Editing IPCC:AR6/WGII/Chapter-11 (section)

==== 11.3.4.4 Marine Food ====

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===== 11.3.4.4.1 Observed impacts =====

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The ecological impacts of climate change on fisheries species have already emerged ( ''high confidence'' ) ( [[#Morrongiello--2015|Morrongiello and Thresher, 2015]] ; [[#Gervais--2021|Gervais et al., 2021]] ). This includes loss of habitats for fisheries species ( [[#Vergés--2016|Vergés et al., 2016]] ; [[#Babcock--2019|Babcock et al., 2019]] ) and poleward shifts in the distribution of barrens-forming urchins ( [[#Ling--2018|Ling and Keane, 2018]] ) impacting abalone and rock lobster fisheries. The percentage of reef as barrens across eastern Tasmania grew from 3.4% to 15.2% from 2001/2002 to 2016/2017, an approx. 10.5% increase per annum over the 15-year period ( [[#Ling--2018|Ling and Keane, 2018]] ). Oysters farmed from wild spat (Sydney rock oysters ''Saccostrea glomerata'' ) are most at risk from climate change, primarily due to observed increases in summer temperatures and heatwave-related mortalities ( [[#Doubleday--2013|Doubleday et al., 2013]] ). The exceptional 2017/2018 summer heatwave caused significant losses of farmed salmon in New Zealand, with farm owners seeking consent to move operations to cooler water ( [[#Salinger--2019b|Salinger et al., 2019b]] ).

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===== 11.3.4.4.2 Projected impacts =====

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Aquaculture is projected to be more easily adapted than wild fisheries to avoid excessive exposure to the physio-chemical stresses from acidification, warming and extreme events ( [[#Richards--2015|Richards et al., 2015]] ). In New Zealand, wild and cultured shellfish are identified as being most at risk from climate change ( [[#Capson--2014|Capson and Guinotte, 2014]] ). Changes in ocean temperature and acidification and the downstream impacts on species distribution, productivity and catch are projected concerns ( ''medium confidence'' ) ( [[#Law--2016|Law et al., 2016]] ) that impact Māori harvesting of traditional seafood and the social, cultural and educational elements of food gathering (mahinga kai) ( [[#MfE--2016|MfE, 2016]] ). Warm temperate hatchery-based finfish species (yellowtail kingfish ''Seriola lalandi'' ) are projected to be the least at risk, because of well-controlled environmental conditions in hatcheries and temperature increases, which are expected to increase growth rates and productivity during the grow-out stage ( [[#Doubleday--2013|Doubleday et al., 2013]] ). For wild fisheries, multi-model projections suggest temperate and demersal systems, especially invertebrate shallow-water species, would be more strongly affected by climate change than tropical and pelagic systems ( ''medium confidence'' ) ( [[#Pecl--2014|Pecl et al., 2014]] ; [[#Fulton--2018|Fulton et al., 2018]] ; [[#Pethybridge--2020|Pethybridge et al., 2020]] ). In New Zealand waters, available habitat for both albacore tuna and oceanic tuna ( [[#Cummings--2021|Cummings et al., 2021]] ) is expected to widen and shift.

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===== 11.3.4.4.3 Adaptation =====

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Selective breeding in oysters is projected to be an important global adaptation strategy for sustainable shellfish aquaculture that can withstand future climate-driven change to habitat acidification ( [[#Fitzer--2019|Fitzer et al., 2019]] ). Less than a quarter of fisheries management plans for 99 of Australia’s most important fisheries considered climate change, and only to a limited degree ( [[#Fogarty--2019|Fogarty et al., 2019]] ; [[#Fogarty--2021|Fogarty et al., 2021]] ). Implementation of management and policy responses to climate change have lagged in part because climate change has not been considered as the most pressing issue ( [[#Hobday--2017|Hobday and Cvitanovic, 2017]] ; [[#Fogarty--2019|Fogarty et al., 2019]] ; [[#Fogarty--2021|Fogarty et al., 2021]] ) (Cross-Chapter Box MOVING SPECIES in Chapter 5).

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