Abstract

Ocean acidification-decreasing oceanic pH resulting from the uptake of excess atmospheric CO2-has the potential to affect marine life in the future. Among the possible consequences, a series of studies on coral reef fish suggested that the direct effects of acidification on fish behavior may be extreme and have broad ecological ramifications. Recent studies documenting a lack of effect of experimental ocean acidification on fish behavior, however, call this prediction into question. Indeed, the phenomenon of decreasing effect sizes over time is not uncommon and is typically referred to as the "decline effect." Here, we explore the consistency and robustness of scientific evidence over the past decade regarding direct effects of ocean acidification on fish behavior. Using a systematic review and meta-analysis of 91 studies empirically testing effects of ocean acidification on fish behavior, we provide quantitative evidence that the research to date on this topic is characterized by a decline effect, where large effects in initial studies have all but disappeared in subsequent studies over a decade. The decline effect in this field cannot be explained by 3 likely biological explanations, including increasing proportions of studies examining (1) cold-water species; (2) nonolfactory-associated behaviors; and (3) nonlarval life stages. Furthermore, the vast majority of studies with large effect sizes in this field tend to be characterized by low sample sizes, yet are published in high-impact journals and have a disproportionate influence on the field in terms of citations. We contend that ocean acidification has a negligible direct impact on fish behavior, and we advocate for improved approaches to minimize the potential for a decline effect in future avenues of research.

Published in

PLoS Biology
2022, Volume: 20, number: 2, article number: e3001511
Publisher: PUBLIC LIBRARY SCIENCE

SLU Authors

• Sundin, Josefin

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    
  • Norwegian University of Science and Technology (NTNU)

Associated SLU-program

SLUsystematic


Sustainable Development Goals

Conserve and sustainably use the oceans, seas and marine resources for sustainable development


UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1371/journal.pbio.3001511

Permanent link to this page (URI)

https://res.slu.se/id/publ/115968