Many of us think nothing of eating a fish sandwich at lunchtime, but if fish stocks continue to decline at the current alarming rate, tuna on rye may soon become a luxury menu item.Environmentalists believe that 80 percent of the world’s stocks are in decline, which is alarming when you consider that one billion people depend on fish as their main source of protein. Environmental pollution and unsustainable fishing practices are two of the causes of the decline.“I do like eating fish,” said JP Skinner, education officer at the Bermuda Institute of Ocean Sciences (BIOS), “but since finding out more about it, I am a bit more hesitant to eat fish. I was lucky enough to have lunch with Sylvia Earle, oceanographer and author of ‘Sea Change: A Message of the Oceans’. She has said that most of the fish stocks of the world are at the point of crashing. She equates eating fish now to catching wild game in Africa. Once it was popular, but due to many species being at the point of extinction, those days are over.”For those who care about protecting the oceans, or even their own health, the list of often contradictory recommendations about fish can be bewildering. Some marine species are being fished irresponsibly in certain parts of the world, while the same species may be fished using sustainable practices in other regions. Some fish contain dangerous levels of mercury while others don’t. On the other hand, there are many health benefits to eating fish. Some studies have suggested that children who eat fish are less likely to develop asthma. Fish rich in omega three fatty acids, such as salmon, mackerel and tuna, can help significantly with heart, brain and eye health. The American Heart Association recommends eating fish, particularly fatty fish, at least twice a week.For guidance, Mr Skinner has turned to a little brochure published by the Monterey Bay Aquarium called ‘Seafood Watch’. It is small enough to fit in your wallet and gives a flash guide to which fish to eat and which to avoid.“It is my go-to pamphlet when I need answers,” said Mr Skinner. “I have one in my wallet when I go out. They have one tailored to sushi. They base it on a few different things, such as sustainable fishing practices. It is not saying ‘don’t eat fish’. It is saying: ‘here are your best choices’. They are also looking for things that are healthy for us. They look at which fish are high in mercury. Usually, the top predators will have a higher content.”The brochure is arranged in a stoplight style. Green means go, yellow means caution and red means avoid. There are also guides targeted at different parts of the world. The brochure for the northeastern United States places albacore tuna caught by longline fishing on the avoid list, while the same tuna caught through trolling or pole fishing is on the go list.Tuna from cooler waters is thought to be better, such as from the Pacific Northwest, because it is generally younger than the tuna that has migrated to warmer waters, and therefore has less contaminants in its system. It is also thought to taste better as tuna from cooler waters has more body fat than those from warmer waters. Albacore tuna is also referred to as longfin tunny and tombo in the marketplace. Longline fishing is bad because of the number of other fish and even birds that are killed in the fishing process.Atlantic char, catfish and farmed mussels and clams are given the go ahead while imported wild sturgeon caviar, Atlantic cod and Chilean sea bass top the avoid list. The caviar is there because of concerns about mercury and other contaminants.“A concern in Bermuda might be wahoo,” said Mr Skinner. “They are a top predator in the food chain. Some studies have found that they have high levels of mercury. Local fish is generally quite safe, but wahoo or tuna are pelagic. They won’t stick around here but will feed in different waters besides Bermuda.”Mr Skinner said one of the simplest things consumers can do is to ask questions about the fish they are eating, and read labels.“In stores, at least you can usually ask if the fish was local or imported,” said Mr Skinner. “Next you might want to ask if the fish was wild or farmed. With tilapia, for example, farmed is on the best choice list. The opposite is true of shrimp. In the Far East, shrimp hatcheries are devastating huge areas of mangrove swamps.”He said groupers from the southeastern United States and the Caribbean were on the red list, because of worries about overfishing.“Down in the Caribbean, Bahamas and Florida you don’t see nearly as many of them as you used to,” he said. “In Bermuda, Nassau groupers have been fished out.”The Nassau grouper began its decline in the 1970s and has shown little response to imposed fishing restrictions in the 1990s. The good news is that black groupers are thought to be making a comeback in Bermuda waters. Fishing concerns tend to be focused on large fishing conglomerates and some smaller companies whose fishing methods are unsustainable. Mr Skinner recommended finding out where the fish you buy comes from, how it is caught and by whom.“The closer you are to your food source, the better,” he said. “Patronising local fishermen is one way to do this. In Bermuda it is possible to find out who fishes in a legal and sustainable way, and ensure they get your business. Most of the fishermen selling locally are extremely knowledgeable and concerned that the local fisheries be protected.“One example, of fish to avoid is Chilean sea bass,” said Mr Skinner. “The marketing makes it sound very attractive. It is a really deep water fish, and is slow to mature and reproduce, which means the species has a hard time recovering from being fished. Fishing boats are going into deeper and deeper waters to fish. Instead of saying our practices are unsustainable, they say, what is the next market we can go to?”He said some of the problems surrounded the method by which the fish were caught.“There are a lot of ways to fish sustainably,” he said. “One concern is about the amount of by-catch. These are the fish and marine life that are inadvertently caught by fishermen while fishing. For example, the tuna industry came under heavy flak several years ago for the number of dolphins caught and killed in tuna nets. Now many brands of canned tuna sport the label ‘dolphin safe’.”Mr Skinner said he is still a sucker for backyard barbecued fish. He particularly liked yellowfin tuna lightly grilled on the barbecue. Yellowfin tuna caught through troll or pole fishing is still on the green list. Trolling is a method of fishing where one or more baited fishing lines is drawn through the water, sometimes behind a moving boat.