The oceans and us 1 The oceans and us Since man first gazed across its watery depths, the sea has been held in special regard. It has evoked visions of splendour and horror. It has provided life-­‐sustaining riches and taken the lives of many in return. The sea is and continues to be a mystery, a symbolic representation of the forces of good and evil; of things that are beautiful and those that are beastly; of that which is human and that which is inspirational. The History of Seafood Of all the things that the oceans provide, perhaps the most important resource for us is the rich array of seafood which we harvest from its depths and shorelines across the world. More importantly, for those of us involved in the seafood industry, from the fishers who catch the fish, to the restaurant or deli owner that sells it, this seafood represents more than just a source of food; it is part of our culture, our heritage and our livelihood. We may not know it but we all depend on the oceans in one way or another. /ƚ ĐŽŶƚƌŽůƐ ŽƵƌ ĐůŝŵĂƚĞ͖ ǁŝƚŚŽƵƚ ƚŚĞ ŽĐĞĂŶ͛Ɛ
moderating effects on the weather, our days would be unbearably hot and our nights freezing cold. The ocean also naturally recycles our water and our air, constantly cleaning it for us to use over and again 24 hours a day, seven days a week. It produces more oxygen than the rainforests and absorbs nearly half of the carbon that we put into the atmosphere. The ocean touches everyone and everything and is essential to life and human survival on this planet. As humans, we are inextricably linked to the oceans, 70 percent of our body is made up of water, the same percentage that covers the Earth's surface, even the blood that runs in our veins has the same salt concentration as seawater, reminding us of our earliest beginnings ŝŶƚŚĞŽĐĞĂŶ͛ƐǁĂƚĞƌƐ͘ Seafood may mean different things to different people. To some, it is the height of luxury; an oyster still fresh from the sea shared over a glass of champagne. To others, it may be the daily meal, the fish brought home after a long time at sea or some mussels gathered at low tide along the rocky shore. Regardless of what seafood may mean to us as individuals, it is important not to underestimate the value of seafood in our lives. Today, almost one in every six people in the world relies on fish as their primary source of protein, and approximately 200 million people around the world rely on fish for all or part of their income. Our relationship with seafood stretches right back to the beginnings of the human race. In fact, it has been suggested that unique substances present in fish consumed in the early human diet led to some of the earliest development and evolution of the modern human brain. And, while a lot may have changed since our early ancestors dined on their first seafood dish, in many ways, things are still very much the same. Understanding this connection and the value of the ocean in our own lives is crucial, not just for our own wellbeing but to ensure that future generations will not have to suffer the consequences of poor decisions made by us today... -­‐Arthur C. Clarke
͞,ŽǁŝŶĂƉƉƌŽƉƌŝĂƚĞƚŽĐĂůůƚŚŝƐ
planet Earth when it is quite clearly Ocean͟ 1 1 An Ancient Trade We knew how to fish long before we knew how to farm. Over 100 000 years before the first seed was sown, Khoi Strandlopers ǁĞƌĞǁĂŶĚĞƌŝŶŐ^ŽƵƚŚĨƌŝĐĂ͛Ɛ
shorelines, harvesting mussels, fish and oysters and any other gifts that the oceans chose to grant our early ancestors. We have come a long way since those early days, and much has changed; we now use very adǀĂŶĐĞĚ ŵĞƚŚŽĚƐ ƚŽ ŚĂƌǀĞƐƚ ƚŚĞ ŽĐĞĂŶ͛Ɛ ƌŝĐŚĞƐ ĂŶĚ
markets for seafood have spread across the world. However, despite these changes, in many ways the seafood industry remains the same... Unlike almost all the other types of food that we may find in restaurants and supermarkets today, most of the seafood we eat still comes from the wild. For many people, this is one of the major attractions of eating seafood; it connects us to those long-­‐forgotten days when humans still had to hunt for their food. For these people, wild caught seafood still evokes romantic images of weathered fishermen practicing their ancient art on a wild ocean in order to bring us fresh fish still smelling of the ocean. More than ever, seafood is a global commodity... However, today, consumers are attracted to more than just the romance of seafood. More and more people are considering seafood as a healthy and alternative natural protein source. At a time when many consumers regard products from conventional commercial land-­‐based farms with increasing suspicion, seafood is growing in popularity. Spurred on by the globalisation of markets, seafood has become the most traded food commodity in the world. Made even more popular by the trend setters in the culinary world, seafood has exploded onto restaurant menus and retail store shelves everywhere. ͞KŶĂǀĞƌĂŐĞĂƌŽƵŶĚƚŚĞǁŽƌůĚ͕ǁĞ
are now eating double the amount of fish today compared to just fifty LJĞĂƌƐĂŐŽ͘͟ 2 ^ŽƵƚŚĨƌŝĐĂ͛ƐKĐĞĂŶƐ On the Southern tip of Africa we are surrounded by the sea, both the Indian and the Atlantic oceans wash against our 3000km shoreline. As a result, our oceans are incredibly rich with over 11 000 different species ƚŚĂƚŚĂǀĞďĞĞŶĚĞƐĐƌŝďĞĚŝŶ^ŽƵƚŚĨƌŝĐĂŶǁĂƚĞƌƐ;ƚŚĂƚ͛Ɛ
1/20th or over 5% of all marine species globally) and almost one in every five of them are endemic, which means that they are found nowhere else in the world. 1 Wild caught fisheries now produce almost 100 million tonnes of fish every year (source: FAO 2006) But the times they are a changing... Sadly, we may never know the oceans in the same way that our ancestors did. Regardless of where you come from in the world, anyone involved in the seafood industry will remember a time when the fish being pulled from the ocean were bigger and more plentiful. Ɛ ƚŚĞ ǁŽƌůĚ͛Ɛ ŚƵŵĂŶ ƉŽƉƵůĂƚŝŽŶ ŚĂƐ ŐƌŽǁŶ͕ ƐŽ ŚĂǀĞ
our demands on the ŽĐĞĂŶ͛ƐƌĞƐŽƵƌĐĞƐ. Whether we like it or not, we can no longer afford to ignore the impact that we are having on our marine ecosystems. Now, more than ever, if we want to ensure the future of the seafood industry and with it, our own livelihoods, we need to start thinking about what sustainability really means to us and our businesses. 3 1 NOTES: ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ 4 Something fish is going on 2 Something fishy is going on... zŽƵĚŽŶ͛ƚŚĂǀĞƚŽ be a fisher to know that something is happening to our fish stocks. It seems clear that all over the world, fish stocks are disappearing, everywhere we look there are signs that the oceans are no longer able to keep up with the demands that human beings are putting on them. Catches of wild ŵĂƌŝŶĞ ĨŝƐŚ ƉĞĂŬĞĚ ŝŶ ƚŚĞ ϭϵϴϬ͛Ɛ͘
Alarmingly, despite major advances in fishing technology since then, the catches of wild marine fish have not increased. Figures for global fish catches can often be misleading as they include farmed fish (produced by aquaculture). They also do not show the changes in the types of fish that are now being caught. If they did we would see a dramatic decrease in popular seafood species such as bluefin tuna and swordfish and an increase in smaller, less-­‐desirable fish, many of which are not even eaten by humans but are used in agricultural feed products. Over the last few decades, many of us involved in the seafood industry have been noticing the telltale signs of this disappearance of fish in the seafood market as: x Fish are getting smaller x Some fish are becoming harder to find, some are no longer available at all x There are fewer seafood options to choose from x All fish species are becoming more expensive Pushing the limits ͞/Ĩ ĐŽŵŵĞƌĐŝĂů ĨŝƐŚŝŶŐ ŝƐ ŶŽƚ ŚĞĂǀŝůLJ
regulated, there will be little left to harvest in the seas outside the lowest levels of the food web. So you don't need to worry about these problems as long as your children like plankton stew" -­‐Daniel Pauly, Professor of Fisheries, University of British Columbia, Canada, Around the world, almost all of the commercially important fish stocks are reaching the limits of what they can produce, many stocks are already fished way past What is ͚ƐƵƐƚĂŝŶĂďůĞ͛? what scientists believe is sustainable. A number of other A sustainable fishery is one that is healthy and stocks have already collapsed... managed in a way which ensures that there will be The latest statistics released by the FAO (Food and seafood for future generations. Likewise, sustainable Agriculture Organisation of the United Nations, 2006) fish farming (aquaculture) respects the surrounding indicate that over three quarters of world's fish stocks environment, uses water and other resources wisely, have been fished at or beyond sustainable levels. Some and does not damage natural, wild fish populations. scientists further report that fishing has wiped out 90% of As yet, only a few fisheries and fish farming ƚŚĞ ŽĐĞĂŶ͛Ɛ ůĂƌŐĞ ƉƌĞĚĂƚŽƌLJ ĨŝƐŚ such as tuna and operations can be considered sustainable, and swordfish. therefore 'ocean friendly'. It seems we are just fishing too hard, there are too many ĨŝƐŚĞƌƐŽƵƚƚŚĞƌĞŚƵŶƚŝŶŐƚŽŽĨĞǁĨŝƐŚ͘DŽƐƚŽĨƚŚĞǁŽƌůĚ͛Ɛ
commercially important fish stocks just cannot breed fast enough to replace the fish that industrial fishing operations are taking out of the ocean. 5 2 ^͛ƐŽůůĂƉƐĞĚ>ŝŶĞĨŝƐŚPopulations In South Africa, six out of the ten most important commercial linefish stocks have decreased to critically low levels including: Kob/kabeljou (both the dusky and silver Kob), cape salmon, red stumpnose, red roman and carpenter or silverfish. Some fish, such as kob (kabeljou) have less than 5% of their original breeding stock left. Due to unregulated fishing between the 1970's & 1990's, many linefish have been fished to the point of collapse. Many of these fish are endemic to South Africa -­‐ meaning they only occur along our South African coastline. Severe over-­‐exploitation of these fish could mean they would be lost to the world forever and because of this the linefishery was declared in a state of crisis in December 2000. Some other highly prized South African species such as abalone or 'perlemoen' haven't been so lucky and unregulated and illegal fishing has forced the closure of the commercial fishery for these species in South African EĞǁĨŽƵŶĚůĂŶĚ͛ƐŽĚ&ŝƐŚĞƌLJ ͞hŶůĞƐƐǁĞĨƵŶĚĂŵĞŶƚĂůůLJĐŚĂŶŐĞƚŚĞ
way we manage our oceans, then this century is the last century of wild ƐĞĂĨŽŽĚ͟ Newfoundland, a small island of the South East coast of Canada, used to be home to some of the largest fish stocks known to man. At the height of the fishery in the 1960͛Ɛ͕ ĨŝƐŚĞƌŵĞŶ ǁĞƌĞ ƉƵůůŝŶŐ ŽƵƚ
over 800 000 tons of cod every year ;ƚŚĂƚ͛ƐƚŚĞƐĂŵĞ
as 130 000 African elephants). However, the oceans could not keep up. By 1992, catches had dropped to just 122 000 tons and the Canadian government was forced to close the fishery completely in an attempt to allow the fishery to recover. Over 30 000 jobs were lost overnight and sadly, to this day, neither the local economy nor the fish stocks have shown any signs of recovery -­‐Steve Palumbi, Marine Scientist, Stanford University The Story of the Seventy-­‐Four Perhaps the most famous example of over exploitation in South Africa is the story of the Seventy-­‐ĨŽƵƌ͘/ŶƚŚĞϭϵϯϬ͛Ɛ͕
the Seventy-­‐four was one of the main linefish species in KZN and the Eastern Cape. In the early years 1910s, fishermen landed over 1000 tonnes per year as they targeted schools of spawning fish. However, this did not last long, by the 1970's catches were down to just 3.5 tons per year. By 1998, fishing for Seventy-­‐four was completely banned, the fish stocks had collapsed. The breeding behaviour of the fish made it completely defenceless to heavy fishing and even after 10 years of protection, it has shown no real signs of recovery. 6 2 But tŚĞƌĞ͛Ɛmore to iƚ͙ /ƚ͛Ɛ ŶŽƚ ũƵƐƚ ƚŚĞ ƚĂƌŐĞƚ ƐƚŽĐŬƐ ƚŚĂƚ ĂƌĞ ƚĂŬŝŶŐ ƐƚƌĂŝŶ
under the pressure that commercial fisheries are putting them under. We now know that our modern-­‐day fishing practices also have significant impacts on the greater marine ecosystem outside of the fishery itself. Bycatch Fishing methods are never totally selective and as a result will catch a number of other species that they don't intend to catch. Although some of these species may have a commercial value, sadly, the majority of this portion of ƚŚĞĐĂƚĐŚ͕ƚƌĂĚŝƚŝŽŶĂůůLJŬŶŽǁŶĂƐ͚ďLJĐĂƚĐŚ͕͛ŝƐŐĞŶĞƌĂůůLJŶŽƚ
considered valuable, and is usually discarded overboard as waste. Globally, it is estimated that almost a quarter of the fish caught in commercial fishing operations are discarded in this way. Unfortunately, many of the animals caught as bycatch often include vulnerable, threatened or even endangered species, such as sharks, turtles, marine mammals and seabirds. Many of these species play important roles in keeping the marine ecosystem healthy, but because of their biology (i.e. they breed very slowly), killing even a few animals can put the entire species at risk. In many cases these unnecessary deaths can be prevented or reduced if the correct mitigation measures are put in place and some fisheries are working very hard to introduce such measures into their fishing practice. For example, trawlers have bird scaring lines which keep the birds at a safe distance from their boats when they are setting their fishing gear. To prevent turtles from drowning in prawn nets, fishers can install turtle ĞdžĐůƵƐŝŽŶĚĞǀŝĐĞƐ;d͛ƐͿǁŚŝĐŚĂůůŽǁƚƵƌƚůĞƐĂŶĚŽƚŚĞƌ
larger marine animals to escape while still keeping the rest of the catch. Globally it is estimated that fisheries kill: ͻ
300,000 seabirds/year ͻ
200,000 loggerhead turtles/year ͻ
50,000 leatherback turtles/year In South Africa, longliners set approximately 40 million hooks and trawlers set 60 000 net every year, catching over: ͻ
20,000 seabirds ͻ
5.5 million sharks ͻ
200 turtles It is important to realize that not all fishing techniques are the same, some are a lot more selective, and therefore more environmentally-­‐friendly, than others. For example the tuna pole fishery has almost no bycatch because it uses very selective lines with single hooks to catch the tuna, while bottom trawling for prawns with nets can be extremely wasteful, with up to 80% of the catch being untargeted and mostly discarded bycatch. Bycatch in the prawn trawl fishery 7 2 Habitat Damage Different fishing methods also have differing impacts on the marine habitats in which they are fishing. It is not hard to imagine that the impact of a bottom trawl net on a marine habitat, which can weigh over two tons and is dragged over the ocean floor, will be far greater than that of a single fishing line with a baited hook. At present, more than half of the world's total marine catch (approximately 81 million tons) is harvested using towed fishing gear. Foodwebs All living things depend on one another to survive. The species which we eat in our seafood dishes, in turn need their own food to grow and develop until they are big enough for us to catch, and so it goes on down the line. All of these connections between the different species in an ecosystem make up what is known as a foodweb. Coral reefs are incredibly sensitive to habitat damage, this is a picture of a coral reef before (left) and after (right) a trawl net has gone over it. Some marine habitats are also more fragile than others and can be permanently damaged by fishing gear, such as trawling over a coral reef. Deep water coral reefs which can take thousands of years to form, may be wiped out in a few minutes. The destruction of these sensitive bottom habitats can have very serious impacts on marine ecosystems. Many species rely on structures such as coral reefs for refuges or shelters from other predators, or to provide safe spawning and nursery grounds. Without these structures these animals have nowhere to live. In Summary Over the last century commercial fishing, to supply the ǁŽƌůĚ͛ƐĚĞŵĂŶĚĨŽƌƐĞĂĨŽŽĚ, has dramatically altered our marine ecosystems. In order to ensure that seafood will be available for future generations, we need to understand not only how our fishing practices impact our marine ecosystems, but also how we can change our fishing methods and seafood choices to prevent further damage and allow recovery of the damaged ecosystems. A typical South African marine foodweb (source: M. Branch, Coastcare Fact Sheet) Removing key species from the food web can cause an imbalance in the entire ocean ecosystem, as it may disrupt other food webs which rely on these key species to live. Many marine ecosystems are particularly vulnerable to the removal of the dominant predators which occur at the top of the food chain such as sharks, dolphins and seabirds. Without these predators regulating the numbers of animals lower down the food web, populations of less-­‐desirable/valuable species such as jellyfish can often flourish uncontrollably, disrupting the entire balance of the ecosystem. 8 Some fish are better choices than others 3 Some fish are better choices ƚŚĂŶŽƚŚĞƌƐ͙ Creating sustainable fisheries does not have to mean that we should stop eating fish, or even reduce the amount of fish we eat. It is important to understand that each seafood species has different environmental impacts associated with it. Some of the fish we eat grow quickly enough to be harvested more regularly while others can take many decades to recover from overfishing. Similarly, the different methods used to catch fish also have different environmental impacts, some of which are worse than others. Making the right choice is all about having the right information. Territorial Biology & Lifestyle Not all seafood species are equal! Some species may even look similar but many of them have completely different biological characteristics, all of which make ƚŚĞŵŵŽƌĞŽƌůĞƐƐǀƵůŶĞƌĂďůĞƚŽĨŝƐŚŝŶŐƉƌĞƐƐƵƌĞ͘>Ğƚ͛Ɛ
take a quick look at some fish biology... Long-­‐lived & Sexual Maturity Some fish species can live for an incredibly long time. These fish tend to grow very slowly and only become sexually mature late in their lives. Some fish, such as the red roman, are even more complicated, as they tend to change sex as they grow older, starting life as a female and then becoming a male later in life. Removing even just a few of these fish from the ocean means that it will take many years for the population to recover. The red steenbras is a good example of a long-­‐lived fish, taking more than 7 years to reach breeding age and able to reach an age of more than 30 years. In comparison, dorado grow very quickly and can reach breeding age in less than a year which makes them much more resilient to fishing pressure. Like humans, some fish ĚŽŶ͛ƚůŝŬĞƚŽůĞĂǀĞƚŚĞĂƌĞĂ
they grew up in, while others may never come back to where they were born and spend their lives moving from one place to another. Many of the territorial fish such as red roman tend to be found around reefs, while the more nomadic fish such as snoek tend to be found in the open ocean. If fishermen target territorial reef fish, many of which are long-­‐lived, they are likely to have a significant impact on their local populations as it will take many years for new fish to re-­‐colonise these areas. Their predictable behaviour also makes it easy for fishermen to know exactly where they can be found. Catch-­‐and-­‐release tagging studies of galjoen have shown that it is not uncommon to find the same fish in exactly the same place it was caught 10 years earlier! Because of their unpredictable movements, nomadic fish such as snoek and yellowtail are far less vulnerable to heavy fishing pressure and are also relatively fast growers which means that their populations can recover faster than resident fish. Rare Some fish are just naturally rarer than others. Just like on the land where there are large herds of antelope but only a few rhinos, the same is true in the oceans. Targeting these rare fish could almost be compared to poaching endangered species like rhinos, the only ĚŝĨĨĞƌĞŶĐĞŝƐƚŚĂƚďĞĐĂƵƐĞǁĞĐĂŶ͛ƚƐĞĞƚŚĞŝŵƉĂĐƚŽƵƌ
fishing is having on these species, we tend to ignore it. In South Africa, many of our linefish species, such as black musselcracker and white steenbras are also endemic, meaning they are only found here and nowhere else in the world. This rockfish could be over 150 years old 9 3 LĞƚ͛ƐůŽŽŬĂƚƚŚĞϯŵŽƐƚĐŽŵŵŽŶĨŝƐŚŝŶŐ
methods and some of their impacts: Trawling Also known as dragging, trawling is the most widely used industrial fishing method. It involves towing a large net across the seabed (bottom or demersal trawling) or through the water (mid-­‐water trawling) to catch fish that live there. Fishing Methods Not only do fish differ in terms of their lifestyles, but they also differ in the methods used to catch them, some of which may be more destructive than others. All fishing methods have some degree of environmental impact. This could be something as simple as a seagull becoming entangled by a piece of discarded nylon fishing line from a recreational angler, to the destruction of centuries-­‐old deep sea corals by heavy trawling gear. Therefore, in order to decide how sustainable our seafood choices are, we also need to consider the environmental impacts of bycatch, habitat damage and the foodweb impacts of each fishing technique. In South Africa, there are 21 commercial fisheries targeting different species. These are some of the more common fishing methods used: x Trawling x
x Beach seining x
x Linefishing x
x Squid jigging x
x Pots, traps and hoop-­‐nets Purse seining Longlining Tuna pole fishing Hand harvesting See Appendix B for detailed descriptions of the fishing methods and their impacts. Hake, sole, and prawns are all species in South Africa commonly targeted using bottom trawl gear. Retained bycatch include other fish (kingklip, monkfish, chub mackerel, john dory, gurnard), sharks, squid, deep water crabs and lobster. The main issue with trawling is that it is non-­‐selective, and depending on the target species may have a substantial bycatch. Prawn trawling is one of the fishing sectors with the highest discarded bycatch (over 70%), accounting for one third of the global discarded catches. Bottom trawling can also alter the structure of the seabed. Mid-­‐water trawling is more selective and does not damage the seabed, and mainly targets horse mackerel or maasbanker. In South Africa, there are a number of regulations in place aimed at reducing the environmental impact of ƚƌĂǁů ĨŝƐŚĞƌŝĞƐ͘ &Žƌ ĞdžĂŵƉůĞ͕ ĐůŽƐĞĚ ͚ŶŽ-­‐ƚƌĂǁů͛ ĂƌĞĂƐ
have been declared for areas in which kingklip are known to breed. Annual catch limits have also been set for valuable bycatch species such as monk and kingklip. 10 South African fishing companies are also implementing measures to reduce their impacts. For example trawlers using bird-­‐scaring lines behind their boats have already reduced their seabird bycatch by as much as 90%. 3 Longlining Longlining is the other major industrial fishing method and involves using a main line with hundreds of baited hooks. Longlines can be up to 100km long with as many as 20 000 baited hooks. Longlines may be set on the seabed (demersal), or near the surface (pelagic), depending on the target species. Species targeted include tunas, sharks and swordfish, hake, and patagonian toothfish. The main issue with longlining is the bycatch of threatened seabirds, turtles, and billfishes and sharks that have vulnerable biologies. These bycatches may be reduced through preventative measures. In South Africa, longline fisheries are also making an effort to reduce their ecological impacts by flying bird-­‐
scaring lines and setting their hooks at night to reduce seabird bycatch as well as using circle hooks to reduce turtle bycatch. Linefishing The traditional linefishery is the oldest commercial fishery in South Africa. It uses hand lines and fishing rods with baited hooks to catch fish like snoek, geelbek, cob/kob, yellowtail and many others. There are over 200 different fish caught in this fishery, 95 of which are considered economically valuable. Commercially legal linefish are caught from commercial ski-­‐boats and sometimes larger deck-­‐boats. It is a fairly selective method with little bycatch, as fishers use varying hook sizes and bait types. The fish caught are also of very good quality as they are individually handled. The biggest problem associated with linefishing is that many of our linefish cannot sustain heavy fishing pressure, the illegal sale of these species by recreational fisherman has added further pressure on the stocks, some of which have now been fished to the point of collapse; many of these stocks are in urgent need of recovery. Some popular linefish species Yellowtail (Seriola lalandi) Dusky cob (Argyrosomus japonicus) A drowned albatross caught on a longline Black musselcracker/Poenskop (Cymatoceps nasutus) 11 3 Is fish farming an alternative? One of the suggested solutions to overfishing and the increased pressure being placed on wild fish stocks is the farming of seafood species, known as aquaculture. Often referred to as the 'blue revolution', farming of fish and seafood products is promoted as a way to increase seafood supply when greater quantities of fish cannot be obtained from the ocean. Although South Africans are less familiar with aquaculture, it has become an increasingly important source of food around the world and currently almost 40% of all fish directly consumed by humans worldwide comes from aquaculture farms. Aquaculture may be conducted either in land-­‐based artificial tanks and ponds in coastal areas or floating net cage enclosures at sea, usually in sheltered bays. Local consumers may not realise it, but there are already many farmed seafood products in our retailer freezers, such as oysters, mussels, salmon and prawns. Most of the Atlantic salmon that is available fresh on our markets is farmed and imported from countries such as Norway, Canada and Chile. Similarly, many of the prawns South Africans enjoy are farmed in the east and imported from China, India, Thailand, Vietnam and Bangladesh. But the rapid onset of fish farming has not been without its own set of problems and environmental concerns. Some aquaculture methods are better than others, for example the farming of mussels and oysters (also practised in South Africa) is seen as a good environmental seafood choice, as these animals are filter feeders and need no nutritional input. On the other hand, farming of carnivorous fin-­‐fish such as salmon, especially under intensive conditions (not unlike cattle in a feedlot) can pose a number of problems. Fish farming facts: ͻ
ͻ
ͻ
ͻ
ͻ
ͻ
To date most aquaculture has involved the farming of fresh water fish-­‐ specifically carp and tilapia. Marine aquaculture-­‐particularly of salmon and prawn/shrimp has been a fairly recent development but is growing rapidly. Salmon farming originated in Norway in the 1970's. Global production of farmed Atlantic salmon now constitutes 60% of fresh and frozen salmon sold on international markets. Numerous other fin fish species are now being farmed, many of them depleted through overfishing such as Atlantic cod, Atlantic halibut, and bluefin tuna. Some aquaculture practices supplement wild fish populations with hatchery fish. This is known as stock enhancement. Shellfish farming in Saldanha Bay 12 3 What are some of the problems associated with aquaculture? ͻ Farming fish does not necessarily mean that there are more fish left in the wild. Small fish caught in the wild are used to make fishmeal for the farmed fish, and it can take between 2-­‐5 times more wild-­‐
caught fish to raise those harvested through aquaculture. The small fish used to make fishmeal and oil are critical food sources for wild marine predators, including many commercially
valuable fish. ͻ Farmed fish regularly escape from farms and pens into the wild. Here they can compete for resources with wild fish, and if the same species, may even interbreed with wild ŝŶĚŝǀŝĚƵĂůƐ ĂŶĚ ƐŽ ͞weaken͟ wild stocks. This can result in there eventually being ŶŽ͚ŐĞŶĞƚŝĐĂůůLJƉƵƌĞ͛ǁŝůĚƐƚŽĐŬƐůĞĨƚ͘ ͻ Fish farmed intensively means that waste, pesticides and hormones pollute the water and surrounding environment. ͻ Diseases and parasites from farmed fish can be transferred to wild populations. ͻ Conflicts over user and property rights can take place in coastal and offshore areas. ͻ Significant amounts of fresh water are required. ͻ Subsistence fishers of wild caught fish could potentially lose their livelihoods as fish farming replaces wild catches. ͻ Fish farming can result in habitat loss for natural populations of wildlife. ͻ Wildlife conflicts can take place, especially efforts to reduce predators (i.e. shooting seabirds or marine mammals that feed on penned fish). ͻ Additives in seafood such as antibiotics, hormones and artificial colourants and dyes are harmful to human health. ͻ Genetically engineered organisms. However aquaculture will undoubtedly become more and more important as an alternative source of seafood and could have many benefits such as: ͻ Supplies a stable and consistent supply of seafood-­‐ which can help to offset the decline in the capture of wild fisheries. ͻ Provides jobs in some coastal areas. ͻ Responsible hatchery programmes can lead to improved numbers of wild populations. Is farmed fish safe to eat? Many questions have been raised about whether farmed fish is safe to eat. Some media reports suggest that some fish and farmed salmon contain toxic substances. Studies have found that farmed salmon can have up to 16 times the levels of PCBs in them than wild salmon, and 3 times the levels in other seafood. (PCBs stand for polychlorinated biphenyls and are a known cause of cancer) Why do farmed Salmon contain more PCB's than Wild Salmon? ͻ PCBs accumulate in the fishmeal that is fed to farmed salmon (as well as added toxins, antibiotics and hormones to control disease) ͻ Farmed salmon are "fatter": they are generally bigger in size, exercise less and therefore contain more fat than wild salmon. PCBs are stored in fat and remain there for an extended period of time. Key Message: Don't give up farmed fish and salmon completely. Try to find alternative sources that are toxin free. Fish is good for you, so rather choose a variety of fish, reduce your salmon intake to twice a month, and include it in a healthy well-­‐balanced diet. Follow these extra guidelines: ͻ Trim the skin and visible fat as PCBs are stored in fat ͻ Cook lean -­‐ grill your fish ͻ Try canned salmon instead as almost all of them are from wild salmon populations. Better yet, give our oceans a break and try a sustainable wild-­‐ĐĂƵŐŚƚ ĨŝƐŚ ƚŚĂƚ͛Ɛ ŶĞǁƚŽ LJŽƵ͊ Or try omnivorous farmed fish like tilapia or catfish. 13 3 So, is there a better way? Retailers, restaurateurs and consumers need to consider that there are some production methods that can have serious negative impacts on both the environment and human health. Luckily, developments are under way globally to develop best practice standards and guidelines for more responsible aquaculture production. One example is an integrated system where fish, mussels, seaweed and other species are being grown close together to recycle wastes. The Aquaculture Dialogues WWF has initiated a number of working groups referred to as ͚ĚŝĂůŽŐƵĞƐ͛ ǁŚŽ Ăŝŵ ƚŽ ĚĞǀĞůŽƉ
better practice standards for aquaculture. The dialogues draw from producers, buyers, non-­‐
governmental organizations and other stakeholders. Once finalized, the standards will minimize the environmental and social impacts responsible for three quarters of the problems caused by aquaculture. Since work started in 1999, the dialogues have identified 12 species for review. To date discussions have focused on tilapia, salmon, molluscs, prawn/shrimp, and catfish. 14 Prawn Aquaculture Prawn or shrimp is the most popular type of seafood in the world. Approximately 5 million tons are consumed annually. One third of the shrimp we eat is produced at farms instead of caught in the wild, making prawn aquaculture one of the fastest growing types of aquaculture. Most prawn aquaculture occurs in China, followed by Thailand, Indonesia, India, Vietnam, Brazil, Ecuador and Bangladesh. The majority of farmed shrimp is imported to the United States, the EU and Japan. The growth has generated substantial income for developing and developed countries-­‐ particularly in Asia, Central America and east Africa, but has also raised concerns about how shrimp farming affects the environment and society. However, developments are under way for implementing minimum standards for responsible shrimp farming which will reduce the key environmental and social impacts (e.g. WWF Aquaculture dialogues). WƌĂǁŶĂƋƵĂĐƵůƚƵƌĞ͛ƐŵĂŝŶŝŵƉĂĐƚƐ͗ Farm design: ecologically sensitive habitats, such as mangrove forests, can be cleared to create ponds for shrimp production. Water use/pollution: salt water from shrimp farms can seep into ground water and onto agricultural land, organic waste, harsh chemicals and antibiotics can pollute water, and aquifers can be drained to supply shrimp farms with fresh water. Feed management: wild stocks of fish are depleted for use in formulated feeds for shrimp production. Broodstock: genetic diversity and health of broodstocks can be compromised due to inbreeding and disease. Escapes: escaped farmed shrimp can affect wild species by competing for food, transferring diseases and interbreeding with them. Socio-­‐economic issues: jobs can be lost when there are fewer wild-­‐caught shrimps to harvest or shrimp farms are forced to close. Communities are also socially affected as livelihoods are lost when local mangrove forests are cleared. Mangroves are important habitats for many species of fish and shellfish, and their loss leaves coastal communities with reduced food security and potential for income generation and land seizures result in displacement of those communities. 3 Shellfish Aquaculture Farmed shellfish Shellfish like clams, oysters, and scallops do not require artificial food after their captive larval period. Shellfish exploit naturally occurring phytoplankton and depend on the natural water filtration and food supply that come from coastal wetlands. They often help keep the water clean by filtering sediment and unwanted nutrients. A more indirect environmental benefit of mollusc aquaculture is that because this type of farming depends on clean water, coastal communities that farm shellfish are often dedicated to protecting water quality. Worldwide, cultured shellfish comprises nearly half of all shellfish (excluding crustaceans) consumed. Potential problems: ͻ Gene transfer to wild populations, introduced species can often out-­‐compete native ones using non-­‐native species in shellfish farming operations can spread diseases to native populations, sometimes with serious consequences. ͻ Habitat interactions, modifications to ecological community structures, harvesting techniques (e.g. dredging), production techniques (e.g. netting). ͻ Pollution from loading of pathogens, use of chemicals and other physical means to prevent and control diseases and pests. Histamine levels in fish? Histamine fish poisoning is one of the third most frequently reported illnesses associated with the consumption of seafood. It occurs as a result of improper preservation and inadequate refrigeration. Histamines develop in the muscles of fish belonging to the Scrombroidae family, which include mackerel and tuna, if the fish are not kept cool after they have been harvested. Sardines, pilchards, herring, dorado and yellowtail may also be common culprits. Histamine poisoning can cause severe discomfort but is mild in nature, rarely lasting for more than one day. Symptoms are sometimes mistaken for those of allergic reaction and includes skin flushing, headache (severe & throbbing), dizziness, dry mouth, nausea and vomiting, diarrhoea, abdominal cramps, palpitations, respiratory distress and chest tightness Mercury in fish? All fish contain some level of mercury and other elements found in nature. Mercury gets into the ocean, and subsequently into fish, from natural gasses released from the Earth's crust, and also from burning wastes, industrial pollution, and fossil fuels. Fish accumulate mercury in their tissues as water passes over their gills and from what they eat. The larger and older the fish, the higher the level of mercury. Because they are at the top of the food chain fish species such as tuna, swordfish and sharks tend to concentrate more of these elements. Pregnant women are advised not to eat fish that may potentially contain any traces of mercury, as mercury is known to cause birth defects in young children. So which is better? Some species, such as prawns, may be fast growing and able to withstand heavy fishing pressure but the fishing or aquaculture techniques used to catch/farm them may be incredibly destructive for surrounding marine ecosystems. At the same time, some fishing methods may be highly selective and have relatively minor environmental impacts, such as linefishing, but their target species cannot sustain heavy fishing pressure. In order to make the most sustainable choice, it is important to understand not only how the fish itself lives but also the impact of the fishing method used to catch it. 15 3 NOTES: ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ 16