Ask the locals: application of fishers ecological knowledge to characterize use of a previously collapsed spawning ground by Atlantic herring (Clupea harengus)

Abstract

Reproduction is a key component of species life history, and understanding spawning habitat, location, and timing is essential for effective population monitoring, conservation, and management. When a spawning ground of a fish population collapses, often monitoring resources are directed away from the area, resulting in a knowledge gap. Fishers who operate on these spawning grounds have extensive local knowledge and can see changes occurring in species occupancy and spawning activity in real time. This study integrates fishers’ ecological knowledge and newly established scientific monitoring to characterize the spawning habitat, locations, and timing of southern Gulf of St. Lawrence spring-spawning Atlantic herring (Clupea harengus) around the Magdalen Islands, a historically critical but collapsed spawning ground. Fisher interviews revealed key spawning locations and identified eelgrass and macroalgae as primary spawning substrates. Fishers reported that spawn timing has remained relatively stable, most commonly occurring between 15 April and 1 May. A confirmed spawning event in Havre Aubert on 21 April 2024 reinforced fisher observations and provided direct evidence that Atlantic herring continue to reproduce around the Islands. Overall, this study illuminates the value of integrating local ecological knowledge with scientific information to better understand the species ecology and inform conservation and management action.