A precise identification and prediction method for net fishing grounds in the Northwest Pacific based on ocean hydrological data

Abstract

This invention discloses a method for precise identification and prediction of purse seine fishing grounds in the Northwest Pacific Ocean based on marine hydrological data. The method includes the following steps: refining and visualizing historical production data and marine hydrological data for different fish species; establishing a refined system of important prediction indicators and parameters for fishing grounds and key hydrological elements; accurately identifying and predicting purse seine fishing grounds based on hydrological parameters; and drawing refined fishing ground locations, fishing ground grades, and spatial extent. This invention uses predicted hydrological elements and visualizes them, providing a simple and convenient way to present the marine environmental characteristics of the fishing ground area for easy viewing. Due to the refined and high-resolution analysis of fishing ground formation patterns in the Northwest Pacific purse seine fishing grounds and the construction of a precise fishing ground prediction indicator system, the accuracy of fishing ground prediction is greatly improved. Furthermore, the identification and prediction of central fishing grounds for different fish species, such as mackerel and sardines, is beneficial for improving enterprise profits and production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of marine fishery fishing ground prediction technology, and in particular relates to a method for accurate identification and prediction of net fishing grounds in the Northwest Pacific Ocean based on marine hydrological data. Background Technology

[0002] Forecasting marine fishing grounds is more difficult than weather forecasting, mainly because people's observation of the ocean is far less than that of land and meteorology. Furthermore, fishing grounds involve marine fish and shrimp, which are mobile and their populations fluctuate significantly from year to year, making accurate forecasting even more challenging.

[0003] The Northwest Pacific net fishing grounds are primarily located in the high seas, mainly between 40° and 44° North latitude. However, due to the fact that this fishing ground has only been developed for six years, some fishing patterns remain difficult to grasp, resulting in blind spots in fishing ground forecasting. While the analysis and imagination on paper may seem perfect, many problems arise in actual fishing ground forecasting. It must be understood that forecasting fish species and fishing grounds in the ocean is far more challenging than weather forecasting. This is because fish are mobile, moving both horizontally and vertically, making their patterns difficult to grasp. Without observational instruments, forecasting relies heavily on historical and field experience. Furthermore, a certain scale of fish population is required to qualify as a fishing ground, and the relationship between the fishing ground and its environment is not easily understood. Real-time monitoring and prediction of the fishing ground environment are also quite difficult.

[0004] The quality of resources also affects the reliability of forecasts. Therefore, a multi-faceted analysis is necessary. Companies typically conduct fishing ground analysis in the morning to direct fishing vessels; forecasts are required several times a week. Factors such as how long a fishing ground will remain, and how many days of fishing will lead to its loss or relocation, are all issues that need to be considered for the accurate identification and forecasting of straggling fishing grounds in the Northwest Pacific. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a method for accurate identification and prediction of net fishing grounds in the Northwest Pacific based on marine hydrological data. This method can summarize and generalize the refined variation patterns of net fishing grounds and establish key influencing factors for fishing ground forecasting. It combines the forecasted hydrological data and visualizes it to establish an accurate identification method, laying the foundation for finding the central fishing grounds.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for precise identification and prediction of purse seine fishing grounds in the Northwest Pacific based on marine hydrological data includes the following steps: refining and visualizing historical production data and marine hydrological data of different fish species; establishing a refined system of important prediction indicators and parameter identification for fishing grounds and key hydrological elements; accurately identifying and predicting purse seine fishing grounds based on hydrological parameters; and drawing refined fishing ground locations, fishing ground grades, and spatial ranges.

[0008] As a preferred embodiment, the identification and prediction method includes the following steps:

[0009] (a) Spatial visualization matching analysis based on historical fishing production and hydrological data from the past 6 years revealed that the maximum spatial variation range of the Northwest Pacific purse seine fishing grounds is 5×5 degrees of latitude and longitude, and is close to the boundary of the Japanese EEZ. The hydrological parameters are ranked by importance as follows: dense area of ​​temperature isolines > surface temperature > periphery of counterclockwise ocean current eddies in the 25m water layer > ocean current velocity level > chlorophyll > periphery of clockwise ocean current eddies in the 25m water layer.

[0010] (b) A marine hydrological data visualization platform is used to accurately simulate the surface temperature, temperature isopleths, ocean current direction and velocity at a depth of 25m, and chlorophyll concentration during the fishing period of the day; the sea temperature isopleths are spaced at 0.2℃ intervals; the ocean current velocity and direction are to be graded and color-coded.

[0011] (c) Accurate identification based on the distribution of fishing grounds for different fish species; the suitable water temperature range for mackerel exhibits seasonal fluctuations each month, ranging from 10 to 17°C from March to May, 13 to 22°C from June to August, and 10 to 21°C from September to November; the suitable water temperature range for sardines is slightly higher than that for mackerel by 1 to 2°C; the monthly temperature range varies by 2 to 4°C, and the intra-month temperature range varies by 1 to 2°C; the large temperature range makes it difficult to achieve precise fishing ground prediction;

[0012] (d) To further reduce the fishing ground range, the suitable ocean current velocity arrows for mackerel are green and blue, corresponding to velocities of 0.1–0.5 m / s; the suitable ocean current velocity for sardines is higher than that for mackerel, and the velocity arrows are green, yellow, and orange, corresponding to velocities of 0.3–1.2 m / s. The color coding for these ocean current grades is shown in [reference needed]. Figure 2 The ocean currents mentioned refer to a 25m water layer and should not be referenced from surface ocean currents.

[0013] (e) The mackerel fishing grounds are closer to the center of the counterclockwise vortex, with an average distance of about 30 nautical miles; while the sardine fishing grounds are farther from the counterclockwise vortex, with an average distance of about 45 nautical miles.

[0014] (f) The location of the central fishing grounds of the Northwest Pacific purse seine varies depending on the month. In the early fishing season from April to August, it is located near the higher areas of the ocean current velocity and dense water temperature zone; in the late fishing season from September to November, it is located in the lower areas of the ocean current velocity and dense water temperature zone.

[0015] (g) Based on the established fishing ground prediction index system and identification method, the location and spatial range of the mackerel and sardine fishing grounds are drawn daily according to the ocean temperature element prediction map at 18:00 local time; the spatial range of the central fishing ground is generally elliptical or oblong.

[0016] As a preferred embodiment, the hydrological parameters include water temperature contour lines, ocean current vortex direction, and ocean current arrow color levels.

[0017] As the preferred embodiment, the spatial variation range of the Northwest Pacific purse seine fishing ground in step (a) varies from year to year, with some years being 5×5 latitude and longitude and others being 2×4 latitude and longitude; the fishing ground is no more than 75 nautical miles from the boundary line in some years and reaches 180 nautical miles in others, but in general it does not exceed 200 nautical miles.

[0018] As the preferred embodiment, the ocean currents in step (b) are preferably those with a current velocity and spatial distribution at a water layer of 25m, or ocean currents at a water layer of 50m can be used as a reference. The ocean currents are classified according to the color levels of arrows such as blue, green, yellow, orange, and red. The chlorophyll concentration is preferably of medium concentration.

[0019] As the preferred embodiment, the water temperature index in step (c) mainly refers to the dense area of ​​water temperature isolines, and fishing grounds may be formed near the dense area; the spatial location of the suitable dense area of ​​water temperature for fishing grounds of different mackerel and sardines is not the same at most times.

[0020] As a preferred embodiment, the suitable ocean currents for mackerel fishing grounds in step (d) are generally located near blue or blue-green ocean currents; the suitable ocean current arrows for sardine fishing grounds are mainly yellow, and in summer, yellow and orange currents result in higher yields.

[0021] As a preferred embodiment, the mackerel and sardine fishing grounds in step (e) should not be too far from the counterclockwise vortex, and the central fishing grounds should not be near the center of the clockwise vortex.

[0022] As a preferred embodiment, the fishery identification in step (f) needs to be determined by combining the dense areas of the water temperature line with the velocity and direction of the ocean current, so as to improve the accuracy of the central fishery.

[0023] As the preferred embodiment, the fishing ground level in step (g) can be divided into three levels: good fishing ground (red background), relatively good fishing ground (yellow background) and average fishing ground (green background), and non-fishing grounds should be avoided; the area of ​​the fishing ground is mainly identified and predicted according to the above method, and the size of the elliptical area represents the predicted area of ​​the fishing ground.

[0024] This invention analyzes the possible locations of fishing grounds based on historical fishing data, vessel positions, sea conditions, and other information, defining fishing grounds into three categories: good fishing grounds, relatively good fishing grounds, and poor fishing grounds. A good fishing ground refers to a central fishing area where net catches are likely to be high, allowing for continuous fishing for more than two days; a relatively good fishing ground indicates a decent net catch with some profit; a poor fishing ground indicates no or very few fish, requiring relocation. Fishing ground area: The area of ​​each fishing ground category is calculated based on possible suitable conditions. Good fishing grounds should have a smaller area, relatively good fishing grounds a larger area, and the area of ​​poor fishing grounds does not need to be calculated or studied.

[0025] By adopting the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0026] 1. By using predicted hydrological elements and visualizing them, the marine environmental characteristics of the fishing grounds can be presented simply and conveniently, making it easy to view;

[0027] 2. Due to the refined and high-resolution analysis of the formation patterns of the Northwest Pacific purse seine fishing grounds and the construction of a precise fishing ground prediction index system, the accuracy of fishing ground prediction has been greatly improved.

[0028] 3. This invention simultaneously identifies and predicts the central fishing grounds of different fish species, such as mackerel and sardines, which helps to improve enterprise profits and production efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the relationship between the Northwest Pacific net fishing grounds and the densely heated surface temperature zone of this invention.

[0030] Figure 2 This is a schematic diagram showing the spatial distribution relationship between the Northwest Pacific net fishing grounds and the 25m ocean current of this invention.

[0031] Figure 3 This is a schematic diagram of the method for identifying and predicting the grade and range of net fishing grounds in the Northwest Pacific Ocean according to the present invention. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, a method for precise identification and prediction of net fishing grounds in the Northwest Pacific Ocean based on marine hydrological data is presented:

[0034] (a) Spatial visualization matching analysis using historical fishing production and hydrological data from the past 5 years revealed that the spatial variation range of the Northwest Pacific purse seine fishing grounds is 5×5 latitude and longitude, and close to the boundary of the Japanese EEZ. The hydrological parameters are ranked by importance as follows: dense area of ​​temperature isolines > surface temperature > periphery of counterclockwise ocean current eddies at 25m water level > ocean current velocity level > chlorophyll > periphery of clockwise ocean current eddies at 25m water level. The spatial variation range of the Northwest Pacific purse seine fishing grounds in step (a) varies from year to year, with some years being 5×5 latitude and longitude and others being 2×4 latitude and longitude. The fishing grounds are located within 75 nautical miles of the boundary line in some years and 180 nautical miles in others, but the total distance does not exceed 200 nautical miles.

[0035] (b) The surface temperature and temperature contour lines for the fishing period of the day were visualized using a marine hydrological data visualization platform. Figure 1 ), ocean current direction and velocity at a depth of 25m ( Figure 2 The ocean currents are accurately simulated, including chlorophyll concentration, etc.; the sea surface temperature isopleths are spaced at 0.2℃ intervals; the ocean current velocity and direction are graded and color-coded; in step (b), the ocean current velocity and spatial distribution at a water layer of 25m are preferred, but a water layer of 50m can also be used as a reference. The ocean currents are classified according to the color levels of arrows, such as blue, green, yellow, orange, and red; a medium chlorophyll concentration is preferred.

[0036] (c) Accurate identification based on the distribution of fishing grounds for different fish species; the suitable water temperature range for mackerel exhibits seasonal fluctuations each month, ranging from 10 to 17°C from March to May, 13 to 22°C from June to August, and 10 to 21°C from September to November; the suitable water temperature range for sardines is slightly higher than that for mackerel by 1 to 2°C; the temperature range is relatively large, making it difficult to achieve precise fishing ground prediction; the water temperature index in step (c) mainly refers to the dense area of ​​water temperature isolines, and fishing grounds may be formed near the dense area; the spatial location of the dense area of ​​suitable water temperature for fishing grounds for different mackerel and sardines is not the same at most times;

[0037] (d) To further reduce the fishing ground range, the suitable ocean current velocity arrows for mackerel are green and blue, corresponding to velocities of 0.1–0.5 m / s; the suitable ocean current velocity for sardines is higher than that for mackerel, and the velocity arrows are green, yellow, and orange, corresponding to velocities of 0.3–1.2 m / s; the color coding for the ocean current grades is shown in [reference needed]. Figure 2 .

[0038] The ocean currents mentioned should not be referenced from surface currents; the ocean currents suitable for mackerel fishing grounds in step (d) are generally better located near blue or blue-green currents; the ocean current arrows suitable for sardine fishing grounds are mainly yellow, and in summer, yellow and orange currents yield higher yields.

[0039] (e) The mackerel fishing grounds are closer to the center of the counterclockwise vortex, with an average distance of about 30 nautical miles; while the sardine fishing grounds are farther from the counterclockwise vortex, with an average distance of about 45 nautical miles; the distance between the mackerel and sardine fishing grounds in step (e) and the counterclockwise vortex should not be too far, and the central fishing grounds should not be near the center of the clockwise vortex.

[0040] (f) The location of the central fishing grounds in the Northwest Pacific purse seine varies depending on the month. In the early fishing season from April to August, it is located near the higher areas of the ocean current velocity and dense water temperature zone; in the late fishing season from September to November, it is located in the lower areas of the ocean current velocity and dense water temperature zone. The identification of the fishing grounds in step (f) needs to be determined by combining the dense areas of the water temperature line with the velocity and direction of the ocean current to improve the accuracy of the central fishing grounds.

[0041] (g) Based on the established fishing ground prediction index system and identification method, the location and spatial extent of the mackerel and sardine fishing grounds are drawn daily according to the ocean temperature element prediction map at 18:00 local time; the spatial extent of the central fishing ground is generally elliptical or oblong; the fishing ground grades in step (g) are divided into good fishing grounds (red background), relatively good fishing grounds (yellow background), and general fishing grounds (green background), and non-fishing grounds should be avoided; the fishing ground area is mainly identified and predicted according to the above method, and the size of the elliptical area represents the predicted fishing ground area, see Figure 3 .

[0042] Furthermore, this invention analyzes the possible locations of fishing grounds based on historical fishing data, vessel positions, sea conditions, and other information, defining fishing grounds into three categories: good fishing grounds, relatively good fishing grounds, and poor fishing grounds. A good fishing ground refers to a central fishing area where net catches are high and fishing can continue for more than two days; a relatively good fishing ground indicates a decent net catch with some profit; a poor fishing ground indicates no or very few fish, requiring relocation. Fishing ground area: The area of ​​each fishing ground category is calculated based on possible suitable conditions. Good fishing grounds should have a smaller area, relatively good fishing grounds a larger area, and the area of ​​poor fishing grounds does not need to be calculated or studied.

[0043] Example:

[0044] In the North Pacific purse seine fishing grounds, with the significant increase in the number of fishing vessels, the fish populations available for fishing gradually decrease, and the number of fishing days in the same location is reduced. This necessitates frequent shifts in fishing grounds or small-scale reconnaissance, increasing the demand for and difficulty of fishing ground forecasting. This invention establishes suitable ocean temperature parameters and fishing ground reference parameters for fishing grounds, and provides refined fishing ground forecasting. This facilitates accurate and real-time central fishing ground forecasting and dissemination to vessels, effectively improving fishing ground control capabilities.

[0045] First, spatial visualization matching analysis was conducted using historical fishing production and hydrological data from the past five years. This revealed that the spatial variation range of the Northwest Pacific purse seine fishing grounds is 5×5 degrees of latitude and longitude, and it is close to the Japanese EEZ boundary. The hydrological parameters were ranked by importance as follows: dense temperature isolines > surface temperature > periphery of counterclockwise ocean current eddies at 25m water level > ocean current velocity level > chlorophyll > periphery of clockwise ocean current eddies at 25m water level. A marine hydrological data visualization platform was used to accurately simulate surface temperature, temperature isolines, ocean current direction and velocity at 25m water level, and chlorophyll concentration during the fishing period of the day. The sea temperature isolines were spaced 0.2℃ apart; the ocean current velocity and direction were graded and color-coded.

[0046] Secondly, precise identification of fishing grounds is achieved based on the distribution of different fish species. The suitable water temperature range for mackerel exhibits seasonal fluctuations: 10-17℃ from March to May, 13-22℃ from June to August, and 10-21℃ from September to November. The suitable water temperature range for sardines is slightly higher, by 1-2℃. However, the large temperature range makes precise fishing ground prediction difficult. Suitable ocean currents for mackerel fishing grounds are generally near blue or blue-green currents. For sardine fishing grounds, the suitable ocean current arrows are predominantly yellow, with higher yields observed in yellow and orange currents during summer. For example, in 2021, when fishing vessels primarily caught sardines, purse seine fishing grounds should be located on the edge of the higher-temperature areas of dense sea surface temperatures, where the ocean currents are predominantly yellow, and higher yields are also observed in orange current areas.

[0047] Finally, the study concluded that mackerel and sardine fishing grounds should not be too far from the counter-clockwise eddy, and the central fishing ground should not be near the center of the clockwise eddy. Fishing grounds can be classified into three levels: good, relatively good, and average; poor fishing grounds should be avoided. In 2021, the difficulty of purse seine fishing in the North Pacific gradually increased, requiring better fishing platforms and fishing ground prediction methods for analysis, especially sea surface height and water temperature indicators. Combined with vessel position analysis and historical catch data analysis, and based on expert experience, precise fish finding can be achieved, but chlorophyll indicators can be disregarded. The high seas purse seine technology team, based on the aforementioned invention, has developed a precise purse seine fishing ground identification method, issuing daily fishing ground forecast maps to purse seine vessels in frontline production and providing detailed guidance to fishermen on fishing ground analysis based on hydrological elements. The annual average fishing ground forecast accuracy rate reaches 85%, significantly improving production output and reducing blind exploration time, shortening fish school detection time by more than one hour per day.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for precise identification and prediction of northwest Pacific dragnet fishing grounds based on marine hydrological data, characterized in that, The method comprises the following steps: fine processing and visualizing historical production data of different fish species and marine hydrological data, establishing a fine fishery and key hydrological factor importance prediction index system and parameter identification, and accurately identifying and predicting the purse seine fishery according to the hydrological parameters, and drawing the fine fishery location, fishery grade and spatial range. The identification and prediction method comprises the following steps: (a) spatial visualization matching analysis is performed on the historical fishing production and hydrological factor data in the latest 6 years to find that the spatial variation range of the northwest Pacific purse seine fishery is 5x5 latitude and longitude, and is close to the Japanese EEZ boundary line; the hydrological parameter importance ranking result is temperature contour dense area > surface temperature > 25m water layer counterclockwise ocean current vortex periphery > ocean current flow rate > chlorophyll > 25m water layer clockwise ocean current vortex periphery; (b) the surface temperature, temperature contour, 25m water layer ocean current flow direction and flow rate, and chlorophyll concentration during the fishing period of the day are accurately simulated by using a marine hydrological data visualization platform; the sea temperature contour interval is 0.2 DEG C; the flow rate and flow direction of the ocean current need to be color-coded; (c) the fishery distribution of different fish species is accurately identified; the suitable water temperature range of chub mackerel shows seasonal fluctuations, and the range is 10-17 DEG C in March-May, 13-22 DEG C in June-August, and 10-21 DEG C in September-November; the suitable water temperature range of sardine is 1-2 DEG C higher than that of chub mackerel; the monthly change range of the temperature range is 2-4 DEG C, and the monthly change range is 1-2 DEG C; (d) in order to further reduce the fishery range, the suitable ocean current flow rate arrow color of chub mackerel is green and blue, and the corresponding flow rate is 0.1-0.5 m / s; the suitable ocean current flow rate of sardine is higher than that of chub mackerel, and the flow rate arrow color is green and yellow and orange, and the corresponding flow rate is 0.3-1.2 m / s; the ocean current is referred to the 25m water layer, and the surface ocean current is not suitable for reference; (e) the chub mackerel fishery is closer to the center of the counterclockwise vortex, and the average distance is 30 nautical miles; and the sardine fishery is farther away from the counterclockwise vortex, and the average distance is 45 nautical miles; (f) according to the position of the northwest Pacific purse seine center fishery in different months, the fishery is located in the high area of the high ocean current flow rate area and the dense water temperature area in the early fishing season of April-August, and is located in the low area of the low ocean current flow rate area and the dense water temperature area in the late fishing season of September-November; (g) according to the established fishery prediction index system and identification method, the fishery position and spatial range of chub mackerel and sardine are drawn according to the marine water temperature factor prediction map at 18 o'clock local time every day; the center fishery spatial range is elliptical or long circular; The hydrological parameters include water temperature contour, ocean current vortex direction and ocean current arrow color grade; The spatial variation range of the northwest Pacific purse seine fishery in step (a) changes every year, and is 5x5 latitude and longitude in some years and 2x4 latitude and longitude in some years; the fishery is not more than 75 nautical miles away from the boundary line in some years, and reaches 180 nautical miles in some years, but is not more than 200 nautical miles in general; The current velocity and spatial distribution of the 25m water layer in step (b) is selected, or the current of the 50m water layer is selected as a reference, and the current is classified according to the color level of the blue, green, yellow, orange and red arrows as the classification standard; The water temperature index in step (c) mainly refers to the dense area of the water temperature contour, and the fishing ground can be formed near the dense area; the spatial position of the suitable water temperature dense area for different tuna and sardine fishing grounds is not the same at most times; The suitable current of the tuna fishing ground in step (d) is located near the blue or blue-green current; the suitable current arrow of the sardine fishing ground is yellow, and the yield is higher in summer; The distance between the tuna and sardine fishing ground and the counterclockwise vortex should not be too far, and the center fishing ground should not be near the center of the clockwise vortex; The fishing ground identification in step (f) needs to be combined with the dense area of the water temperature line and the velocity and direction of the current to improve the accuracy of the center fishing ground.

2. The method of claim 1, wherein the method is characterized by, The fishing ground level in step (g) can be divided into three levels: good fishing ground, better fishing ground and general fishing ground, and non-fishing ground needs to be avoided; the fishing ground area is identified and predicted according to the above method, and the size of the elliptical area represents the predicted area of the fishing ground.

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