1. Adrian Grozea 1,2 Alexandru Draşovean 1 Alexandru Draşovean 1 Dacian Lalescu 1 Dacian Lalescu 1 Dénes Gál 2 Dénes Gál 2 FEEDING BEHAVIOUR OF THE PIKEPERCH INTO TANKS FROM RECIRCULATING AQUACULTURE SYSTEMS 1 Banat’s University of Agricultural Sciences and Veterinary Medicine „King Michael I of Romania” from Timişoara, 300645-Timisoara, Calea Aradului 119, Romania 2 National Agricultural Research and Innovation Centre, Research Institute of Fisheries and Aquaculture (NARIC-HAKI), 5540-Szarvas, Anna-liget 8, Hungary

2. was to carry out a “round the clock” behaviour study a “round the clock” behaviour study regarding pikeperch distribution into the rearing regarding pikeperch distribution into the rearing tank, linked with their feeding activity during 24 hours tank, linked with their feeding activity during 24 hours 2 THE AIM OF THE STUDY STUDY THE AIM OF THE STUDY STUDY

3. MATERIAL AND METHODS 3 Pikeperch individuals used Pikeperch individuals used in this study were obtained and reared in in this study were obtained and reared in Recirculating Aquaculture System (RAS) from the Aquaculture Research from the Aquaculture Research Laboratory at the Banat’s University of Laboratory at the Banat’s University of Agricultural Sciences and Veterinary Agricultural Sciences and Veterinary Medicine „King Michael I of Romania” Medicine „King Michael I of Romania” from Timisoara from Timisoara The fish

4. Eighty-five fish with an average weight of 117.40±3.14 g were monitored into a rectangular tank (1.5 × 1.5 × 0.7 m), part of a recirculating aquaculture system (RAS) The fish were fed during experimental days with 150 g dry food/day. They were fed with SteCo SUPREME 10 - 4.5 mm (Coppens International, Holland) using a belt feeder (FIAP, Germany) which assured a continuously feeding (24/24 hours).

5. Fish behaviour was recorded using a cam recorder CCTV (CC9622BIR, PANASONIC®) connected to a PC unit through a capture card (AVerMedia® NV5000 Security DVR Card). After three days of accommodation, the fish behaviour was recorded continuously for 10 days. 5 Experimental design

6. Each snapshot was used for observation and counting of the fish distribution into the four quadrants of the tank. The quadrants were obtained by splitting the tank image with two lines from the opposite corners. The quadrants were marked in clockwise direction from 1 to 4, the first one being with the feeder (C). 6

7. The water flow was adjusted at about 17 litters per minute. 17 litters per minute. Each day, 10% of the water from RAS was removed and replaced with fresh water from well in order to keep the main water parameters at optimal level Each day, 10% of the water from RAS was removed and replaced with fresh water from well in order to keep the main water parameters at optimal level The main physical-chemical parameters of the water were continuously monitored using SC 1000 controller (Hach Lange, Germany) with different sensors. The main physical-chemical parameters of the water were continuously monitored using SC 1000 controller (Hach Lange, Germany) with different sensors. 7 Water quality and and rearing conditions

8. Results and discussion all the snapshots at hourly intervals revealing that more than 40% of the fish preferred the first quadrant (C 1 ) where the feeder was disposed in the first 24 hours of observations, the minimum number of the fish in the C 1 (35 fish; 41% from total) was observed at 7:00 a.m the maximum number of the fish (43 fish; 52% from total) in the same quadrant, was observed at 10:00 a.m., 12:00 a.m. and 16:00 a.m. 8 The pikeperch spreading into rearing tank was deeply into rearing tank was deeply influenced by the position of the influenced by the position of the belt feeder belt feeder

9. 9 The observations revealed that first quadrant (C 1 ) was preferred by the quadrant (C 1 ) was preferred by the largest number of fish largest number of fish 38.81±0.89 (45.66% 38.81±0.89 (45.66% On the second place was the 4 th quadrant (C 4 ), but high (Δ=16.99 fish) and significant differences (p<0.001) were registered comparing with C 1. This tendency could be explained by the presence of the belt feeder on C 1, and the rotation direction of the water into tank (counterclockwise direction) which move uneaten pellets from C 1 in C 4, prior to rich the tank’s botom This tendency could be explained by the presence of the belt feeder on C 1, and the rotation direction of the water into tank (counterclockwise direction) which move uneaten pellets from C 1 in C 4, prior to rich the tank’s botom.

10. 10 In the other quadrants, the number of the fish was significantly of the fish was significantly lower (p<0.001) than in lower (p<0.001) than in C 1 and C 4 C 1 and C 4 Due to these results, it could be Due to these results, it could be speculated that the volume of the tank could be better used, and a higher biomass of fish could be reared and fed in the same tank if the feeding line is extended. speculated that the volume of the tank could be better used, and a higher biomass of fish could be reared and fed in the same tank if the feeding line is extended. The results suggest that in these two quadrants, the fish do not spent a long period of time.

11. 11 The presence of the fish in the first quadrant in a large number is better observed at certain in a large number is better observed at certain period of the day. period of the day. The tree diagram established by Ward method, based on all observations during experimental period revealed that fish number on first quadrant does not have a consecutive order Tree diagram for feeding behaviour of pikeperch (based on presence for the fish in feeding zone – C 1 ), established by Ward method

12. 12 the pikeperch could be fed 24/24 hours be fed 24/24 hours the fish show interest for food the fish show interest for food even during the night, at some even during the night, at some hours being the quite similar hours being the quite similar feeding activity like during feeding activity like during the day. the day. According According with these with these observations observations Anyway, the feeding frequency do not seems to affect the growth rate or conditions of the juvenile pikeperch (Zakęś et al., 2006; Wang et al., 2009), but more study should be made in this respect for bigger fish.

13. Acknowledgments This research has been partially supported by the AQUAREDPOT project supported by the AQUAREDPOT project funded by the European Commission (FP7- 316266) and partially supported by the project „Doctoral studies for research in training”, POSDRU /107/1.5/S/80127 founded by European Social Fund through the Sectorial Operational Programme for the HumanResources Development 2007-2013. 13

14. Thank you! 14