WO2008009773A1

WO2008009773A1 - Morphometric image analysis device for establishing feeding strategies for use in aquaculture

Info

Publication number: WO2008009773A1
Application number: PCT/ES2007/070125
Authority: WO
Inventors: Juan Antonio Rielo Zurita; Jaume PEREZ SÁNCHEZ
Original assignee: Consejo Superior De Investigaciones Científicas
Priority date: 2006-07-20
Filing date: 2007-07-02
Publication date: 2008-01-24
Also published as: ES2289940B1; ES2289940A1

Abstract

The invention relates to a device which can be used to establish a feeding strategy at a fish farm by evaluating nutritional states and determining growth potential. Prior to the assessment of a specific population, the device can be used to develop a reference growth model for the species in question, for which purpose the device establishes allometric relationships between the data obtained from the images and analyses and processes same using multivariate statistical analysis techniques.

Description

TITLE

MORPHOMETRIC IMAGE ANALYSIS DEVICE FOR DEVELOPING FOOD STRATEGIES IN AQUACULTURE

SECTOR OF THE TECHNIQUE

The present invention falls within the sector of Zootechnics and specifically in Aquaculture. It is a device that, based on images of fish made by video or photo cameras, allows to establish a feeding strategy in a fish farm.

STATE OF THE TECHNIQUE

Fish are animals that grow continuously throughout their life, unlike mammals that reach their maximum size at maturity. The growth of the fish despite being continuous is not always done at the same rate, the growth rate being greater in its youth. In addition, this growth is carried out at more or less discrete pulses. Fish farming is developed taking advantage of precisely the period of the fish's life where growth is fastest, in the first years of its life, usually in the juvenile period before reaching sexual maturity. Currently, the control of the production in a fish farm - especially those located in floating cages in the sea - is carried out by periodic sampling of a part of the population. This implies fishing from a vessel to be able to sample and obtain data (weight and length) of the population under study. Sometimes, in order to minimize manipulation, the weighing is done in groups. Both one and the other, have the great disadvantage of subjecting the entire population of fish to enormous stress, which implies the almost certain loss of a day of feeding and a poor metabolic use of the food for one or two days, even of placing the animals in states of immunological weakness which makes them, in that period, more susceptible to contracting infectious diseases. Another way to classify fish by size is to pass them through slots of different sizes. Such is the case of the devices offered by the company FAIVRE.

More novel is the use of sonar or video telemetry gadgets, infrared, photoelectric cells to measure animals, and the approximate weight of the individual is determined from regressions. Some patents (UK Patent application GB 2 2001 772 "An opto-electronic method for determining by length-measurement the quality of cultured fish and a device for implement the method") establish methods for determining the quality of farmed fish by indirect measures of Ia length using photoreceptor cells and gonadal state by ultrasound. In these devices the fish are classified when they pass through a translucent tube and interrupt the light beams from a light source to a series of photodetectors placed along the tube, while an ultrasound of the gonads is performed. These devices are designed to work with salmonids. In the case of the golden one, reliable information on the gonadal state would not be obtained since it is during the juvenile phase when they begin to develop them. In all the procedures mentioned above, the data obtained are static values that do not give information on growth or fattening potential, they only give weight and length, which are not sufficient data to determine said potential. At best, in obese individuals, it can be said that they have eaten enough. But obesity can sometimes be a brake on growth. The present invention is a device, which in addition to obtaining the weight and size, offers information on the ability to grow and fatten the fish, allowing decisions on the feeding strategy.

DESCRIPTION OF THE INVENTION Brief Description

The object of the present invention is to provide a device that allows assessing their nutritional status and their growth potential for design a feeding strategy without removing it from its natural habitat.

This device consists of the following elements: housing, transparent transverse tubes, light source, diffuser screen, photodetectors, video cameras and hardware (figure 1).

After submerging the device in the pond or cage with, at least, the transparent tubes under water, the photodetectors are activated at the passage of the fish and, when the cameras are shot, their images are collected and sent to a computer system. The images obtained are downloaded and processed for marking the points that appear in Figure 5 and their coordinates are processed by the software to establish the distances between the points. Prior to the use of the device object of the invention, a growth reference model must be constructed for the species under study. This must be done using a sufficiently large group of individuals in whom the measures described above are taken, using the device object of the invention. The team calculates the distances between the points measured in the images obtained from each individual for each measurement of the fish, and builds models based on the general equation of the allometry of the type "Y = aX ^b ". The designed model includes the multifactor linear equations obtained through principal component analysis based on the covariation of the deviations of each measurement with respect to the model measurements. Subsequently, in the study of the nutritional status and growth potential of a specific population, the team calculates the distances between the points measured in the images obtained from each individual and solves the system of linear equations applied to the deviations resulting from the comparison of all the measures taken with those of the reference model. From the analysis of main components, several scores of each fish are obtained, where each one explains how the main physiognomic characters of the fish develop during their growth. Since the software includes equations for predicting the growth of fish and bibliographic data of weight of the species in question, the The device allows, through allometric equations, to evaluate the nutritional status and growth potential of a specific individual. The information output classifies the animals into 4 groups, allowing the aquaculturist to make the most appropriate feeding decision and in automatic systems to allow the computer system to handle the feeding management autonomously.

Detailed description

The object of the present invention is to provide a device that, in addition to providing static information of individuals (weight and height), allows assessing their nutritional status and their growth potential to design a feeding strategy without removing it from its natural habitat This device consists of the following elements: housing, transparent transverse tubes, light source, diffuser screen, photodetectors, video cameras and hardware (figure 1).

The housing (1) can have different shapes that allow hydrodynamic stability against sea currents and waves. The basic form would be spherical, due to its similarity to the buoys that surround the fish farms since it does not scare the fish.

It is a sealed enclosure that contains the rest of the structures inside. This housing is crossed by one or more transparent tubes (4) through which the fish pass. Inside the housing and above the tubes there is a light source (2) and, between it and the tubes, a diffusing screen (3). The photodetectors (6) are located in the lower part of the housing and below the transparent tubes. Laterally and in contact with the transparent tubes are placed as many video or photographic cameras (5) as tubes. The device is submerged in the pond or cage by an anchor or allowed to float semi-submerged with at least the transparent tubes under water thanks to the ballasting system. Photodetectors are activated at the passage of fish, and photographic cameras whose images are collected and sent to a computer system are fired. The "interface" system can be of type wireless In the event that the camera allowed to work with infrared, the light source would only act as an attractant for the fish. The images are downloaded, in a computer system, and processed for marking the points that appear in Figure 5. The calculations are made on direct images not on alterations of fields formed by radiation beams (visible or infrared or magnetic). An operator marks the points established in Figure 5 and their coordinates are processed by the software to establish the distances between the points. The distance data taken includes all possible relationships of the points with each other, that is, the distances of all the points, and each of them, with all the others are taken.

Prior to the use of the device object of the invention in the assessment of the nutritional status and potential growth of a specific fish population, a growth reference model for the species under study must be constructed. This must be done using a sufficiently large group of individuals in whom the measures described above are taken, using the device object of the invention. At this point, the team calculates the distances between the points measured in the images obtained from each individual for each measurement of the fish, on the general equation of the allometry of the type "Y = aX ^b " in its logarithmic form (Ln Y ₀ = Ln a + b Ln X _{0+ ε} ), where Y ₀ and X ₀ is the distance between two specific points measured in the fish (see figure 5), a and b are fixed parameters (see table 1), and after normalizing the values of ε for each measure and for each individual, the reference model of the species under study is constructed. The growth reference model thus obtained, considers the development of the different physiognomic characteristics of the fish in relation to its size, since it is necessary to compare individuals of the same size with each other to know the way in which each species develops its characters along of growth, and therefore, to be able to build its reference model. The designed model includes the multifactor linear equations obtained through principal component analysis based on the covariation of the deviations of each measurement. In the study of the nutritional status and growth potential of a specific population, the team calculates the distances between the points measured in the images obtained from each individual and solves the system of linear equations applied to the deviations resulting from the comparison of all the measures taken with those of the reference model. From the analysis of main components, 3 scores of each fish are obtained, one for each multivariate equation obtained, the coefficients obtained in the case of the study of the gilthead are those that appear in table 1. That is, the statistical analysis synthesizes all the information obtained and presents in three groups ("axes" of the tablai), where each of them explains how the main physiognomic characters of the fish develop during their growth:

- Axis 1, gives information on evolution of the size of the trunk of the fish

- Axis 2, gives information on the cephalic and caudal heights

- Axis 3, gives information on the size of the anterior half of the caudal peduncle

TABLE 1

The device offers the scores in a three-dimensional Cartesian space, that is, with three coordinate axes. For an understandable visualization the information is offered in two flat graphics. In the first, graph 1, the scores of the first two equations are collected, and in the second, graph 2, the scores of the first and third equations are represented.

-0.50 0.00 0.50 1.00 1.50

Figure 1

Quadrant I

-0.50 0.00 0.50 1.00 1.50

Figure 2

Each animal species undergoes a series of physiognomic changes during its growth and in the passage from young individual to adult. By taking an individual and observing their external characteristics, depending on whether all these changes have already happened or not, and observing the reference model of the same species, it is possible to know if the individual must still complete his development, that is, his increase. On these premises, the software includes growth prediction equations based on photoperiod and temperature, while so far the predictions were made only based on temperature, and gives information about the growth potential of each individual. On the other hand, by means of the comparison with bibliographic data of weight included in the software, the device obtains the so-called condition factor (K), which is a measure of the fattening state, and which is calculated as the ratio between the weight and the cube length In this way, the device allows, through allometric equations, to evaluate the nutritional status and growth potential of a specific individual. The information output classifies the animals into 4 groups, allowing the aquaculturist to make the most appropriate feeding decision and, in automatic systems, allowing the computer system to handle the feeding management autonomously. In addition, each animal is obtained: length, estimated weight, estimated condition factor (K) and expected length. The groups and subgroups are as follows:

• Group I (fish classified in quadrant I of figure 1): Fish to which the intake should be reduced.

• Group Il (fish classified in quadrant Il of figure 1). Fish that have to maintain or increase their intake.

Subgroup II + (Fish classified in quadrant Il of figure 1 and in positive ordinates of figure 2): Maintain intake. Subgroup II- (Fish classified in quadrant Il of figure 1 and in negative ordinates of figure 2): Increase intake. • Group III (Fish classified in quadrant III of figure 1). Fish to which the intake should be increased.

• Group IV (Fish classified in quadrant IV of Figure 1). Fish that have to maintain or decrease their intake

Subgroup IV + (positive ordinates of Figure 2): Decrease Subgroup IV - (negative ordinates in Figure 2): Maintain

Thus, another object of the present invention consists of a procedure that allows the use of the device object of the invention in the design of feeding strategies characterized by the following steps:

1. Take pictures of a large number of individuals covering the full range of sizes possible.

2. Taking measures between individual points of each individual.

3. Determination of an allometric equation (variation of the measure of a specific character with respect to the measure of a character taken as a reference) for each measure. 4. Factor analysis, through the study of main components, to obtain scoring equations that constitute a reference model.

5. Calculation of individual deviations from the theoretical value in each allometric equation, for all individuals.

6. Analysis of a sample using steps 1, 2 and 5 and application to the equations obtained in point 4 to obtain the scores of each individual.

7. Based on these scores, the need to increase, decrease or maintain the intake of the individuals of an industrial crop population or to anticipate the behavior of a wild individual regarding their food capture needs is determined.

8. Diagnosis of the average state of the population with the data obtained in the previous steps. 9. Proposal of the decisions to be taken.

Another object is the use of the device to determine the food intake needs of farmed or wild fish species.

DESCRIPTIONS OF THE FIGURES

Figure 1: Side view (profile). Components: 1-housing; 2-light sources; 3- diffuser screen; 4-transparent tubes; 5-cameras; 6-photoelectric receivers; 7-anchor system. Figure 2: Front view (elevation). Figure 3: Top view (floor). Figure 4: All views. Figure 5: Points used in the images for the study of measurements. EXAMPLES OF EMBODIMENT OF THE INVENTION

Example 1 - Diagnosis of the feeding status of a population of sea bream in industrial cultivation in floating cages.

In a fish farm dedicated to the cultivation of gilthead sea bream in floating cages in the sea where the low growth of a group of gilthead breams is observed, a sample of the population of 60 animals was submitted to the diagnosis of this device, obtaining the values shown in the following table and they were classified mostly in group 3 as animals that were receiving little food. When the ration was increased, they compensated for the growth retardation.

Weight (g) Size (cm) K Sampled fish Estimated weight (g) Classification quadrant

67.6 14.1 2.41151161 fish 1 70.9696215 Il

91.7 15.5 2.46248867 fish 2 97.1328199 IV

78 14.3 2,66738983 fish 3 75.572919 IV

108.9 16 2,65869141 fish 4 106,241665 IV

95.2 15.2 2,71085435 fish 5 94,1587063 Il

82.8 14.7 2.60662366 fish 6 83.5429603 III

91.7 15.8 2.3248668 fish 7 96.5164287 III

77.8 14.7 2,44921885 fish 8 77.4847264 III

77 14.5 2,52572881 fish 9 73,8563803 IV

105.2 15.8 2,66713181 fish 10 108.594049 III

125.6 16.9 2.60213321 fish 11 126.51305 III

97.6 15.8 2.47444928 fish 12 103.627592 III

112 16.6 2,4484642 fish 13 108,304352 III

70.8 14.7 2.22885211 fish 14 71.8235645 III

112 16.4 2,53913901 fish 15 112,528277 IV

102 15.2 2,90448681 fish 16 92,288613 IV

90.2 15.8 2.28683735 fish 17 91.8758937 III

92.5 15.3 2.58266121 fish 18 85,304123 III

99.3 15.3 2.77252171 fish 19 103.882561 III

91.6 15.3 2.55753262 fish 20 90.8743367 III

98.2 15.6 2.58665015 fish 21 93.7553393 Il

100 15.5 2,68537478 fish 22 103,817717 IV

85.6 15.2 2,43749089 fish 23 85,0881758 III

84.5 15 2.5037037 fish 24 85.8067934 III

97.1 15.8 2.4617288 fish 25 95.8608373 IV

92.3 15.6 2.43124041 fish 26 99.4514126 IV

103 15.6 2.71308518 fish 27 100.356567 III

84 15.2 2.39193031 fish 28 87.2354217 IV

80 14.5 2,62413383 fish 29 80,0137073 III

90.2 15.9 2.24396028 fish 30 91,1098468 III

77.4 14.2 2.70318599 fish 31 73.1458328 III

102 15.9 2.53751606 fish 32 101.172999 I

100.8 16 2,4609375 fish 33 98,2922091 III

88 15 2,60740741 fish 34 90,4654417 III

94.8 15.6 2.49709199 fish 35 96.3933262 IV

90.3 15 2,67555556 fish 36 89,7551375 III

87 15 2,57777778 fish 37 87,7406078 Il

98 15.8 2.48459047 fish 38 97.5679271 III

90.2 15.5 2,42220805 fish 39 90,7463004 III

86.1 15 2.55111111 fish 40 86.6451977 III

116 16.8 2.44641507 fish 41 122.14739 IV

var 1

and were classified within group 3 as animals that were receiving little food. When the ration was increased, they compensated for the growth retardation.

Most of the fish are located within the third quadrant, which is indicating that we need to increase the intake of the population although some animals are framed in groups Il and IV, that is to say in doubtful conditions, and only one fish is placed in Quadrant I, which means that it has been fed sufficiently. In conclusion we must increase the intake of animals.

The brothers of these fish, which we had kept in the laboratory with satiety controlled feeding were classified, 80% in quadrant I and the rest in quadrant IV

Example 2: Diagnosis of the feeding status of gilthead populations in industrial cultivation in ponds excavated on land and in cages. In this case, the problem was the poor feed efficiency in the last phase of the crop in one of the industrial fattening facilities. Underwent the animals to the diagnosis of the device and, on this occasion, the fish were classified, those of the farm 1, within group I, as fish to which the ration should be reduced; and those of farms 2 and 3 in the fourth quadrant as animals to which the ration must be maintained or decreased. That is to say, the problem was the excessive intake of food in the farm 1, which was precisely the one that used ponds dug in the ground. Possibly, in farms 2 and 3, excess food was also being supplied but the intake would be compensated for the loss of feed through the cage nets, therefore, being correct the intake was excessive hence the poor conversion of the feed In these last two cases, what should be done is to change the feeding strategy by increasing the number of less abundant intakes or improving the distribution of feed within the cages.

-3.00 -2.00 -1, 00 0.00 1, 00 2.00 c.p.1

Farm 1

0 Farm 2

Δ Farm 3 In this case we have avoided representing the estimate of weights given the excessive number of data, which would not clarify the example.

Example 3: Monitoring of fish subjected to a period of fasting in the laboratory.

A group of 70 goldfish, which were fed according to commercial rationing tables, were classified by the device between groups I and IV +. After a fasting period of 15 days (the fish slowly mobilize the reserves because they need very little energy in the aquatic environment) they were again subjected to the classification of the device and, on this occasion, these same fish were classified among group IV - (need to maintain the food supply) and in group IV + (decrease the food supply). The correct interpretation of the result should consider that it is based on a situation of overfeeding, very common in industrial aquaculture, and that after fasting, a displacement of the situation of the animals can be seen from the overfeeding towards the correct feeding situation.

Fish Weight

Weight (g) Size (cm) K Estimated sampled quadrant (g)

Before fasting

334 ^""""" 210T ^""""" 2778124995 ¡mgd3303.jpg ~ ^"™ 3Ϊ5Í994843 fvϊ

374 23.6 2,84534933 imgd3306.jpg 310,955438 I

347 23 2.85197666 imgd3308.jpg 315.366671 I

386 23.6 2,93664396 imgd3309.jpg 374,761706 I

245 21, 2 2,57133405 imgd3311.jpg 233,349009 IV +

570 26.3 3,13334063 imgd3312.jpg 516,703473 I

427 24.4 2,93939801 imgd3315.jpg 409,36337 I

399 24.2 2,81531373 imgd3316.jpg 377,553365 I

407 23.5 3,13610664 imgd3317.jpg 405,358804 I

347 22.8 2,92768895 imgd3318.jpg 348,904854 I

424 24.4 2.9187465 imgd3321.jpg 409.673231 I

392 23.7 2,94469981 imgd3322.jpg 389,69012 I

327 23.2 2,61868824 imgd3323.jpg 309,902856 I

387 24 2,79947917 imgd3324.jpg 372,397791 IV +

462 24.7 3,0658515 imgd3401.jpg 459,933215 IV +

363 22.7 3.10333782 imgd3403.jpg 367.255011 I

472 24.6 3,17056512 imgd3404.jpg 468,299807 IV + 407 23.7 3,05737965 imgd3405.jpg 397,347315 IV +

464 24.9 3.00552219 imgd3408.jpg 455.819566 I

394 24 2,85011574 imgd3409.jpg 373,439515 IV +

503 25.11 3.17707778 imgd3410.jpg 468.352394 I

415 23 3,41086546 imgd3411.jpg 383,031033 IV +

278 21.7 2,72060564 imgd3412.jpg 291,640092 IV +

371 23.4 2,89551846 imgd3413.jpg 366,527801 IV +

443 24.1 3.16484612 imgd3414.jpg 411,901331 IV +

329 22.9 2,73961447 imgd3415.jpg 323,468873 IV +

495 25.1 3,13028611 imgd3416.jpg 467,135635 IV +

427 23.8 3,16735691 imgd3417.jpg 410,280727 I

328 22.6 2,84150567 imgd3418.jpg 336,511717 I

498 25.3 3,07516044 imgd3419.jpg 485,046345 I

350 22.5 3,07270233 imgd3420.jpg 341,238819 IV +

274 23 2.2519931 imgd3421.jpg 360,108675 IV +

After fasting

365 24.5 2.48195905 ayud3302.jpg 383,486145 I

225 21.3 2,32832557 ayud3303.jpg 226,401031 IV-

304 23 2,49856168 ayud3305.jpg 315,844195 IV-

300 22.9 2,49812869 ayud3306.jpg 314,794002 IV-

357 24 2,58246528 ayud3307.jpg 360,51767 I

382 23.8 2,83356051 ayud3308.jpg 421,23922 IV +

267 21.6 2,6494151 ayud3309.jpg 279,130032 IV +

387 24.7 2,56814834 ayud3311.jpg 403,313245 IV-

317 23 2,60540807 ayud3312.jpg 601,519005 IV-

316 23.3 2,49815465 ayud3313.jpg 336,340803 IV-

297 22.2 2,714548 ayud3315.jpg 312,683716 IV + -

399 24.8 2,61588022 ayud3316.jpg 412,93024 IV-

375 23.7 2,816996 ayud3317.jpg 417,400556 IV-

514 26.6 2,73097805 ayud3318.jpg 511,025081 I

396 24.4 2,72599909 ayud3319.jpg 436,113061 IV-

271 21.8 2,61577154 ayud3320.jpg 297,132822 IV-

337 23.6 2.56385755 ayud3321.jpg 341.943365 IV-

351 24 2,5390625 ayud3324.jpg 376,786056 IV +

297 22.8 2.50583175 ayud3401.jpg 303.211366 IV-

336 23.3 2,6562657 ayud3402.jpg 298,867408 IV-

454 25.2 2,83696665 ayud3403.jpg 462,848993 IV-

364 24.5 2,47515916 ayud3404.jpg 377,806997 IV-

297 22.5 2,60740741 ayud3406.jpg 317,119065 I

372 23.4 2,90332309 ayud3408.jpg 378,073836 IV +

378 24.2 2,66713932 ayud3410.jpg 397,64307 IV +

427 24.6 2,86828666 ayud3411.jpg 464,575654 IV +

412 24.8 2,7011094 ayud3412.jpg 433,313014 IV +

397 24 2,87181713 ayud3413.jpg 413,578901 IV + 259 21.9 2,46585434 ayud3414.jpg 283,59309 IV +

447 24.7 2,96631087 ayud3415.jpg 466,180982 IV +

369 22.8 3,11330612 ayud3416.jpg 368,110928 IV-

450 25.3 2,77875943 ayud3418.jpg 506,327384 I

366 23.6 2,78448624 ayud3419.jpg 377,277793 IV-

320 22.3 2.88559508 ayud3420.jpg 329.991726 IV-

333 22.7 2,84686362 ayud3421 jpg 340,8584 IV-

296 22.3 2,66917545 ayud3422.jpg 308,421837 IV-

417 24.7 2,7672296 ayud3423.jpg 443,236278 IV-

In triangles the animals before fasting. In white circles, the same individuals after fasting, which have decreased score to pass from group I to group IV.

Claims

1. A morphometric analysis device for marine and continental fish species characterized in that it allows the design of feeding strategies in these species and studies on the nutritional status with the following structure: a. housing, b. transparent transverse tubes, c. light source, diffuser screen, photodetectors d. video cameras e. standard interface to a computer where all the information is processed f. specific information processing software

2. A device, according to claim 1, characterized in that it measures distances between specific points of the image of the individuals and, after defining a reference growth model, calculates the deviations with respect thereto.

3. A device, according to claims 1 and 2, characterized in that it performs a multifactohal analysis of all the deviations taken, defines the growth reference model, characterizes the overall state of the individual and correlates it with a moment in the model of reference growth.

4. A procedure for the design of feeding strategies characterized by the following steps: a. Taking pictures of a large number of individuals covering the full range of sizes possible. b. Taking measures between specific points of each individual. C. Determination of an allometric equation (variation of the measure of a specific character with respect to the measure of a character taken as a reference) for each measure. d. Factor analysis, through the study of main components, to obtain scoring equations that constitute a reference model. and. Calculation of individual deviations from the theoretical value in each allometric equation, for all individuals. F. Analysis of a sample through the steps a, byey application to the equations obtained in point d to obtain the scores of each individual. g. Determination, based on these scores, the need to increase, decrease or maintain the intake of individuals from a population in industrial cultivation or to anticipate the behavior of a wild individual regarding their needs for food capture. h. Diagnosis of the average state of the population with the data obtained in the previous steps. i. Generation of the proposal of the decisions to be taken.

5. The use of the device characterized according to claims 1 to 4, to determine the food intake needs of cultivated or wild fish species.