ARTIFICIAL FISH SHELTERS DEVELOPED BY A STATISTICAL APPROACH ON NATURAL FISH HABITATS Fishshelter deposed brand Project manager : Ir. S Den Doncker (Stream And River Consult) Statistics assistance : Adrien Latli (Namur University)
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What is considered as a fish shelter? - FWD, LWD, OV, BOU, Roots, Undercut banks, mixed - Deep pool not considered - norms : cf. Neumann, 2002; Hagstrom and al. 1995, Stevenson and al.,1999 f.i. FWD less than 10 cm diameter and > 1meter long What fish shelter density we found in natural rivers? 5 NZ rivers: - Ngaawapurua stream (Ngaruroro tributary) 90 to 100% of the river stretch contains shelters (mainly rocks) - Waimarino river : 69% of the river stretch contains shelters - Waipa river : 75% of the river stretch contains shelters
6 Belgian rivers
Belgian rivers 7 Source : Vers l Avenir
Observation : lack of hiding habitat : Against predators (birds ) Specifically for juveniles Refuge when flooding Day shelter for eels 8
Observation : fish use (a lot) shelters in natural stream Observation : lack of shelter in damaged rivers, with specific hydraulic and space constraints in urban areas Observation: not a lot of data (from natural rivers) to build specific artificial shelters in urban river restoration no artificial river shelters on the market Pupose : create this artificial shetlers for fish continuity, and fish abondance in urban areas 9 Fishshelters from SAR Consult : build from field data considering fish efficiency and
CRITERION # Criterion 1 Fish efficiency 2 No significant hydraulic impact 3 Production cost 4 Installation cost 5 Durability 6 Aesthetic 7 Transport 8 Maintenance 9 Biodiversity 10 Adaptability 10
SALMONID BOX 11
12 => Species found: trout, roach, chub, bullhead, minnow, eel, pike, perch, crayfish, stickleback, gudgeon,
The scientific project (Belgium-New Zealand): To increase knowledge about natural fish shelters (type, dimensions, density, ) To figure out what characteristics are preferred by fish To test numerous prototypes in rivers, streams and ponds (lakes) 13
The scientific project (Belgium-New Zealand): More than 100 natural fish shelters in 2 different rivers (NZ) : Characteristics Water velocity Fish shelter dimensions (2.1 length, 2.2 width, 2.3 depth); volume Entrance area shape how many entrance(exit) for the fish Light permeation Lasting quality (valuation) On the bottom (yes/no) River substrate Fish use 1232 NZ fish sampled in by electric fishing, others monitored by pit tag (mainly trout) 50 Belgian fish shelters monitored by sub aquatic camera 14
Hypothesis 0 (Waimarino river) : compare volume versus artificial/natural fish shelters 15
Hypothesis 1 (Waimarino river) : fish density higher in artificial shelters -Prob > F 0,0028 16
Hypothesis 2 (Waimarino river) : fish density depend on shelter type A A A C B Prob > F <,0001 17
Hypothesis 3 (Waimarino river) : more species in artificial shelters Prob > F 0,3138 18
Hypothesis 4 (Waimarino et Waipa river) : is there some fish shelter characteristics influencing fish number (or the number of fish species)? LOG Nb poisson ~ log lmoy+ eshape + bottom + nature RSquare 0,409937 RSquare Adj 0,378881 Root Mean Square Error 0,752809 Mean of Response 1,745352 Observations (or Sum Wgts) 101 Term Prob> t Intercept 0,0440* log Lmoy 0,0032* eshape{open-very Closed&BIT Closed} 0,0503 bottom[no] 0,1833 nature{ov-mixt Roots UcutB&Roots&Mixt OV Roots&Mixt FWD OV&Mixt LWD 0,0004* Roots&LWD&Mixt FWD UcutB&FWD&Art} nature{mixt Roots UcutB&Roots&Mixt OV Roots&Mixt FWD OV&Mixt LWD Roots&LWD&Mixt 0,0066* FWD UcutB-FWD&Art} Nb taxa ~ log volume+ eshape + resilience + nature RSquare 0,311276 RSquare Adj 0,277843 Root Mean Square Error 0,848787 Mean of Response 1,724771 Observations (or Sum Wgts) 109 Prob > F <,0001* Term Prob> t Intercept <,0001* log volume 0,0039* eshape{open-very Closed&BIT Closed} 0,0006* resilience{good-medium&poor} 0,0512 nature{bou&ov&roots&mixt FWD UcutB&Mixt LWD Roots&Mixt Roots UcutB&Mixt OV Roots- 0,0212* LWD&Art&Mixt FWD OV&FWD} nature{bou-ov&roots&mixt FWD UcutB&Mixt LWD Roots&Mixt Roots UcutB&Mixt OV Roots} 0,2560 19
Hypothesis 4 (Waimarino et Waipa river) : is there some fish shelter characteristics influencing fish number (or the number of fish species)? Cumulative projected inertia (%): en R - ACP Ax1 Ax1:2 Ax1:3 Ax1:4 Ax1:5 29.62 46.14 20
Hypothesis 5 (TC Stream) : pit tag on trout juveniles Data analysis still in progress Obervations : Fish (trout) use artificial shelters even if there is natural shelters near by Fish can share the space in the artificial shelter Fish from stocking seem to not use the artificial shelters we made 21
Monitoring : 50 artificial fish shelters summer 2017 Max 3 espèces par cache => 11 species 22
Unexpected applications also to restore rivers in rural areas (our main job) By this study, we learn about naturals fishsheters, the diversity /density of them, We now build new rivers considering our results and all the others studies we know on the subject 23
THANK YOU! ALSO THANK TO DR M. DEDUAL (DOC, NZ), DR B. DAVID (WRC, NZ), J. LOVELL (CONFLUENCE INC, USA) CONTACT Ir. Sébastien Den Doncker sdendoncker@streamandriver.com Tel. + 32 (0) 485 21 54 25 info@streamandriver.com 24 www.streamandriver.com