Havbruksinstituttet AS. Documentation of the CompHatch hatching cabinet. and the new innovative EasyHatch hatching substrate

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1 Havbruksinstituttet AS Documentation of the CompHatch hatching cabinet and the new innovative EasyHatch hatching substrate

2 Report no Availability Closed Høyteknologisenteret I Bergen, Thormøhlensgate 55, 5008 Bergen Tel: Fax: bjorn.guldberg@hi.no Report title Documentation of the new EasyHatch hatching substrate and the CompHatch hatching cabinet for roe of salmon Date: Number of pages: 6 Principal Alvestad Marin AS Principal s ref.: Runar Alvestad Author Main area of expertise Name Biology/subject, fish farming, production, operations: Bjørn Guldberg Collaborating companies: Test host: Stolt Seafarm, dept. Kvingo Marine Harvest Sør, dept. Fister Smolt

3 Summary The new EasyHatch substrate and the new CompHatch hatching cabinet have been compared with the traditional method which is traditionally used for salmon at the installation at Kvingo as control: Astro Turf substrate in 1m tanks with hatching inlays. At Fister Smolt, only substrate was compared to Astro Turf, both in 1m tanks with adapted hatching inlays as well as in 0.78m 2 round hatching inlays placed in 1m tanks. With reference to growth in the yolk bag phase and through initial feeding, no significant differences were recorded at Fister Smolt between the two types of hatching substrate. At Kvingo, decisively better values as to survival up to the age of 4 weeks into the initial feeding were recorded for EasyHatch. Up to 21% lower mortality than with Astroturf, depending on the type of incubation unit. The weight of the fish 4 weeks into the initial feeding showed a small difference, median weight of 0.77 g for EasyHatch compared to 0.82 g for Astroturf. As to practical operations, EasyHatch hatching substrate came out best with clear advantages in the following areas: simple assembly, reduced risk of fry getting caught between the mat and the bottom of the tank, cleaning/picking of dead fry during operations, cleaning after the end of the season, total hygiene during operations. The project proves that EasyHatch has a capacity of at least 33 % more yolk bag fry than Astroturf without compromising survival and growth. The hatching cabinet CompHatch with EasyHatch gave 21% lower mortality than 1m tanks with Astroturf. 1m tanks with Astroturf weight at initial feeding at 0.17g compared to 0.16g for CompHatch. The hatching cabinet EasyHatch requires considerable less space than a 1m tank and the roe incubation in an eight tray/drawer cabinet is carried out in approximately 25% of the area compared to 1m tanks with Astroturf. CompHatch has a practical and well arranged system for adjusting and visualizing the water consumption per unit in the cabinet which is not available for a 1m tank. CompHatch is quicker to care for all in all. Introduction Alvestad Marin AS (AM) has developed a hatching cabinet CompHatch for incubation of roe and yolk bag fry from salmon fishes until initial feeding. AM has also developed a proprietary substrate EasyHatch for use in the cabinet and/or other incubation units. The cabinet with EasyHatch substrate was tested against 1m incubation tanks with the traditionally used substrate Astro Turf. The tests also included tests of various densities of roe in the 1m tanks for the two substrates. The objective was to provide documentation of advantages/disadvantages connected with the use of the new hatching cabinet and the hatching substrate on salmon compared to the use of Astroturf hatching substrate in 1m tanks with hatching inlays. Material and method Kvingo Fish material Roe of the salmon breed Bolaks from Erfjord Stamfisk was incubated in the various incubation units to be tested. The supplier informed us that the roe had a size of 5078 roe grains per litre and looked even and fine at receipt. A roe group of a somewhat larger roe size, 4900 roes per litre was used for the roe that was incubated at the highest densities in 1m tanks (hatching units 12-14). Incidentally, the roe groups were from the same parent

4 fish group and with the same age at delivery, 430 and 432 day degrees, and they were delivered at the same time. Incubation units and substrate The incubation units were CompHatch hatching cabinet with EasyHatch hatching substrate and 1m tanks with hatching substrate in which 2 different substrates were tested: Astroturf and EasyHatch. EasyHatch is manufactured from a plastic material which is very smooth and which is not adhesive. This substrate has pins of various lengths which limit the swimming activity of the yolk bag fry in contrast to Astroturf which has grass turf as an activity restrainer for the fry. Water environment and cleaning The environments of the hatching units were as uniform as possible with respect to lighting, temperature, water flow and oxygen levels. This was balanced by using the same source for supply of water for all units and we secured an oxygen level of approximately 90% at discharge (minimum 85%) for each unit. Temperature of 8 o C until the initial feeding and then an increase to 10 o C through the yolk bag phase and o C from the initial feeding to the end of the project. We employed cover plates for the 1m tanks until almost half of the yolk bag was consumed. CompHatch hatching cabinet does not need this as it admits very little light in to the yolk bag fry when the trays/drawers are closed. Dead roe/fry was collected every day from all units. Survival and weight at the initial feeding and 4 weeks after initial feeding will describe any differences between the incubation units. The mortality figures are collected from the installation s recordings of such figures. Initial feeding The initial feeding was performed in 3m tanks in which there was established a minimum of one tank with fry from each substrate type. It was secured that each tank for initial feeding received fish from incubation units with similar density. Fish weights are found as an average of 50 fish at initial feeding and the average of fish at the end of the project 4 weeks after the initial feeding. Practical operations The operators at the installation made a subjective assessment as to how practical the two substrates were when it comes to handling and how this affects the workload and the hygiene in the production units. Capacity and density In choosing the density of individuals for the various substrates that were included in the project, we also considered the density of individuals of the actual roe size which is required to fill the substrate, e.g. that there is no more room for more individual yolk bag fry that finds support in the substrate.

5 Fister Smolt Fish material Roe of the salmon breed AquaGen was incubated in the various incubation units to be tested. The supplier stated that the roe size was 5200 roe grains per litre. The age at delivery was 428 day degrees. Incubation units and substrate The incubation units were 1m tanks with adapted hatching inlays as well as in 0.78 m 2 round hatching inlays placed in 1m tanks in which 2 different substrates were tested: Easyhatch and astroturf. Water environment and cleaning The environments of the hatching units were as uniform as possible with respect to lighting, temperature, water flow and oxygen levels. This was balanced by using the same source for supply of water for all units and we secured an oxygen level of approximately 80-90% at discharge for each unit. Dead roe/fry was collected every day from all units. Survival and weight at the initial feeding and 30 days after initial feeding will describe any differences between the incubation units. The mortality figures are collected from the installation s recordings of such figures. Initial feeding The initial feeding was performed in 1m tanks. Fish weights are come by as the average of 50 fish. Practical operations The operators at the installation made a subjective assessment as to how practical the two substrates were when it comes to handling and how this affects the workload and the hygiene in the production units. Results Comparison between hatching cabinet and 1m tanks with hatching inlays Survival Incubation in CompHatch hatching cabinet gave significantly better survival from the roe inlays to initial feeding as opposed to 1m tanks with hatching inlays (See chart 1). CompHatch gave 21% lower mortality than for 1m tanks with Astroturf and 6% lower mortality than 1m tanks with EasyHatch (tanks which had another roe group are left out). Weight at initial feeding Incubation in 1m tanks did not provide any difference in weight at initial feeding when the same substrate was employed (chart 1). When using Astroturf in 1m tanks, the weight

6 at initial feeding was significantly a little higher; 0.17g as opposed to 0.16g for the hatching cabinet (chart 1). Chart 1. Weight at initial feeding as well as % mortality in the roe phase and the yolk bag phase for Roe incubated in CompHatch hatching cabinet and 1m tanks with hatching inlays. Hatching Average % substrate weight mortality total density Hatching incubation % yolk bag % start unit grams mortality fry mortality number number/m2 unit no. Astroturf 1m 0,17 3,9 0,6 4, Astroturf 1m 0,17 2,8 0,6 3, Astroturf 1m 0,17 3,6 1,2 4, Astroturf 1m 0,17 3,7 0,8 4, Average 0,17 3,5 0,8 4,3 Median 0,17 3,7 0,7 4,5 EasyHatch 1m 0,16 3,2 0,7 3, EasyHatch 1m 0,15 3,2 0,6 3, EasyHatch 1m* 0,17 2,0 0,5 2, EasyHatch 1m* 0,17 1,3 0,5 1, EasyHatch 1m* 0,16 1,8 0,4 2, Average 0,16 2,3 0,5 2,8 Median 0,16 2,0 0,5 2,5 EasyHatch cabinet 0,16 2,7** 0,8 3, A EasyHatch cabinet 0,16 2,7** 0,8 3, B EasyHatch cabinet 0,16 2,7** 0,7 3, A EasyHatch cabinet 0,16 2,7** 0,6 3, B Average 0,16 2,7 0,7 3,4 Median 0,16 2,7 0,8 3,5 * The roe is from another roe group than the others and may thus not be employed for direct comparison of mortality and size at initial feeding. The fields of interest also shaded. ** In the roe phase, all dead roe was counted as the total for the units in the hatching cabinet. This is the average. Capacity and density At the highest density, the units were filled up by yolk bag fry so that there was no more room for finding support for more individuals. The use of CompHatch with EasyHatch and 8 trays/drawers gives a capacity of individuals distributed on 1.28 m 2, e.g roe per m2, as opposed to roe in a 1m tank with Astroturf distributed on 1m 2. This means that CompHatch only needs nearly 25% of the space required of a 1m tanks or that CompHatch is 4 times more space efficient. Operational considerations In working with the hatching units in CompHatch, the operators work more easily with shorter distance to the roe/fry than in a 1m tank. In an 8 tray/drawer CompHatch cabinet,

7 the operator will have to go down in a sitting position to handle the lowest units. The highest units will require an elevated working platform when performing his work. CompHatch has a practical and clear system for adjusting and visualizing of the water consumption per unit in the cabinet without having to open the cabinet or inspect each unit. A similar system is not available for 1m tanks.

8 Comparison between the hatching substrates Weight The results from the roe inlay to 4 weeks after the initial feeding for each of the installations show that at Fister Smolt, there is no difference in weight between fish that is incubated with the two substrates 2 weeks into the initial feeding, both for the average values and median (chart 2). At Kvingo, on the other hand, there is a small difference (6.7%) in favour of Astroturf when you look at the average size 4 weeks into the initial feeding (average of the average and median) (chart 3). Chart 2. Weight and survival for roe inlays till 2 weeks after initial feeding at Fister Smolt Hatching Average Acc. weight % start Outgoing Outgoing density Hatching mort numb grams ality er number Initial feeding bio mass kg kg/m3 tank no. to tank no. substrate Astroturf 0,34 4, Astroturf 0,31 4, Astroturf 0,36 3, Astroturf 0,43 4, Average 0,36 4,1 Median 0,35 4,3 EasyHatch 0,33 3, EasyHatch 0,34 4, EasyHatch 0,36 7, EasyHatch 0,33 4, EasyHatch 0,36 5, EasyHatch 0,36 4, EasyHatch 0,35 4, EasyHatch 0,34 3, EasyHatch 0,36 3, EasyHatch 0,38 4, EasyHatch 0,39 4, Average 0,35 4,5 Median 0,36 4,4 Chart 3. Weight and survival for roe inlays till 4 weeks after initial feeding at Kvingo Hatching Average Acc. weight % Outgoing Outgoing density Hatching mort start grams ality number number Initial feeding bio mass kg kg/m3 tank no. to tank no. substrate Astroturf 0,84 4, Astroturf 0,80 5, Average 0,82 4,9 Median 0,82 4,9

9 EasyHatch 0,77 5, EasyHatch 0,73 2, % of EasyHatch 0,79 2, % of Average 0,76 3,4 Median 0,77 2,6

10 Survival At Fister Smolt there was no difference in survival between fish incubated with the two substrates (chart 2). At Kvingo, we recorded a clear difference of 3.0% as opposed to 4.9% when you look at an average of the average and median, in favour of EasyHatch (chart 3). It was roe from the group with the largest roe size which had the best survival (incubated in hatching units 12-14). This group was also incubated with the greatest density in the yolk bag phase when substrate was employed. Capacity and density EasyHatch manages at least 33% higher density than Astroturf before the substrate is full. For Astroturf there is a tendency to the fact that weight and survival is worse at high densities. EasyHatch presents just as good qualities at high density as at low density. Operational considerations As to practical operations, EasyHatch hatching substrate came out best with clear advantages in the following areas: simple assembly, reduced risk of fry getting caught between the mat and the bottom of the tank, cleaning/picking of dead fry during operations, cleaning after the end of the season, total hygiene during operations. The description is a short summary of the comments provided by the operators at the two installations. The two operations managers have reported that by using Astroturf, they spend 4-5 times more time on cleaning than by using EasyHatch.

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