Fishing, predation, and temperature drive herring decline in a large marine ecosystem. Issue 24 (14th December 2021)

• Record Type: Journal Article
• Authors: Boyce, Daniel G.; Petrie, Brian; Frank, Kenneth T.
• Is Part Of: Ecology and evolution. Volume 11:Issue 24(2022)
• Page Start: 18136
• Page End: 18150
• Publication Date: 2021-12-14
• Subjects: Atlantic herring -- climate change -- ecosystem -- ecosystem‐based -- egg predation -- exploitation -- fisheries -- forage -- herring; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.8411
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Since 1960, landings of Atlantic herring have been the greatest of any marine species in Canada, surpassing Atlantic cod and accounting for 24% of the total seafood harvested in Atlantic Canada. The Scotian Shelf‐Bay of Fundy herring fisheries (NAFO Division 4VWX) is among Canada's oldest and drives this productivity, accounting for up to 75% of the total herring catch in some years. The stocks' productivity and overall health have declined since 1965. Despite management measures to promote recovery implemented since 2003, biomass remains low and is declining. The factors that drive the productivity of 4VWX herring are primarily unresolved, likely impeding the effectiveness of management actions on this stock. We evaluated potential drivers of herring variability by analyzing 52 time‐series that describe the temporal and spatial evolution of the 4VWX herring population and the physical, ecological, and anthropogenic factors that could affect them using structural equation models. Variation in herring biomass was best accounted for by the exploitation rate's negative effect and the geographic distribution of fishing and recruitment. Thermal phenology and temperature adversely and egg predation positively impacted the early life stage mortality rate and, ultimately, adult biomass. These findings are broadly relevant to fisheries management, but particularly for 4VWX herring, where the current management approach does not consider their early life stage dynamics or assess them within the ecosystem or climate change contexts. Abstract : The productivity and overall health of Scotian Shelf‐Bay of Fundy herring (NAFO Division 4VWX) have declined since 1965 and have failed to improve despite recovery measures in place since 2003. We evaluated potential drivers of herring decline by analyzing 52‐time series that describe the temporal and spatial evolution of the 4VWX herring population and the physical, ecological, and anthropogenic factors that could affect them using structural equation models. Variation in herring biomass was best explained by the adverse effect of exploitation rate and positive impact of the geographic distribution of fishing and recruitment, while thermal phenology, egg predation, and temperature impacted the early life stage mortality rate and, ultimately, adults' biomass.