In many aquatic ecosystems, dams have isolated fish populations for decades to centuries and the isolated populations have diverged both morphologically and genetically. Secondary contact between previously isolated populations will occur as these dams are removed or restoration efforts restore spatial connectivity. This RAPID project will examine the ecological and evolutionary consequences of the initial stages of secondary contact; restoration of river connectivity will soon allow secondary contact between anadromous alewife populations and landlocked populations in Rogers Lake, Connecticut. Divergence in morphology, foraging behavior, and migration has altered the ecological role of these two alewife life history forms over the past 250-350 years. Research will examine the inbreeding between anadromous and landlocked alewife using genetic markers to track introgression. It will document changes in food web structure, nutrient loading, and habitat and resource use by alewife at the initiation of secondary contact. By documenting these important direct and indirect effects of initial contact between anadromous and landlocked populations, the project will significantly advance our understanding of a process that is fundamental to the origin and maintenance of biodiversity.
Although anadromous alewives are a critical resource in freshwater and marine habitats and a federally listed species of conservation concern, landlocked alewives are invasive across their range. The investigators will continue work with local lake associations, land trusts and the regional conservation and management community to aid anadromous alewife restoration efforts by contributing results from this study. They will take advantage of an NIH-funded Yale program to recruit under-represented minority undergraduate students to the project, and will train them in the broader scientific context of the research, research methods, data analysis, and written and oral project reports. Outreach talks to the general public, education programs targeting underrepresented minority groups, interactive displays, and digital outreach via internet and social media are also planned.
