The critical thermal limits for the bullhead, Cottus gobio, from three populations in north‐west England

Abstract

1. The objective was to determine the thermal limits for feeding and sur\'ival in the bullhead, Cottus gobio, using juveniles (total length 20-30 mm, live weight 0.5-1.5 g) from one population and adults (50-70 mm, 3.5-5.5 g) from three populations. 2. Fish were acclimated to constant temperatures (3, 7, 10, 15, 20, 25 or 27 °C) and the temperature was then changed at a rate of 1 °C /30 min to determine the critical limits for feeding, survival over 7 days (incipient lethal temperature), or survival for 10 min or less (ultimate lethal temperature). The rate of 1 °C/30 min was the optimum value from preliminary experiments, using nine rates from 0.5 °C/48 h to 18 °C h"'. As values for adults were not significantly different between populations, they were pooled to provide arithmetic means (with 95% CL) for the thermal limits at each acclimation temperature. 3. Feeding limits increased with acclimation temperature to upper and lower mean values (± 95% CL) of 26.5 ± 0.16 °C and 4.2 ± 0.20 °C for adults, 26.6 ± 0.59 "C and 5.0 ± 0.55 °C for juveniles. Incipient lethal levels defined a tolerance zone within which fish survive indefinitely; upper limits increased with acclimation temperature to a plateau of 27.6 ± 0.22 °C for adults and 27.5 ± 0.47 "C for juveniles, lower limits increased from near 0 °C to 2.5 ± 0.31 °C for adults and 2.7 ± 0.47 °C for juveniles. Ultimate lethal levels increased with acclimation temperature to a plateau of 32.5 ± 0.24 °C for adults and 32.6 ± 0.46 °C for juveniles, whilst the lower limits increased from near 0 to 0.9 ± 0.29 °C. Upper feeding, incipient and ultimate lethal values were significantly lower for juveniles than those for adults at acclimation temperatures < 20, < 20 and < 15 "C, respectively. 4. The thermal tolerance of bullheads was slightly lower than that of stone loach, similar to that of juvenile Atlantic salmon and higher than that of brown trout; the thermal limits for feeding were much wider than those for salmon or trout.

Evidence that elevated water temperature affects the reproductive physiology of the European bullhead Cottus gobio

“…Thus, changing temperature profiles within rivers arising from climate change can influence the physiology and ecology of a variety of organisms including fish species. The temperatures applied in the present study were far below the upper limit of normal feeding or death for C. gobio which was found to be 27.7°C (Elliott and Elliott 1995). That being so, the current study showed that exposure to temperatures from 4 to 8°C higher than temperature C. gobio would have experienced in the wild during the recrudescence and mating periods significantly influenced its reproduction.…”

“…Bullhead typically lives in well-oxygenated stream waters from 2 to 16.5°C (Andreasson 1971), whereas Elliott and Elliott (1995) found the critical thermal limits of bullhead to be 4.2 and 27.7°C. It has been selected in our study as a candidate sentinel species reflecting the biodiversity of headwater zones in river networks (Habitats Directive 2007).…”

Direct and Correlated Responses to Artificial Selection on Acute Thermal Stress Tolerance in a Livebearing Fish

“…CTmax was defined as the point at which ventilation (flaring of the gills) ceased. CTmin was defined as the point at which the righting response was lost; this is a traditional measure of thermal stress tolerance in physiological zoology (Prosser 1973;Bulger and Schultz 1979;Fields et al 1987;ForsterBlouin 1989;Elliot et al 1994;Elliot and Elliot 1995;Meffe et al 1995). Thermal stress was continued until half the individuals in a trial had reached the critical thermal limit (analogous to an LD50).…”

The influence of calcium concentration on the distribution of the river bullheadCottus gobioL. (Teleostes, Cottidae)

“…Temperature plays an important role in the ecology of C. gobio as stated by Elliot and Elliot (1995), and the lack of difference between PA and AA, both in winter and in summer, only means that the two adjacent areas share the same climate.…”