How to Increase Recovery of Salmon and Trout in Sweden

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1 SMOLTPRO Aims To develop ecologically and ethically sound methods for supplementary rearing of salmonids, using a multidisciplinary approach To increase the socioeconomic returns of hatchery-produced salmon and trout in Sweden and Scandinavia

2 ..focusing on survival in the wild Fat reserves Early maturation of males Behaviour & Physiology Salmon Surival Predators Pathogens Stress and energy reserv

3 SMOLTPRO Shelter & Density: Effects on stress, physiology and migration

4 Infection by pathogens: bacteria and virus Some important fish/salmon pathogenes: Bacterial: Winter ulcer disease Moritella viscosa Viral: IPN virus Furunculosis Aeromonas salmonicida

5 First line of defence the primary barriers Skin Gills Intestine

6 The intestinal primary barrier Intestinal lumen bacteria glucose viruses amino acids acid fatty acids Mucosal folds Muscle layers Goblet cells Lamina propria Serosa Epithelial cells Circulatory system

7 P app mannitol (10-6 * cm s -1 ) Acute handling stress => decreased barrier function 4 Fed fish 72 hours starvation b 3 b 2 1 a a a a 0 Pre-stress 4h-stress Post-stress Olsen et al. 2005

8 Olsen et al also seen as epithelial damages Proximal Distal Control intestine 4 h post stress

9 Stress Hypothalamus Primary responses Pituitary Interrenal tissue Cortisol Chromaffin tissue Catecholamines Secondary responses Immunological Primary barriers Cellular Ionic Metabolic Nutrients Circulatory Respiratory Tertiary responses Growth Disease resistance Behaviour Reproduction

10 P app mannitol (10-6 * cm s -1 ) Bacterial translocation % of mucosal concentration Mild chronic stress 1,6 1,4 1, ,8 0,6 0,4 0, Normoxia Hyperoxia Normoxia Hyperoxia Sundh et.al 2010

11 Cumulative mortality (%) Deleterious effects in later life stages 45 Hyperoxia and low water flow Normoxia and normal water flow Days post IPNV challenge Fridell et al 2007

12 Hatchery reared salmon Sea Migrate River Hatchery River Sea River Hatchery Sea Hatchery River Migrate

13 Hypothesis - When fish live too packed, they experience stress - Adding structure and shelter creates a more complex and natural environment that may protect from stress Hatchery alterations - Environmental enrichment (structure) - Decrease densities

14 SMOLTPRO-studies Study I Structural Enrichment (stress physiology, behaviour) Study II Structural enrichment & Density (stress physiology, barrier functions, migration) Aim: Improve wellfare in the hatchery & produce a more wild-like fish

15 Wall Studie I- Strukturell Berikning Standard: Barren(B) Berikad I: Tubes (T) Berikad II: Shredding (S) -0+ (vilda föräldrar) -80 ind/1m² x2 x2 x2 Tank Setup Walkway J Näslund, M Rosengren, D Villar, Gansel, Jo Norrgård, L Persson, J Winkowski, E Kvingedal. Can. J. Fish. Aquat. Sci, 2013, 70(4)

16 Experimental Time-line Sep Nov March May Start Weight & Lenght Fin damage Weight and Lenght Blood sample Stress test Shelter seeking behaviour Weight and Lenght Fin damage Weight and Lenght

17 Kortisol (ng/ml) Stresshormoner & Fenskador Basal Stress Fenskador (nov-maj) Change in fin score

18 Proportion fish sheltering Skyddsök Single trials Group trials

19 Wall Studie II- Strukturell Berikning & Densitet High density No shelter (HDNS) Low density No shelter (LDNS) High density Shelter (HDS) Low density Shelter (LDS) 0+ (vilda föräldrar) Låg densitet 50/m² Hög densitet 150/m² x3 x3 x3 x3 Tank Setup Walkway

20 Experimental Time-line Sep Dec Jan Feb April May Start Size Blood sample Blood sample Blood sample Stress test Shelter seeking Size Blood sample Intestinal Function Shelter seeking Fenskador Migration Size

21 Frequency Final body lenght (mm) Tillväxt & Fenskador LDNS HDNS HDS LDS Initial body lenght (mm) Utan skydd Bättre tillväxt Låg densitet, utan skydd bäst tillväxt No Shelter Shelter High Density Low Density Fin damage

22 C o rtis o l (n g /m l) Results- Kortisol (Basal) * H D N S H D S L D N S 2 0 L D S D e c J a n F e b M a y

23 C o rtis o l (n g /m l) Kortisol (Stress) Inducerad tankstressor (2 min) Skapade ljud och vibrationer 6 0 b b N o S h e lte r 5 0 S h e lte r 4 0 c 3 0 c a a a a 0 B a s a l S tre s s H ig h D e n s it y B a s a l S tre s s L o w D e n s it y

T E R ( *cm - 2 ) Resistance T E R ( *cm - 2 ) Tarmbarriärfunktion 1 5 0 1 2 5 1 0 0 7 5 Framtarm P r o x im a l In te s tin e * 0.

3 1 5 0 1 0 0 7 5 a P r o x im a l In te s tin e Baktarm D is ta l In te s tin e * a b a b N o S h e lte r S h e lte r N o S h e

24 T E R ( *cm - 2 ) Resistance T E R ( *cm - 2 ) Tarmbarriärfunktion Framtarm P r o x im a l In te s tin e * 0. 5 N o S h e lte r S h e lte r a P r o x im a l In te s tin e Baktarm D is ta l In te s tin e * a b a b N o S h e lte r S h e lte r N o S h e lte r S h e lte r b 0 H i g h D e n si ty L o w D e n si ty L y s in e u p ta k e ( n m o l* m in - 1 * c m -2 ) H i g h D e n si ty L o w D e n si ty 0. 0 H i g h D e n si ty L o w D e n si ty

25 Proportion sheltering Skyddsök II Feb Efter störning HDS LDS HDNS LDNS HDS HDS LDS LDS HDNS HDNS LDNS LDNS May Efter störning HDS LDS HDNS LDNS HDS LDS HDNS LDNS

26 Migration HDNS 29% 180/Behandling HDS 15% LDNS 32% LDS 24% Stark storlekseffekt- Ju större desto bättre! HDS migrerar sämst

27 Mean migration probability Migration High Density Low Density No Shelter Shelter Lenght (mm)

28 Konklusion I & II Skydd kan påverka tillväxt negativt Mindre aktiva Skydd minskar fenskador Lägre interaktion/aggression Temporära ökningar av stress hormoner i LDNS ( störning/inom tank aggression, minskad välfärd?) Skydd skyddar mot störningsstress Ökad välfärd Låg Densitet positiva effekter på tarmbarriären Skydd i tankar ökar skyddsök Låg vilja att söka skydd som smolt Stora fiskar migrerar bäst! HDS negativa effekt på migration

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