| 词条 | Canadian Atlantic Cod |
| 释义 |
}} Canadian Atlantic Cod or Gadus morhua, are cold water fish, which weigh 2 to 3 kg in the wild [6]. Atlantic Cod were originally found in the Atlantic Ocean, along the borders of both Canada and England and all the way down to the southern United States. Heavy fishing in these areas, in the late 1800s and early 1900s led to a massive decline in Cod population.[7] Today, they are grown in onshore temperature controlled, seawater tanks as eggs and eventually taken to sea cages when more developed.[2] The majority of these artificial environments found in Canada, are located in British Columbia, New Brunswick and as well as Newfoundland and Labrador. It takes about 6 months for the fish to hatch followed by a 2 to 3-year period for them to reach their maximize selling size, therefore taking an average of 3 years for a fish to reach market which is 3 to 5 kg.[2] According to Fisheries and Oceans Canada (2014) in 2013 1 kg of Cod was being sold for on average $7.12 fish.[4] Overall, Atlantic Cod are a relatively recent farmed fish, however are gaining popularity due to price, nutrition and feed to growth ratio. Raising Atlantic CodIn our modern society almost all fish, including Atlantic Cod, are now produced through aquaculture. Aquaculture is defined as "the rearing (raising) of aquatic animals or the cultivation of aquatic plants for food". The raising of Atlantic Cod starts with the selection of the best female stock breed.[2] These fish are selected from previously grown market fish, located in off shore sea cages. They are selected based on weight; typically the heavier the fish the more eggs it can produce. The female fish are breed in onshore tank facilities and can produce 450,000 eggs per kg of body weight. After separating the females, the eggs are incubated in a temperature controlled tank for about 14 days until hatching. The baby cod or 'larvae' are then transferred to larval tanks. During this stage the larvae are feed yolk from a yolk sack for 3 to 4 days. After this period, once the larvae have grown large enough, they are fed tiny plank-tonic animals (ground plankton). Then after a duration of 35 to 40 days of being fed plank-tonic animals, the larvae should have undergo metamorphosis and are now considered fish. They are removed from the larval tanks and put into circular tanks in an onshore facility. They remain in this stage for 6 months or until they are 10 to 20 grams or centimeters in length.[2] After they have reached this, size a microchip is sometimes inserted into the fish to monitor growth and collect information.[8] Finally the fish are taken to sea cage sites via industrial trucks and barges.[2] In the sea cages the Cod will grow until they reach market weight which can take 24 to 36 months. During that period all fish are fed, and cage sites cleaned on a daily basis to maintain the healthiest standards.[2] Facilities and equipmentIn commercial aquaculture there are two main areas of farming: the onshore facility and the offshore sea cages. In the onshore facility there are a number of storage tanks that are key to the early development of Cod and many other cold water fish. These livestock storage include: the incubators (where eggs are fertilized and allowed to hatch), the larval tanks (slightly larger tanks where the larvae is grown), the circular tanks (last stage before fish leave the onshore facility, where metamorphosis occurs) and finally storage tanks where the fish can be temporarily stored as they are transported from truck, to boat, to sea site.[2] Before the fish are taken to sea cage sites, some companies insert microchips into the fish to monitor population and patterns in the fish to improve the raising for future generations.[8] The microchips are removed once fish are ready for market. After being transported to the ocean via private company or government ships, the fish are gently poured into a sea cage.[1] There are many different types of sea cages depending on the location and style of aquaculture. Some common sea containers include: aqua pod (completely sealed bubble), open water (with the hope that the fish will naturally return), sea cages (simple netting tied to the ocean floor), and raceways (often in rivers or ponds).[8] Some facilities (non-coastal regions) contain land based re circulation where all fish are in an indoor water circulated facility. The most common of these however is the sea cages, due to its inexpensive and ability to hold lots of fish. Finally with any of these sites a vacuum system must be present at the bottom of the water facility to absorb fish feces and to circulate the water.[8] This prevents any chance of disease and improves water quality. LaborIn both onshore and offshore facilities Cod require daily maintenance. In the onshore facility an estimated team of 4 or 5 laborers are required for daily tasks, which include: feeding plank-tonic animals, regulating tank temperatures, monitoring health of fish (removing any sick fish), and general maintenance to the water facilities.[2] One must also consider labor for transport, which would include a truck driver, a machine operator (fork lift/crane for moving fish) and a team operating a sea barge (is located far enough off shore). Transport and sea cage crew included would be an estimated 10 people depending on the size of the operation. InputsAs mentioned earlier in the egg stage of development, Cod are fed yolk, followed by plank tonic animals (ground plankton) in the larvae stage, and finally a pellet feed after leaving the onshore facility. The pellets fed to Atlantic Cod are mostly grain based, which are made of fish oil, bone meal, vitamins and minerals.[2] Atlantic Cod have a superb 1 kg of feed to 1 kg of weight gain ratio.[8] In some open water environments this ratio is even more efficient, because Cod will eat other small natural organisms in the water. Cod fish are actually carnivorous animals and will even eat each other if prevalent size ratios are available. However aquatic farms have recently been trying to turn Atlantic Cod's carnivorous diet to a more herbivorous one; as already done in chickens[8] This would drastically lower the already low price of feed for future generations.
Once market size is available Atlantic Cod fish offer a bounty of nutrients including a surplus amount of complete proteins, omega-3-fatty acids, iron and B vitamins.[2] A serving or 98g of Atlantic Cod offers us 40% of our daily protein intake, while at the same time containing low sodium levels[5] Atlantic Cod when compared to other meat have a much lower level of saturated fat, while still holding a high protein level. In comparison, 98g of chicken provides about 18g of protein (under 40%).[9]
Atlantic Cod gives a direct 8000 full-time jobs in Canada and this number is growing.[2] More jobs are becoming available due to increase in demand for fish. In 1986 Canadian Aquaculture production was valued at 35 million, by 2006 it was valued at 912 million and this pace is still growing as illustrated in figure 1. The jobs being created by this industry are also 90% located in rural, Aboriginal or small coastal cities. Just one example of this is in B.C, Kitasoo First Nation community, where aquaculture helped reduce unemployment to zero from 80 percent. Also an analysis by Indian and Northern Affairs determined that 61 First Nations could support salmon farms, 130 could develop trout farms and 123 would have access to clam, mussel and oyster farming.[2]
After the near extinction of natural Atlantic Cod in the wild, strict laws were made to prevent fishing of any sort. This led to aquaculture. However, the fishing industry in Canada is severely limited and regulated. 73 pieces of federal and provincial legislation regulates what is exactly allowed.[2] Any new aquaculture of any sort is not allowed in Ontario.[8] Only coastal areas like British Columbia, Newfoundland and Labrador or New Brunswick are free to build more fish farms under permission from the government.[8] Environmental sustainabilityAquaculture (fish farming) is used for all Atlantic Cod production, so that the environment and natural (wild) fish species are essentially unaffected. Fish are sold without further processing, so little to none of the animal is wasted. The only environmental concern from Atlantic Cod is excess nutrients produced in their feces. If left un-filtered in natural environments, these feces could lead to denitrification. However, in almost all commercial fish farms, feces are utilized (via vacuum) as liquid fertilizer, to be used for farm activities. Other beneficial environment factors are: factories are not required for further processing and feed source has minimal requirements from environment.[4] Finally aquaculture developments need in-depth environmental review which includes Canadian Environmental Assessment Act (CEAA), to prevent harm from ocean habitats.[2] Organic Atlantic Cod is also available as an alternative product. These fish are prohibited from antibiotics, herbicides, GMOs, parasiticides and practices that minimize negative effects on the environment.[2]
Cooke Aquaculture is an independent family-owned aquaculture company based in Blacks Harbour, New Brunswick.[3] They employ 1500 people in Atlantic Canada and generate more than $270 million in annual sales.[3] Alternative productsAquaculture in Canada has a variety of different products to offer. In Canada the top aquaculture products are Salmon and mussels followed by trout. Although these products are popular in North America, they would be too expensive in a developing country. An affordable alternative could be Canadian Arctic Char, or Canadian Farmed Talapia. Both fish are farmed in Canada and have similar environmental friendly regulations and benefits as Atlantic Cod does to Canada. References1. Canadas Economic Action Plan. (2012). Near Shore Fisheries Research Vessels. http://actionplan.gc.ca/en/initiative/near-shore-fisheries-research-vessels 2. Canadian Aquaculture Industry Alliance. (2012). Canadian farmed Atlantic Cod. Aquaculture in Canada, several pages under subheadings (organic standard, economic benefits, health and nutrition). http://www.aquaculture.ca/files/species-atlantic-cod.php 3. Cooke Aquaculture. (2014). Cooke aquaculture. http://www.cookeaqua.com/index.php/videos 4. Fisheries and Oceans Canada. (2014). Trade by species group and species, 2013. Canadian Trade Exports, table/figure. http://www.dfo-mpo.gc.ca/stats/trade-commerce/can/export/xsps13-eng.htm 5. Food and Agriculture Organization. (1989). Yield and nutritional value of the commercially more important fish species. http://www.fao.org/docrep/003/T0219E/T0219E03.htm#ch3.6 6. Food and Agriculture Organization. (2014). Cultured Aquatic Species Information Programme. http://www.fao.org/fishery/culturedspecies/Gadus_morhua/en 7. Hutchings J.A. (2011) Life history consequences of overexploitation to population recovery in Northwest Atlantic cod (Gadus morhua). http://www.nrcresearchpress.com/doi/abs/10.1139/f05-081#.VG4k0_nF_sY 8. Robinson, A, (2014) Personal Communication by lecture (AGR1110, University of Guelph). Date: November 5, 2014. T. Animal Science Professor. 9. Self Nutrition Data. (2014). Nutrition Fact Fish, cod, Pacific, raw. http://nutritiondata.self.com/facts/finfish-and-shellfish-products/4045/2 2 : Aquaculture|Agriculture in Canada |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。