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Food supply falls as fish flee warmer seas

Food supply falls as fish flee warmer seas

Both jobs and food are at risk as fish evade rising warmth. Image: By Lalo on Unsplash

On the fishing grounds, they already know about global warming. As fish flee warmer seas there are winners – but many more losers.

LONDON, 4 March 2019 – Global warming has already begun to affect fishing worldwide as fish flee warmer seas, a new study says.

In the last 80 years, there has been an estimated drop of more than 4% in sustainable catches for many kinds of fish and shellfish. That is the average. In some regions – the East China Sea, for instance, and Europe’s North Sea–  the estimated decline was between 15% and 35%.

In the course of the last century, global average temperatures have crept up by about 1°C above the average for most of human history, as a reaction to the unconstrained burning of fossil fuels. If the world continues to burn ever-greater volumes of coal, oil and natural gas, it could be 3°C warmer or more by the end of the century.

Last year was only the fourth warmest for air surface temperatures, but the warmest since records began for the world’s oceans.

“Fisheries around the world have already responded to global warming. These aren’t hypothetical changes some time in the future”

US researchers report in the journal Science that they looked at the impact of ocean warming in 235 populations of 124 species of fish, crustaceans and molluscs in 38 ecological regions between the years 1930 and 2010.

They then matched the world data on fish catches with ocean temperature maps to estimate what warming has done to the sustainable catch – that is, the biggest haul fishing crews can make without reducing breeding stocks for the seasons to follow.

 …click on the above link to read the rest of the article…

Warmer waters leave Irish anglers fishless

Warmer waters leave Irish anglers fishless

Anglers’ prize: But the salmon is not doing well in Irish waters. Image:  Via Wikimedia Commons [public domain]

Irish anglers are having little luck as fish feel the effects of warmer waters − which are also increasing greenhouse gases.

WEST OF IRELAND, 16 January, 2019 − Unusually high temperatures in 2018 have left many Irish anglers frustrated as fish struggle to survive in the Emerald Isle’s lakes and rivers, with the rising heat also causing an increase in methane emissions.

Now changes in climate could threaten the anglers’ activities, putting in jeopardy what is a multi-million euro leisure industry.

Inland Fisheries Ireland (IFI), a state agency, says that a heat wave across Ireland in the summer of 2018 caused temperatures in the country’s lakes and rivers to rise to what it describes as lethal levels for a number of freshwater fish species.

The IFI’s findings, reported in the Irish Times newspaper, indicate that the two most affected species were salmon and trout – both prized by the freshwater fishing community.

“The 2018 summer water temperatures need to be considered in the context of climate change predictions”, Cathal Gallagher, the IFI’s head of research, told the Irish Times.“If temperatures continue to increase, sensitive cold water fish species will be at risk.”

Long heat

The warming trends were most noted in the west of Ireland, says the IFI. One of the worst affected rivers was the Owenriff in County Galway, where temperatures well above summer time norms were recorded over a prolonged period.

Dr Gallagher says high temperatures could lead to localised extinction of native fish diversity in the future; there would be knock-on economic losses.

“We would reach a stage where the Owenriff catchment or similar catchments become inhospitable to brown trout and salmon over the summer period in the near future.”

…click on the above link to read the rest of the article…

As Disease Ravages Coral Reefs, Scientists Scramble for Solutions

A research diver looks for signs of stony coral tissue loss disease in Florida Keys National Marine Sanctuary.

A research diver looks for signs of stony coral tissue loss disease in Florida Keys National Marine Sanctuary. JIM ABERNETHY

As Disease Ravages Coral Reefs, Scientists Scramble for Solutions

As oceans warm, coral reefs are suffering not only from bleaching but from deadly outbreaks of disease. Researchers are developing remedies, but the key question is whether these solutions can work on a large-enough scale to save vast reef systems from Florida to Australia.

In September 2014, William Precht received an alarming phone call. “I’m seeing something funky out on the reef,” a colleague reported. “It looks like disease.” At the time, Precht, a marine biologist and environmental consultant working in coral reef restoration, had been monitoring a Port of Miami dredging project to ensure preservation of the nearby ecosystem. When Precht donned his scuba gear and dove to the site to investigate a few weeks later he couldn’t believe what he found. “The whole reef was lit up in disease,” he recounts. There were more than 30 coral colonies (each 4 to 16 inches across) with white bands and lines on them, and other corals were entirely white. “You could see this line of mortality moving across the reef — I was blown away.”

Precht was witnessing the early signs of a new and rapidly spreading coral disease outbreak sweeping along the Florida coastline, threatening the third-largest reef ecosystem in the world. The outbreak first appeared in pockets of diseased coral near Miami. Four years later, it covers 96,000 acres of reef extending about 275 miles from West Palm Beach to the lower Florida Keys. By some estimates, as much as 35 percent of the coral population has been lost. Several species have nearly vanished, including majestic colonies of pillar corals (Dendrogyra cylindrus), a threatened species that can reach heights from 6 to nearly 10 feet. The few surviving colonies are now known as “the last unicorns.”

…click on the above link to read the rest of the article…

British Columbia First Nations’ Failing Fisheries

Climate change means marine creatures are migrating—away from First Nations’ territory.

As a new study warns, “unprecedented climate change poses a considerable threat” to First Nations’ food, cultural, and economic values. By 2050, aboriginal catches are expected to decline significantly, depriving indigenous people from 16 coastal communities of up to CAN $12-million annually in commercial fisheries, the study shows.

Warming and changing oxygen concentrations in the ocean, spurred on by anthropogenic climate change, will send marine life swimming northward at an average rate of about 10 to 18 kilometers per decade. For the 98 fish and invertebrate species studied, this will equate to an average drop in annual catches of 4.5 to 11 percent, with the declines being much higher for certain species.

The study shows that two critical species will suffer the greatest declines: salmon by 17 to 29 percent; and their prey, herring, by 28 to 49 percent. Catches of green sea urchin could shrink by as much as 36 percent, flounder and sole by 30 percent, shrimp and prawns by 18 percent, and halibut by 13 percent.

Aboriginal groups located in British Columbia’s more southerly waters are expected to suffer the greatest catch losses: up to 27 percent for the Tsawwassen First Nation near the Canada-United States border, compared with 6.6 percent for the Haida First Nation off the province’s north coast.

…click on the above link to read the rest of the article…

Olduvai IV: Courage
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Olduvai II: Exodus
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