Mariculture on the move: climate change impacts on species diversity and richness of salt-water farming

Study of 85 important mariculture species suggest varied and regional effects of climate change with major declines in diversity for tropical and subtropical farming locations

GBIF-mediated data resources used : 681,878 species occurrences
Fish farming near Amarynthos, Euboea, Greece.
Fish farming near Amarynthos, Euboea, Greece. Photo by Jebulon via Wikimedia Commons.

In recent decades, marine aquaculture has played an increasingly important role in supplying nutrition and food security, particularly to the 3.2 billion people who rely on seafood for at least 20 per cent of their protein intake.

To understand the impacts of climate change on these critical yet undervalued resources, a Canadian author team examined the potential reduction and redistribution of 85 species commonly farmed in the world's fjords, inshore and open waters, and saline inland seas. These 55 chordates and 30 mollusks are economically and nutritionally important, accounting for 70 per cent of all taxa used in mariculture.

Using multispecies distribution models that leveraged more than 680,000 GBIF-mediated occurrences with records from OBIS, FishBase and IUCN, the study calculated likely changes to the cultivated species' suitable habitat under both strong and no mitigation policy emissions scenarios across the 2000s, 2050s and 2090s.

While models suggest the expansion of suitable areas in some locations and relatively modest overall reductions in a global-scale index of "marine species richness potential," direct effects of climate change will be much more varied and stronger regionally. For example, changes to the conditions needed for optimal growth in current tropical and subtropical farming locations could see 10 to 40 per cent declines in the number of suitable species. Likewise, suitable marine areas for top-producing countries of Atlantic salmon, cobia and European bass may be lost.

With such changes ahead, this study provides a basis for informing planned adaptation and minimizing potential local-scale environmental impacts and cross-sectoral conflicts.

Oyinlola MA, Reygondeau G, Wabnitz CCC and Cheung WWL (2020) Projecting global mariculture diversity under climate change. Global Change Biology. Wiley 26(4): 2134–2148. Available at: https://doi.org/10.1111/gcb.14974