Foraging behaviour, swimming performance and malformations of early stages of commercially important fishes under ocean acidification and warming

Abstract

Early life stages of many marine organisms are being challenged by climate change, 35 but little is known about their capacity to tolerate future ocean conditions. Here we 36 investigated a comprehensive set of biological responses of larvae of two 37 commercially important teleost fishes, Sparus aurata (gilthead seabream) and 38 Argyrosomus regius (meagre), after exposure to future predictions of ocean warming (+4 ºC) and acidification (ΔpH=0.5). The combined effect of warming and 40 hypercapnia elicited a decrease in the hatching success (by 26.4 and 14.3% for S. 41 aurata and A. regius, respectively) and larval survival (by half) in both species. The 42 length for newly-hatched larvae was not significantly affected, but a significant 43 effect of hypercapnia was found on larval growth. However, while S. aurata growth 44 was reduced (24.8-36.4% lower), A. regius growth slightly increased (3.2-12.9% 45 higher) under such condition. Under acidification, larvae of both species spent less 46 time swimming, and displayed reduced attack and capture rates of prey. The 47 impact of warming on these behavioural traits was opposite but less evident. While 48 not studied in A. regius, the incidence of body malformations in S. aurata larvae 49 increased significantly (more than tripled) under warmer and hypercapnic 50 conditions. These morphological impairments and behavioural changes are 51 expected to affect larval performance and recruitment success, and further 52 influence the abundance of fish stocks and the population structure of these 53 commercially important fish species. However, given the pace of ocean climate 54 change, it is important not to forget that species may have the opportunity to 55 acclimate and adapt.

Effects of ocean acidification increase embryonic sensitivity to thermal extremes in Atlantic cod, Gadus morhua

“…Future levels of P CO 2 are thus likely to exacerbate the impacts of warming and/or thermal extreme events, such as cold snaps or heat waves, which are expected to become more frequent and more intense with climate change (Stocker et al ., ). Reduced heat tolerance in response to experimental ocean acidification has been reported for early life stages of marine fish species (Pimentel et al ., , ; Flynn et al ., ) and various marine invertebrates (reviewed by Przeslawski et al ., ). In line with these previous studies, our results strengthen the hypothesis that physiological constraints imposed by elevated P CO 2 enhance the susceptibility of organisms to thermal extremes (Pörtner, ), in this case possibly due to an increase in oxygen demand (Fig.…”

Ocean warming has a greater effect than acidification on the early life history development and swimming performance of a large circumglobal pelagic fish

“…In contrast to temperature, there was no effect of elevated p CO 2 on survival, growth or development of larval and juvenile yellowtail kingfish, apart from an increase in the length of larvae at 1 dph. End of century p CO 2 levels, similar to those used in the current study, have been found to increase mortality of larval Atlantic silverside (Baumann, Talmage, & Gobler, ), Atlantic cod (Stiasny et al., ), gilthead seabream and meagre (Pimentel et al., ). In cod, elevated p CO 2 caused the mortality rate to double, which was projected to reduce recruitment to the adult population to just 8–24% of current‐day recruitment in two separate populations (Stiasny et al., ).…”

“…The effects of elevated p CO 2 on fish early life history growth and development are highly variable. Elevated p CO 2 has been observed to reduce (Baumann et al., ; Bignami et al., ; Frommel et al., ; Pimentel et al., ), increase (Bignami et al., ; Chambers et al., ; Munday, Donelson et al., ; Pimentel et al., ; Pope et al., ) or have no effect (Bignami et al., ; Frommel et al., ; Hurst et al., ; Munday, Gagliano, Donelson, Dixson, & Thorrold, ) on larval and juvenile growth in a variety of species. Here, p CO 2 had no effect on growth or morphological development, except at 1 dph, when fish were longer (SL, TL, BL) at elevated p CO 2 compared with control p CO 2 .…”

Embryonic canalization and its limits—A view from temperature

“…A literature search found a few examples of testing embryogenesis to failure under high‐temperature challenge. One case in fish revealed defects in notochord development associated with rearing at high temperature, suggesting that axial mesoderm morphogenesis is particularly sensitive to high temperature (Lopes, Araújo‐Dairiki, Kojima, Val, & Portella, 2018; Pimentel et al, 2014, 2016). Similar results were found by Irvine et al (2019) in the ascidian C. intestinalis , where deformities in the notochord are the first apparent defects found as rearing temperature increased.…”