Elevated water temperature impairs fertilization and embryonic development of whitefish Coregonus lavaretus

Abstract

The adverse effects of high temperatures on the early life stages of anadromous whitefish Coregonus lavaretus were experimentally examined by assessing fertilization success, the percentage of developmental abnormalities, cumulative mortality and the rate of embryogenesis across a range of temperatures. Temperatures >or= 7 degrees C increased the proportion of unfertilized and abnormally dividing eggs, deformed embryos and consequent mortality. The higher the temperature, the more severe were the effects. When eggs were fertilized and constantly incubated at various temperatures, the effective level for 50% of the eggs and embryos (EL50) of temperature was 7.6 degrees C at the developmental stage when eye pigmentation was visible. Fewer developmental abnormalities and a lower cumulative mortality rate were observed when embryos were exposed to high temperatures from the later, gastrula stage, than from fertilization or the four-cell stage. Irrespective of retarded development in terms of day-degrees (i.e. the sum of daily mean temperatures), a high incubation temperature reduced the development time of C. lavaretus, leading to earlier hatching, and hatched fry were shorter than at the reference temperature of 4-5 degrees C. Global warming will particularly pose risks for stenothermic species such as C. lavaretus, with early life stages being especially susceptible. Thus, relatively small increases and fluctuations in river water temperatures during the spawning season of this anadromous species may have substantial negative impacts on its recruitment and population persistence.

Effects of Water Temperature on Gonad Development in the Cold-Water Fish, Kumgang Fat Minnow <i>Rhynchocypris kumgangensis</i>

“…Spawning activity and the mRNA expression levels of gonadotropins were impaired by elevated water temperatures in both sexes of the pejerrey (Elisio et al 2012, Soria et al 2008. Water temperature elevation during the spawning season increased the proportion of unfertilized and abnormally dividing eggs in the whitefish, Coregonus lavaretus, leading to increased mortality of early-stage fish (Cingi et al 2010). Early in their life cycles, fish are highly sensitive to various environmental factors, including mineral balances, pH, heavy metals, and oxygen (Finn 2007).…”

Spawning migration and larval drift of anadromous North Sea houting (Coregonus oxyrinchus) in the River IJssel, the Netherlands

“…1), as demonstrated for a few specimens tagged with transponders that last for periods up to 4 years. Development of eggs from spawning until hatching was estimated in terms of day degrees (i.e., the sum of daily mean temperatures) for anadromous C. lavaretus with a mean (50% hatching) at 455 AE 20°C and a start (i.e., 10% hatching) at 413 AE 27°C (Cingi et al 2010). In this fourth season, abundance of NSH larvae peaked around the 17th of March 2010.…”

Fish communities in the Anthropocene: detecting drivers of changes in the deep peri-alpine Lake Geneva

“…comm.). Furthermore, experimental studies have demonstrated the negative effects of temperatures >7 °C on the success of fertilization, viability of eggs, and survival of embryos (Cingi et al 2010). During the spawning season, water temperatures exceeding 8 °C, as are expected due to climate change, will likely cause a decline in whitefish reproductive success (Gillet 1991, Anneville et al 2013.…”