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Study: Climate, Environmental Change Puts 90% of World’s Marine Food at Risk

Thai fishermen catch freshwater white tilapia fish at a fish farm in Samut Prakarn province June 6, 2012. (Reuters)
Thai fishermen catch freshwater white tilapia fish at a fish farm in Samut Prakarn province June 6, 2012. (Reuters)
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Study: Climate, Environmental Change Puts 90% of World’s Marine Food at Risk

Thai fishermen catch freshwater white tilapia fish at a fish farm in Samut Prakarn province June 6, 2012. (Reuters)
Thai fishermen catch freshwater white tilapia fish at a fish farm in Samut Prakarn province June 6, 2012. (Reuters)

More than 90% of the world's marine food supplies are at risk from environmental changes such as rising temperatures and pollution, with top producers like China, Norway and the United States facing the biggest threat, new research showed on Monday.

"Blue food" includes more than 2,190 species of fish, shellfish, plants and algae as well as more than 540 species farmed in fresh water, helping sustain 3.2 billion people worldwide.

But not enough is being done to adapt to growing environmental risks, a study published in the Nature Sustainability journal said.

"Although we have made some progress with climate change, our adaptation strategies for blue food systems facing environmental change are still underdeveloped and need urgent attention," said Rebecca Short, researcher at the Stockholm Resilience Center and co-lead author.

Overproduction in the industry, which has driven the destruction of wetland habitats, has caused significant environmental damage but other "stressors" are also impacting the quantity and quality of blue foods.

They include rising sea levels and temperatures, ocean acidification, changes in rainfall, as well as non-climate factors like algal blooms and pollution from mercury, pesticides or antibiotics.

"Vulnerability caused by human-induced environmental change ... puts blue food production under a lot of pressure," said Ling Cao, professor at China's Xiamen University, who also co-wrote the paper.

"We know aquaculture and fisheries support billions of people for their livelihoods and their nutritional security."

China, Japan, India and Vietnam account for more than 45% of global landings and 85% of aquaculture production, and the study said reducing their vulnerability should be a priority. Small island nations that depend on seafood are also especially vulnerable.

Cao said a UN treaty on sustainable development in the high seas, signed in March, could enable stakeholders to act in the common interest when it comes to protecting blue food resources but other risks are on the horizon.

Nauru in the Pacific Ocean is at the forefront of efforts to mine ocean beds for metals, which environmentalists say can cause immense damage to marine life. Norway, another major seafood producer, also came under fire last week after announcing it would open up sea areas to mining.

"Ocean floor mining will have an impact on the wild fisheries population," said Cao. "Many scientists are now calling on governments to evaluate where they do ocean mining in order to minimize the impact."

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Researchers Document Huge Drop in African Elephants in a Half Century

Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
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Researchers Document Huge Drop in African Elephants in a Half Century

Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo
Elephants walk at the Amboseli National Park in Kajiado County, Kenya, April 4, 2024. REUTERS/Monicah Mwangi/File Photo

African elephants are Earth's largest land animals, remarkable mammals that are very intelligent and highly social. They also are in peril. Fresh evidence of this comes in a study that documents alarming population declines at numerous sites across the continent over about a half century.

Researchers unveiled on Monday what they called the most comprehensive assessment of the status of the two African elephant species - the savanna elephant and forest elephant - using data on population surveys conducted at 475 sites in 37 countries from 1964 through 2016.

The savanna elephant populations fell by about 70% on average at the surveyed sites and the forest elephant populations dropped by about 90% on average at the surveyed sites, with poaching and habitat loss the main drivers. All told, there was a 77% population decrease on average at the various surveyed sites, spanning both species, Reuters reported.

Elephants vanished at some sites while their populations increased in other places thanks to conservation efforts.

"A lot of the lost populations won't come back, and many low-density populations face continued pressures. We likely will lose more populations going forward," said George Wittemyer, a Colorado State University professor of wildlife conservation and chair of the scientific board of the conservation group Save the Elephants, who helped lead the study published in the journal Proceedings of the National Academy of Sciences.

Poaching typically involves people killing elephants for their tusks, which are sold illegally on an international black market driven mostly by ivory demand in China and other parts of Asia. Agricultural expansion is the top factor in habitat loss.

The forest elephant population is estimated to be about a third that of savanna elephants. Poaching has affected forest elephants disproportionately and has ravaged populations of both species in northern and eastern Africa.

"We have lost a number of elephant populations across many countries, but the northern Sahel region of Africa - for example in Mali, Chad and Nigeria - has been particularly hard hit. High pressure and limited protection have culminated in populations being extirpated," Wittemyer said.

But in southern Africa, elephant populations rose at 42% of the surveyed sites.

"We have seen real success in a number of places across Africa, but particularly in southern Africa, with strong growth in populations in Botswana, Zimbabwe and Namibia. For populations showing positive trends, we have had active stewardship and management by the governments or outside groups that have taken on a management role," Wittemyer said.

The study did not track a continent-wide population tally because the various surveys employed different methodologies over different time frames to estimate local elephant population density, making a unified head count impossible. Instead, it assessed population trends at each of the surveyed sites.

A population estimate by conservationists conducted separately from this study put the two species combined at between 415,000 and 540,000 elephants as of 2016, the last year of the study period. It remains the most recent comprehensive continent-wide estimate.

"The loss of large mammals is a significant ecological issue for Africa and the planet," said conservation ecologist and study co-author Dave Balfour, a research associate in the Centre for African Conservation Ecology at Nelson Mandela University in South Africa.

The world's third extant elephant species, the slightly smaller Asian elephant, faces its own population crisis, with similar factors at play as in Africa.

Of African elephants, Wittemyer said, "While the trends are not good, it is important to recognize the successes we have had and continue to have. Learning how and where we can be successful in conserving elephants is as important as recognizing the severity of the decline they have experienced."

Wittemyer added of these elephants: "Not only one of the most sentient and intelligent species we share the planet with, but also an incredibly important part of ecosystems in Africa that structures the balance between forest and grasslands, serves as a critical disperser of seeds, and is a species on which a multitude of other species depend on for survival."