The effect of ocean warming on black sea bass (Centropristis striata) aerobic scope and hypoxia tolerance

Abstract

Over the last decade, ocean temperature on the U.S. Northeast Continental Shelf (U.S. NES) has warmed faster than the global average and is associated with observed distribution changes of the northern stock of black sea bass ( Centropristis striata ). Mechanistic models based on physiological responses to environmental conditions can improve future habitat suitability projections. We measured maximum, standard metabolic rate, and hypoxia tolerance (S crit ) of the northern adult black sea bass stock to assess performance across the known temperature range of the species. Two methods, chase and swim-flume, were employed to obtain maximum metabolic rate to examine whether the methods varied, and if so, the impact on absolute aerobic scope. A subset of individuals was held at 30°C for one month (30 chronic °C) prior to experiments to test acclimation potential. Absolute aerobic scope (maximum–standard metabolic rate) reached a maximum of 367.21 mgO 2 kg -1 hr -1 at 24.4°C while S crit continued to increase in proportion to standard metabolic rate up to 30°C. The 30 chronic °C group exhibited a significantly lower maximum metabolic rate and absolute aerobic scope in relation to the short-term acclimated group, but standard metabolic rate or S crit were not affected. This suggests a decline in performance of oxygen demand processes (e.g. muscle contraction) beyond 24°C despite maintenance of oxygen supply. The Metabolic Index, calculated from S crit as an estimate of potential aerobic scope, closely matched the measured factorial aerobic scope (maximum / standard metabolic rate) and declined with increasing temperature to a minimum below 3. This may represent a critical threshold value for the species. With temperatures on the U.S. NES projected to increase above 24°C in the next 80-years in the southern portion of the northern stock’s range, it is likely black sea bass range will continue to shift poleward as the ocean continues to warm.

Overwintering survivorship and growth of young-of-the-year black sea bass Centropristis striata

“…At 32 PSU, the maximum aerobic scope of adult C . striata occurs at 24.4°C [ 55 ] and the optimal temperature for juvenile growth occurs near this temperature (25.6°C at about 23 PSU) [ 56 ], but these two studies did not explore the impact of salinity on optimal growth. When the effect of salinity was examined near optimal temperatures for juvenile C .…”

“…Our results fill important gaps in previous studies that have examined the effect of temperature and salinity on growth, survival and metabolism in the northern stock of C. striata. At 32 PSU, the maximum aerobic scope of adult C. striata occurs at 24.4˚C [55] and the optimal temperature for juvenile growth occurs near this temperature (25.6˚C at about 23 PSU) [56], but these two studies did not explore the impact of salinity on optimal growth. When the effect of salinity was examined near optimal temperatures for juvenile C. striata (22-25˚C), slightly higher growth occurred at 20-25 PSU and were reduced at extreme high (30 and 34 PSU) and extreme low (10 PSU) salinities [43,56].…”

Synergistic Effects of Ocean Warming and Cyanide Poisoning in an Ornamental Tropical Reef Fish

“…Following, all fish were divided into three different groups and a thermal ramp (1 • C day −1 ) was applied to reach the following temperatures: control 26 • C (stocking temperature at the local supplier facilities, which is within the thermal range that these species experience in the wild) and experimental temperatures of 29 and 32 • C. No fish mortality or shifts in water quality parameters were recorded during the thermal ramp performed. The chosen thermal ramp allowed fish to acclimate and prevented sudden heat-shock, falling within values regularly used in other studies (1-2 • C day −1 ) (e.g., Slesinger et al, 2019). The fish were housed at these temperatures (90-L tanks, n = 20 fish tank −1 , 1 tank temperature −1 ) for 1 week, provided by 300-W submergible heater (Eheim Jäger 300 W, Germany).…”

Analytical methods matter too: Establishing a framework for estimating maximum metabolic rate for fishes

“…Window widths vary across studies and may even go unreported; 1-5 min is common, but much longer windows are not unusual (e.g., 10 and 15 min) (Killen et al, 2007;Závorka et al, 2018). In some cases, the window width is tailored to each individual and thus varies across individuals within a study (Slesinger et al, 2019). However, the degree to which MMR estimates are affected by the choice of regression window width, and under what experimental conditions, is unknown.…”