Where you are Raised Does Matter: The Use of Semi-natural Rearing Ponds as an Atlantic Salmon Conservation Tool

Transcription

1 Where you are Raised Does Matter: The Use of Semi-natural Rearing Ponds as an Atlantic Salmon Conservation Tool Kurt Samways: Canadian Rivers Institute, University of New Brunswick, Fredericton, NB. Danielle MacDonald: Fisheries and Oceans Canada, St. Andrews, NB.

2 Enhancement Historical and Present use of Salmon Hatcheries

3 Mitigation

4 Nature vs. Nurture STAGE Nature Hatchery EGGS/ALEVIN FINGERLINGS/PARR Gravel, redds, upwelling current, predation, natural temperature regimes, constant dark Natural feed, foraging, natural substrate (cobble), complex flow regimes, predation, competition, natural temperature variation, dynamic stream environments with a variety of micro and macro habitats, natural light variation Troughs, incubators (with or without substrate), varied lighting, artificial temperature regimes, handling, therapeutants Tanks generally without substrate, pelleted feed provided at intervals, constant flow, little temperature variation, homogeneous rearing environment lacking complexity, no predation, no competition with other species, high densities

5 Wild Fish Hatchery Fish On Your Own Increased Selective Pressures High Mortality in Early Life Stages Increased Natural Adaptations Constant Care Decreased Selective Pressures Low Mortality in Early Life Stages Decreased Natural Adaptations

6 With the Best of Intentions

7 Salmon News THE WORLD S FAVOURITE NEWSPAPER - Since B Stocked Atlantic Salmon Missing! Every year, over 5 billion hatchery reared Atlantic salmon are stocked into natural rivers and streams around the world. Yet, in many areas there have been sharp declines in salmon numbers in the wild over the last couple of decades. So where did all these stocked salmon go? Global climate change is being considered as one of the potential variables resulting in the declining returns of mature adult salmon to their natal habitats. Other studies are looking at the effects of diseases, parasites, habitat degradation as well as other anthropogenic impacts. Conservation and restoration are now key priorities for these populations. Folks who used to cast their lines into salmon pools are now sitting shoulder to shoulder with scientists, governments and the interested public at large to find solutions to restore this king of fish to its former glory. To that end, the Atlantic Salmon Federation is hosting a restoration workshop What Works, What Doesn t in September.

8 Goal of Conservation To restore self sustaining populations in the wild

9 Paradigm Shift To Convert Production Facilities to The end result would therefore become the Conservation Facilities the traditional production of ecological viable fish better fish culturists should switch from a prepared for natural releases and survival goal of maximizing productivity to a in a wild habitat. goal of maximizing biodiversity.

10 But How?

11 Research Question Can semi-natural rearing ponds be used as a Conservation Tool in Atlantic Salmon restoration?

12 Study Metric To measure the morphological responses of Atlantic salmon fingerlings to conventional, semi-natural and wild rearing conditions

13 Study Ponds Conventional Semi-Natural Drainage Screens Riffle Run Drainage Screens Riffle Inflow Inflow Run

14 Flow Patterns Conventional Semi-Natural

15 CONV 289 fish/m fish/m fish/m fish/m 3 SN HD 319 fish/m fish/m fish/m fish/m 3 SN LD 127 fish/m fish/m fish/m fish/m : Emergent 2010: SN MD 192 fish/m fish/m fish/m fish/m 3

16 Timelines 2009: Length, Weight, Photographs June July August September October 2010: Length, Weight, Photographs & Fin Condition

17 Steps for Shape Analysis for the Science Geeks 1) Landmark

18 Steps for Shape Analysis for the Science Geeks Landmark Configurations Centered Around Centroid Superimposition of all Configurations 1) Landmark 2) GLS 1) Landmark 2) Generalized Orthonganol Least-squares Procustes Superimposition (GLS) Produces a data matrix (Partial Warp Scores) Represents all shape descriptors Rotate, Translate and Scale Images and Calculate the Procustes Distance (Reference Form)

19 Steps for Shape Analysis for the Science Geeks 1) Landmark 2) GLS 3) PCA 1) Landmark 2) Generalized Orthonganol Least-squares Procustes Superimposition 3) PCA on Partial Warps Produces a Relative Warp Score matrix A multivariate description of shape variation

20 Steps for Shape Analysis for the Science Geeks 1) Landmark 2) GLS 3) PCA 4) ANCOVA 1) Landmark 2) Generalized Orthonganol Least-squares Procustes Superimposition 3) PCA on Partial Warps 4) ANCOVA to Test for Allometry Does shape vary with size? Remove linear dependencies of shape on size Standardize relative warp scores

21 Steps for Shape Analysis for the Science Geeks 1) Landmark 2) GLS 3) PCA 4) ANCOVA 5) DFA 1) Landmark 2) Generalized Orthonganol Least-squares Procustes Superimposition 3) PCA on Partial Warps 4) ANCOVA to Test for Allometry 5) DFA on Standardized Relative Warps Test for group membership & characterize variability between rearing treatments MANOVA for Differences between Groups Differences between rearing treatments Post-hoc univariate F-tests for differences between groups

22 Discriminant Function II ( 17.3%, p<0.0001) 2009 Shape Analysis Results Discriminant Function I ( 65.9%, p<0.0001)

23 2010 Shape Analysis July August

24 2010 Shape Analysis Sept Oct

25 Discriminant Function II (21.5%, p<0.0001) Discriminant Function II (18.8%, p<0.0001) Discriminant Function II (18.0%, p<0.0001) Discriminant Function II (12.9%, p<0.0001) July n=147 August n=191 September n=173 Discriminant Function I (74.7%, p<0.0001) October n=155 Discriminant Function I (74.3%, p<0.0001) Discriminant Function I (67.1%, p<0.0001) Discriminant Function I (74.9%, p<0.0001)

26 Why Shape Matters WILD Emergent Emergent WILD SN MD SN MD WILD CONV CONV

27 2010 Fin Condition The Frantsi Index Fin Index = Total sum of fin erosion observed in treatment Max. total of fin erosion for single fish X # of fish sampled

28 Fin Erosion Index (% Fin Tissue Missing) Fin Condition Results CONV 90.5% (% of Fish Affected) SN HD 16.5% June July Aug Sept Oct SN MD 3.0% SN LD 3.5% Right Left Upper Lower Dorsal Pectoral Pectoral Caudal Caudal Fin Index Erosion Erosion Erosion Erosion Erosion Score % of Fin Contributing To Total Erosion

29 Why Fins Matter Keeps fish upright, controls directional swimming Station holding, balance, steering, vertical movement Forward propulsion, redd digging in females

30 Summary Semi-natural ponds produce fish more similar in shape and fin quality to their natural counterparts. Shape plasticity is not an immediate response in novel environments and can take months to fully occur. Substrate produces better fin qualities even at high densities. Increased habitat and flow complexity is beneficial in producing fish with a more wild-like shape Fish reared in semi-natural ponds may be better suited for life in the wild than their conventionally reared counterparts for a number of reasons including their overall shape and fin-condition (better at foraging, recognition of complex habitat structures, predator avoidance, etc )

31 Thank You Mactaquac Biodiversity Facility: Trevor Goff, Stephanie Ratelle, and staff Memorial University of Newfoundland: Ian Fleming University of New Brunswick: Rick Cunjak Government of Canada: Interdepartmental Recovery Funds

32 Other Research in these Ponds The use of semi-natural ponds for wild-like spawnings- DFO, UNB, MUN Over-wintering of hatchery smolts- DFO Over-wintering of fall to spring parr- PCA, MUN Over-wintering of eggs to emergent fry/parr- DFO, UNB, MUN Effects of hydro-peaking on smoltification-unb Continued use of ponds for SJR program fingerling rearing

33 Shape Analysis Principles: Size Doesn t Matter original scaling (same size) and centering reflection Minimize and calculate distance Procustean rotation

34 June October June Conventional October Wild Initial Stocking High Density Low Density Emergent Conventionally Hatched Substrate Hatched Wild Hatched

35 June August October Wild Conventional Conventional Initial Stocking High Density High Density Medium Density Medium Density Low Density Low Density June August October