| 1. |
- Wexler, J. B., et al.
(författare)
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The effect of ocean acidification on otolith morphology in larvae of a tropical, epipelagic fish species, yellowfin tuna (Thunnus albacares)
- 2023
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Ingår i: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 569
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Tidskriftsartikel (refereegranskat)abstract
- Increasing ocean acidification is a concern due to its potential effects on the growth, development, and survival of early life stages of tuna in oceanic habitats and on the spatial extent of their suitable nursery habitat. To investigate the potential effects of increasing CO2 on otolith calcification of 9-day old pre-flexion stage yellowfin tuna (Thunnus albacares), an experiment was conducted at the Inter-American Tropical Tuna Commission's Achotines Laboratory in Panama during 2011. Fertilized eggs and larvae were exposed to mean pCO2 levels that ranged from present day (355 mu atm) to two levels predicted to occur in some areas of the Pacific in the near future (2013 and 3321 mu atm), and to an extreme value equivalent to long-term projections for 300 years in the future (9624 mu atm). The results indicated significantly larger otoliths (in area and perimeter) with significant, and increasing, fluctuating asymmetry at acidification levels similar to those projected for the near future and long-term. Otoliths increased significantly in size despite a significant decrease in somatic length with increasing pCO2. A consistent correlation between otolith and somatic growth of yellowfin tuna larvae among treatments was evident (i.e., larger otoliths were still associated with larger larvae within a treatment). The observed changes in otolith morphology with increasing ocean acidification have the potential to indirectly affect larval survival through dysfunction of the mechanosensory organs, but this remains to be verified in yellowfin tuna larvae.
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| 2. |
- Bromhead, D., et al.
(författare)
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The potential impact of ocean acidification on eggs and larvae of the Yellowfin Tuna.
- 2015
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Ingår i: Deep-sea research. Part II, Topical studies in oceanography. - : Elsevier BV. - 0967-0645. ; 113, s. 268-279
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic carbon dioxide (CO2) emissions are resulting in increasing absorption of CO2 by the earth's oceans, which has led to a decline in ocean pH, a process known as ocean acidification (OA). Evidence suggests that OA may have the potential to affect the distribution and population dynamics of many marine organisms. Early life history processes (e.g. fertilization) and stages (eggs, larvae, juveniles) may be relatively more vulnerable to potential OA impacts, with implications for recruitment in marine populations. The potential impact of OA upon tuna populations has not been investigated, although tuna are key components of pelagic ecosystems and, in the Pacific Ocean, form the basis of one of the largest and most valuable fisheries in the world. This paper reviews current knowledge of potential OA impacts on fish and presents results from a pilot study investigating how OA may affect eggs and larvae of yellowfin tuna, Thunnus albacares. Two separate trials were conducted to test the impact of pCO2 on yellowfin egg stage duration, larval growth and survival. The pCO2 levels tested ranged from present day ($400 μatm) to levels predicted to occur in some areas of the spawning habitat within the next 100 years (o2500 μatm) to 300 years ($ o5000 μatm) to much more extreme levels ($10,000 μatm). In trial 1, there was evidence for significantly reduced larval survival (at mean pCO2 levelsZ4730 μatm) and growth (at mean pCO2 levels Z 2108 μatm), while egg hatch time was increased at extreme pCO2 levelsZ10,000 μatm (nintermediate levels were not tested). In trial 2, egg hatch times were increased at mean pCO2 levelsZ1573 μatm, but growth was only impacted at higher pCO2 (Z8800 μatm) and there was no relationship with survival. Unstable ambient conditions during trial 2 are likely to have contributed to the difference in results between trials. Despite the technical challenges with these experiments, there is a need for future empirical work which can in turn support modeling-based approaches to assess how OA will affect the ecologically and economically important tropical tuna resources.
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| 3. |
- Frommel, A. Y., et al.
(författare)
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Ocean acidification has lethal and sub-lethal effects on larval development of yellowfin tuna, Thunnus albacares
- 2016
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 482, s. 18-24
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification (OA), the process by which increasing atmospheric CO2 is absorbed by the ocean, lowering the pH of surface waters, has been shown to affect many marine organisms negatively. It has been suggested that organisms from regions with naturally low pH waters, such as upwelling areas, could serve as models for future effects of OA and may be adapted to increased pCO(2) levels. In this study, we examined the effects of OA on yellowfin tuna, a highly pelagic species that spawns in the eastern tropical Pacific, an area that includes regions of strong upwelling events. Larvae reared at decreasing pH levels (pH 8.1, 7.6, 7.3 and 6.9) showed increasing organ damage in the kidney, liver, pancreas, eye and muscle, which correlated with decreased growth and survival. These findings complement earlier studies on organ damage in Atlantic cod and herring larvae and demonstrate that OA may have detrimental effects on fish larvae, regardless of their pre-exposure to low pH waters.
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| 4. |
- Nicol, S., et al.
(författare)
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Ocean Futures for the World’s Largest Yellowfin Tuna Population Under the Combined Effects of Ocean Warming and Acidification
- 2022
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The impacts of climate change are expected to have profound effects on the fisheries of the Pacific Ocean, including its tuna fisheries, the largest globally. This study examined the combined effects of climate change on the yellowfin tuna population using the ecosystem model SEAPODYM. Yellowfin tuna fisheries in the Pacific contribute significantly to the economies and food security of Pacific Island Countries and Territories and Oceania. We use an ensemble of earth climate models to project yellowfin populations under a high greenhouse gas emissions (IPCC RCP8.5) scenario, which includes, the combined effects of a warming ocean, increasing acidification and changing ocean chemistry. Our results suggest that the acidification impact will be smaller in comparison to the ocean warming impact, even in the most extreme ensemble member scenario explored, but will have additional influences on yellowfin tuna population dynamics. An eastward shift in the distribution of yellowfin tuna was observed in the projections in the model ensemble in the absence of explicitly accounting for changes in acidification. The extent of this shift did not substantially differ when the three-acidification induced larval mortality scenarios were included in the ensemble; however, acidification was projected to weaken the magnitude of the increase in abundance in the eastern Pacific. Together with intensive fishing, these potential changes are likely to challenge the global fishing industry as well as the economies and food systems of many small Pacific Island Countries and Territories. The modelling framework applied in this study provides a tool for evaluating such effects and informing policy development.
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