Introduction – Canned tuna quickly grew into one of the most popular seafood products in the United States due to low cost, and its source of protein; making it number two in the top ten consumed seafood products (Campling et al. 2007). Harvesting of the canned Tuna species has raised significant ecological issues and concerns related to economic and environmental sustainability (WWF n.p).
Types of Canned Tuna Species
There are five main commercial tuna species: Albacore, Yellowfin, Bluefin, Big Eye, and Skipjack. The most commonly canned species, though include the Albacore Tuna, the Yellowfin tuna species, and the Skipjack tuna species (Canned Tuna, 2014). The following sections provide information regarding the biological species, habitat, trade name, fishing methods and their related advantages, disadvantages and the sustainability of the various canned tuna species.
The scientific name for the Albacore tuna is the Thunnus Alalunga. It is typically a large fish, ranging at approximately 4 to 5 feet in length and weighs roughly 80-90 pounds. It is metallic, identified by a dark blue color running along its topside and a silvery white strip marking the sides of its belly. The Albacore is found in the tropical and warm temperate oceans. The specific locations of the species include the Atlantic, the Pacific and the Indian Ocean. According to the sustainable canned tuna website, the Albacore Tuna is the most abundant and popular species of the canned fish because of its ability to survive in large populations in the temperate and tropical oceans. The trade name of the canned Albacore is the white meat tuna (Hilderbrand, 1-3).
Katsuwonus is the scientific name for the Skipjack tuna. It is a streamlined fish of medium size, weighing in at about 70 pounds, with a maximum length of about 4 feet. Compared to other tunas this particular species have a short life span ranging from 8-12 years. They do not have scales, except on the corselet, these fish swim in schools and are opportunistic feeders, preying on a variety of fish. The canned skipjack tuna is found in the tropical, subtropical, and warm temperate waters. Trade name for the Skipjack is the light meat tuna. (NOAA, n.p)
The Yellowfin tuna is known scientifically as the Thunnus albacares. This species grows rather rapidly, and has been known to reach lengths of up to 6 feet and weigh up to 400 pounds; they are able to reproduce once they reach the age of two and have a short life span of 6-7 years. These are torpedo-shaped fish, they can change in color from yellow to silver on their belly region, and are overall a metallic dark blue hue. Their name is attributed to their dorsal and anal fins and filets that are bright yellow. Yellowfin tuna is found in the tropical and subtropical oceans around the world. Trade name for this species is the chunk light tuna, these can be canned in either oil, brine (salt water), or natural spring water (NOAA, n.p).
Methods of harvest
There are several methods of harvest for these species; the Albacore tuna for canning purposes is caught using the surface troll method. According to the ‘Goodfishbadfish’ website, sustainable Albacore fisheries emphasize on the use of the pole and the line harvesting technique. The yellow fin tuna and the skipjack are harvested using the long line fishing, the pole and line method and the purse seine fishing method (NOAA, n.p).
Advantages and Disadvantages of the Tuna Fishing Methods
There are several methods for harvesting the tuna fish for home consumption and the canned market industry. Proper fishing methods are likely to lead to a sustainable fish market while improper fishing methods may have adverse effects on the available stocks of the tuna fish due to overfishing and degradation of the environment such as the use of chemicals, dredging and explosives. It is important for consumers to be aware of the various ways in which the tuna fish are caught and to ensure that they consume only the tuna fish that comes from fisheries that practice sustainable breading, stocking and harvesting methods. The following section examines the advantages and disadvantages of four of the most commonly used harvesting methods for the canned tuna fish species.
The Pole and Line Method
This particular method is the most commonly used and sustainable technique of harvesting the tuna fish for commercial canning purposes. Several fishermen use fishing poles to capture and harvest the tuna fish. This procedure uses a pole and a long line with a lure or bait attached to its far end. The bait attracts the tuna fish, which is then caught by the hook, thus enabling the fishermen to bring it to the surface of the ocean. The main advantage of this method is that it is environmentally and ecologically sustainable. This method only captures the targeted mature tuna fish, and does not result in excessive bycatch thus has little or no adverse impact on the oceanic ecosystem. In addition, it is possible to return any bycatch to the ocean quickly with minimum or no harm (goodfishbadfish, n.p). The pole and line fishing method is the only sustainable way of preserving the aquatic ecosystem, survival of the tuna fish, and ensuring continued supply of the canned tuna into the market (Maguia, 2014). However, this method is tedious and strenuous and may not be suitable when harvesting huge volumes of tuna for commercial purposes (Canned tuna n.p).
Surface Troll Method
The surface troll is another commonly used method of harvesting of the tuna fish. This technique uses several rigs with lines that drag lures and hooks under the sea using trolling boats. The trolling boat moves on the surface of the ocean, identifies the school of tuna fish and drops the rigs. This method is advantageous because of three reasons: first, it captures adequate amounts of tuna fish in a short period of time; second, the hooks and lures are strong and durable thus enabling the fishermen to reuse them for a longer period; third, it enables the fishermen to bring the tuna fish to the surface quickly and allows them to return any unwanted fish to the ocean. The main disadvantage of this method is that it may promote overfishing. However, this method is sustainable because it does not result in huge amounts of bycatch (Wild Planet n.p).
The purse seine fishing method
The purse seine fishing technique is the last and most discouraged method of harvesting tuna fish. According to the canned tuna website, this method uses a wide net that is hauled by a large ship. The only advantage of this method is that it enables the fishermen to capture large quantities of the tuna fish for commercial purposes within a short period of time. It is also a less tedious technique and more economical for harvesting tuna fish. However, this method is the most disastrous, indiscriminative, and unsustainable fishing technique due to the capture of other fish apart from the tuna, which are often discarded as bycatch. The use of the fish aggregation devices (FAD’s) often result into the capture of dolphins, sharks, turtles and young tuna fish which often die after being removed from the ocean (Greenpeace 1). This type of fishing is unsuitable and leads to the depletion of the tuna population and other organisms in the aquatic ecosystem (Wild planet n.p). The WWF position paper also argues that the FAD’s are unsustainable and a threat to the ocean environment.
Ecological sustainability of the Tuna fish
According to the Greenpeace International, these tuna species are experiencing possible extinction threats due to over consumption. This results in the depletion of available stocks and the increase of excessive fishing because of the use of unsustainable fishing technology that affects other organisms in the marine environment.Currently the Albacore Tuna is not under threat of extinction due to the availability of sustainable fishing methods and stock management practices. However, according to the sustainable canned tuna website, the use of unsustainable fishing and harvesting methods are threatening the sustainability of the Albacore tuna fish and the entire ocean ecosystem. Individuals and organizational consumers are advised to purchase and consume Albacore fish that has been harvested using only sustainable methods such as the use of the pole and line techniques. Information regarding certified and sustainable fisheries, which use the appropriate harvesting and stock management techniques, can be obtained from the Marine Stewardship Council website. The organization promotes sustainable fishing by recognizing and rewarding individuals and organizations that use sustainable fishing methods and practices, influencing the buying decisions of consumers for the seafood and encouraging partner organizations to promote development of a sustainable seafood market and industry.
The Yellowfin tuna species has been on the decline due to overfishing and the use of poor fishing methods. According to the Sustainable Canned Tuna website, the Yellowfin tuna are under threat of extinction due to excessive consumption and unsustainable fishing practices. The use of the long line and purse seine harvest technique causes stress to the Yellow fin tuna species and disrupts the normal ocean environment and ecosystem thus threatening the survival of the fish. According to the Greenpeace International website (n.p), in order to ensure the ecological sustainability of the yellow fish, the following recommendations are worth being considered:’ There is a need for effective management of the stocks of the yellow fish.’ There is a need for support of fishing methods that are both sustainable and equitable.’ There is a need for consumers to purchase canned fish that has been harvested using sustainable methods only.’ There is a need for consumers and other partners to support conservation and preservation initiatives for the yellow fin tuna.According to the American association of the advancement of science (n.p), the canned Skipjack tuna is the most stable and sustainable fish. This is because of its high reproductive and fast growth rate, making it the most popular fish in commercial hatcheries and canned fish markets. However, according to the Sustainable Canned Tuna website, harvesting the Skipjack tuna fish using the purse seine method is not sustainable because it kills other aquatic species such as the turtles, sharks and young tuna fish. This is a serious threat to the sustainability of the canned Skipjack fish and the marine environment. In order to ensure sustainability of the tuna fish, consumers are advised to purchase canned tuna that was harvested using the pole and line method or those that are harvested by fisheries, which are certified and recognized by the Marine Stewardship Council.Grocery Store Evaluation’ Bumble Bee: 1. Chunk Light Tuna (in water) 2. Solid White Albacore’ Starkist Selects:1. Yellow Fin Marinated Tuna2. Solid White Albacore’ Chicken of the Sea:1. Chunk Light Tuna (in oil)These three are the most common canned tuna sold where I live, as I evaluated the tuna cans I noticed that all three of them had the ‘dolphin-safe’ label, to my knowledge at that moment I thought that that label was supposed to mean that these manufacturers would not, had not, and should not harm dolphins. After some research, I was surprised to find out that these brands are known as ‘the big three’. Meaning that these were known for being part of the dolphin label scheme, according to the Tuna Truth Squad, these three manufacturers are not considered dolphin-safe. They have continued to mislead consumers to believing that they use the most sustainable methods, but the truth is that they have killed tens of thousands of dolphins each year. It is said that the Bumble Bee brand will improve its sustainable methods for the Skipjack tuna. If in fact this manufacturer follows through, they will be the first to actually adopt the dolphin-safe or the eco-safe label. (Eco-Safe Tuna, 2014).