Operational Welfare Indicator (OWI) Protocols
One type of welfare protocol that is used in commercial aquaculture settings are Operational Welfare Indicator (OWI) protocols. OWIs are a practical, science-based approach to understand how fish welfare in commercial settings. OWIS are generally grouped into three categories:
Individual-based indicators (animal-based outcome measures): These assess the physical condition of individual fish (including parameters such as fin condition and skin condition) through sampling. Individual-based indicators directly reflect how the fish has been affected by its environment and management, providing outcome measures of their welfare state.
Group-based indicators (outcome measures): These assess group-level patterns, including behavior and mortality rates.
Environment-based indicators (input measures): These assess the aquatic environment, including dissolved oxygen and temperature. Environmental indicators represent the conditions fish experience and are critical determinants of welfare, although they are inputs (what is provided) rather than direct outcomes (how fish are affected).
Following a published, standardized OWI protocol ensures that your welfare monitoring is consistent, transparent, and aligned with the best scientific evidence.
Centre for Aquaculture Progress Welfare Protocols
The Centre for Aquaculture Progress develops practical, evidence-based welfare protocols that are designed for real-world commercial use. Our guidelines draw on the strongest available scientific literature and are developed in collaboration with scientists, incorporating feedback from producers, certifiers, and seafood buyers.
Our protocols are updated on a regular basis, incorporating new scientific evidence and input from our partners.
Other Welfare Protocols
There is a number of other OWI protocols and resources which have been published by different groups. The protocols here are listed for informational purposes only, and the Centre for Aquaculture Progress does not endorse any particular protocol. Note that some protocols cover multiple species, and in that case are listed under each species they cover. This list is updated as new protocols are published.
Atlantic Salmon (Salmo salar)
Laksvel: A standardised, operational welfare monitoring protocol for Atlantic salmon held in sea cages, Nilsson et al., Institute of Marine Research, 2025
Welfare Indicators for farmed Atlantic salmon: tools for assessing fish welfare, Noble et al., Nofima, 2018
Salmon Welfare Index Model (SWIM 1.0): a semantic model for overall welfare assessment of caged Atlantic salmon: review of the selected welfare indicators and model presentation, Stein et al., Institute of Marine Research, 2013
Salmon welfare index model 2.0: an extended model for overall welfare assessment of caged Atlantic salmon, based on a review of selected welfare indicators and intended for fish health professionals, Pettersen et al., Norwegian School of Veterinary Science, 2013
Ballan Wrasse (Labrus bergylta)
RENSVEL OWI FACT SHEET SERIES: An introduction to Operational and Laboratorybased Welfare Indicators for ballan wrasse (Labrus bergylta), Noble et al., Nofima, 2019
Common Carp (Cyprinus carpio)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
Farming, transport, and slaughter: Common carp survey guidelines for a National Animal Welfare Monitoring, Reiser et al., National Animal Welfare Monitoring, 2024
Farming, transport, and slaughter: Rainbow trout survey guidelines for a National Animal Welfare Monitoring, Lugert et al., National Animal Welfare Monitoring, 2023
Eel (Anguilla anguilla)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
European Sea Bass (Dicentrarchus labrax)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
Welfare assessment study for European sea bass, Pavlidis et al., University of Crete, 2024
A Guide on Fish Welfare in Spanish Aquaculture – Volume 3: Welfare of European Sea Bass, Arechavala López et al., Spanish Aquaculture Business Association, 2024
Manual for use on field Operational Welfare Indicators (OWIs) of Sea bass (D. labrax) and Sea bream (S. aurata) breeding in sea cages, Manfrin, AdriAquaNet, 2022
Testing of the Salmon Welfare Index Model (SWIM 1.0) as a computational welfare assessment for sea-caged European sea bass, Yildiz et al., Ankara University, 2021
Methodology for assessing welfare in MMFF, Petochi et al., PerformFISH, 2021
Mediterranean Fish Welfare: Guide to good practices and assessment indicators, Pavlidis and Samaras, Hellenic Aquaculture Producers Association, 2019
Gilthead Sea Bream (Sparus aurata)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
A Guide on Fish Welfare in Spanish Aquaculture – Volume 3: Welfare of Gilthead Sea Bream, Arechavala López et al., Spanish Aquaculture Business Association, 2024
Manual for use on field Operational Welfare Indicators (OWIs) of Sea bass (D. labrax) and Sea bream (S. aurata) breeding in sea cages, Manfrin, AdriAquaNet, 2022
Methodology for assessing welfare in MMFF, Petochi et al., PerformFISH, 2021
Report on fish welfare and list of operational welfare indicators in sea bream, Roque et al., MedAID, 2020
Mediterranean Fish Welfare: Guide to good practices and assessment indicators, Pavlidis and Samaras, Hellenic Aquaculture Producers Association, 2019
Grass Carp (Ctenopharyngodon idella)
New indices for the diagnosis of fish welfare and their application to the grass carp (Ctenopharyngodon idella) reared in earthen ponds, Pedrazzani et al., Wai Ora, 2022
Lumpfish (Cyclopterus lumpus)
Lumpfish Welfare Watcher, Garcia de Leaniz et al., Swansea University, 2021
Development, validation and testing of an Operational Welfare Score Index for farmed lumpfish Cyclopterus lumpus L, Gutierrez Rabadan et al., Centre for Sustainable Aquatic Research, 2020
RENSVEL OWI FACT SHEET SERIES: An introduction to Operational and Laboratory-based Welfare Indicators for lumpfish (Cyclopterus lumpus L.), Noble et al., Nofima, 2019
Pikeperch (Sander lucioperca)
MyFishCheck: A Model to Assess Fish Welfare in Aquaculture, Tschirren et al., Zurich University of Applied Sciences, 2021
Rainbow Trout (Oncorhynchus mykiss)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
Fish welfare evaluation index (fWEI) based on external morphological damage for rainbow trout (Oncorhynchus mykiss) in flow through systems, Weirup et al., University of Kiel, 2022
MyFishCheck: A Model to Assess Fish Welfare in Aquaculture, Tschirren et al., Zurich University of Applied Sciences, 2021
Welfare Indicators for farmed rainbow trout: tools for assessing fish welfare, Noble et al., Nofima, 2020
Sturgeon (Acipenser Spp.)
Manuale benessere specie ittiche allevate: Guida per l'operatore / Welfare manual for farmed fish species: Guide for operators, Spezzani et al., Istituto Associazione Piscicoltori Italiani, 2025 (Italian)
Tilapia (Oreochromis spp.)
An overview of operational welfare indicators for farmed Nile tilpia (Oreochromis niloticus), Meyer and Emam, Ethical Seafood Research, 2024
From egg to slaughter: monitoring the welfare of Nile tilapia, Oreochromis niloticus, throughout their entire life cycle in aquaculture, Pedrazzani et al., Wai Ora, 2023
Assessment of Tilapia (Oreochromis spp.) Welfare in the Semi-Intensive and Intensive Culture Systems in Thailand, Lertwanakarn et al., Kasetsart University, 2023
White-Leg Shrimp (Penaeus vannamei)
Non-Invasive Methods for Assessing the Welfare of Farmed White-Leg Shrimp (Penaeus vannamei), Pedrazzani et al., Wai Ora, 2023