Signatures of the collapse and incipient recovery of an overexploited marine ecosystem

• Published in: Royal Society Open Science
• Main Authors: Eric J. Pedersen, Patrick L. Thompson, R. Aaron Ball, Marie-Josée Fortin, Tarik C. Gouhier, Heike Link, Charlotte Moritz, Hedvig Nenzen, Ryan R. E. Stanley, Zofia E. Taranu, Andrew Gonzalez, Frédéric Guichard, Pierre Pepin
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2017
• Subjects: community ecology; ecosystem-based management; community synchrony; spatial ecology; regime shifts; marine ecology; Science; Q; atlantic cod; Northwest Atlantic
• Online Access: https://doi.org/10.1098/rsos.170215; https://doaj.org/article/c1e0c8b6c91a4f17a556e500dd00dfb9

The Northwest Atlantic cod stocks collapsed in the early 1990s and have yet to recover, despite the subsequent establishment of a continuing fishing moratorium. Efforts to understand the collapse and lack of recovery have so far focused mainly on the dynamics of commercially harvested species. Here, we use data from a 33-year scientific trawl survey to determine to which degree the signatures of the collapse and recovery of the cod are apparent in the spatial and temporal dynamics of the broader groundfish community. Over this 33-year period, the groundfish community experienced four phases of change: (i) a period of rapid, synchronous biomass collapse in most species, (ii) followed by a regime shift in community composition with a concomitant loss of functional diversity, (iii) followed in turn by periods of slow compositional recovery, and (iv) slow biomass growth. Our results demonstrate how a community-wide perspective can reveal new aspects of the dynamics of collapse and recovery unavailable from the analysis of individual species or a combination of a small number of species. Overall, we found evidence that such community-level signals should be useful for designing more effective management strategies to ensure the persistence of exploited marine ecosystems.