Determination of Upper Temperature Tolerance in June Sucker Larvae: Is the Transition to Utah Lake Temperatures a Recruitment Bottleneck?

Abstract

The June sucker Chasmistes liorus is an endangered adfluvial fish species that is endemic to the Utah Lake basin. This species remains endangered due to a lack of recruitment. Anthropogenic changes to June sucker lotic and lentic habitat has likely led to recruitment failure. Changes to Utah Lake include increased water temperature, increased turbidity, and eutrophic and saline conditions. The remaining spawning habitat for June suckers in the Provo River has experienced flow, temperature, and channelization modifications. We tested the hypothesis that recruitment failure is caused by a thermal shock that occurs when larvae are transported in the drift out of the Provo River (12-198C) and into Utah Lake (17-258C). We used two laboratory methods-direct transfer and acclimated chronic exposure (ACE)-to determine (1) the upper lethal temperature (ULT) and (2) the acute and chronic mortality associated with larval exposure to an acute thermal shock. The ULT of larvae acclimated to 168C was 338C. Survival varied from 81% to 95% for larvae that were directly transferred from 168C (acclimation temperature) to 19-298C and held for 7 d; survival was not significantly different from that of the 168C control. A modified ACE method was used to mimic the riverto-lake transition. Acclimation temperatures of 12, 16, and 198C were increased by 5-88C over 4-6 h. After approximately 30 d, survival ranged from 42% (transition from 168C to 218C) to 87% (transition from 198C to 278C). Mean weight of fish that received the 19-278C transition treatment was significantly greater than that of all other treatment groups except the 19-258C transition group. Warmer incubation and rearing temperatures led to increased growth and survival. We conclude that thermal shock does not explain June sucker larval recruitment failure in Utah Lake, and we suggest that other factors are responsible for the recruitment failure.

Fish Assemblage Associations with Floodplain Connectivity Following Restoration to Benefit an Endangered Catostomid

“…Delta side channels were substantially warmer than other habitats in Utah Lake in which larvae would have drifted during the critical period in June and July. Kindschi et al (2008) found juvenile June Sucker metabolic rate highest at 22 C and larval growth was greatest in the highest temperatures of the treatment, which extended to 27 C (Kappenman et al 2010). Causation for June Sucker survival in the restoration area is speculative given the low number collected, but these results are promising and corroborate evidence of recent natural recruitment within Utah Lake (Wolff et al 2013).…”

Lethal Thermal Maxima for Age‐0 Pallid and Shovelnose Sturgeon: Implications for Shallow Water Habitat Restoration

“…Acclimation temperature (Sylvester, 1975;Schultz and Bertrand, 2011;Zhang and Kieffer, 2014) and latitude (Stewart and Allen, 2014) are two of the main factors that have been shown to significantly affect the upper temperature tolerance of fish. In particular, knowledge of the upper thermal thresholds for fish is useful for predicting physiological responses in thermally dynamic environments (Selong et al, 2001;Kappenman et al, 2010).…”

Critical thermal maximum and minimum of juvenile shortnose sturgeon ( Acipenser brevirostrum ) acclimated to 12 and 18°C

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It has been suggested that the mean global surface temperature has increased by 0.7°C over the past 100 years (IPCC 2007, in Lassalle et al, 2010, and it is expected that continued temperature increases could have additional and significant effects on the distribution and survival of many species (Beitinger & Lutterschmidt, 2011;Lassalle et al, 2010). Thermal tolerance data provides information about the potential effects of climate change on fish populations (Beitinger et al, 2000;Deslauriers et al, 2016), and can be useful for predicting physiological responses in thermally dynamic environments (Deslauriers et al, 2016;Kappenman et al, 2010;Tattersall et al, 2012). Various measures of thermal tolerance have been developed; of these, the critical thermal methodology, CTM, (CT max and CT min ) is the most common (Beitinger et al, 2000), and is often used to provide an ecologically and physiologically valuable reference point.

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