Control y caracterización del Atún Rojo en Jaulas Marinas

Atlantic Bluefin tuna (Thunnus thynnus) is a highly value specie that was endangered during the turn of the century by overfishing. Due to the massive resource exploitation, a recovery plan was implemented by the International Commission for the conservation of Atlantic Tunas (ICCAT). That plan enforces three major rules: to establish a fishing quota, to impose a closed fishing seasons and to fix minimum catching size (30kg). With the aim to control and improve as much as possible the fattening process turns necessary develop tools to help tuna ranchers. These tools will help them to improve tuna production efficiency in sea cages. Moreover, it is necessary the improvement of fishing quota control mechanisms. Acoustic techniques have been revealed as an efficient biomass control tool in aquaculture cages (mainly to salmon and gilthead sea bream). However, underwater acoustic methods (that are used to remote sensing of fish schools in free water) are not usually applied in sea cages. Nowadays, production control, in tuna fattening cages, has made either by manual sampling or by the use of stereoscopic cameras system. The former, it can cause damages to fishes and increases costs to ranchers. The latter, it is non-intrusive to tuna but it is affected by depth and water turbidity and it is limited by camera field of vision. A feasibility study of the use of acoustic techniques in tuna fattening cages to production control as well as to evaluate tuna behavior in captivity is presented In this thesis. Research and development of techniques together with experimental setups used are limited by tuna size and cage volume. General information about Bluefin tuna and their farming in sea cages is included in Chapter 2. In order to provide the necessary understanding of the field, Chapter 3 perform a progressive introduction of theoretical concepts in relation with underwater acoustic techniques linked with biomass estimation. To find out the tuna behavior inside the cages after being captured an experiment was carried out. Likewise, a second experiment was proposed to evaluate the response of tunas to certain anthropogenic sounds (as those produced by offshore wind turbine). The methodology and results of both studies presented are discussed in Chapter 4. Chapter 5 shows the feasibility of the use of acoustic techniques to evaluate "ex situ" dorsal target strength (TS). A relationship between dorsal aspect TS and tuna length was obtained. To perform it, four different tuna size in four separated sea cages were measured using two EK60 echosounders working at 120 and 200 kHz respectively. Using data from tuna slaughter on a farm, relations between the weight and the different dimensions of the tuna: length, maximum width and height have been looked for. Obtained expressions allow to calculate fattened tunas weight from the three tuna dimensions. Results are shown in Chapter 6. In order to expand the study carried out in Chapter 5, an experiment was proposed to determine the relationship between ventral TS and tuna size. In this case, measurements were carried out using acoustic and optic techniques in a new setup concept. A stereoscopic vision system synchronized with two echosounders (EK60) emitting at 120 and 200 kHz were used. With this setup, it is possible to know the value of the TS for a certain tuna that was recorded and measured with the cameras. As in the dorsal measures case, it was sought to know the applicability degree of combined technique in fattened tuna cages. This study and its results are presented in Chapter 7. Finally, in Chapter 8, a new method to counting tuna using acoustic techniques is presented. This method is intended to facilitate counting tuna during transfer process. The use of underwater acoustic techniques allows to automate tuna counting and to make it immune to water turbidity during transfers. To achieve it, a side scan sonar working 200 kHz was used.El atún rojo (Thunnus thynnus) es una especie de alto valor económico que se vio amenazada en el cambio de siglo por la sobrepesca. Este hecho llevó a la Comisión Internacional para la Conservación del Atún Atlántico (ICCAT) , a establecer un Plan de recuperación cuyas tres ejes principales fueron: imponer un férreo sistema de cuotas de pesca, limitar los periodos en los que esta especie puede ser capturada y fijar una talla mínima de captura .Los productores, afectados por las restricciones impuestas a la captura necesitan de herramientas para el control del proceso de engrase que permitan mejorar la eficiencia de dicho proceso. Del mismo modo se precisa la mejora de las herramientas utilizadas para el control de la cuota pesquera asignada. El control de la biomasa en las jaulas de engrase de atunes se realiza, bien mediante muestreos manuales que pueden provocar daños a los peces y resultar costosos operacional y económicamente, o bien mediante el uso de sistemas de cámaras estereoscópicas, no invasivas con los peces, pero que se ven limitadas por el alcance del campo de visión de las cámaras, la profundidad y la turbiedad del agua. Las técnicas acústicas se han revelado como una herramienta eficiente para el control de la biomasa en jaulas de cría para otras especies de gran consumo, como la dorada o el salmón. En esta tesis se propone estudiar la viabilidad del uso de las técnicas acústicas para el control de los atunes en las jaulas de engrase, así como para la evaluación del comportamiento de los atunes cuando pasan de vivir en estado salvaje a estar confinados en jaulas marinas. El tamaño de los atunes, así como la forma y tamaño de las jaulas donde son engrasados, limita los estudios y las configuraciones de medida presentadas en el presente documento. En el Capítulo 2 se incluye información general sobre del atún rojo y sobre su engrase en cautividad. Seguidamente, en el Capítulo 3, se ofrecen los conceptos básicos y la formulación sobre acústica submarina para facilitar la comprensión del resto de capítulos. Se realizó un experimento con el objetivo de conocer cómo se comporta el atún rojo en cautividad y si dicho comportamiento se veía alterado cuando era sometido a estímulos sonoros externos de carácter antropogénico. La metodología y los resultados de este estudio se muestran en el Capítulo 4. En el Capítulo 5, se evalúa la idoneidad del uso de técnicas acústicas para establecer una relación entre el tamaño del atún rojo y el TS (a 120 y 200 kHz), cuando se realizan las medidas desde la superficie del mar y con los sensores orientados hacia el fondo (vista dorsal de los peces). A partir de datos provenientes del sacrifico de peces engrasados, se han buscado relaciones entre el peso y las dimensiones del atún rojo. De este modo se han obtenido expresiones que predicen el peso medio de los peces engrasados en una jaula a partir de su longitud, altura y anchura máxima. Dichas expresiones se muestran en el Capítulo 6. Haciendo uso de las técnicas acústicas combinadas con un sistema de visión estereoscópica, se ha estudiado la viabilidad de obtener relaciones entre la longitud del atún rojo y el TS (a 120 y 200 kHz) en jaulas de engrase desde el punto de vista ventral. Para ello, se dispusieron los equipos en el fondo de la jaula de engrase y se registraron los datos con todos los sensores sincronizados y mirando hacia la superficie. De este modo se pudo conocer el valor del TS de un pez determinado que es grabado con un sistema estereoscópico que nos facilitara datos sobre su longitud, anchura máxima y orientación respecto del transductor. Se presenta en el capítulo 8 un método para el conteo de atunes mediante técnicas acústicas usando un sonar de barrido lateral trabajando a 200 kHz. Esta técnica novedosa pretende facilitar el conteo de ejemplares durante los procesos de transferencia, automatizándolo en gran medida y haciéndolo inmune a la faLa tonyina roja (Thunnus thynnus) és una espècie d'alt valor econòmic que es va veure amenaçada durant el canvi de segle per la sobrepesca. Este fet va portar a la Comissió Internacional per a la Conservació de la Tonyina Atlàntica (ICCAT), a establir un pla de recuperació que tenía com a eixos principals imposar un ferri sistema de quotes de pesca, limitar els períodes en què esta espècie pot ser capturada, a fixar una talla mínima de captura. Els productors, afectats per les restriccions imposades a la captura necessiten de ferramentes per al control del procés de engreixament que permeten millorar l'eficiència del procés. De la mateixa manera, es precisa la millora de les ferramentes utilitzades per al control de la quota pesquera assignada. El control de la biomassa en les gàbies d'engreixament de tonyines es realitza, bé per mitjà de mostrejos manuals que poden provocar danys als peixos i resultar costosos operacional i econòmicament, o bé per mitjà de l'ús de sistemes de càmeres estereoscòpiques no invasives amb els peixos, però que es veuen limitades per l'abast del camp de visió de les càmeres, la profunditat i la terbolesa de l'aigua. Les tècniques acústiques s'han revelat com una ferramenta eficient per al control de la biomassa en gàbies de cria per a altres espècies de gran consum com la daurada o el salmó. En esta tesi es proposa estudiar la viabilitat de l'ús de les tècniques acústiques per al control de les tonyines en les gàbies engreixament, així com per a l'avaluació del comportament de les tonyines quan passen de viure en estat salvatge, a estar confinades en gàbies marines. La grandària de les tonyines, així com la forma i grandària de les gàbies on són engreixades, limita els estudis i les configuracions de mesura presentades en este document. En el Capítol 2, s'inclou informació general sobre la tonyina roja i sobre el seu engreixament en captivitat. A continuació, en el Capítol 3, s'ofereixen els conceptes bàsics i la formulació sobre acústica submarina per a facilitar la comprensió de la resta de capítols. Es va realitzar un experiment amb l'objectiu de conèixer com es comportava la tonyina roja en captivitat, i si este comportament es veia alterat quan era sotmesa a estímuls sonors externs de caràcter antropogènic. La metodologia i els resultats d'este estudi es mostren en el Capítol 4. En el Capítol 5, s'avalua la idoneïtat de l'ús de tècniques acústiques per a establir una relació entre la grandària de la tonyina roja i el TS (a 120 i 200 kHz), quan es realitzen les mesures des de la superfície del mar i amb els sensors orientats cap al fons (vista dorsal dels peixos). A partir de dades provinents del sacrifici de peixos engreixats, s'han buscat relacions entre el pes i les dimensions de la tonyina roja. D'esta manera, s'han obtingut dades que prediuen el pes mitjà dels peixos engreixats en una gàbia a partir de la seua longitud, alçària i amplària màxima. Estes dades es mostren en el Capítol 6. Fent ús de les tècniques acústiques combinades amb un sistema de visió estereoscòpica, es va estudiar la viabilitat d'obtindre relacions entre la longitud de la tonyina roja i el TS (a 120 i 200 kHz) en gàbies d'engreixament des del punt de vista ventral. Per a això, es van disposar els equips en el fons de la gàbia marina i es van registrar les dades amb tots els sensors sincronitzats i mirant cap a la superfície. De aquesta manera, es va poder conèixer el valor del TS d'un peix determinat que és gravat amb un sistema estereoscòpic que ens facilitarà dades sobre la seua longitud, amplària màxima i orientació respecte del transductor. Finalment, en el Capítol 8, es presenta un mètode per al comptatge de tonyines per mitjà de tècniques acústiques fent ús d'un un sonar d'escombrat lateral treballant a 200 kHz . Esta tècnica nova pretén facilitar el comptatge d'exemplars durant els processos de transferència, auPuig Pons, V. (2017). Control y caracterización del Atún Rojo en Jaulas Marinas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86213TESI

Monitorización y medida de atunes en jaulas mediante el uso combinado de técnicas acústicas y ópticas

Este trabajo presenta un dispositivo experimental diseñado para poder monitorizar el crecimiento del atún rojo (Thunnus thynnus) en jaulas ,mediante la combinación de técnicas ópticas y acústicas . Las medidas obtenidas nos permitirán decidir si la metodología es apta para establecer una relación entre el TS y el tamaño de los atunes. This paper presents an experimental setup designed to monitor the growth of bluefin tuna (Thunnus thynnus) in cages, using a combination of optical and acoustic techniques. The measurements obtained enable us to decide whether the methodology is suitable for establishing a relationship between the TS and the size of tuna.Puig Pons, V. (2010). Monitorización y medida de atunes en jaulas mediante el uso combinado de técnicas acústicas y ópticas. Universitat Politècnica de València. http://hdl.handle.net/10251/10336Archivo delegad

Vision-based discrimination of tuna individuals in grow-out cages through a fish bending model

This paper proposes a robust deformable adaptive 2D model, based on computer vision methods, that automatically fits the body (ventral silhouette) of Bluefin tuna while swimming. Our model (without human intervention) adjusts to fish shape and size, obtaining fish orientation, bending to fit their flexion motion and has proved robust enough to overcome possible segmentation inaccuracies. Once the model has been successfully fitted to the fish it can ensure that the detected object is a tuna and not parts of fish or other objects. Automatic requirements of the fishing industry like biometric measurement, specimen counting or catch biomass estimation could then be addressed using a stereoscopic system and meaningful information extracted from our model. We also introduce a fitting procedure based on a fitting parameter - Fitting Error Index (FEI) - which permits us to know the quality of the results. In the experiments our model has achieved very high success rates (up to 90%) discriminating individuals in highly complex images acquired for us in real conditions in the Mediterranean Sea. Conclusions and future improvements to the proposed model are also discussed.This work was partially supported by the EU Commission [2013/410/EU] (BIACOP project). We acknowledge funding of ACUSTUNA project ref. CTM2015-70446-R (MINECO/FEDER, UE).Atienza-Vanacloig, V.; Andreu García, G.; López García, F.; Valiente González, JM.; Puig Pons, V. (2016). Vision-based discrimination of tuna individuals in grow-out cages through a fish bending model. Computers and Electronics in Agriculture. 130:142-150. https://doi.org/10.1016/j.compag.2016.10.009S14215013

Efficiency of parametric ultrasound generation in relaxing media for very shallow-water echo sounders

Parametric acoustic generation provides the possibility to obtain narrow and nearly side-lobe free acoustic beams for low frequencies. In this way, the nonlinear interaction of two intense beams with close frequencies generates combinations of the spectral components: high frequency harmonics, difference-frequency harmonics and sum harmonics. The most used in underwater acoustics to obtain the advantages above mentioned is the difference-frequency harmonic for its lower attenuation. Moreover, sea water ultrasound absorption presents not only thermo viscous, but also ionic relaxation losses, both at the primary beam (due to magnesium sulfate presence), and at lower frequencies (boric acid ions). In this work, a computational finite differences method for nonlinear acoustical propagation with relaxation losses is employed to study the efficiency of the parametric sound generation in sea water. Thereby, we present the design and development of parametric echo sounders for very shallow water (<20m), with typical wider beam apertures than commercially available scientific or parametrical echo sounders. This kind of devices, with low frequency narrow beams, provides the possibility to go through a fish school without screening effects due to the proximity between the targets. Beam spatial properties has been studied both numerically and experimentally.The work was supported by Spanish Ministry of Science and Innovation through project FIS2011-29731-C02-01.Ordoñez-Cebrian, P.; Jimenez, N.; Espinosa Roselló, V.; Puig Pons, V.; Soliveres, E. (2014). Efficiency of parametric ultrasound generation in relaxing media for very shallow-water echo sounders. http://hdl.handle.net/10251/79163

Enhanced fish bending model for automatic tuna sizing using computer vision

[EN] This paper presents a non-invasive fully automatic procedure to obtain highly accurate fish length estimation in adult Bluefin Tuna, based on a stereoscopic vision system and a deformable model of the fish ventral silhouette. The present work takes a geometric tuna model, which was previously developed by the same authors to discriminate fish in 2D images, and proposes new models to enhance the capabilities of the automatic procedure, from fish discrimination to accurate 3D length estimation. Fish length information is an important indicator of the health of wild fish stocks and for predicting biomass using length-weight relations. The proposal pays special attention to parts of the fish silhouette that have special relevance for accurate length estimation. The models have been designed to best fit the rear part of the fish, in particular the caudal peduncle, and a width parameter has been added to better fit the silhouette. Moreover, algorithms have been developed to extract snout tip and caudal peduncle features, allowing better initialization of model parameters. Snout Fork Length (SFL) measurements using the different models are extracted from images recorded with a stereoscopic vision system in a sea cage containing 312 adult Atlantic Bluefin Tuna. The automatic measurements are compared with two ground truths: one configured with semiautomatic measurements of favourable selected samples and one with real SFL measurements of the tuna stock collected at harvesting. Comparison with the semiautomatic measurements demonstrates that the combination of improved geometric models and feature extraction algorithms delivers good results in terms of fish length estimation error (up to 90% of the samples bounded in a 3% error margin) and number of automatic measurements (up to 950 samples out of 1000). When compared with real SFL measurements of the tuna stock, the system provides a high number of automatic detections (up to 6706 in a video of 135¿min duration, i.e., 50 automatic measurements per minute of recording) and highly accurate length measurements, obtaining no statistically significant difference between automatic and real SFL frequency distributions. This procedure could be extended to other species to assess the size distribution of stocks, as discussed in the paper.This work was supported by funding from ACUSTUNA project ref. CTM2015-70446-R (MINECO/ERDF, EU). This project has been possible thanks to the collaboration of IEO (Spanish Oceanographic Institute). We acknowledge the assistance provided by the Spanish company Grup Balfego S.L. in supplying boats and divers to acquire underwater video in the Mediterranean Sea.Muñoz-Benavent, P.; Andreu García, G.; Valiente González, JM.; Atienza-Vanacloig, V.; Puig Pons, V.; Espinosa Roselló, V. (2018). Enhanced fish bending model for automatic tuna sizing using computer vision. Computers and Electronics in Agriculture. 150:52-61. https://doi.org/10.1016/j.compag.2018.04.005S526115

Automatic Bluefin Tuna sizing using a stereoscopic vision system

[EN] This article presents a non-invasive fully automatic procedure for Bluefin Tuna sizing, based on a stereoscopic vision system and a deformable model of the fish ventral silhouette. An image processing procedure is performed on each video frame to extract individual fish, followed by a fitting proce- dure to adjust the fish model to the extracted targets, adapting it to the bending movements of the fish. The proposed system is able to give accu- rate measurements of tuna snout fork length (SFL) and widths at five predefined silhouette points without manual intervention. In this work, the system is used to study size evolution in adult Atlantic Bluefin Tuna (Thunnus Thynnus) over time in a growing farm. The dataset is composed of 12 pairs of videos, which were acquired once a month in 2015, between July and October, in three grow-out cages of tuna aquaculture facilities on the west Mediterranean coast. Each grow out cage contains between 300 and 650 fish on an approximate volume of 20 000 m3.Measurements were au- tomatically obtained for the 4 consecutive months after caging and suggest a fattening process: SFL shows an increase of just a few centimetres (2%) while themaximum width (A1)shows arelative increaseofmorethan20%,mostlyinthe first 2months in farm. Moreover, a linear relation (with co- efficient of determination R2> 0.98) between SFL and widths for each month is deduced, and a fattening factor (F) is introduced. The validity of the measurements is proved by comparing 15 780 SFL measurements, obtained with our automatic system in the last month, versus ground truth data of a high percentage of the stock under study (1143 out of 1579), obtaining no statistically significant difference. This procedure could be extended to other species to assess the size distribution of stocks, as discussed in the article.This work was supported by funding from ACUSTUNA project ref. CTM2015-70446-R (MINECO/ERDF, EU). This project has been possible thanks to the collaboration of IEO (Spanish Oceanographic Institute).Muñoz-Benavent, P.; Andreu García, G.; Valiente González, JM.; Atienza-Vanacloig, V.; Puig Pons, V.; Espinosa Roselló, V. (2018). Automatic Bluefin Tuna sizing using a stereoscopic vision system. ICES Journal of Marine Science. 75(1):390-401. https://doi.org/10.1093/icesjms/fsx151S39040175

Automatic Bluefin Tuna Sizing with a Combined Acoustic and Optical Sensor

[EN] A proposal is described for an underwater sensor combining an acoustic device with an optical one to automatically size juvenile bluefin tuna from a ventral perspective. Acoustic and optical information is acquired when the tuna are swimming freely and the fish cross our combined sensor's field of view. Image processing techniques are used to identify and classify fish traces in acoustic data (echogram), while the video frames are processed by fitting a deformable model of the fishes' ventral silhouette. Finally, the fish are sized combining the processed acoustic and optical data, once the correspondence between the two kinds of data is verified. The proposed system is able to automatically give accurate measurements of the tuna's Snout-Fork Length (SFL) and width. In comparison with our previously validated automatic sizing procedure with stereoscopic vision, this proposal improves the samples per hour of computing time by 7.2 times in a tank with 77 juveniles of Atlantic bluefin tuna (Thunnus thynnus), without compromising the accuracy of the measurements. This work validates the procedure for combining acoustic and optical data for fish sizing and is the first step towards an embedded sensor, whose electronics and processing capabilities should be optimized to be autonomous in terms of the power supply and to enable real-time processing.This work was supported by funding from ACUSTUNA project ref. CTM2015-70446-R (MINECO/ERDF, EU) and PAID-10-19 (UPV).Muñoz-Benavent, P.; Puig Pons, V.; Andreu García, G.; Espinosa Roselló, V.; Atienza-Vanacloig, V.; Pérez Arjona, I. (2020). Automatic Bluefin Tuna Sizing with a Combined Acoustic and Optical Sensor. Sensors. 20(18):1-17. https://doi.org/10.3390/s20185294S117201

Target strength measurements of gilthead sea bream with single-beam quantitative echosounder

[EN] Target strength (TS) measurements for ventral aspect of gilthead sea bream (Sparus aurata) have been performed in a scaled aquaculture cage. The measurements have been made with a Simrad EK-60 scientific echososunder working at 200 kHz with a single-beam composted transducer specific of the Simrad ES15 echosounder (aperture of 30 degrees), designed for aquaculture control among other applications. Linear relationships of TS versus the logarithms of length have been derived. It must been underlined the obtaining of high values of the correlation coefficients and a high resolution of the ventral expressions for fish size predictions. Lower mean values of TS distributions are obtained for single-beam mesurements respect split-beam measurements as expected.Llorens Escrich, S.; Soliveres, E.; Pérez Arjona, I.; Espinosa Roselló, V.; Puig Pons, V.; Ordoñez Cebrian, P. (2016). Target strength measurements of gilthead sea bream with single-beam quantitative echosounder. Universidade do Porto. 1-6. http://hdl.handle.net/10251/181090S1

Influence of high intensity ultrasound application on mass transport, microstructure and textural properties of pork meat (Longissimus dorsi) brined at different NaCl concentrations

[EN] The aim of this work was to evaluate the effect of high intensity ultrasound and NaCl concentration on the brining kinetics (5 ± 1 C) of pork loin as well as its influence on the textural and microstructural changes. In order to identify the effect of both factors on NaCl and moisture transport, kinetics were analyzed by taking the diffusion theory into account. The textural and microstructural analysis of raw and brined meat both with and without ultrasound application was carried out. The experimental results showed that the brine NaCl concentration not only determined the final NaCl content in meat samples but also the direction of water transport. The NaCl and moisture effective diffusivities were improved by ultrasound application. The final NaCl and moisture content and the ultrasound application promoted changes in instrumentally measured meat texture, which were confirmed via microstructural observations.This work is financed by Project CARNISENUSA (CSD2007-00016) included in the CONSOLIDER-INGENIO-2010.Ozuna López, C.; Puig Gómez, CA.; García Pérez, JV.; Mulet Pons, A.; Cárcel Carrión, JA. (2013). Influence of high intensity ultrasound application on mass transport, microstructure and textural properties of pork meat (Longissimus dorsi) brined at different NaCl concentrations. Journal of Food Engineering. 119(1):84-93. https://doi.org/10.1016/j.foodeng.2031.05.016S8493119

Ultrasonic monitoring of early larval development of fish in tanks. Case study: Gilthead seabream (Sparus aurata)

[EN] Swimbladder inflation is a significant matter in intensive fish farming, since it is related to larval survival rate and the morphological quality of individuals. In this work, we propose a non-invasive acoustic technique using ultrasound to monitor the swimbladder development of gilthead seabream (Sparus aurata) in tanks. The fundamental hypothesis is that, due to the high acoustic contrast of gas, the swimbladder¿s inflation process can be detected by measuring the larvae¿s target strength during their early development. Backscatter numerical models using the finite element method, developed from biological measurement data, were applied to evaluate the feasibility of the proposed method. The acoustic measurements were obtained using an EK60 Simrad echosounder working at 200 kHz. The target strength values were evidenced with and without the presence of a developed swimbladder, showing a statistically significant relationship with the swimbladder¿s standard length, area and the percentage of larvae with a swimbladder. The experiments were carried out in the Spanish Institute of Oceanography (IEO)¿s marine aquaculture plant at Mazarrón (Murcia, Spain).This work was supported by funding from Generalitat Valenciana (Regional Valencia Government) through the AICO/2020/064 project and the Spanish Government through ACUSTUNA project ref. CTM2015-70446-R (MINECO/ERDF, EU) , financing the experimental work carried out in the context of the competitive access ACUSTUNA in the ICTS-ICAR ( www.icar.ieo.es)Ladino-Velásquez, A.; Puig Pons, V.; Espinosa Roselló, V.; Pérez Arjona, I.; De La Gandara García, F.; Ortega, A. (2022). Ultrasonic monitoring of early larval development of fish in tanks. Case study: Gilthead seabream (Sparus aurata). Aquacultural Engineering. 98:1-11. https://doi.org/10.1016/j.aquaeng.2022.1022631119