# Tracking on-farm innovations related to agroecological principles in french trout farming

Christophe Jaeger, Jean-Marc Meynard, Louis Pimont, Aurélien Tocqueville, Valérie Viaud

► To cite this version:

Christophe Jaeger, Jean-Marc Meynard, Louis Pimont, Aurélien Tocqueville, Valérie Viaud. Tracking on-farm innovations related to agroecological principles in french trout farming. 8th International Farming System Design Conference, INRAE; AgroParisTech; Ideas, Aug 2025, Palaiseau (Université Paris-Saclay), France. 23 p. hal-05233595

HAL Id: hal-05233595

https://hal.inrae.fr/hal-05233595v1

Submitted on 1 Sep 2025

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Agricultural systems
by design

# 8th International Farming System Design Conference
## Palaiseau – 25-29 August 2025

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ideas
INITIATIVE FOR DESIGN
IN AGRIFOOD SYSTEMS
# Tracking on-farm innovations related to agroecological principles in french trout farming

Christophe Jaeger¹, Jean-Marc Meynard², Louis Pimont¹, Aurélien Tocqueville³, Valérie Viaud¹

¹ INRAE, Institut Agro, SAS, France

² INRAE, AgroParisTech, SADAPT, France

³ ITAVI, France

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ideas
INITIATIVE FOR DESIGN
IN AGRIFOOD SYSTEMS
# Introduction

## Context

* Worldwide:

* Aquaculture production > capture fisheries production

* Finfish production from inland fish farms (53 Mt/year) > marine fish farms (9 Mt/year) (FAO, 2024)

* France:

* Trout (32 000 t/year) > marine fish (5 000 t/year) (Agreste, 2024)

* Trout production tends to decrease

* Loss-making national market for trout (France AgriMer, 2023)

* Strong political will to achieve "food sovereignty" for aquatic products

=> **Context positive for trout production increase, but ...**

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# Introduction

## Challenges

... need to face challenges to develop, like:

* Limiting inputs:

* antibiotics and pest control products to avoid resistances (Done et al., 2015)

* fishmeal and fish oil in fish feed to avoid use of wild-captured forage fish, (Smith et al., 2011)

* Limiting outputs:

* waste water recycling from fish farms (Klinger and Naylor, 2012)

=> Agroecology related to livestock systems (Dumont et al., 2013) relevant:

i) animal health,

ii) limiting the use of inputs,

iii) limiting pollution,

iv) enhancing diversity,

v) preserving biodiversity

## Are there innovating fish farmers that integrate agroecological principles into their systems?

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# Material and methods

Tracking unusual on-farm innovations to unearth agroecological farming system (Salembier et al. 2021)

Method in 5 steps

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Agricultural systemsy design
# Material and methods

## 1/ Defining the dominant system:

* In order to detect what is innovative/unusual

* Based on experts' opinion

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Agricultural systems by design
# Material and methods

1/ Defining the dominant system:
In order to detect what is innovative/unusual
Based on experts' opinion

2/ Identifying on-farm innovations:
Different from the dominant system
Related to principles of agroecology

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Agricultural systems
by design
# Material and methods

## 1/ Defining the dominant system:

In order to detect what is innovative/unusual

Based on experts' opinion

## 2/ Identifying on-farm innovations:

Different from the dominant design

Related to principles of agroecology

## 3/ Learning about innovations:

Understanding and describing innovation

Mechanisms promoting innovation

Obstacles overcome

Evolution of practices and learnings

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Agricultural systems
by design
# Material and methods

1/ Defining the dominant system:

In order to detect what is innovative/unusual

Based on experts' opinion

2/ Identifying on-farm innovations:

Different from the dominant design

Related to principles of agroecology

3/ Learning about innovations:

Understanding and describing innovation

Mechanisms promoting innovation

Obstacles overcome

Evolution of practices and learnings

4/ analyzing learnings from innovations:

Shedding light on key elements of logic actions

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Agricultural systems
by design
# Material and methods

1/ Defining the dominant system:

In order to detect what is innovative/unusual

Based on experts' opinion

2/ Identifying on-farm innovations:

Different from the dominant design

Related to principles of agroecology

3/ Learning about innovations:

Understanding and describing innovation

Mechanisms promoting innovation

Obstacles overcome

Evolution of practices and learnings

4/ analyzing learnings from innovations:

Shedding light on key elements of logic actions

5/ generating fish farming knowledge:

Sum up of knowledge to present practice(s)

unearthed

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# Material and methods

1/ Defining the dominant system:
In order to detect what is innovative/unusual
Based on experts' opinion

2/ Identifying on-farm innovations:
Different from the dominant design
Related to principles of agroecology

3/ Learning about innovations:
Understanding and describing innovation
Mechanisms promoting innovation
Obstacles overcome
Evolution of practices and learnings

4/ analyzing learnings from innovations:
Shedding light on key elements of logic actions

5/ generating fish farming knowledge:
Sum up of knowledge to present practice(s)
unearthed

9 experts (/12 contacted) :
Advisors from national and local fish farmers' union, from fish health protection organization, and teachers from aquaculture high schools

47 fish farms considered as innovative by experts
10 rejected (not innovative, no trout production, practice not associated to agroecology)

37 fish farms contacted → 27 surveyed
according to semi-structured interviews

4 agroecological innovative practices identified among 10 fish farms

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# Results

## Description of the dominant systems

### Mass-market system

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Rainbow trout (*Oncorhynchus mykiss*)

**Monoculture**
Fish density up to 100 kg/m³

### Direct-sale system

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Rainbow trout (*Oncorhynchus mykiss*)

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Brown trout (*Salmo truta*)

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Brook trout (*Salvenius fontinalis*)

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Arctic char (*Salvenius alpinus*)

**Monoculture of several species**
Fish density = 30 kg/m³

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# Results

## Description of the dominant systems

### Mass-market system

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Feed formulated mainly on plant-based ingredients

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### Direct-sale system

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Feed formulated mainly on fishmeal

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### Mass-market system

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Objective of production = very large trout (>2.5 kg)

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### Direct-sale system

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Objective of production = from portion-sized trout (300 g) to very large trout (>2.5 kg)

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# Results

## Description of the dominant systems

### Mass-market system

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Market = fish processing workshops

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### Direct-sale system

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Market = direct sale and angling

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# Results

## 4 innovative agroecological practices unearthed

* Fish management to control Proliferative Kidney Disease (PKD)

* Replacing fishmeal in feed with insects or processed animal protein

* Coupling vegetable production with trout production in the same system to use fish waste as a nutrient source for the vegetables

* Help preserve kingfisher (Alcedo atthis) neighboring population by producing more trout fingerlings to compensate for that preyed by birds

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# Results

## Focus on practice to control Proliferative Kidney Disease (PKD)

* PKD due to a parasite (*Tetracapsula bryosalmonae*) present in water river

* PKD occurs when mean water t°>15°C (Chilmonczyk et al., 2002)

* Damage kidney

* Anemia

* More than 70% of death

* No treatment available

* Fish can develop immunity but must develop first signs of PKD to induce immunity

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Photo credit: Robert Le Coat
Calendar
example

<table><tr><td>April</td><td>May</td><td>June</td><td>July</td><td>August</td><td>September</td><td>October</td><td>November</td><td>December</td><td>January</td><td>February</td><td>March</td></tr></table>

Water t°>15°C

Trout is infected with parasite but temperature is too low for PKD occurrence
Trout develops its immunity

Water from river with parasite
(Trout is infected with PKD)

Exposition time to
critical period is long
enough in order to PKD
fully occurs, inducing
fish death

Critical period
Calendar
example

<table><tr><td>April</td><td>May</td><td>June</td><td>July</td><td>August</td><td>September</td><td>October</td><td>November</td><td>December</td><td>January</td><td>February</td><td>March</td></tr></table>

Water t°>15°C

Trout is infected with parasite but temperature is too low for PKD occurrence
Trout develops its immunity

Water from river with parasite
(Trout is infected with PKD)

Exposition time to
critical period is long
enough in order to PKD
fully occurs, inducing
fish death

* Trout is infected with PKD

* Water temperature is maintained below 15°C

Exposition time
to critical period
is too short in
order to PKD
fully occurs

Water from river with parasite

Critical period

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Calendar
example

<table><tr><td>April</td><td>May</td><td>June</td><td>July</td><td>August</td><td>September</td><td>October</td><td>November</td><td>December</td><td>January</td><td>February</td><td>March</td></tr></table>

Water t°>15°C

Trout is infected with parasite but temperature is too low for PKD occurrence
Trout develops its immunity

Water from river with parasite
(Trout is infected with PKD)

Exposition time to
critical period is long
enough in order to PKD
fully occurs, inducing
fish death

* Trout is infected with PKD

* Water temperature is maintained below 15°C

Exposition time
to critical period
is too short in
order to PKD
fully occurs

Water from river with parasite

* Water is PKD free, such as artesian or natural spring

* Trout is PKD free

Infection is too late
in order to PKD has
time to fully occur

Water from river with parasite

Critical period
Calendar
example

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# Discussion/conclusion

* Some innovative agroecological practices exist in French trout farms

* Tracking on-farm highlights unusual practices from fish farmers-designers

* Tracking on-farm helps also to identify some lack of knowledge, for instance: what are the mechanisms inducing immunity against PKD?

## Perspectives :

* With the aim to design agroecological systems, practices are useful to help designers (Quinio et al., 2022)

* The survey also gave information on territories and the actors involved => open others ways to design agroecological trout farms.

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Thank you !

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Agricultural systemsy design

8th International Farming System Design Conference – Palaiseau, France – 25-29 August 2025