Live fish transport

the listing of commercial fish and the transfer of fish fry species between regions require the healthy and fresh state of fish in transport. Because fish breathe differently from land animals, often need to bring water transport and some special equipment, increasing transport costs, therefore, in order to minimize transport costs while maintaining fish health, is the requirements of live fish transport.live fish no bacterial corruption, strong safety, can maximize the preservation of the original nutritional value, so that live fish more and more favored by domestic and foreign markets, live fish and frozen fish price difference almost doubled. For example , Hong Kong's per capita annual consumption of aquatic products is 40 kg , of which 90 % is fresh , and the import of live fish from Japan is increasing at a rate of 5 % every year . Chinese cooking in China also has characteristics in the food culture, especially in eating seafood, pay attention to eat raw seafood. Many cities have established live wholesale markets, forming a live fish sales industry chain. As far as marine fish farming is concerned, it is not possible to raise marine fish in the inland areas of our country. And the south all year round are suitable for aquaculture, after winter aquaculture products mostly reach commodity specifications, the formation of the peak market, the phenomenon of low prices almost every year. For example, from November to December 2001, fujian Province' real production price of 10 to 12 yuan / 500 g, while Qingdao ship side delivery price of 24.5 yuan / 500 g, Wuhan, Changsha more up to 30 yuan / 500 g. Therefore, we should make full use of the coastal and inland, winter and spring south and north fish market volume difference to fill the gap, can promote live fish transport technology, to solve the problem of fish difficult to sell in the production area, fish difficult to eat in the marketing area.。 Catalog
. . . Factors affecting transport survival. . . pre-transport preparation and transport equipment. . . fish fry, fish species transport. . transport of pro-fish. . transport of edible fish. The high density of fish (fish) and the limited dissolved oxygen content (water) of water in transportation containers are the main contradictions in transportation. Any factors that affect the change of dissolved oxygen content of water and the low oxygen tolerance of fish will affect the survival rate of live fish transportation. Therefore, the method of improving the survival rate of fish transportation mainly includes two aspects in principle: first, to reduce the metabolic strength of fish (to reduce fish oxygen consumption); Specifically, the following factors affect the survival rate of transport: fish species specifications and other characteristics of their own physical fitness, water temperature and water quality during transport, transport time, distance and mode, as well as the bumpy condition of the road., the species, size and physique of fish
metabolism, constantly draw oxygen from the water to eliminate carbon dioxide. The amount of oxygen a fish absorbs from water is expressed in terms of oxygen consumption (i.e. milligrams of oxygen consumed per gram of fish per hour). The oxygen consumption rate of fish larvae such as yellow fins, flat slugs and spiked slugs was determined as shown in Table 9-1.(i) The oxygen consumption rate of fish decreased relatively with weight gain, e.g. the oxygen consumption rate of 1.215 grams of flat seedlings was 1.192 mg/g/h, while the oxygen consumption rate of 4.467 grams of seedlings decreased to 0.756 mg/g/h. Therefore, the unit volume load weight, small individuals than large individuals less.(ii) The oxygen consumption rate of fish increases with the increase of water temperature, such as the oxygen consumption rate of yellowfin larvae increases with the increase of water temperature, so in the same volume, the low water temperature is more than the fish fry installed at high water temperature, so the effect of transporting fish fry in the low temperature season is better.(iii) there are some differences in the oxygen consumption rate of fish. Therefore, according to the oxygen consumption rate of different fish, the reasonable shipment volume of water per unit volume should be determined.before transport, if fish are strong and adaptable to adverse environments, the survival rate of transport is high. When fish are caught in transport equipment, because of the new environment is not adapted to or frightened, will swim and struggle fiercely, which will make the muscle contraction, resulting in a large amount of lactic acid accumulated in the muscle blood vessels, resulting in a decrease in the pH of the blood. Because acidic blood will reduce the affinity of red blood cells to oxygen, reduce the oxygen supply to the
tissues
organs of the fish body, so that the fish in the transport of 24 hours is not easy to return to normal. So be sure to pick strong individuals before transportation to ensure survival., dissolved oxygen
water insufficient oxygen will make fish in the transport process can not breathe normally, if serious lack of oxygen, but also cause fish asphyxiation death, thereby affecting survival rate. Dissolved oxygen in water should be kept above 5 mg/L during general transport. Therefore, the fish fry transport to ensure the supply of oxygen.(a) oxygen supply method 1, often injected in transit equipped with new water, can increase the amount of dissolved oxygen in the water, the temperature and salinity of the new water should be basically similar to the raw water.2, the transporter for a moderate oscillation, so that the water fluctuates from time to time, in order to increase the contact surface of water and air, increase dissolved oxygen. Be aware that the transporter should not shake too hard to avoid harming the fish body.3, set up some mesh plates on the water inside the transporter, so that it continues to swing slowly to increase the oscillation of water.4, in the transport process to install oxygen booster or inflator, can be at any time oxygenation.5, with compressed oxygen cylinders to supply pure oxygen.(ii) oxygen supply equipment 1, compressed oxygen cylinders for a small number of transport. The oxygen cylinder port is equipped with a pressure control valve to control the flow, with a plastic tube into the bottom of the container, and at the end of the air stone, so that the amount of bubbles is many and small, increase the area of dissolved oxygen in the water, to achieve the purpose of oxygenation.2, oxygen booster generally with inflatable oxygen booster and water spray oxygen machine, but also with steel comb and jet oxygen booster, with oxygenation, stirring water and aeration three functions. Safety should be paid when installing the oxygen booster, and a safety isolation net should be set up around the oxygen booster.3, oxygenation machine in the bottom of the transport tank set up a plastic tube and oxygenation machine, through the plastic tube in the transport water body to discharge bubbles, so that the flow of water to produce gas exchange, to increase dissolved oxygen. At present, small (93W or 120W) DC and AC air compressors are used on board ships or cars for gas-sourced oxygenation., temperature
fish are warming animals. Body temperature varies with the temperature of the water. All kinds of fish have their own temperature range, beyond the temperature range is easy to die. Be sure to control the water temperature during transportation. High temperatures, high metabolic and oxygen consumption rates of fish bodies, and the resulting carbon dioxide and ammonia nitrogen content, while dissolving oxygen reduces the affinity of blood and oxygen in fish. So when changing water, adding new water, or freezing, prevent a sharp change in temperature. Water temperature mutation, the fish body internal machine can be immediately adjusted to adapt to this change, fish prone to disease. Summer temperatures are too high, so you can put some broken ice on the water surface, so that it gradually melts, can reduce the water temperature. Winter water temperature is too low, to take anti-freeze measures. Changes in water temperature are generally suitable for temperature differences of no more than 5 degrees C.temperature range, the higher the water temperature, the greater the metabolic intensity of fish, the greater the need for oxygen, while metabolic waste is also increased, easy to cause water pollution, so that vitality decline. Therefore, cooling is an effective measure to improve the survival rate of fish transportation. The temperature of the suitable water body for cold water fish transportation in summer is 6 to 8 degrees C, the temperature of warm water fish is 10 to 12 degrees C, the temperature of the suitable water body for cold water fish transportation in spring and autumn is 3 to 5 degrees C, the temperature of warm water fish is 5 to 6 degrees C, and the temperature of suitable water body for fish transportation of 2 kinds of different ecological environments in winter is 1 to 2 degrees C., carbon dioxide
fish breathing in the water will emit carbon dioxide, so that the concentration of carbon dioxide in the water increased. It has been determined that the harmful concentration of carbon dioxide to fish is 60-80 mg /L, at which time even if the dissolved oxygen in the water is saturated, the fish can not breathe normally and will suffocate to death. During general transportation, the concentration of carbon dioxide in the tank is 20-30×10-6. If the concentration of carbon dioxide exceeds this range, it should be inflated into the water to remove carbon dioxide and increase dissolved oxygen in the water to maintain a normal living environment for the fish.5, ammonia nitrogen
due to the fish excreted feces, bait, dirt and bacteria, the water ammonia nitrogen content continues to improve, when the accumulation of ammonia nitrogen in the water to a certain concentration, will weaken the fish's oxygen absorption capacity, hindering the normal breathing of the living body. Ammonia is harmful to fish bodies, and when the general concentration exceeds 0.012×10-6, fish are in mortal danger. Usually when the water temperature rises, the fish's ammonia discharge increases, and the small fish's ammonia discharge is larger. Therefore, the transport volume should be a large amount of oxygen supplementation, so as not to poison the fish fry in the middle of the death, resulting in economic losses., pH, and
pH in water can affect fish. When the acidity of the water increases to a certain limit, the fish reduces the ability to draw oxygen from the surrounding water environment, even in oxygen-rich water, the fish will feel "oxygen" shortage., the osmosis pressure of the fish body
the fish body surface has secreted mucus or scales, can maintain the osmosis pressure balance in the body. In the transport process, due to the vibration of transport equipment, the body surface of the fish fry will often be affected by the water tank or the net box mechanical damage, resulting in scales and mucus off, the skin scraped, so that the body osmosis pressure regulation out of balance, reducing the fish fry's resistance to disease. Therefore, we should try to avoid damage to the surface of the fish body, in order to maintain the normal osmosis pressure of the fish body., prevent the reproduction of bacteria fish in the transport process if in an uncomfortable environment, will secrete a lot of mucus and excreta. These secretions become a
of
, allowing bacteria to multiply rapidly. On the one hand, germs can infect fish fry, on the other hand, the reproduction of germs to consume oxygen. Reduces dissolved oxygen in the water and makes it easy for fish fry to die of lack of oxygen. In addition, in the course of transport, if fish's digestive tract retains residual food, bacteria will also multiply with the entry into the intestines and stomachs, coupled with the fish itself in the transport of weak physical strength, more susceptible to disease. In order to improve the survival rate of fish fry transportation. In the temporary breeding of fish before transport, the fish should disinfect the fish body with drugs and "eliminate the belly" so that they can excrete the feces, so as to avoid or reduce the pollution and deterioration of water in transit and improve the survival rate of fish fry.addition, foam and slag in water are also factors that affect survival, especially when metabolites are high, and adding sodium chloride can reduce the amount of foam in the water.。 Pre-transport preparation and transportation equipment Edit this paragraph Back catalogue First, pre-transport preparation
(i) develop a well-planned transportation according to the number, specifications, type and mileage of transport seedlings, determine the means and methods of transport, and negotiate relevant transport matters with the transport department.(ii) To prepare means of transportmainly means of transport, shipping tools and oxygen-for-water equipment. Check the means of transport and inflators to avoid malfunctions in transit. (iii) to investigate and understand the water source and water quality of the stations in transit, contact and determine the water change location along the way. (iv) According to the road and transport volume, organize and arrange transportation management personnel with certain technology in order to do a good job of carrying and shipping and loading and unloading. (v) do a good job of seedling treatment before the transport of fry 1, good quality, which is a prerequisite for improving the survival rate of transport. To choose neat specifications, strong body, bright body color, swimming lively fish fry for transport, can not choose scales off, body injury, blind-eyed fish fry, body surface ulcers with germ seedlings can not be selected. 2, the fish fry to be transported should first be placed in the net box temporary, so that it can adapt to static water and fluctuations, and during the temporary period to change the box 1-2 times, so that the fish fry get exercise, while the opportunity to change the box to remove dead fish, dirt and fish secretions, in order to improve survival rate on the way. 3, fish species before the start of transport to pull the net exercise 2-3 times; , transport means
means of transport include traditional pick-up, canvas and other land transport, as well as modern live fish transport vehicles and so on. 。 Fish fry, fish species transport Edit this paragraph back catalogue fish fry transport generally uses sealed oxygenation transport, that is, fish and water in sealed containers, and filled with pure oxygen to ensure the need for fish breathing in transport. Sealed transport water is small in size and dense in fish loading, suitable for the transport of fish fry, small size species or fish without hard stings. The advantages are simple equipment, appliances, small transport volume, shipping density, suitable for a variety of means of transport, high survival rate, generally do not need to change water, can greatly reduce labor intensity and labor savings. use containers such as plastic bags, rubber capsules and plastic buckets. the mode of transport based on the number of fry shipped and the traffic conditions from the place of shipment to the place of arrival. There are three modes of fry transport, namely air, land and sea. (a) Air transport suitable for long-distance transport, fast transport speed, short time, high survival rate. However, the requirements of strict packaging, low transport density, packaging and transport costs are high. package is inflated in a double-layered polyethylene bag and placed in an aviation-specific box. Commonly used bags are generally white transparent, high pressure resistant, film thickness of 0.lmm to 0.18mm, length 70 to 80cm, width 35 to 40cm, volume of about 20L. Some places are designed to protrude the bag port about 15cm wide and 10cm wide. When used, water is injected about 1/3 of the bag. Too much not only increases the transport weight, but also reduces the oxygenation space. Add water and put in a certain number of fry, squeeze out the air in the bag, and attach a rubber or plastic tube to the oxygen cylinder