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Two-thirds of the world's fish stocks are either fished at their limit or over fished. The UN food and agriculture organisation (FAO) has estimated that 70 percent of the fish population is fully used, overused or in crisis.
Marco Lambertini, director general of WWF International, told Reuters mismanagement was pushing "the ocean to the brink of collapse.".
"There is a massive, massive decrease in species which are critical," both for the ocean ecosystem and food security for billions of people, he said. "The ocean is resilient but there is a limit."
It has been some time since most humans lived as hunter-gatherers – with one important exception. Fish are the last wild animal that we hunt in large numbers. And yet, we may be the last generation to do so.
Entire species of marine life will never be seen in the Anthropocene (the Age of Man), let alone tasted, if we do not curb our insatiable voracity for fish. Last year, global fish consumption hit a record high of 17 kg (37 pounds) per person per year, even though global fish stocks have continued to decline. On average, people eat four times as much fish now than they did in 1950.
But by 1989, when about 90 million tons (metric tons) of catch were taken from the ocean, the industry had hit its high-water mark, and yields have declined or stagnated ever since. Fisheries for the most sought-after species, like orange roughy, Chilean sea bass, and bluefin tuna have collapsed. In 2003, a scientific report estimated that industrial fishing had reduced the number of large ocean fish to just 10 percent of their pre-industrial population.
Faced with the collapse of large-fish populations, commercial fleets are going deeper in the ocean and father down the food chain for viable catches. This so-called "fishing down" is triggering a chain reaction that is upsetting the ancient and delicate balance of the sea's biologic system.
A study of catch data published in 2006 in the journal Science grimly predicted that if fishing rates continue apace, all the world's fisheries will have collapsed by the year 2048.
Few fishing boats head out from Bonavista anymore, and none that fish for cod—there has been a near-total ban on cod fishing in Newfoundland since 1992, when stocks finally collapsed completely.
The study found that global fish catches peaked at 130 million tonnes in 1996 and have declined by around 1.2 million tonnes per year since then as a result of overfishing exhausting the supply.
In contrast, the official figures compiled by the UN’s Food and Agriculture Organisation state that the peak in 1996 was 86 million tonnes and has since then been declining by a relatively modest rate of about 0.38 million tonnes per year.
Following World War Two, industrial fishing rapidly expanded with rapid increases in worldwide fishing catches. However, many fisheries have either collapsed or degraded to a point where increased catches are no longer possible.
It is clear that marine fishes have experienced extraordinary declines relative to known historic levels (figure 1). These data are based on populations for which time series extend at least 10 years, with a mean of 25 years and a maximum of 73 years. Taken as a whole, the median maximum population decline among the 232 populations for which data are available is 83%; well over half of the populations (58%) exhibited maximum declines of 80% or more. The strong negative skew in the data, and the high median decline in abundance, are also evident at lower taxonomic levels. Among 56 populations of clupeids (including Atlantic herring, Clupea harengus), 73% experienced historic declines of 80% or more. Within the Gadidae (including haddock [Melanogrammus aeglefinus] and cod [G. morhua and other species]), of the 70 populations for which there are data, more than half declined 80% or more. And among 30 pleuronectid populations (flatfishes, including flounders, soles, and halibuts), 43% exhibited declines of 80% or more.
These results are sobering for two reasons. First, many of them have occurred in spite of an enormous effort to prevent them from happening. Second, as noted above, they are based on “historic” maxima that are not really historic at all, most fisheries having been well under way decades or centuries before the time series of data began. In the absence of longer-term data, researchers' perceptions tend to scale to time periods that they, or perhaps their parents, can remember. This results in the “shifting baseline syndrome” (Pauly 1995), whereby scientists accept data from more and more recent periods as baselines, forgetting that this allows drastically reduced populations to substitute for the much higher baselines that occurred before humans began having major impacts on populations.
All the world's oceans are at risk, but the Pacific Ocean is of particular concern. There are fewer regulations in Asia, and they are fishing more waters...
...Many of the species that are dying are vital food sources around the world -- especially for poorer countries who rely primarily on the fish population for food. Also, the ecology of the oceans is greatly impacted.
[Andy] Baker says there’s a common misconception that heat pumps circulate corrosive seawater. Not true. The seawater raises the temperature of a coolant loop through a heat exchanger, and then is returned to the ocean.
And for corrosion-resistance, the heat exchanger — like the one in Seward — is made from titanium.
“And so this is really the star of the system. There’s no moving parts. That’s a $28,000 unit. It’s about 7-feet tall. There are 126 plates in it. In advance of it is an in-line filter that traps particles, so we don’t have clogging in the plate exchanger. And the Science Center here is looking at having a similar system — similar hardware, but on a smaller scale. And this is one of the most important investments. If you do this right and size it right, you’ll have plenty of heat coming into your system.”
Baker also discussed expanding a seawater system beyond a single building — into a neighborhood district. The concept is already in use in Scandanavia. It functions like any utility, electricity or drinking water, but it this case it would be a coolant loop. Residents could connect heat pumps to it, or not. And cities understand pipes.
Since August 2004, a deep lake water cooling system has been operated by the Enwave Energy Corporation in Toronto. It draws water from Lake Ontario through tubes extending 5km into the lake, reaching a depth of 83m. The SWAC system, part of an integrated district cooling system that covers Toronto's financial district, has a cooling power of 59,000t (207MW). The SWAC system currently has enough capacity to cool 3,200,000 m2 of office space, making it the largest system in North America.
In addition to the SWAC system in Toronto, Canada has two operational systems at Halifax, Nova Scotia. The original system at Purdy’s Wharf was the world’s first and has been operational since 1986, cooling a 700,000-ft2 office complex. The second system at Alderney 5 became operational in February 2010, cooling a 330,000-ft2 office building. The Directors report that the two systems offer an annual $400,000 cost saving when compared to traditional air conditioning systems.
Hawaii has used cold seawater to air-condition a few buildings at the Natural Energy Laboratory of Hawaii Authority on the Big Island. The lab “has been saving up to $4,000 per month since it switched its three buildings to deep seawater-based cooling,” according to its Web site.
"Nature gives us endless amounts of cold sea water that we have access to. We've got hot buildings and cold sea water really close to each other, so why not bring those two things together and really just cool using Mother Nature essentially?" explained Murray.
Honolulu Seawater Air Conditioning's district cooling system is designed to collect seawater from more than 1,700 feet below sea level. It will pump back to a cooling station in Kaka'ako, where it will transfer the coldness to freshwater that will be distributed to customer buildings through underground pipes.
"Buildings can see savings of about 70 - 80% in their electricity costs that they normally would be spending on air conditioning," described Masutomi.
Project developers say it will reduce Hawaii's dependency on oil by eliminating the need for 178,000 barrels per year, while also saving about 260 million gallons of fresh water each year.
Largest OTEC plant operated during the last decade, with largest net power output and first net power production from open-cycle process 10 ft diameter, 7.5 ton turbine rotated at 1800 rpm synchronised with power grid through a fluid clutch.
Developed use of magnetic bearings for high efficiency, very high speed (to 48,000 rpm) vacuum pumps
Developed and utilised a flexible PC-based monitoring and control system.
Verified spout evaporator effectiveness data and demonstrated very high condenser efficiency from structured-packing design
Operated continuously for eight days, though not designed for continuous use.
Successfully demonstrated about 7000 gal/day fresh water production with minimal power loss from an auxiliary vapour to liquid surface condenser (designed and added following completion of the initial facility).
Demonstrated increased fresh water production from an auxiliary direct contact condenser fed with fresh water chilled by cold seawater in a standard titanium plate heat exchanger.
Following successful completion of these experiments, the 210 kW OTEC plant was shut down and demolished in January 1999.
Makai’s OTEC plant forms part of its OTEC heat exchanger test facility and marine corrosion lab, named Ocean Energy Research Center (OERC), located at the NELHA site, which was opened in 2011, following the award of a fund by the US Navy in 2009.
"The OTEC technology uses the temperature difference between the cold water in the deep sea (5°C) and the warm surface seawater (25°C) to generate clean, renewable electricity."
The OREC is capable of testing six heat exchangers simultaneously and also conducts research programmes on seawater air-conditioning (SWAC), corrosion prevention and heat exchangers for other marine applications.
The research and development work at OERC was funded by the Office of Naval Research (ONR) through the Hawaii Natural Energy Institute (HNEI). The funding for the OTEC plant’s infrastructure was provided by the Naval Facilities Engineering Command (NAVFAC).
The US Navy’s special engagement in the research centre is driven by its target of generating 50% of its shore-based energy from renewable sources by 2020. The heat exchanger research facility is necessary as the components are estimated to make up approximately one-third of the overall cost in developing a commercial OTEC plant, primarily suited for offshore locations.
In 2014, the research centre completed the test of seven heat exchangers that are constructed of either aluminium or titanium. The US Navy awarded Makai a contract to add a turbine generator to complete the power plant and test the OTEC technology on the grid in 2013.