Climate change will alter this region's fisheries, in many cases making them more productive, but in some cases having negative results, according to a study released yesterday in the journal Nature Climate Change. Because of the many ways in which fisheries will change in the next 20, 50 and 100 years, nations need to prepare and adapt, say the authors of the study.
These authors, a set of scientists mostly from around the region, looked at how climate change would affect the location of schools of tuna, freshwater fisheries, aquaculture and coastal fisheries around coral reefs and in mangrove forests.
Their "end to end" analysis combined models and scenarios with economic impacts and recommendations for adaptations to limit negative effects on local people and economies.
The hope, said study co-author Peter Gehrke, an Australia-based fisheries ecologist, is that the analysis will serve as a guideline for countries crafting climate adaptation policies and for entities undertaking development projects in the region.
"It's not just a description or some projections of what the effects of climate change are going to be on fisheries," but a means to improve actual policies, Gehrke said.
One key finding of the study was the projection that economically important skipjack tuna populations will move toward the eastern part of the region over time.
Changing the economics of licensing
Since a number of the island countries in this region receive significant tax revenues from the tuna fishing licenses they sell to other nations, this could have an effect of moving the benefits of that resource to more Eastern countries. This might be a good thing, said Johann Bell, a fisheries scientist and another of the study's authors.
"Small countries in the East don't have a lot of way of making more money. So they should be in a position of having more fishing going on in their zones and can attract higher taxes," Bell said.
In the meantime, relatively larger countries like Papua New Guinea in the western part of the region will still be able to capitalize on the infrastructure they have for canning and processing the tuna, which will still be transported there for those value-adding activities, Bell said.
Despite this potential boon to Eastern island nations from climate change-forced tuna migration, Patrick Lehodey, a paper co-author and expert on tuna, noted that overfishing must be addressed if countries wish to continue to benefit economically from tuna fishing.
"It's important to mention that even [in] the case of Pacific skipjack tuna, the last stock assessment studies indicate that the species exploitation level is still above its maximum sustainable yield. Fishing remains today and for the coming decade the major driver of this (and many other) fish populations," Lehodey wrote in an email.
Because coral reefs and mangroves in the region are going to be negatively affected by climate change, the study suggests that island countries help locals, who in some rural areas get 50 to 90 percent of their protein from fish around coral reefs as well as from tuna, transition to getting more of their food from other ocean fish, too.
One way of doing this is to install fish aggregating devices, called FADs. These are basically stationary objects, like a buoy, that attract fish. In recent years, inexpensive FADs have been developed for just this purpose, Bell said.
The study also found a potential negative impact on the lucrative black pearl industry, which is worth upward of $100 million a year in French Polynesia. People on remote atolls in the region have historically earned a living cultivating the pearls, but ocean acidification will weaken oyster shells and also possibly negatively affect the quality of pearls.
The black pearl industry has already taken a hit due to the global financial crisis and oversupply, which lowered prices in recent years, Bell said.
The study's authors recommended relocating pearl farming operations to sites where these impacts won't be felt as much, such as deeper waters or those protected by coral reefs and seagrass.
More rain could mean more fish
In freshwater systems, the study found that increased rainfall and warmer temperature are likely to boost fish populations, as long as logging, mining and agricultural activity are managed to reduce erosion and pollution of rivers.
Freshwater aquaculture could also develop more due to these factors. More rain means locals could easily invest in simple, rain-fed tilapia ponds. This could help them have another source of protein and income.
Because there are so many potential benefits from climate change to productivity in freshwater ecosystems, Australia's Gehrke highlighted how important it is for these developing nations to protect those resources.
As populations in these regions boom, companies look to capitalize on resources like metals and timber, and as the countries look to develop, they need to have an eye to how these activities interact with the effects of climate change.
"I think the thing that I would highlight really is that the importance of sound [river] catchment management and vegetation management and planting trees now to improve water quality," Gehrke said. "What's good for local catchments is good for coral reefs and offshore fisheries, as well."
To aid in this effort, the authors of the study have also produced a book on vulnerabilities and adaptation to climate change in tropical Pacific industries.