Sensitivities of an endemic, endangered California smelt and two non-native fishes to serial increases in temperature and salinity: implications for shifting community structure with climate change

Davis, Brian A.; Cocherell, Dennis E.; Sommer, Ted; Baxter, Randall D.; Hung, Tien‐Chieh; Todgham, Anne E.; Fangue, Nann A.

doi:10.1093/conphys/coy076

Cited by 31 publications

(46 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…36 to 40°C (Smith & Scott, 1975) while delta smelt range from c. 26 to 29°C, depending on acclimation temperature (Davis et al, 2019;Komoroske et al, 2014;Swanson, Reid, Young, & Cech, 2000). Under the warm temperature treatment at 21°C, delta smelt swimming velocity significantly increased, which may have led to physiological stress.…”

Section: Temperature Effects On Predationmentioning

confidence: 99%

“…Testable study ques- Mahardja, Conrad, Lusher, & Schreier, 2016;Schreier, Baerwald, Conrad, Schumer, & May, 2016) and may compete for similar resources; therefore, Mississippi silversides are likely to be susceptible to similar predation pressures as delta smelt. The present study tested chronic and acute exposures to 21°C, a moderate thermal challenge well within tolerance limits (Davis et al, 2019;Jeffries et al, 2016;Komoroske et al, 2014) of fishes that will provide relevant information to current and future habitat conditions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Consequences of temperature and temperature variability on swimming activity, group structure, and predation of endangered delta smelt

et al. 2019

Self Cite

View full text Add to dashboard Cite

1. The effects of water temperature on individual and group movement behaviour in prey fish can affect ecological interactions such as competition and predation, but how variability in temperature influence fish behaviour is less understood.Of particular concern is how increased warming in tidally fluctuating estuaries may impact the native and endangered delta smelt (Hypomesus transpacificus, Osmeridae).2. To help address this issue, we tested the effects of increased water temperature (fluctuating [17-21°C] and warm [21°C] acclimated treatments) on juvenile delta smelt individual and group behaviour, response to chemical alarm and predator cues, as well as capacity to evade predation. In addition, predation of delta smelt was tested in the presence of a dominant invasive competitor, Mississippi silversides (Menidia beryllina, Atherinopsidae), as well as comparative predation mortality on Mississippi silversides when isolated.3. After 7 days of increased temperature treatments, delta smelt in the warm treatment increased swimming velocity, decreased turning angle, and altered group structure with larger inter-individual distances compared to fish in the control (17°C) and fluctuating temperature treatments. Following conspecific and predator chemical alarm cues, delta smelt showed anti-predator responses. Control and fluctuating treatment fish responded to conspecific cues with increased swimming speeds, decreased inter-individual distances and near-neighbour distances, and, after 15 min, fish recovered back to baseline behaviours. In contrast, fish in the warm treatment had not recovered after 15 min, and swimming speeds were maintained at roughly 25 cm/s, close to maximum capabilities. Fish in control and fluctuating treatments showed minimal responses to predator cues, whereas delta smelt exposed to warm conditions significantly increased swimming speeds and decreased turning angle. Predation of delta smelt by largemouth bass (Micropterus salmoides, Centrarchidae)was greatest under the warm treatment, correlating with altered behaviours of | 2157 DAVIS et Al.

show abstract

Section: Temperature Effects On Predationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Consequences of temperature and temperature variability on swimming activity, group structure, and predation of endangered delta smelt

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Differences between treatments reflect the different water sources (FCCL: Old River surface water, PUC: Putah Creek well water, CABA: CABA well water). Salinity was maintained at different levels based on known Delta Smelt preferred rearing conditions and experimental requirements . Variations in salinity were achieved by mixing of synthetic sea salt (Instant Ocean, Blackburg, VA, USA) with the corresponding water source and thus do not reflect the mixture of different water sources that would change the δ 18 O water value.…”

Section: Methodsmentioning

confidence: 78%

“…Due to the endangered status of Delta Smelt and limited availability of fish, strategic research planning and collaboration are required to gain more understanding of this species. A study conducted by Davis et al provided an opportunity to obtain Delta Smelt with known rearing conditions including the duration of treatments, water source, temperature, and δ 18 O water values (Table ).…”

Section: Methodsmentioning

confidence: 99%

“…We used offspring from wild‐wild parent crosses that were reared at FCCL under known conditions. After ~135 days post‐hatch (dph) fish were transferred to the UC Davis Putah Creek Aquaculture Facility (PUC) and split into two experimental temperature acclimation treatments . After completion of the temperature acclimation study the remaining fish were transferred to the UC Davis Center for Aquatic Biology and Aquaculture (CABA) at ~170 dph (Figure ).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Calibrating temperature reconstructions from fish otolith oxygen isotope analysis for California's critically endangered Delta Smelt

Willmes

Lewis

Davis

et al. 2019

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

Rationale: Oxygen isotope ratios (δ 18 O values) of fish otoliths (ear bones) are valuable geochemical tracers of water conditions and thermal life history. Delta Smelt (Hypomesus transpacificus) are osmerid forage fish endemic to the San Francisco Estuary, California, USA, that are on the verge of extinction. These fish exhibit a complex life history that allows them to survive in a dynamic estuarine environment; however, a rapidly warming climate threatens this thermally sensitive species. Here we quantify the accuracy and precision of using δ 18 O values in otoliths to reconstruct the thermal life histories of Delta Smelt. Methods: Delta Smelt were reared for 360 days using three different water sources with different ambient δ 18 O water values (−8.75‰, −5.28‰, and −4.06‰) and different water temperatures (16.4°C, 16.7°C, 18.7°C, and 20.5°C). Samples were collected after 170 days (n = 28) and 360 days (n = 14) post-hatch. In situ δ 18 O values were measured from the core of the otolith to the dorsal edge using secondary ion mass spectrometry (SIMS) to reconstruct temporally resolved thermal life histories. Results: The δ 18 O otolith values for Delta Smelt varied as a linear inverse function of water temperature: 1000 ln α = 18.39 (±0.43, 1SE)(10 3 TK −1 ) − 34.56 (±1.49, 1SE) and δ 18 O otolith(VPDB) − δ 18 O water (VPDB) = 31.34(±0.09, 1SE) − 0.19(±0.01, 1SE) × T°C. When the ambient δ 18 O water value is known, this species-specific temperature-dependent oxygen isotope fractionation model facilitated the accurate (0.25°C) and precise (±0.37°C, 2σ) reconstruction of the water temperature experienced by the fish. In contrast, the use of existing general fractionation equations resulted in inaccurate temperature reconstructions. Conclusions: The species-specific δ 18 O otolith fractionation equation allowed for accurate and precise reconstructions of water temperatures experienced by Delta Smelt. Characterization of ambient δ 18 O water values remains a critical next step for reconstructing thermal life histories of wild Delta Smelt. This tool will provide new insights into habitat utilization, potential thermal refugia, and resilience to future warming for this critically endangered fish.

show abstract

Resistance and resilience of pelagic and littoral fishes to drought in the San Francisco Estuary

Mahardja

Tobias

Khanna

et al. 2021

Ecological Applications

Self Cite

View full text Add to dashboard Cite

Many estuarine ecosystems and the fish communities that inhabit them have undergone substantial changes in the past several decades, largely due to multiple interacting stressors that are often of anthropogenic origin. Few are more impactful than droughts, which are predicted to increase in both frequency and severity with climate change. In this study, we examined over five decades of fish monitoring data from the San Francisco Estuary, California, U.S.A, to evaluate the resistance and resilience of fish communities to disturbance from prolonged drought events. High resistance was defined by the lack of decline in species occurrence from a wet to a subsequent drought period, while high resilience was defined by the increase in species occurrence from a drought to a subsequent wet period. We found some unifying themes connecting the multiple drought events over the fifty-year period. Pelagic fishes consistently declined during droughts (low resistance), but exhibit a considerable amount of resiliency and often rebound in the subsequent wet years. However, full recovery does not occur in all wet years following droughts, leading to permanently lower baseline numbers for some pelagic fishes over time. In contrast, littoral fishes seem to be more resistant to drought and may even increase in occurrence during dry years. Based on the consistent detrimental effects of drought on pelagic fishes within the San Francisco Estuary and the inability of these fish populations to recover in some years, we conclude that freshwater flow remains a crucial but not sufficient management tool for the conservation of estuarine biodiversity.

show abstract

Sensitivities of an endemic, endangered California smelt and two non-native fishes to serial increases in temperature and salinity: implications for shifting community structure with climate change

Abstract: This study showed that in three quite different fish species from the San Francisco Estuary, stress from elevated temperature or salinity did not reduce their ability to cope with subsequent stressors.

Cited by 31 publications

References 65 publications

Consequences of temperature and temperature variability on swimming activity, group structure, and predation of endangered delta smelt

Consequences of temperature and temperature variability on swimming activity, group structure, and predation of endangered delta smelt

Calibrating temperature reconstructions from fish otolith oxygen isotope analysis for California's critically endangered Delta Smelt

Resistance and resilience of pelagic and littoral fishes to drought in the San Francisco Estuary

Contact Info

Product

Resources

About