In less than four months this year, two tragedies swept through Pangasinan’s bangus (milkfish) sanctuaries – the wrath of Typhoon Cosme in June which damaged 80 out of 300 fish cages in Sual town, and the mysterious slashing of six fish cages in the same town in September.
The impact of these two misfortunes was seen and felt immediately, causing the selling price of bangus to record lows and record loss for fish-cage operators. Come to think of it, we are talking about a popularly cultured fish where shelter and food are provided, and its reproduction well attended by humans. But have we seriously given a thought about mass extinction of fish species from our marine, estuarine (fresh and salt water mix), and freshwater reserves?
Reports from numerous international organizations showed that over the past 50 years, bodies of water all over the world have been heating up because of global warming. Most of these reports have similar findings: even the slightest rise in water temperature could have severe effects on fish and aquatic ecosystems, and ultimately on the global food supply and economic stability.
Looking through the fish eyes
In July 2005, the World Wildlife Fund (WWF) released the report, Are we putting our fish in hot water?, which explains the effects of climate change on fisheries worldwide. The report presents a comprehensible account of the plight of fish as they are increasingly threatened by global warming. It avers that fish are more sensitive to temperature than other animals and they cannot survive in temperatures out of the range that they prefer or have been used to.
The metabolism of fish, the report points out, slows down when the water is too cold for them, making them sluggish. But as the water around them warms up, their metabolism speeds up, making them digest their food more rapidly, hence, they grow more quickly and have more energy to reproduce.
“But fish need more food and more oxygen to support this higher metabolism. Warmer fish tend to mature more quickly, but the cost of this speedy lifestyle is often a smaller body size. Ninety percent of aquatic animals like fish raised in warm water end up smaller than their peers raised at cooler temperatures. Many fish will also have less offspring as temperatures rise, and some may not be able to reproduce at all,” the WWF report stated.
“Water may all look the same to us, but for fish, the world is made up of very distinct layers – each with its own temperature and supply of food and oxygen,” the report added. According to WWF, as the water near the surface continues to heat up, it becomes lighter and makes the mixing with the cooler, denser layers of water below harder. Eventually, “as fish crowd into bottom refuges, competition for prey will intensify, and the stresses of low oxygen, low food supply, combined with an increase chance of disease transmission, will make fish more susceptible to disease.”
The food chain effect
Unfortunately, the distress of fish is felt by every living thing that is directly or indirectly affected by its troubles. In the Gulf of Alaska, where large glaciers are found, the fish are shifting to deeper waters. The WWF recounted that when fish in the Gulf moved deep in 1993, about 120,000 seabirds starved to death, most likely because they could not dive deep enough to catch their relocated prey.
“Billions of people throughout the world rely on fish as a primary source of protein, particularly in developing countries with rapidly expanding populations,” the WWF said. In their report, the WWF lamented the fact that though the declining numbers of fish could have a devastating impact on humans both for their health and business, a bigger danger is in store for other wildlife. They cited an 18-year study in Ghana showed that during the years when fish supply was low, sales of meat from a variety of wild animals soared, poaching increased, and 41 species of wild, terrestrial mammals experienced sharp population declines.
Passing on the poison
The WWF report likewise stated that warm water increases the toxicity of pollutants. Thus, as fish pump more water through their gills to meet increased metabolic needs, they also collect more pollutants. The terrifying findings of WWF is that while warmer fish can flush out the extra load of some types of toxins, fish in warmer water accumulate mercury more rapidly even if only small amounts are present.
“Mercury poisoning is already a major economic problem for fisheries in Canada, Japan, and Scandinavia, and poses a significant public health risk. A recent study of 1,700 American women of childbearing age found that blood mercury concentrations were seven times higher in women who ate fish more than twice a week, and because mercury is transferred directly to the fetus during pregnancy, 300,000 babies born each year in the US alone may be exposed to levels of mercury high enough to harm their neurological development,” said WWF.
Recently, tuna producers in the Philippines expressed their anxiety over the dwindling tuna catches over the past few years. According to Mike Lamberte, Fish Port Authority manager in General Santos City, tuna catch in the city has dropped by as much as 34 percent from January to June compared to the same period last year. The tuna industry is considered one of the few bright sectors in our economy and such incidence is bad news for our country. Reports of major dailies said that in 2007, industry players blamed rising global temperature as one of the primary causes of reduced catch. This year, they put the blame squarely on high fuel costs.
Yet it is interesting to note an observation echoed by Dr. Mina T. Gabor, president of the Small and Medium Business Development Foundation, Inc. (PHILSMED) and former Tourism Secretary when she served as one of the resource persons in the technology forum organized by the Bureau of Agricultural Research (BAR) in 2006, and she talked about the prospects of agribusiness in the country. According to her, the Japanese, who import most of Philippine fresh tuna, are becoming quite fastidious when it comes to buying our fish. Apparently, the Japanese are wary about the mercury content in our tuna. Having encountered that report from WWF, we could now relate to the troubles faced by the Americans about mercury poisoning from fish and any health risk we may incur from the exposure of fish to pollutants. Consequently, just by learning about the effects of climate change to the lowly fish, the interconnectivity of all living things on the planet we share and how even the seemingly mundane occurrence could affect everyone else is easier to understand now. But can we do anything about it?
Climate change overload
What is certain is that it’s not only WWF that is raising the flag about climate change. One can easily access an abundance of reports and studies about the effects of climate change to fisheries. Some of these are reports from the United Nations Environment Programme (UNEP), the international marine watchdog group Reef Check, Inter-governmental Panel on Climate Change (IPCC), and the list goes on. In short, the world is now starting to take notice and take the cudgels for saving what we can still enjoy for now.
In the country, there is little literature available or accessible for everyone to peruse. Perhaps, we need to do some catching up on this since the forecast is that the Philippines is among the most vulnerable to the devastating effects of climate change. “The Philippines is not emitting a lot of carbon dioxide, but it’s going to be the biggest victim of climate change,” said Dr. Josefino Comiso, a Filipino senior scientist at the National Aeronautics and Space Administration (NASA). He is also a contributing author to the report on climate change of Nobel winner Inter-governmental Panel on Climate Change. He recently returned to Manila to share his knowledge with the academe under the DOST’s “Balik-Scientist Program”.
Comiso said that since the country is home to a high diversity of species, we are more vulnerable to the effects of temperature escalation. “In the Philippines, there’s more diversity. If you lose 10 percent of them, we’re talking of thousands of species,” he said.
In a collaborative study by the University of California and WWF in 2005 on the Effects of global climate change on marine and estuarine fishes and fisheries, Roessig, et al. said that there is a need to research the physiology and ecology of marine and estuarine fishes, particularly in the tropics where comparatively little research has been conducted. They said that as a broader and deeper information base accumulates, researchers will be able to make more accurate predictions and forge relevant solutions. Now, that’s a green light for our R&D.