Vulnerability of coastal fisheries - Chapter 9 -

Presented byMorgan Pratchett

Importance of coastal fisheriesFiji

Coastal Fisheries Production

Gillett 2009

Coastal Fisheries Production

What are coastal (inshore) fisheries?

i. Demersal fish

ii. Nearshore pelagics

iii. Invertebrates

What are not considered (so far)i. Deepwater snapper

ii. Sharks

i. Demersal fish

ii. Nearshore pelagic fish

iii. Invertebrates

Coastal fisheries - Fiji

17,450 t/yr

5,270 t/yr

4,180 t/yr

Indirect effects of climate change

Seagrass area

Coral cover

65% decline in abundance

and diversity of fishes

Pro

port

iona

l cha

nge

Time after extensive coral loss (years)

0 1 2 3 4 5 6 7 8 9 10

0.5

0

-0.5

-1

Macroalgae

Coral cover

Habitatcomplexity

Effects of habitat degradation

Pro

port

iona

l cha

nge

Time after extensive coral loss (years)

0 1 2 3 4 5 6 7 8 9 10

0.5

0

-0.5

-1

Coral reef fishes

Macroalgae

Coral cover

Habitatcomplexity

Effects of habitat degradation

Coral associatedHighly vulnerable

Reef associatedVulnerable

GeneralistsNot vulnerable

Catch composition

Catch composition - Fiji

Catch composition - Fiji

Direct effects of climate change

Temperature

pH

Temperature (oC)Temperature (oC)

Maximum growth28-30oC

Acanthochromis polyacanthus

Projected Projected increaseincrease

33ooC by 2100C by 2100

Effects of temperature

Zarco Perello and Pratchett 2012

Maximum growth28-30oC

Effects of temperature

Fewer &smaller fishes

Declines in: growth lifespan reproduction

Projected Projected increaseincrease

33ooC by 2100C by 2100

Temperature (oC)Temperature (oC)

Zarco Perello and Pratchett 2012

Effects of temperature

Nor

mal

spa

wni

ng t

empe

ratu

re

Effects of ocean acidificationAbalone

Byrne 20120

Effects of ocean acidification

Munday et al 2012

Effects of ocean acidification

Munday et al 2012

Pro

ject

ed c

hang

es in

m

axim

um f

ishe

ries

prod

uctio

n

2000 2020 2040 2060 2080 2100

100

80

60

40

20

0

B1A2

20302-5% decline in demersal fishesPotential increase in nearshore pelagics2-5% decline in invertebrates

2100•Response conditional on emission scenario•Up to 50% decline in production, due mostly to habitat degradation and effects on fishes•Declines may be partly offset by slight increase in nearshore pelagic fishes

Projected coastal fisheries productionFiji

Fisheries % 2035 2050 2100 Main effects

Demersal fish 65 -2 to -5% -20% -20 to -

50%

Habitat loss and

degradation

Nearshore pelagic fish 20 +15 to

20% +20% +10%Changes in

distribution of tuna

Invertebrates 15 0 to -5%

-5 to -10%

-10 to -20%

Declining aragonite saturation

Page 54, Country summaries

Priority adaptations1. Protect the structural complexity and biological

diversity of coral reefs, mangroves and sea grasses to sustain fisheries and maximize adaptation potential.

2. Recognise the ecological importance of specific fishes (e.g, herbivorous fishes on coral reefs), and ensure stocks of these species are sufficient to maintain key ecosystem functions.

Priority adaptations3. Diversify coastal fisheries activities to target

species and habitats that will be least affected (or favoured) by climate change

4. Build the effects of climate change into fisheries

management and planning, particularly the need to maintain adequate spawning stocks to overcome the shocks of greater climate extremes

Conclusions• Coastal fisheries are critically important for

both food security and livelihoods across the Pacific

• Effects of climate change will compound upon existing anthropogenic disturbances and pressures (e.g., overfishing).

Conclusions

• Improved data on coastal fisheries catches is important for monitoring, understanding and predicting the effects of climate change on coastal fisheriesReporting– subsistence fisheries catches– separate data for distinct fisheries sectors

and species, wherever possible

• Up until 2035, effects of climate change will be difficult to detect against the backdrop of existing anthropogenic disturbances, but urgent action on climate change is critical to minimize long-term impacts

Conclusions%

cha

nge

2000 2020 2040 2060 2080 2100

100

80

60

B1A2