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

S Bignami, S Sponaugle, RK Cowen
2014 Aquatic Biology  
Negative impacts of CO 2 -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
more » ... e. Mahi-mahi larvae were raised for up to 21 d under either ambient seawater conditions (350 to 490 µatm pCO 2 ) or projected scenarios of ocean acidification (770 to 2170 µatm pCO 2 ). Evaluation of hatch rate, larval size, development, swimming activity, swimming ability (U 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 pCO 2 via a corresponding decrease in routine swimming velocity. Furthermore, larvae had significantly larger otoliths at 2170 µatm pCO 2 , and a similar but non-significant trend also occurred at 1200 µatm pCO 2 , 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. KEY WORDS: Ocean acidification · Larval fish · Otolith · Mahi-mahi · CO 2 · U crit · Behavior OPEN PEN ACCESS CCESS LITERATURE CITED Anderson J (1988) A review of size dependent survival during pre-recruit stages of fishes in relation to recruitment. J Northwest Atl Fish Sci 8: 1−12
doi:10.3354/ab00598 fatcat:tmyatavodjalbiab7y3iyj4d3y