Shandong Long Island North Five Islands Xu's Flat Carp Fry Land and Sea Relay Transport Technology
_Takahama
It is a near-shore demersal marine fish that often inhabits rocky reef areas with clear water. Distributed in China, the Korean Peninsula, Japan, the southern part of the Sea of Okhotsk, mainly distributed in the Yellow Sea and the East China Sea, it is a common edible fish, but also an offshore breeding and artificial breeding object. Its seed source is widespread, disease resistance is strong, low temperature resistance, fast growth rate, is an important cage cultured fish in northern China, especially in the coastal waters of Shandong.
Fry transportation is very important in the aquaculture production of Xu's flat carp, because of its large fin spines, the transportation process is easy to stab each other, resulting in losses, so the transportation of its fry requires special methods. Shandong Changdao North Five Islands is a concentrated breeding area of Xu's Pingqi, while Xu's Pingqi Nursery Factory is concentrated in Weihai Rongcheng and Rushan areas, so it needs an insured and safe land-sea relay transportation method.
In the past, live seafood barrels (canvas barrels, tanks, etc.) were used in the transport of fish fry, transported by live seafood transport trucks by land transport, and transported by aerobic fishing vessels at sea. When fingerlings are smaller, they are oxygenated in plastic bags. In the land transport link, the FRP tank directly holds fish fry to the fish in the basket and then puts them into the FRP tank, and the seawater transport link increases the seawater circulation water supply. Such changes not only improve the survival rate of transportation, but also improve the ease of operation. The technology is introduced as follows.
1 Prepare before shipping
1.1 Fry are stopped
The feeding of Xu's flat squid fry is stopped two days before transportation to reduce the oxygen consumption of the fry during transportation, increase the survival rate, and reduce fecal excretion during transportation and reduce water pollution.
1.2 Preparation of tool materials
The main tools required are fishing nets, pots, fishing tanks, buckets, water pipes, water temperature meters, dissolved oxygen analyzers, etc.
Fishing frame: The basket is a custom-made lidded leaflet basket, measuring 80 cm long, 40 cm wide and 10 cm high. Prepare 400 according to the space of the fiberglass groove of the transporter.
Live fish transport vehicle: The transport vehicle is a thermal insulation vehicle, which is equipped with a FRP sink, laid under the oxygen head, and drives the air pump through the diesel engine to provide oxygen supply. The transporter in use has a total of 10 FRP grooves, each of which can hold 40 fishing frames.
Canvas drum: The outside of the canvas barrel is a 1.2 m×1.1 m ×1.1 m frame welded with galvanized steel pipe, the size of the canvas bag is 1 m×1 m×1 m, the canvas bag is fixed to the frame with a rope, and a layer of plastic pocket is laid inside the canvas bag to prevent the canvas bag from scratching the fish body during transportation. 12 canvas barrels are required.
Fishing boats: Fishing boats are equipped with centrifugal pumps and water pipes, which can pump seawater into the canvas barrel at any time to promote the circulation of seawater in the canvas barrel. In addition, the ship is also equipped with oxygen cylinders, trachea, aerosols, etc., which are used for oxygenation during transportation.
1.3 Planning transit times
The body length of Xu's flat squid fry generally reaches 5 to 10 cm, and can be transported to the sea for cage culture. The time is generally from July to August of each year, when the daytime temperature is too high, so fry transportation is generally carried out at night and needs to be transported to the cage before the morning.
For example, from Weihai Rushan to Nanhuang Island, it takes 2 h to load, 3 h to land transport, 1 h to ship, 4.5 h to sea transport, and the whole process takes 10 to 11 h. Therefore, if you plan to arrive at the cage at 06:00 on the second day, you need to start loading at 19:00 on the same day.
2 Fry loading
2.1 Add water to the transport vehicle
First of all, the fiberglass tank of the transport vehicle is added with seawater, which requires the seawater water temperature to be about 5 °C lower than the water temperature in the breeding pond, and reducing the water temperature can weaken the vitality of the fry, reduce the chance of injury, and weaken the metabolic rate of the fry, reduce the oxygen consumption, and increase the transport safety of the fry. Other water quality requirements meet the xu's flat carp aquaculture water standards.
2.2 Fry loading
After the transport truck is filled with water, the fry are loaded into the truck. First, the water of the pond is put to the level where the fish can be caught with a net, and the oxygen is maintained, and then the fry are transported to the sub-tank in a bucket. Two fish troughs need to be prepared, one for fry points and the other for fry framing. Running water is maintained in the two fish tanks to ensure that there is no lack of oxygen during the loading of fry.
After the fry are poured into the fishing trough, the artificial points are loaded into the pot and then into the baskets, each of which contains 200 to 300 fish. After reaching the predetermined number, the vehicle is capped and loaded.
When loading the car, 10 fish baskets are installed in a group and are fixed with a specific basket holder. Each FRP sink is packed with 4 groups. Each vehicle is loaded with 400 baskets, which means that the maximum transport capacity per vehicle is about 120,000.
3 Shipping
3.1 Land Transport
When transporting by land, a diesel engine is used to drive the air pump to oxygenate. Check whether the vehicle and oxygenation are normal before departure, and record the water temperature. During transportation, stop every 0.5 h or so to check the oxygenation status, the status of the fish and the water temperature to ensure the safety of transportation.
0.5 h before reaching the dock, contact the crew, report the arrival time and the water temperature on the car, let the crew add seawater to the canvas bucket in advance, and adjust the water temperature in the bucket through ice cubes, so that the water temperature in the bucket is ≤ 2 °C difference between the water temperature in the bucket and the water temperature on the car.
3.2 Shipment
After the vehicle arrived at the dock, the water temperature in the FRP sink and the canvas bucket was measured again, and the ship was loaded after determining that the difference was not large.
First of all, each canvas barrel places an air stone, and then open the pure oxygen, adjust the oxygen valve, oxygen should not be too large, control oxygen can just splash. If the inflation is too large, it will impact the fry, causing the fry to hit the wall of the barrel and be injured, which is also the reason why air is not used for oxygenation. Similarly, oxygen should not be too small, and ρ (dissolved oxygen) >7 mg/L must be guaranteed.
After adjusting the oxygen, the fish are unloaded, the baskets are opened one by one and the fry are poured into the boat's canvas barrels, each of which can hold about 10 000 fry. When the fry are loaded into the boat, the basket is completely immersed in the water, and then the basket is gently flipped so that the fry swims into the bucket on its own, in a gentle motion to avoid scratching the fry.
3.3 Carriage by Sea
There is no water change 0.5 h before sea transport, so that the fry gradually adapt to the environment. After 0.5 h, open the pump, start to add water to each canvas bucket with water pipe, when adding water, ensure that the water inlet is facing the canvas barrel wall, so that the sea water flows into the barrel along the barrel wall, and the water outlet is prohibited from being directly inserted into the barrel, so as to prevent the fry from flipping up and down in the bucket and hitting the barrel wall due to excessive water flow. At the same time as adding water, the water pipe is drained through the siphon, so that the sea water in the canvas barrel forms a circulation. A strainer is placed at one end of the pipe inserted into the bucket to prevent the fry from being pumped away. The circulating water flow rate is around 2 m3 /h.
During the transportation process, the status of the fry is observed in real time, and the water circulation is observed so that it does not overflow or lack water. Water temperature and ρ (dissolved oxygen) are measured every 0.5 h to ensure safe transport of fry.
3.4 Unloading fish
After arriving at the breeding area, measure the water temperature in the canvas barrel and cage, and start unloading the fish if the difference is not large. The fish are sucked into the cage from the canvas bucket by siphoning, until the water in the bucket cannot be siphoned, and the lined plastic pocket is lifted and poured directly into the cage. This process needs to be handled with water completely so as not to damage the fry.
4 Advantages of transporting in fish baskets
Xu's flat carp is a reef-loving fish, belongs to the bottom fish, in the confined space, the nursery will be concentrated in the bottom layer, can not make full use of the water body space, and the use of fish basket transportation is more in line with its habits, disguised to increase the transportation space.
When transported in baskets, the impact of water shaking in transport on fry can be reduced, thereby reducing the chance of fry being injured. It is more convenient and faster when unloading fish, which shortens the loading and unloading time and reduces fry damage.
5 Precautions for land and sea transport
Throughout the transport process, fry move from one water environment to another, with a temperature difference of ≤5 °C to prevent stress reactions. It is necessary to stop eating > 2 days before transport and ensure that ρ (dissolved oxygen) >7 mg/L during transport.
Sea transport is open-air transport, so try to ensure that it is transported in the evening or early in the morning to prevent the sun from rising the water temperature too quickly and increasing the risk of transport.