|We have a lot to learn about fishing |
Thursday, April 21 2011
MANY NATURAL fisheries (a location to catch or rear fish) around the world have shown a decline in stock, hence the simultaneous rise in aquaculture (the cultivation of aquatic animals or plants for food).
Tilapia, a fish most people in Trinidad and Tobago are familiar with, is now the third most popular fish being reared on fish farms.
Statistics quoted by Professor of Applied Ichthyology (Fisheries and Aquaculture) at the University of the West Indies (UWI) St Augustine campus, Indar Ramnarine, at his inaugural professorial lecture last week at UWI’s Daaga Auditorium, indicated how popular tilapia had become.
“In 2008, 2.8 million tonnes of tilapia was grown and...in 2010, the production was up to 3.2 million metric tonnes, which is quite significant,” he said.
The lecture focused on fisheries and aquaculture, asking the question “Fisheries in crisis: Is Aquaculture the Saviour?” Addressing a packed Daaga Auditorium, Professor Ramnarine examined the pros and cons of aquaculture. While he is a supporter of it as a viable, affordable food source, he warned fisheries must still be managed and protected to ensure the survival of wild fish stocks.
“Fisheries are in crisis. We have seen that many of the stocks are over-fished and in fact, marine research ecologist and Associate Professor at Dalhousie University Boris Worm has (predicted) that by the year 2048, virtually all the fisheries in the world would collapse because of over-fishing and that must be taken seriously,” he said.
However Ramnarine said this can be reversed but it requires some hard decisions.
“We do need to change how we operate fisheries, we need to manage (and) protect those fisheries.
So if we ask ourselves if aquaculture can actually solve this crisis I would say ‘no.’ Fisheries have to solve their own problems and there are ways in which to do it,” he said “Aquaculture on the other hand,” Ramnarine noted, “can take up the slack that fisheries cannot meet. With a growing human population there is need for fish. Fish is a really good source of protein and nutrition so any increase in fish production must come from aquaculture but we need to consolidate our fisheries.” The professor also spoke about the negative aspects of aquaculture, saying if it is not done properly, some aquaculture ponds end up producing a lot of effluents which can cause problems in the environment.
“You can have escape of exotic species, which sometimes can be invasive. You can be introducing fish parasites and pathogens by bringing exotic stock into your country. So there are problems with aquaculture as well but if managed very carefully, aquaculture can take up the slack,” Ramnarine said.
This he advised, must include optimal use of supplements to avoid over-crowding in the fish tanks.
“Once you know which supplements to use, once you ensure there is good nutrition (and) good water quality, there should not be any serious problems. It really comes down to proper husbandry,” Ramnarine told Business Day.
China is the leader in tilapia farming with significant production also coming from Indonesia, Thailand, Philippines and Egypt.
This does not mean TT cannot aim to join their ranks, as one of the world’s poorer nations has done, with guidance from Ramnarine and his colleague from another Caribbean university.
“Bangladesh has come from nowhere to be one of the major producers and I’m very proud to say that I had some input in this.
I did two projects with Bangladesh several years ago and together with Professor Dr James Rakocy from the University of the Virgin Islands, we actually showed them how to grow Tilapia and we designed hatcheries for them,” he said.
There is a growing market for Tilapia in the United States and other countries. Ramnarine noted that in 2000, Tilapia was eleventh in per capita consumption.
That figure has since risen and within another ten years, it is estimated that tilapia might be actually be second only to shrimp in US consumption, so it has a lot of potential as a cultured or farmed species.
Ramnarine’s aquaculture research has focused within recent times on two different systems.
One is an intensive system of producing fish, which is a bypod or “green-water” system. The other system is aquaponics — integration of the intensive system of culturing fish with a hydroponic method of growing vegetables.
When UWI St Augustine principal Professor Clement Sankat asked Ramnarine about the sustainability of tilapia farms in TT, following the collapse of similar initiatives in the 1980’s, the professor said TT cannot compete with China.
Citing increasing concerns about food security, Ramnarine said we should focus instead on feeding our own population.
“Fish prices over the last four years globally have increased about 40 percent. We need to grow our own fish. I have been working on a particular system - the ‘green-water’ biofloc (bioflocculant) system. It is a really good system because you can use cheaper food to produce the same fish and in so doing, cut back on production costs,” he said. Ramnarine told Sankat and the wider audience that “green-water” aquaculture is not restricted to tilapia and his research team will soon begin experiments on rearing marine fish this way.
“We hope to work with people to actually develop the industry and we do have a lot of support from the Minister of Food Production in this aspect,” he said.
“Green-water” aquaculture refers to colour of the water in fish ponds/tanks, which is caused by the presence of single-celled algae suspended in the water. If conditions are right, with plenty of nutrients and sunlight, as many as five million algae cells can be found in each millilitre of water.
Aquaculture can be done on a small scale in a person’s backyard to feed their family or on large farms to feed a nation.
Ramnarine noted tanks used in biofloc or “green-water” systems can be 10x10 metres in size and produce two tonnes of tilapia.
“It is an intensive system. Four tanks would require no more space than 400 square metres and could actually produce 16 tonnes of Tilapia per year, which is quite a large production from a small area.” The professor has helped to design an aquaponic system for the Seafood Industry Development Company (SIDC), which he said is being tested to determine what kind of production they can get out of it.
Ramnarine gave a general outline of its operation.
“The water from these tanks goes to a clarifying system where a large funnel removes solids.
“The water then moves to filter boxes which remove the suspended solids, then the water goes to a ‘gaser’ which removes toxic acids,” he said.
“The water which goes into the hydroponic tanks is clear water but it can take a lot of nutrients.
“Nutrients that the plants require, meaning nitrates, phosphates (et cetera), so the plants actually act as a filter, removing those nutrients which are toxic to the fish and then the water goes back into the fish tanks.
“So it is a closed, re-circulating, intensive system,” he said. The professor noted the added benefits of this type of tilapia farming.
“There are many things that you can grow in hydroponic troughs – lettuce, chive, mint, pak choi, watermelon, melongene, cucumbers, squash, tomatoes, celery, ochro, even flowers you can grow with this system,” he said.
Ramnarine revealed he has started building a research system on campus to support the development of the local industry.
He has also worked with private sector individuals.
The by-products of tilapia, namely the skin and scales, are also being utilised now.
“This has been piloted by Brazilians. They have actually taken the tilapia skins and turned them into leather, which is used to make bags and wallets among other things.
“Even the scales now are being used to make leather, so no part of the Tilapia is thrown away. It is all used,” Ramnarine said.
The professor said while UWI already provides support to the local agriculture sector, a lot of research is still needed to ensure aquaculture systems operate properly.
In the meantime, Ramnarine is preparing to teach a course, which he first offered last year, on aquaculture.
He said it is already over-subscribed