The influence of hydrography on pelagic fish distribution and communities in a sub-arctic estuary (Lake Melville, Labrador) ...

• Main Author: Small, Tiffany
• Format: Text
• Language: English
• Published: Memorial University of Newfoundland 2023
• Subjects: Arctic; Lake Melville
• Online Access: https://dx.doi.org/10.48336/nbbm-e013; https://research.library.mun.ca/16007/

Estuaries are semi-enclosed bodies of water that are influenced by freshwater runoff and saltwater from neighbouring oceans. Water masses in estuaries can be strongly stratified and are often influenced by geological, hydrological and hydrographical features. The stratification of the water column in estuaries creates important nursery habitats for larvae and juvenile fish populations. The Lake Melville system, a highly stratified sub-arctic estuary in Labrador, spans 2100 km2 and is considered the longest single body of water in Labrador (250 km). By pairing seasonal hydroacoustic surveys conducted in summers 2018-2019 and winters 2019-2020 with ichthyoplankton and gill nets sampling as well as environmental DNA, we test the hypothesis that the strong water stratification prevailing in upper Lake Melville provides a refuge for early life stages of fish. We found that adult pelagic fish occupied the Atlantic waters below the steep pycnocline, while ichthyoplankton aggregated just above and within the ...