Comparisons of Walleye Larval Development in Warm vs. Cold Water: Implications of Climate Change on Walleye Reproductive Success
Mentor 1
Dong-Fang Deng
Start Date
28-4-2023 12:00 AM
Description
Sander vitreus, a bottom-dwelling freshwater fish commonly known as walleye, are prized amongst seafood enthusiasts for their taste, as well as anglers for the recreation opportunities they offer. They are a culturally and ecologically important fish, but wild populations are now challenged by climate change. Stocking lakes with walleye produced through aquaculture helps to sustain populations, making this research valuable for fish hatcheries as well. The objective of this study was to investigate the impact of different water temperatures on the development and endogenous nutrient storage of post-hatch walleye larvae. Fertilized eggs were incubated under two temperature systems: the cold water group was incubated starting at 6.8°C and hatched at 13.9°C 20 days post fertilization, while the warm water group was incubated starting at 9.2°C and increased to 14°C by 14 days post fertilization. We measured the length, yolk and oil drop areas (endogenous nutrition), total area, and evaluated swim bladder inflation of walleye from 0-12 days post-hatch using Image-J software. Results showed larvae reared in the cold water system maintained a larger yolk and oil drop than those reared in the warm water system. This indicates that warm water reared fish will start searching for external food sources earlier to support their development. The warm water reared fish showed earlier inflation of the swim bladder than the cold water reared larvae. The depletion of yolk was faster than the oil drop in larvae reared in both systems suggesting proteins may be the major nutrient sources for development during this stage. These preliminary findings suggest increases in water temperatures due to climate change can significantly impact walleye larvae development and thus wild walleye populations, but further research is needed to obtain a better understanding of the long term impacts.
Comparisons of Walleye Larval Development in Warm vs. Cold Water: Implications of Climate Change on Walleye Reproductive Success
Sander vitreus, a bottom-dwelling freshwater fish commonly known as walleye, are prized amongst seafood enthusiasts for their taste, as well as anglers for the recreation opportunities they offer. They are a culturally and ecologically important fish, but wild populations are now challenged by climate change. Stocking lakes with walleye produced through aquaculture helps to sustain populations, making this research valuable for fish hatcheries as well. The objective of this study was to investigate the impact of different water temperatures on the development and endogenous nutrient storage of post-hatch walleye larvae. Fertilized eggs were incubated under two temperature systems: the cold water group was incubated starting at 6.8°C and hatched at 13.9°C 20 days post fertilization, while the warm water group was incubated starting at 9.2°C and increased to 14°C by 14 days post fertilization. We measured the length, yolk and oil drop areas (endogenous nutrition), total area, and evaluated swim bladder inflation of walleye from 0-12 days post-hatch using Image-J software. Results showed larvae reared in the cold water system maintained a larger yolk and oil drop than those reared in the warm water system. This indicates that warm water reared fish will start searching for external food sources earlier to support their development. The warm water reared fish showed earlier inflation of the swim bladder than the cold water reared larvae. The depletion of yolk was faster than the oil drop in larvae reared in both systems suggesting proteins may be the major nutrient sources for development during this stage. These preliminary findings suggest increases in water temperatures due to climate change can significantly impact walleye larvae development and thus wild walleye populations, but further research is needed to obtain a better understanding of the long term impacts.
