging from 28.2 to 30.7°C for YOY shortnose sturgeon ranging from 70 to 120 days old.…”

Thermal tolerance of allis shad (Alosa alosa) embryos and larvae: Modeling and potential applications

“…Living Resour. 30, 2 (2017) 3 from acclimating to intermediate temperatures before reaching the targeted temperature (Becker and Genoway 1979;Ziegeweid et al 2008). The maximum time to reach the experimental temperature was 2 h 30 min for extreme temperatures.…”

“…Thermal tolerance generally increases as individuals progress from embryonic to adult phases (Coutant 1987;Elliott and Elliott 2010;Souchon and Tissot 2012). Therefore, survival at early developmental stages could influence population persistence as temperatures continue to increase (Delage et al 2014;Ziegeweid et al 2008) due to climate change.…”

Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon

“…It has been well documented that congeners of fish (e.g., cyprinid Danio species: Danio rerio, Danio albolineatus, Danio choprae; Sidhu et al, 2014) and different fish populations within a species (e.g., common killifish: Fundulus heteroclitus macrolepidotus, Fundulus heteroclitus heteroclitus; Fangue et al, 2006;Healy and Schulte, 2012) can show variation in upper thermal tolerance. Acclimation to different temperatures is also known to affect thermal tolerance in fishes (e.g., Ziegeweid et al, 2008;Fangue et al, 2011); however, acclimation temperature was similar for both sturgeon and therefore unlikely to be the cause of differences in upper temperature tolerance.…”