Tag Archives: sustainable fisheries

Open-Ocean Farming

image from https://www.innovasea.com/

Ocean Farm 1is the first of six experimental fish farms ordered by SalMar, a Norwegian firm, at a total cost of $300 million. InnovaSea, an American firm, makes large open-ocean aquaculture nets called SeaStations, which are currently used off the coast of Panama and Hawaii, but Ocean Farm 1 is “by far the largest open-ocean fish farm in the world,” says Thor Hukkelas, who leads research and development on aquaculture at Kongsberg Maritime, a Norwegian engineering company. Mr Hukkelas’s team provided Ocean Farm 1’s sensor system: 12 echo sounders mounted on the bottom of the frame, high-definition cameras dangled into the water at different depths, oxygen sensors and movable, submerged feeding tubes.

Fish farming plays an increasingly central role in the provision of sufficient amounts of protein to Earth’s population. People eat more fish globally than beef, and farmed fish account for almost half of that amount  Many wild fisheries are already at or past their sustainable capacity, so efforts to make fish farming more productive are vital.

Ocean Farm 1 aims to automate what is an expensive and difficult business, and to solve two key problems that occur in near-shore aquaculture: that there is not enough space and that it is too polluting. The excrement from millions of salmon can easily foul up Norway’s fjords, and their shallow, relatively still water is a breeding ground for sea lice. In the open ocean the water is deeper and better oxygenated. The currents are stronger and so better able to sweep away excrement.

Near-shore farms normally spread feed on the water’s surface and allow it to sink, but Ocean Farm 1 has 16 valves at varying depths, through which feed can be pushed. By putting it farther down in the cage it is able to keep the salmon in deeper water. The salmon are fine with this. The sea lice, which like the shallows, are not.

All of this means the number of fish can be increased. The Norwegian government wants to triple its aquaculture production by 2030 and quintuple it by 2050. “Scaling up of traditional aquaculture is not going to reach these high-growth ambitions,” says Mr Hukkelas.

Kongsberg is gathering data from all the sensors on the farm to build a machine-learning model, called SimSalma, which learns the behaviour of the salmon in order to optimise their feeding. Currently, human operators on the structure decide when and where to feed the fish by examining the data. By 2019 Kongsberg plans to have automated this, pushing feed at optimum times and places and reducing human involvement. The success and expansion of such projects would represent a major step towards maintaining global fish stocks.

Net gains: Open-ocean fish farming is becoming easier, Economist,  Mar. 10, 2018.

Regulation of Deep-Sea Fishing by Depth: the scientific facts

setting a trawl. image from wikipedia

A study published in 2009 suggested that in all but the deepest of their waters—those with a seabed closer than 1,500 metres to the surface—yields had dropped by 70% over 25 years. Even in the abyss below that depth, the fall was 20%. To try to stem this decline the European Union, which regulates fishing in much of the area, is proposing to limit the depth at which trawling can take place. This would, in effect, create a marine reservoir below that level, a form of protection additional to the system of species-specific quotas that already exists. The question is where the line below which trawl-gear is forbidden should be drawn. And, until now, there have been few scientific data to inform that decision.
This has just changed, however, with the timely publication, inCurrent Biology, of a study by Jo Clarke of Glasgow University and Francis Neat of Marine Scotland Science, a government agency. Their work suggests that the appropriate cut-off would be at a depth of 600 metres—below which the ecological damage caused by trawling increases substantially.

Ms Clarke and Dr Neat derive their conclusion from data collected between 1978 and 2013 by Marine Scotland Science and the Universities of Aberdeen and St Andrews. These data record species caught, and also the depths of the trawls that caught them, which ranged from 250 to 1,500 metres.

The researchers note that biodiversity increases with depth. On average, an extra 18 fish species show up with each 100-metre increase. Many of these, though, are of little commercial value. Such so-called by-catch gets thrown back, but by then most of it is dead. And that, particularly because deep-sea species tend to grow more slowly than those which live near the surface, and have lower fecundity rates, can have profound effects on ocean ecology.  Trawls at 300 metres, Ms Clarke and Dr Neat found, have a ratio of catch to by-catch (in terms of weight) of five to one. At 600 metres the ratio is around three to one. At 800 metres, though, it is ten to nine; at 1,000 metres one to one; and at 1,200 metres, one to two.

Based on these findings, Ms Clarke and Dr Neat suggest that a trawl limit of 600 metres would be a suitable compromise between commercial reality and ecological necessity.

Excerpts from Fisheries: Drawing the line, Economist, Sept.  5, 2015, at 80

The Coral Triangle, biodiversity, fisheries and climate change

Stretching across six countries in Southeast Asia and Melanesia (Indonesia, the Philippines, Malaysia, Papua New Guinea, Solomon Islands and Timor Leste), the Coral Triangle contains the richest marine ecosystems on earth. While encompassing just over 1.5% of the world’s oceans (and1% of the earth’s surface), it contains a staggering proportion of the world’s marine diversity: 76% of reef-building coral species, and 37% of coral reef fi sh species. The Coral Triangle is the epicentre for the biodiversity of not only corals and fi sh, but many other marine organisms as well….The signifi cance of the marine ecosystems lining over 132,800 km of coastline within the Coral Triangle goes far beyond their biological value or evolutionary signifi cance. Coastal ecosystems in this region are critically important for human livelihoods and communities, providing food and resources to over 100 million people. Many people in this region forage on coral reefs and other coastal ecosystems such as mangroves, to collect their daily food and income. Commercial fi sheries provide over $3 billion per year to the six nations. These ecosystems also contribute to the maintenance of water quality along coastlines, with mangroves and seagrass beds stabilising sediments and acting as fi ltration systems as water runs from land to sea. Coral reefs provide important coastal barriers in many regions, reducing the power of waves and preventing damage to human communities and infrastructure. These functions cannot be replaced if these ecosystems are removed.

Unfortunately, coastal ecosystems throughout the Coral Triangle are being severely threatened by the activities of humans. These threats arise from two distinct sources. The first set arise from local sources such as destructive fishing practices, deteriorating water quality, over-exploitation of key marine species, and the direct devastation of coastal ecosystems through unsustainable coastal development. The second set arise from rapid anthropogenic climate change, which is caused by the build up of greenhouse gases such as carbon dioxide in the Earth’s atmosphere. These threats are escalating and ecosystems like coral reefs are already showing major changes to sea temperature and acidity. Further changes are putting the future of these important biological systems in serious doubt.

Excerpt from Executive Summary from THE CORAL TRIANGLE AND CLIMATE CHANGE, (2009)

More on the Threats and Recommendation for action (pdf)

See also Integrating Fisheries, Biodiversity, and Climate Change Objectives into Marine Protected Area Network Design in the Coral Triangle (pdf, 2012)

Sustainable Fisheries: quotas and Peru

For decades anchovetas have been ground into fishmeal, of which Peru is the world’s top producer. They have suffered from rampant overfishing, whose effects are sometimes amplified by the disruptive El Niño and La Niña weather patterns. The annual catch peaked at 12m tonnes before the stock collapsed in 1972, taking years to recover.

Now Peru is trying to make better use of one of its prime resources, in two ways. The government has introduced a quota aimed at ensuring that 5m tonnes of anchoveta are left each year as spawning stock. Since 2009 this has been refined so that the overall quota (set at 4.1m tonnes this year for the first of the two fishing seasons) is divided up among the country’s 1,600 registered trawlers. Each boat’s quota is transferable; the aim is to have a smaller, more efficient fleet.

In January the minister of production, Jorge Villasante, ended the season with less than 35% of the quota caught because there were too many juveniles, he says. Management of the fishery has improved, concedes Patricia Majluf, a zoologist at Lima’s Cayetano Heredia University, but she says there is still not enough information about stocks to know whether it is sustainable.

At the same time, some in the fishing industry have realised that selling anchoveta as food for people, rather than as fertiliser or animal feed, is more profitable. Human consumption of anchoveta in Peru has risen from 10,000 tonnes in 2006 to 190,000 tonnes in 2010. Most of this is canned, like sardines.

One fishing company, Inversiones Prisco, has begun to produce salted and cured anchovy fillets. They are smaller than the prized Mediterranean or Cantabrian anchovy. But supply is far more abundant. Prisco is already the world’s “fifth or sixth” biggest exporter of anchovies, according to Hugo Vernal, its manager. It is investing $30m to double production.

Fishing in Peru, The Next Anchovy, Economist, May 7, 2011, at 41