Fish acute toxicity test

Authors:

Ioanna Katsiadaki

Tim Ellis

Linda Andersen

Philipp Antczak

Ellen Blaker

Natalie Burden

Tom Fisher

Christopher Green

Briony Labram

Audrey Pearson

Karina Petersen

Dan Pickford

Chris Ramsden

Anita Rønneseth

Kathryn O. Ryder

Dominic Sacker

Chloe Stevens

Haruna Watanabe

Hiroshi Yamamoto

Fiona Sewell

Dr Penny Hawkins

Hans Rufli

Richard D. Handy

Samuel K. Maynard

Miriam N. Jacobs

Publication:

Ecotoxicology and Environmental Safety 223, 112585

Publish Date:

15 October 2021

Background

The fish acute toxicity test (TG203) is one of the most severe scientific procedures used to estimate the concentration that kills 50% of the fish (LC50) over a 96-hour exposure period and is globally employed in hazard and risk assessment. While refinements have been implemented to reduce the number of fish used, the introduction of earlier mortality endpoints has not been considered feasible during the 2019 update of TG203.

Summary

This report was compiled from a UK-based stakeholders' meeting to discuss refinements of TG203. Participants identified two key opportunities to reduce fish suffering: the application of clinical signs to predict mortality, and shortening the test duration. Additionally, this report outlines the challenges that must be addressed before these refinements can be implemented.

Key Actions

Apply early endpoints that predict death and/or toxicity.
Reduce the duration of the test (< 96 hours).

Read the full Fish acute toxicity test report

Download report

Further questions

Early euthanasia of moribund fish is already practised and encouraged, e.g. in European countries. But there is no universally agreed-upon definition of moribundity, which can be challenging. Harmonised guidance and training materials would help to ensure consistent and objective recording of clinical signs across laboratories
In theory, the exposure period could be shortened (e.g. to 24 or 48 hours), given that most acute toxicity signs often appear within the first 24 hours. The scientific justification for a strict 96-hour duration is weak from a physiological perspective. However, reducing test duration will generally result in higher (less protective) LC50 values, creating logistical challenges that need to be addressed.

Authors

Ioanna Katsiadaki - Weymouth Laboratory

Tim Ellis - Weymouth Laboratory

Linda Andersen - ILAB

Philipp Antczak - University of Liverpool; University Hospital Cologne

Ellen Blaker - Weymouth Laboratory

Natalie Burden - NC3Rs

Tom Fisher - Chemical Regulation Division

Christopher Green - Department for Environment, Food and Rural Affairs

Briony Labram - NC3Rs

Audrey Pearson - Environment Agency

Karina Petersen - NIVA

Dan Pickford - Syngenta Ltd

Chris Ramsden - AgroChemex Environmental

Anita Rønneseth - University of Bergen

Kathryn O. Ryder - Northern Ireland Animals (Scientific Procedures) Act (ASPA) Inspectorate

Dominic Sacker - Covance CRS Research Limited

Chloe Stevens - RSPCA Animals in Science Department

Haruna Watanabe - National Institute for Environmental Studies

Hiroshi Yamamoto - NIES

Fiona Sewell - NC3Rs

Penny Hawkins - RSPCA Animals in Science Department

Hans Rufli - ecotoxsolutions

Richard D. Handy - University of Plymouth

Samuel K. Maynard - AstraZeneca

Miriam N. Jacobs - Public Health England