Projecting climate change impacts on Mediterranean finfish production: a case study in Greece

Abstract

Finfish aquaculture in the Mediterranean Sea faces increasing challenges due to climate change, while potential adaptation requires a robust assessment of the arising threats and opportunities. This paper presents an approach developed to investigate effects of climate drivers on Greek aquaculture, a representative Mediterranean country with a leading role in the sector. Using a farm level approach, dynamic energy budget models for European seabass and meagre were developed, and environmental forcing was used to simulate changes in production and farm profitability under IPCC scenarios RCP45 and RCP85. The effects of temperature and extreme weather events at the individual and farm levels were considered along with that of husbandry parameters such as stocking timing, market size, and farm location (inshore, offshore) for nine regions. The simulations suggest that at the individual level, fish may benefit from warmer temperatures in the future in terms of growth, thus reaching commercial sizes faster, while the husbandry parameters may have as large an effect on growth as the projected shifts in climatic cues. However, this benefit will be largely offset by the adverse effects of extreme weather events at the population level. Such events will be more frequent in the future and, depending on the intensity one assigns to them, they could cause losses in biomass and farm profits that range from mild to detrimental for the industry. Overall, these results provide quantification of some of the potential threats for an important aquaculture sector while suggesting possibilities to benefit from emerging opportunities. Therefore, they could contribute to improving the sector’s readiness for tackling important challenges in the future.

Influence of Production Strategy on Gross Waste Output and Temporal Pattern of Gilthead Seabream (Sparus Aurata) Farming: Implications for Environmental Management

“…The chosen production strategy can also serve as a mechanism through which fish farms can adapt to the effects of climate change. In the case of GHSB growing in cage farms in the Mediterranean, sea water warming will enhance the growth rate, and the fish will reach commercial size faster, provided that the upper temperature tolerance threshold is not exceeded [37,53]. However, the increased temperature is expected to favor the spread of parasites and diseases and may even result in the emergence of new ones.…”

“…Fish of different ages (size) are therefore present within the farm at any given time. The dates of fish entry-four per year-were set according to a schedule resembling the Mediterranean GHSB stock management farming conditions [37]-i.e., in April, June, August, and September for a culture length of 16, 15, 15, and 17 months, respectively-predicted according to Mayer et al [33]. The temperature regime is shown in Figure 1.…”

Metabolic scope, performance and tolerance of juvenile European sea bass Dicentrarchus labrax upon acclimation to high temperatures

“…This is critical for the aquaculture industry in the context of climate change since appropriate management and climate mitigation strategies must rely on sound biological grounds. Enhancing our understanding on the optimal temperatures and the tolerance thresholds for a species, which this study strives to do, could contribute not only to decisions regarding site selection as mentioned previously but also to altering management practices such as the timing of seeding and the harvesting size in order to optimize production at a given area [4,6,8]. For instance, adjusting the time of seeding may allow certain areas to benefit from the prolonged warmer season in terms of growth [4] while areas where summer temperatures are already close to the thermal limits reported here may benefit from a harvesting strategy towards smaller sizes, thus, minimizing losses due to heatwaves.…”

“…The species is eurythermal and known to have great adaptation capacity to rapidly fluctuating temperatures [2]; traits which have contributed to its widespread distribution and commercial exploitation. However, it is uncertain whether the production of such a key species will remain secure in the future in the context of global warming, with studies postulating on the potential effects of climate change on the species and the overall aquaculture production across its distribution range [3][4][5]. Depending on the region and choice of climate scenario, such effects may include, among others, positive or negative changes in growth performance, seasonal shifts in growth patterns, adverse impacts of extreme events on survival and growth, changes in the physiology and health status of the fish, as well as changes in production volumes and the profitability of the farms [3][4][5][6][7][8].…”

“…However, it is uncertain whether the production of such a key species will remain secure in the future in the context of global warming, with studies postulating on the potential effects of climate change on the species and the overall aquaculture production across its distribution range [3][4][5]. Depending on the region and choice of climate scenario, such effects may include, among others, positive or negative changes in growth performance, seasonal shifts in growth patterns, adverse impacts of extreme events on survival and growth, changes in the physiology and health status of the fish, as well as changes in production volumes and the profitability of the farms [3][4][5][6][7][8]. In that regard, assessing the vulnerability of E. sea bass to climate change necessitates consideration of both chronic and acute effects of elevated temperatures on its physiology.…”