Nordic Stakeholder Meeting September 1 st 2016, Sjlyckan Gteborg - - PowerPoint PPT Presentation

Nordic Stakeholder Meeting

September 1st 2016, Sjölyckan Göteborg

Project participants

The SalmoInvade consortium covers Scandinavia and continental Europe, and insights from North American Salmonid invasions.

Partner institutions

• University of Gothenburg (Sweden)
• Leibniz-Institute of Freshwater Ecology and Inland

Fisheries in the Forschungsverbund Berlin e.V. (Germany)

• Norwegian Institute for Nature Research, NINA (Norway)
• CNRS/University Paul Sabatier (France)
• Memorial University (Canada)

Steering group

• Jörgen Johnsson, Sweden (coordinator)
• Robert Arlinghaus, Germany
• Julien Cucherousset, France
• Kjetil Hindar, Norway
• Ian Fleming, Canada

The main objectives of SalmoInvade are:

• 1. to evaluate current releases of non-native salmonids in

Europe and the social, economic and ecological mechanisms underlying their invasion potential,

• 2. to investigate the ecological and evolutionary impacts of

biological invasions by salmonids,

• 3. to evaluate how salmonid invasions are perceived by the

public and by key stakeholders and

• 4. to provide integrated recommendations for policy and

management of salmonid invasions. SalmoInvade will integrate novel eco-evolutionary and socio-economic hypotheses to evaluate the impacts and consequences of non-native salmonid invasions. The results are expected to influence policy and management of this economically important group of fish. WP1

Mechanisms of establishment

WP2

Ecological impact

WP3

Social evaluation

WP4

SALMOINVADE Policy and

Management

Governance of salmonid stocking and introductions – a North Atlantic five-jurisdiction comparison

Øystein Aas, Robert Arlinghaus, Mathieu Buoro, Frederic Santoul Julien Coucerrouset, Ian Fleming, Johan Höjesjö, Jörgen Johnsson, Christian Wolter, Kjetil Hindar SalmoInvade Wp 1.1 Manuscript in revision for: Aquatic Conservation: Marine and Freshwater Ecosystems

Background

– Salmonids highly valued species, subject to severe conflicts, intense management and enhancement efforts – Artificial propagation and techniques for long-distance transfer since the early 1800s – Extensive cultivation, stocking and transfer of salmonids for 150 years – Conservation challenges due to a range of anthropogenic impacts – Increased knowledge of impacts of salmonid stocking and transfer:

• Does it work/is it cost-efficient?
• Unforeseen impacts of diseases and parasites
• New knowledge of genetic population structure of salmonids and selective

impacts of hatchery environment: «Paradigm Shift» – From a policy of «Tilling the water» (Bottom 1996) to «Conserving Biodiversity» – International and national objectives rapidly changed during the 1990s – Yet stocking can have important roles in current and future fishery management

– Identify and point out differences in salmonid stocking governance in five jurisdictions important for salmonids around the North Atlantic Ocean: Atl Canada, F , G, N, S – Assess differences between governance (de jure) and on-the ground practice (de facto) – Method: Multi-national team of fishery experts reviewed salmonid stocking governance following jointly developed specifications – Sources: research articles, official statistics and national reports (‘grey literature’)

Purpose, study area and method

Governance history

Atlantic Canada France Germany Norway Sweden Area (km2)

502 927 (6.5 % water) 551 695 (1.35 % water) 357 021 (2.2 % water) 324 260 (5.2 % water) 450 295 (8.7 % water)

Inhabitants (year)

2.33 mill (2011) 64 mill (2014) 81 mill (2014) 5.1 mill (2014) 9.7 mill (2014)

First hatchery established (year)

1868 1853 1869/1882 1855 NA

First introductions of non-native salmonids from (year, species)

1882: S. trutta 1887: O. mykiss

1877: O. tschawytscha 1878: S. fontinalis 1881: O. mykiss

1882: O. mykiss 1877: S. fontinalis 1900: O. mykiss 1892: O. mykiss and S. fontinalis

Formal policies vs practical management

• General policies and objectives similar and «state-of-

the-art», addressing genetic integrity and biodiversity

• Becomes different when looking at more specific

guidelines and practices for decisions on salmonid stocking and introductions

• Germany, France: Pragmatic, high volumes of stocking;
• Norway and Canada: Restrictive, reduced volumes;
• Sweden in a mid-position, diversified policies
• (In addition to intentional stocking, there are a number of

salmonids escaping from aquaculture operations, especially in Norway and Canada, but these are not treated here)

Sectorial Organisation

– Fish health/veterinary demands and regulations generally similar across all cases – Environment sector responsible in Norway, in all other jurisdictions the Fisheries sector is responsible – Key level of decision-making: Regional in Canada, Norway and Sweden, Local in Germany and France – Vertical distance larger in Germany (and France?) than in N, S – Public/private involvement: Public authorities key actors in C, N, S. Private (angling clubs) in F, G (except for S. salar in F) – Hydro power sector important in Norway and Sweden

Conclusions

• Governance varies between legislations, in terms of objectives, legal

requirements, organisation/sectorial responsibility and involvement of public and private stakeholders

• Objectives at the general level is rather similar and reflecting international

guidelines/new knowledge, yet legal and practical adaptions modify and even undermine the overall objectives in some cases

• All cases lack proper monitoring of stocking and transfer, especially of brown

trout in Europe and brook trout in Canada

• Despite these findings, the general impression is that stocking and transfer of

non-native species is reduced during the last decade(s) - and distribution of O. mykiss and S. fontinalis is reduced in Europe

• Stocking and transfer of non-native populations (of native species) is still common

in many jurisdictions, even if that too is reduced in some areas

• On-the-ground impacts (to the extent we can monitor these) partly reflect

differences in governance

Reasons for differences in stocking governance and practice DIFFERENCES IN:

• Biogeography, including differences in composition/diversity
• f freshwater fish communities (Fitzgerald et al. 2015)
• Historical development, path dependency, incumbents
• Social importance and valuation of wild salmonids versus stocked, non-

native salmonids

• Scientific uncertainty (Sandstrom 2010, Sevä 2013)
• Evidence of severe loss of native aquatic (fish) biodiversity from

stocking («has stocking caused losses?»)

• Organisational differences (Sevä, 2013) :
• Sectorial responsibility (Fisheries vs environment)
• Vertical responsibility and coordination (national, regional, local)
• Private – public responsibilities and ownership structures

X V X V V X V V

SalmoInvade National Stakeholder Workshop in Sweden / Norway 1 Sept 2016 Carsten Riepe, Jürgen Meyerhoff, Marie Fujitani, Sophia Kochalski & Robert Arlinghaus

SalmoInvade WP 3.1: Public perceptions of biodiversity and conservation of salmonids

• Results from a 4-country survey –

Draft manuscript, unpublished.

Method

• 4-country general population survey

(high-quality online panels)

• representative of the online

populations in G, F , N, S

• N = 1,000 completed interviews per

country

• data collection in autumn 2015

Reasons to conduct this survey

• Citizens ...

− perform pro-environmental behaviors − vote in general elections − contribute to the public discourse about biodiversity conservation ► are thus at the societal core of biodiversity conservation in the future

Results: Subjective knowledge

How informed do you feel about the potential threats caused by the introduction

• f nonnative fishes?

How informed do you feel about the topic

• f biodiversity in fishes?

► The vast majority of citizens in all countries did not feel (well) informed. ► Lack of subjective knowledge lowest in N.

Results: Knowledge of salmonids

Which of these fish species have you heard of? If heard of: Which of these species are native to the inland waters of <YOUR COUNTRY>?”

Atlantic salmon Brown trout Rainbow trout Brook trout Atlantic salmon Brown trout Rainbow trout Brook trout

►Recognition of native salmonids, and rainbow trout, quite high in G, N, S, though Atlantic salmon low in G. ►Recognition of species names low in F . ►Overall, lowest familiarity with brook trout, particularly in F . ►Atlantic salmon perceived as native by the vast majority of Norwegians, only by a minority of Swedes and Frenchmen, and hardly by any German. ►Brown trout mostly perceived as native in all countries. ►Rainbow trout viewed as native by a majority in G and F, only by about half of the respondents in Scandinavia. ►Except in S, brook trout viewed as native.

Results: Risk perception

How dangerous is the introduction of nonnative fishes to the rivers of <YOUR COUNTRY> for the natural environment?

► Only a small minority in all countries seemed to completely lack risk awareness. ► Risk perception higher in Scandinavia than in G and F.

How strongly do these human-made factors contribute to fish biodiversity loss?

► Water pollution considered most threatening. ► Habitat loss perceived as more relevant in G and F than in Scandinavia. ► Introduction of nonnative fishes ranks midway between pollution / habitat loss and overfishing / hydropower dams (and is highest in N). ► Overfishing of least concern in S, hydropower dams equally important in all countries.

1 = no contribution / 4 = very strong contribution

Results: Attitudes towards salmonids (means)

1 = very bad / 5 = very good

► Past introduction of nonnative salmonids not perceived as bad, even slightly positive in G and S. ► Current releases of nonnative salmonids viewed as slightly worse, still not really bad. ► Current reintroductions of Atlantic salmon and sturgeon for conservation purposes were appreciated in all countries, particularly in G. ► Atlantic salmon escaping from aquaculture: − interbreeding with conspecifics viewed as bad, − transmission of diseases / parasites as even worse.

Discrete choice experiment (DCE): Method

Key question: Which ecologically relevant attributes of a river determine the publics' preferences for a river development program? Task: "Which river development program do you prefer?" (Choice sets describing alternative rivers along 6 attributes plus financial contribution as price vehicle) 8 choice sets per respondent (= 8,000

• bservations per

country) 8 blocks of choice sets (= 64 different sets) randomly spread across the sample

DCE results: significant marginal willingness-to-pay (WTP) estimates (Euro)

► Native salmonids generally more appreciated than nonnatives in G, N and S. ► In F none of the species contributed to river utility. N also valued sturgeon. ► Species abundance increased river utility in F and S. ► Native biodiversity was valued in all countries, particularly in S. ► The more hydropower dams in a river, the less it was valued, particularly in G and S. Better accessibility of the river banks and better bathing water quality increased total river utility.

France Germany Norway Sweden

Fish species in the river: Brook trout 118.84 WTP compared to referen ce Rainbow trout 156.79 132.15 species (bream) Atlantic salmon 367.38 Brown trout 90.83 325.58 176.07 European eel Sturgeon 88.97 Grayling Abundance: share of individual fish (%)* 0.69 1.20 Biodiversity: share of native animal and plant species (%)* 0.79 1.29 1.43 2.74

* Increase in WTP (Euro) per

Hydropower dams**

• 30.76
• 63.86
• 22.48
• 75.33

% increase ** Increase in WTP (Euro) for every increase in attribute

Accessibility of banks** 13.58 28.12 47.36 Bathing water qulity** 23.49 44.87 50.76 86.94

levels: Hydropower dams: no / few / many / very many dams Accessibility of banks: very difficult / difficult / easy / very easy Bathing water quality: poor / moderate / good / very good

Carsten Riepe, Marie Fujitani, Julien Cucherousset, Thilo Pagel, Mathieu Buoro, Frédéric Santoul, Rémy Lassus & Robert Arlinghaus

SalmoInvade WP 1.1.2: Psychological, contextual and socio-cultural determinants of salmonid transfer

• Results from a survey among angling club heads in Germany and France –

Manuscript in revision in Fisheries Research.

Method

• Random samples of stocking decision

makers in angling clubs in D and F (club heads, water bailiffs)

• Identical self-completion mail qu'res
• D: n = 1,222, F: n = 533 returned qu'res

(response rates 61% and 66%, resp.)

• data collection in D: 2011, in F: Winter

2014 / 2015 Reasons to conduct this survey

• Angling clubs are ...

− the key local-level fisheries managers in Germany and France − main vectors of the introduction of (non)native salmonids to European waters.

• Understand decision-makers' views on

and behaviors related to the stocking of (non)native salmonids.

Results

Stocking densities (kg / ha) by club type (D and F pooled; means)

Club typology was developed in 3 successive steps: 1.Culture-based clubs (stocked ≥ 20% biomass as nonnative salmonids) 2.Stock enhancement-

• riented clubs (stocked ≥

20% biomass as native salmonids) 3.All remaining clubs (reference category)

► Nonnative salmonids were more densely stocked than natives, particularly by culture-based clubs. ► Stock enhancement-oriented clubs stocked predominantly native salmonids. ► Conservation-oriented stocking of salmonids was hardly done by any club type.

Results

* *

* p < .05

► Club types moderated the impact of the psychological disposition of the club heads

• n stocking decisions, e.g.:

− Respondents' increasing satisfaction with the status of the club waters (i.e., with the fish stocks, the catch success, the success of stocking measures) led to a decreased intention to stock harvestable fishes in the future – particularly in stock enhancement-oriented clubs. − As social norm (i.e., pressure from club members to stock) increased, so did the intention to increase the stocking of fry and juvenile fish in the future – but only in culture-based clubs. ► Overall, there was little, if any, influence of potentially negative genetic or ecological effects of stocking on intentions to alter stocking in the future.

Conclusions

• Citizens in all 4 countries did not feel informed about fish biodiversity and potential

threats associated with the introduction of nonnative fishes to domestic rivers.

• This finding was partly mirrored by lacking knowledge of salmonid species and erroneous

assumptions about their biogeographical origin.

• Despite these confusions, vast majorities in all countries were intuitively concerned about

risks associated with the introduction of nonnative fishes.

• Citizens were neutral regarding the (past and contemporary) introduction of nonnative

salmonids and positive about restoration programs for native, and (nearly) extinct, fishes including Atlantic salmon.

• Escapees from salmon aquaculture: Potential genetic risks were not perceived as negative

as the potential transmission of diseases or parasites to wild living conspecifics.

• Respondents stated a preference, if any, for native salmonids and in general for salmonid-

friendly river conditions (high native biodiversity, few hydropower dams, good bathing water quality) but also preferred accessibility of the banks.

• Angling clubs in D and F were found to be major vectors of salmonid introductions to their
• freshwaters. Clubs could be separated in culture-based vs. stock enhancement-oriented
• clubs. The impact of the psychological disposition of the stocking decision makers on the

clubs' stocking decisions varied significantly with the type of club respondents were managing.

• Potential negative genetic or ecological effects of fish stocking hardly affected stocking

decision making.

Investigating the ecological impacts of salmonid invasions: a meta-analytic approach at the global scale

WP2 Task 2.1 Global ecological impact

Mathieu Buoro & Julien Cucherousset

Manuscript published in Ecology Letters

Buoro et al. (2016), 19(11):1363-1371.

No studies have quantitatively assessed the scientific knowledge on the ecological impacts of non-native salmonids

Context

No studies have quantitatively assessed the scientific knowledge on the ecological impacts of non-native salmonids

Objectives

1.Investigating the global ecological impacts of salmonid invasions 2.Determine which introductions (intraspecific vs interspecific) have the strongest ecological impacts

Context

No studies have quantitatively assessed the scientific knowledge on the ecological impacts of non-native salmonids

Hatchery

Objectives

1.Investigating the global ecological impacts of salmonid invasions 2.Determine which introductions (intraspecific vs interspecific) have the strongest ecological impacts

Hypotheses

Intraspecific invasions have stronger impacts at lower levels of biological organization

Vs.

Interspecific invasions have stronger impacts at higher levels of biological organization

Vs.

Wild Brown trout Other salmonid species Wild

Context

• Literature review (ISI Web of Science)
• Manipulative studies only
• Across levels of biological organization

(genetic, individual, population, community, ecosystem)

Methods: A global meta-analysis

• Literature review (ISI Web of Science)
• Manipulative studies only
• Across levels of biological organization

(genetic, individual, population, community, ecosystem)

• 64% of studies in North America

27 studies from USA 11 studies from Europe only!

• Dominated by 3 introduced species:

Brown trout (28%) Rainbow trout (21%) Brook trout (14%)

Methods: A global meta-analysis

Number of studies

Methods: A global meta-analysis

sd mean Control (native only) Treatment (non-native added)

+

Baxter et al. (2004)

Methods: A global meta-analysis

Control (native only) Treatment (non-native added) SMD= (meantreatment −meancontrol) sd

pooled

• Standardized Mean Difference

(SMD) as the metric of impact (effect size)

• SMD gives the intensity of the

impact and its direction

• Negative values of SMD indicate a

negative effect of non-native salmonid

• Measured across :
• levels of biological organization
• organisms (fish, invertebrate,

amphibian)

• response traits (size, growth,

survival, biomass,...)

sd mean

+

Baxter et al. (2004)

Results: Intra vs. Interspecific impacts

Intraspecific

(wild vs hatchery)

Interspecific

(native vs non-native species)

Overall impact No impact

Overall negative ecological impacts of salmonids introductions

Average effect Uncertainty

Results: Intra vs. Interspecific impacts

Intraspecific

(wild vs hatchery)

Interspecific

(native vs non-native species)

Overall impact No impact

Overall negative ecological impacts of salmonids introductions Introduced native salmonids have stronger overall impacts than non-native salmonids

Average effect Uncertainty

Significant difference

Results: impacts across levels of biological organization

Introduced native salmonids induced impacts at the individual level

Significant difference

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Results: impacts across levels of biological organization

Introduced native salmonids induced impacts at the individual level Knowledge gap of introduced native salmonids on recipient communities and ecosystems!

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Results: impacts across levels of biological organization

Introduced native salmonids induced impacts at the individual level Knowledge gap of introduced native salmonids on recipient communities and ecosystems! Non-native salmonids induced impacts at all levels of organization

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Results: impacts across groups of organisms

Introduced native salmonids induced stronger impacts on native fish

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Results: impacts across groups of organisms

Introduced native salmonids induced stronger impacts on native fish Knowledge gap of introduced native salmonids on other native organisms

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Results: impacts across groups of organisms

Introduced native salmonids induced stronger impacts on native fish Knowledge gap of introduced native salmonids on other native organisms Non-native salmonids induced significant impacts on all taxonomic groups

Intraspecific (wild vs hatchery) Interspecific (native vs non-native species)

Conclusion

Impacts of native salmonids rival, or possibly exceed those associated with non-native salmonids BUT… Knowledge gaps of introduced native salmonids on native organisms and recipient communities and ecosystems! → see WP 1.2 /2.2 « Performance of con- and heterospecific salmonid

invaders and the regional ecological impacts of con- vs. heterospecific salmonid invasions»

Ecological impacts of non-native and native salmonid invaders WP 1.2 and 2.2

Line Sundt-Hansen (NINA) Julien Cucherousset (Universite Paul Sabatier) Kjetil Hindar (NINA) Manuscript in preparation.

I- Objectives of the WP Native invaders: Same species as the native species, but different phenotype or genotype (i.e. farmed salmon or genetically modified salmon) Non-native invader: Different species (i.e. rainbow trout) Task 1.2 Competitive interactions between non-native and native salmonids.

• How will non-native and native invaders perform relative to native

species?

• Will invasive non-native and native invaders species have an impact
• n growth and survival of native juvenile Atlantic salmon?
• Will non-native and native invaders in competition with native

juvenile Atlantic salmon affect algae biomass and the presence of benthic invertebrates differently than wild salmon alone?

II- Experimentation 2014: Competitive interactions between non-native and native salmonids

Competitive interactions between non-native and native salmonids and their ecological consequences

• Performance of invaders
• Effect on native species
• Ecological impact:
• Benthic invertebrates
• Algae biomass

Native Invading Nantive/non- native ECOSYSTEM

II- Experimentation 2014 Competitive interactions between non-native and native salmonids WS N=5 WS+WS N=5+5 WS+FS N=5+5 WS+RT N=5+5 WS+BT N=5+5 No fish

x 6

• Atlantic salmon, Imsa strain (WS) Native salmonid species
• Farmed Atlantic salmon (FS) Native invader
• Rainbow trout (RT) Non-native invader
• Brown trout (local strain) (BT) Native salmonid species

• Farmed salmon (FS) and brown trout

(BT): Significantly higher growth rate than wild salmon (WS) and rainbow trout (RT)

WS WS+ WS+ WS+ WS FS BT WS+ RT

* *

• Significant difference between WS+WS

and WS+RT

• Significant effect of initial length

Performance of invasive species/genotypes: Farmed salmon (FS) and brown trout (BT); significantly better growth rate compared to wild salmon (WS) and rainbow trout (RT)

Effect of invasive species/genotypes on native salmon: No effect on survival Juvenile native salmon in competition with RT higher SGR (length) than alone in same number. Green alge biomass significantly higher in treatment WS+RT

II- Experimentation 2014: Consequences of interspecific differences (heterospecifics) INVADERS NATIVE

• Gap of knowledge on the ecological impacts of

conspecific native Salmonids invaders at higher levels

• f biological organisation:
• Community level
• Ecosystem level

WP2, Task 2.1 Global ecological impact

? ?

Nature, Nov. 2015

This is despite the facts that:

• Non-native invaders induced important community

and ecosystem impacts

• Increased risk of farmed and GM salmonids to be

introduced in the wild

Objective: Quantify experimentally the performances and ecological impacts of GH-treated Atlantic salmon

Task 2.2 “Ecological impacts of native invaders”

Integrative and complementary designs Increased level of ecological complexity

• +

A) INDOOR B) RIVER PARK C) ÅLABEKK STREAM Performances: Growth / Survival Trophic niche Performances: Growth / Survival Trophic niche Impacts: Community / Ecosystems Performances: Growth / Survival Trophic niche ⇒ 1008 YOY salmon treated (504 SHAM & 504 GH) and PIT-tagged for the 3 experiment Task 2.2 “Ecological impacts of native invaders” 2015 Experiment

Task 2.2 “Ecological impacts of native invaders” 2015 Experiment A) STABLE ISOTOPE ANALYSES δ15N: Position in the food chain δ13C: Origin of the food consumed B) COMMUNITY EFFECTS: Abundance, diversity and structure of invertebrates community C) ECOSYSTEM EFFECTS: Primary production and decomposition rate

Herbivores Carnivores Top-predators Plants

δ13C δ15N α β α β α β

) g ( s as m

• d

y B

2 4 6 8 10 12 14 GH SHAM T0 T2

Body mass (g)

2 4 6 8 10 12 14 GH SHAM

Body mass (g)

2 4 6 8 10 12 14 GH SHAM

Task 2.2 “Ecological impacts of native invaders” 2015 Experiment

• +

Increased level of ecological complexity

A) INDOOR B) RIVER PARK C) ÅLABEKK STREAM

GH SHAM

BODY SIZE RESULTS T0: GH and SHAM treatment (release of fish in Ålabekk) T1: Release of fish in the river park T2: Termination of experiments

T0 T1 T2

Treatment: p = 0.005 Initial body mass: p < 0.001 Treatment: p = 0.001 Initial body mass: p < 0.001

T0 T2

Treatment: p < 0.001 Initial body mass: p < 0.001 Initial body mass* Treatment: p < 0.001

Task 2.2 “Ecological impacts of native invaders” 2015 Experiment

δ15N

ANOVAs δ13C: p = 0.094 δ15N: p < 0.001 δ13C => When released in the stream, GH-treated fish displayed a higher trophic position => Community and ecosystem results still under statistical analyses… STABLE ISTOPE ANALYSES - ÅLABEKK STREAM

GH SHAM

Task 2.2 “Ecological impacts of native invaders” 2016 Experiment Complementary experiment – Stream Channels (1m2, n = 40) Community and ecosystem impacts (n = 20) Behaviour and activity (n = 20) S H A M G H A G H B N F 4 Treatments:

• NF (no fish)
• SHAM (6 fish)
• GHA (6 GH fish)
• GHB (5 GH fish)

=> X 5 replicates

Libor Závorka1, Barbara Köck2, Julien Cucherousset1, Jeroen Brijs2, Joacim Näslund2, David Aldvén2, Johan Höjesjö2, Ian Fleming3, Jörgen I. Johnsson2

1Université Toulouse, 2BioEnv, University of Gothenburg, 3Memorial University of Newfoundland

Manuscript in revision in Functional Ecology

Co-existence with non-native brook trout disrupts the pace-of-life syndrome in native brown trout

Manuscript in revision in Functional Ecology

Model system: Invasive brook trout vs native brown trout

Hypothesis: Invasive species will induce novel competition pressures reducing the predictability of resource distribution in the environment. This will disrupt the adaptive association among phenotypic traits in the native species reducing its fitness Predictions: Brown trout living in sympatry with invasive brook trout will show weaker associations among phenotypic traits and reduced growth and/or survival – compared to brown trout living in allopatry

Study area

In total, 151 age-1 brown trout (body length mean±SD: 83.7±16.9) and 70 age-1 brook trout (body length mean±SD: 86.7±9.9) were collected

Methods

Traits measured

Phenotypic traits

• specific growth rate
• body shape (Rohlf 2008)
• standard metabolic rate
• aerobic scope (Clark et al 2013)
• Lab activity

(Adriaenssens & Johnsson 2013)

Ecological niche traits

• home range size
• daily movement
• diet composition

(Cucherousset et al. 2007)

Methods

Estimation of home range and movements

• portable RFID antennas and GPS

Methods

Brown trout in allopatry have more and overall stronger associations among phenotypic traits and ecological niche traits

Allopatric Sympatric

Results

Results

Brown trout in sympatry with brook trout grow slower, have a more stout body shape and eat more terrestrial prey

(p = 0.06)

Results

Allopatric Sympatric

Summary and Conclusions

• The overall strength of phenotypic associations was considerably

reduced in brown trout living in sympatry with brook trout

• This breakdown of phenotypic associations in the sympatric situation

was accompanied by a decrease in growth rate, as well as a shift in ecological niche and body shape

• Our results are consistent with the hypothesis that non-native invaders

can reduce the fitness of native species by disrupting adaptive associations among their phenotypic traits

• Manipulative field experiments are needed to further disentangle

by which mechanisms non-native invaders affect native species

ORGANISATIONSNAMN (ÄNDRA SIDHUVUD VIA FLIKEN INFOGA SIDHUVUD/SIDFOT)

with friends Julien Jeroen Ian Libor Joacim Barbara Johan David Niklas Magnus Jörgen

Task 1.3: The role of angling in affecting invasion success of salmonids

Koeck B., Zavorka L., Aldven D., Arlinghaus R., Loven Wallerius M., Näslund J., Thörnqvist P .O., Winberg S., Björnsson B. T., Johnsson J. I. Manuscript submitted to Journal of Applied Ecology

Task 1.3 main Aim

Can angling be used as a selective removal method to mitigate the invasion potential of introduced fish?

 Do rainbow and brown trout differ in their vulnerability to angling? Is the relative vulnerability of brown and rainbow trout specific to the used angling technique?  At the species level, are some individuals more vulnerable to angling than others? Is this related to their individual behavioural and physiological stress response?  Do short term fishing closures affect catchability of rainbow trout?

4 mesocosms ponds

• 25 + 25 size-matched brown and rainbow trout in each pond
• Monitoring of behaviour of tagged fish (activity)
• Full-scale angling experiments

1877 1877 Experimental set-up

with the participation

• f volunteer Anglers!

Angling experiment 1 Angling experiment 2

Angling treatments

Fish naive to angling Fish previously exposed to angling

Lure : active angling technique: fish has to swimm after

Bait :

passive angling technique

+

25 m 30 m

≈ 2 m depth

• 72 fish

caught: 55%

• f all Bt 90%
• f all Rt

Days

Rainbow trout >> Brown trout Rainbow trout ≈ Brown trout

Overall higher catch rate of RT

Vulnerability to angling varies between species

• but technique-specific

relative vulnerability

• f Rt and Bt

• PROACTIVE Individuals: are

active and have a suppressed physiological stress response  are more vulnerable to angling

• REACTIVE Indiviudals: are

passive and have a strong physiological stress response  are less vulnerable to angling For rainbow trout under repeated exposure to angling, we can distinguish individuals with different responses: Physiological stress (Cortisol, Brain Activity) Behaviour (Activity) Vulnerability to angling

• +
• Vulnerability to angling

varies within species

For rainbow trout, proactive individuals are more vulnerable to angling than reactive ones

Conclusion

At the species level, angling can reduce the invasions risks

• f non-native fish by targeting the most

stress-resilient & active individuals Domesticated hatchery reared rainbow trout are more vulnerable to bait-angling than native brown trout The angling technique-specific species selection indicates that angling can be tailored to mitigate the invasion of bolder fish species, such as rainbow trout

Task 1.3 main Aim

Can angling be used as a selective removal method to mitigate the invasion potential of introduced fish?

 Do rainbow and brown trout differ in their vulnerability to angling? Is the relative vulnerability of brown and rainbow trout specific to the used angling gear?  At the species level, are some individuals more vulnerable to angling than others? Is this related to their individual behaviour and physiological stress response?  Do short term fishing closures affect catchability

• f

rainbow trout?

Angling treatments

 3 duplicated treatments  2 anglers per pond and fishing day  with alternatively bait or lure rods  same angling effort of 5 angling days  but different intervals between angling days

Treatment 1 day interval Treatment 4 days interval Treatment 7 days interval

week 2 week 4 week 6 week 1 week 3 week 5

every day

Replace with new fish + 5 days acclimation

4 d. 4 d. 4 d. 4 d.

5 days acclimation

7 d. 7 d. 7 d. 7 d. 7 d. 7 d. 7 d. 7 d. every day

Pond 1 Pond 2 Pond 3 Pond 4

Replace with new fish + 5 days acclimation

5 days acclimation 5 days acclimation 5 days acclimation

4 d. 4 d. 4 d. 4 d.

1 day interval

42 % of uncaught rainbow trout less than 2 fish recaptured per pond

4 days interval

20 % of uncaught rainbow trout more than 5 fish recaptured per pond

7 days interval

20 % of uncaught rainbow trout 8 fish recaptured per pond

= = > <

Effect of short-term angling closures on catchability

Angling days Proportion of uncaught fish

Intervals between successive angling days

1 day 4 days 7 days

Short-term angling closures reduce the avoidance behaviour

• f fish caused by

the exposure to angling The number of caught fish increases with short term angling closures Angling closures in Catch & Release fisheries can thus :

• increase the satisfaction of anglers
• help to reduce the pressure for

stocking of non-native fish

Conclusion

The main objectives of SalmoInvade are:

• 1. to evaluate current releases of non-native salmonids in

Europe and the social, economic and ecological mechanisms underlying their invasion potential,

• 2. to investigate the ecological and evolutionary impacts of

biological invasions by salmonids,

• 3. to evaluate how salmonid invasions are perceived by the

public and by key stakeholders and

• 4. to provide integrated recommendations for policy and

management of salmonid invasions. SalmoInvade will integrate novel eco-evolutionary and socio-economic hypotheses to evaluate the impacts and consequences of non-native salmonid invasions. The results are expected to influence policy and management of this economically important group of fish. WP1

Mechanisms of establishment

WP2

Ecological impact

WP3

Social evaluation

WP4

SALMOINVADE Policy and

Management