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of the warm pool and the central distributions of tropical tuna “On the grandest scale, increasing water temperatures
species are projected to move easterly in response. are affecting the global movement of the cold oceanic deep
Pacific Community (SPC) Senior Coastal Fisheries scientist, water which underpin the current systems of the world,” says
Andrew Halford says the flow-on effects of mass coral Halford. “These currents drive the current climate patterns
bleaching events, such as those being witnessed in Australia and if significant changes occur to these systems, they will
“are being more frequently documented with evidence not likely be reversed, even if global warming processes are
that fish and invertebrate communities, which rely on coral substantially reduced.
reef ecosystems for their survival, are being fundamentally “Substantial loss of coral reef habitats and associated
changed. ecosystems (seagrass meadows for example have suffered
“As well as being a key source of food and shelter for badly from heat waves and also cyclone related turbidity)
communities, coral reefs also buffer the erosion effects will reduce the habitat needed for many species of fish and
of waves and swell on island shorelines,” says Halford. invertebrates to recruit to, shelter in and feed within and
“Degraded coral reefs not only support less fish and on. This will lead to substantial changes in the abundance
invertebrates, but they also become less effective at and distribution of many species that are part of food fish
moderating shoreline erosion around island communities. This assemblages across the Pacific,” he states.
situation is escalating because rising ocean temperatures are “A potentially more significant issue are the effects of
also causing sea levels to rise which is working in tandem with climate change on the early and relatively less well studied
eroding reef systems to cause more frequent inundation of parts of the life cycle of fish and invertebrates,” says
coastal land and higher levels of erosion. Drowning of land has Halford. “Changes to the reproductive capacity of fishes and
direct effects on agricultural output, another mainstay of food invertebrates, the access to food when they are part of the
security in the PICTs.” plankton and their ability to grow and recruit successfully to
He says that water temperature is a key component of their adult habitats are all possible under changing climate
modulating ocean acidity, with increasing temperature conditions. Very small differences at the beginning of the
increasing the acidity of sea water. Organisms that produce lifecycle can have very profound changes on adult populations
a calcium-based skeleton such as corals, clams, oysters and and their ability to persist.
lobsters are vulnerable to a more acidic environment due to “Perhaps the largest effect will be on social and socio-
a reduced uptake of calcium carbonate, resulting in thinner economic systems within the Pacific which are so intrinsically
skeletons that are more prone to damage. Water chemistry bound to the sea. Large changes in the availability of marine
is critical to so much of the life cycle of marine organisms protein could have major flow-on effects which could
with documented effects on, for example, fertilisation rates, de-stabilise work-life systems that have been in place for
larval development, and the ability of fish to avoid predation. millennia.”
Changes to the chemistry of sea water due to climate change
is already having a significant effect on marine productivity editor@islandsbusiness.com
and the global carbon cycle upon which life depends.

MICRO PLASTICS, MACRO PROBLEM

By Samantha Magick agreement on combatting marine plastic litter and plastic pol-
lution for consideration by the end of next year.
An estimated 150 million tonnes of plastic are circulating UNEP Executive Director, Inger Andersen, called it the most
in our oceans, and that figure is growing by the equivalent of important international multilateral environmental deal since
one-truckload every minute, the United Nations Environment the Paris climate accord.
Program says. The agreement will cover the full life cycle of plastics from
Plastic pollution was a critical concern at the Our Ocean production to disposal and will include microplastics in its
conference in Palau this year, which ended with 71 com- scope. Plastic takes hundreds of years to break down; it’s be-
mitments worth US$3.3 million to tackle marine pollution, lieved just 20% of the plastic created since the 1950s has been
including AUD$15 million from Australia for a Pacific waste incinerated or successfully recycled.
program
Plastic appears to be embedded throughout the food chain. Running a tight ship
In Palau, President of the UN General Assembly, Abdulla While most ocean pollution comes from land sources, the
Shahid, said: “Just last week, researchers found, for the first Pacific is also focussed on cutting plastic waste from fishing
time, microplastics in lungs of humans, highlighting the scale vessels.
and severity of the problem.” Recent studies cited by the International Union for Conser-
Given the threat posed by plastic waste, the March session vation of Nature (IUCN) have suggested that “between 46%
of the UNEP assembly resolved to work towards a new global and 70% of the floating macroplastics in the ocean gyres is

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