Author(s): Muhammad Usama Ashraf; Daniel P. Zielinski; Reid G. Swanson; Andrew M. Muir; Robert L. Mclaughlin; Thomas C. Pratt; R. Andrew Goodwin; Aline J. Cotel; Peter J. Hrodey; C. Michael Wagner; Jesse Eickholt; Claudio Comoglio; Jonathan D. Bolland

Linked Author(s): R. Andrew Goodwin, Claudio Comoglio

Keywords: Fish passage; Selective connectivity; Trait-based management; Fish sorting technologies; Invasive species connectivity

Abstract: The fragmentation of riverine ecosystems represents a critical threat to freshwater fish biodiversity worldwide. While engineered fish passage structures are implemented to mitigate fragmentation impacts on migratory species, these same structures can also create routes that allow invasive species to spread. This situation creates a management dilemma known as the "connectivity conundrum," in which efforts to restore longitudinal connectivity may inadvertently facilitate the spread of invasive species. Selective connectivity seeks to resolve this dilemma by passing desireable species while simultaneously blocking or removing undesireable ones, using fish sorting technologies that exploit interspecific differences in fish traits. This review synthesizes over seven decades of research (1950s - present) on fish sorting and guidance technologies through a trait -based framework to evaluate their potential for selective fish passage. Using an expert -informed literature review and structured data extraction, we compiled over 1, 500 treatment records from more than 340 unique studies focused on 30 migratory fish species most common in Boardman/Ottaway River in Michigan, USA, across 18 technologies. These technologies were categorized based on four key fish traits: behavioral, morphological, physiological, and phenological. Behavioral guidance technologies often achieve moderate to high but context- dependent blockage efficacies by acting on fish sensory systems. Morphological technologies exploit body form and size differences to achieve separation. Physiological technologies leverage differences in fish swimming and leaping abilities to perform fish sorting, whereas phenological approaches provide predictable seasonal and diel migration windows to add a temporal axis of selectivity. Data coverage remains heavily skewed toward sea lamprey, salmonids, and invasive carp, with many native species underrepresented. Our synthesis suggests that achieving selective connectivity in mixed fish assemblages requires moving beyond single-technology solutions toward integrated, multi-tool installations that exploit specific trait differences. The findings from this synthesis are intended to (i) provide the empirical basis for designing and testing multi- tool sorting and guidance system at FishPass, the capstone to the 20y res toration of the Boardman/Ottaway River, and (ii) inform multispecies management, research prioritization, and design strategies for diverse freshwater systems across the Laurentian Great Lakes and beyond.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.248

Year: 2026