Effects of ocean acidification on the larvae of a high-value pelagic fisheries species, mahi-mahi Coryphaena hippurus

• Main Authors: Bignami, Sean, Sponaugle, Su, Cowen, Robert K.
• Format: Article in Journal/Newspaper
• Language: English; unknown
• Published: Inter-Research
• Subjects: Ocean acidification
• Online Access: https://ir.library.oregonstate.edu/concern/articles/qb98mh272

Negative impacts of CO₂-induced ocean acidification on marine organisms have proven to be variable both among and within taxa. For fishes, inconsistency confounds our ability to draw conclusions that apply across taxonomic groups and highlights the limitations of a nascent field with a narrow scope of study species. Here, we present data from a series of 3 experiments on the larvae of mahi-mahi Coryphaena hippurus, a large pelagic tropical fish species of high economic value. Mahi-mahi larvae were raised for up to 21 d under either ambient seawater conditions (350 to 490 μatm pCO₂) or projected scenarios of ocean acidification (770 to 2170 μatm pCO₂). Evaluation of hatch rate, larval size, development, swimming activity, swimming ability (U[subscript crit]), and otolith (ear stone) formation produced few significant effects. However, larvae unexpectedly exhibited significantly larger size-at-age and faster developmental rate during 1 out of 3 experiments, possibly driven by metabolic compensation to elevated pCO₂ via a corresponding decrease in routine swimming velocity. Furthermore, larvae had significantly larger otoliths at 2170 μatm pCO₂, and a similar but non-significant trend also occurred at 1200 μatm pCO₂, suggesting potential implications for hearing sensitivity. The lack of effect on most variables measured in this study provides an optimistic indication that this large tropical species, which inhabits the offshore pelagic environment, may not be overly susceptible to ocean acidification. However, the presence of some treatment effects on growth, swimming activity, and otolith formation suggests the presence of subtle, but possibly widespread, effects of acidification on larval mahi-mahi, the cumulative consequences of which are still unknown. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Inter-Research. The published article can be found at: http://www.int-res.com/journals/ab/ab-home/. Keywords: U[subscript crit], CO₂, Mahi-mahi, Ocean ...