[LINK] Farmed Fish Welfare Report

[kierangreig]

https://​​animalcharityevaluators.org/​​research/​​other-topics/​​farmed-fish-welfare-report/​​?fbclid=IwAR1lUk99Z7FbS3lVaFnUTAvsX3NT0M_1FQcVvpUQ0tjr-ijPCsbb6uAQOyw

[Disclosure: I was the lead author of this report and previously worked at ACE]

A brief summary of the report;

This report notes that according to the INT framework, improving farmed fish welfare seems to score highly and plausibly ought be a priority for the animal advocacy community.

The report then assesses different indicators of fish welfare and includes a literature review and an overview of the methodology. It also includes recommendations for promising reforms, and some clarification of pressing research questions still outstanding.

Shifting away from slaughter by asphyxia and live chilling to correctly used electrical or percussive stunning appears promising. The same can be said for boosting dissolved oxygen levels in the water that fish are kept in. For Atlantic salmon in particular, opposing triploidy seems beneficial. This may or may not be cross applicable to other fish.

Mixed or lacking evidence allows for significantly lower confidence in environmental enrichment and certain methods for reducing the number of wild fish added to farmed fish feed. While environmental enrichment may look more promising after additional research, the effect of changes to farmed fish feed faces a large amount of uncertainty. Transitioning a carnivorous species to a plant-based feed requires investigation into how that may impact average survival rates, weight at the time of slaughter, the amount time fish spend on a farm, and the degree to which supply of wild-caught fish is responsive to changes in demand.

Interventions that would still require further research to assess their potential include:

• Anaesthesia for reducing stress during slaughter

• Use of sedatives during transport

• Minimizing the handling of fish, particularly out of water

• Water quality parameters other than dissolved oxygen

• Decreasing stocking density

The report also highlights a need for a stronger understanding of relevant economic considerations and the ethology of the most numerous farmed fish species.

[Aaron Gertler]

This post was awarded an EA Forum Prize; see the prize announcement for more details.

My notes on what I liked about the post, from the announcement:

While kierangrieg’s report on fish welfare first appeared on the website of Animal Charity Evaluators, the author added a lot of extra value by:

1. Writing a novel summary of his findings in the Forum post.

2. Responding at length to a comment on the report.

Eventually, I’d like to see every major research article in EA find its way to the Forum, ideally with summaries and authorial responses. This report is an excellent example of how to bring interesting work to a broad audience.

[utilitarian01]

Also worth noting that aeration of the water has many economic incentives (preventing die offs) to it so there’s a good chance that fish aren’t suffering from low oxygen levels.

[kierangreig]

I think that your general model is wrong. Briefly, here’s a couple of reasons why:

First, producers strongest economic incentive is net-profit maximization.

Net-profit= #fish sold * (average revenue per fish sold—average cost to farmer per fish sold)

Farming fish at quite high stocking densities without counteracting aeration causes low dissolved oxygen levels. These high stocking densities cause a greater number of fish to be sold. As long as the increase in net-profit caused by the increase in the # fish sold is greater than the decrease in net-profit caused by the decrease in marginal profit per fish, farmers have economic incentive to do that. Therefore farmers would have their strongest economic incentive be in favor of some negative outcomes caused by lower oxygen levels as long as these were outwieghed and lead to them increasing their net-profit, namely through them being able to farm a greater number of fish.

Second, fish farming is still a young and rapidly evolving industry so farming practices may not totally align with economic incentives. One sentiment I have heard expressed is that for fish welfare there still are a lot of either welfare and economic wins-wins or win-ties. That is, there are opportunities for fish welfare to be improved without costing economic productivity.

Third, regardless of the incentives or possibility of welfare and economic win-wins or win-ties, it still empirically seems true that a) many farmed fish seem subject to sub-optimal dissolved oxygen levels and b) mass die-offs are not rare. Given the frequency of sub-optimal dissolved oxygen and mass die-offs this is probably evidence farmers currently don’t overall have very strong incentives to prevent these issues. So, while there is limited evidence in general on the topic, here are some of the counterexamples to the general model you seem to propose:

In channel catfish, the most farmed fish in the US, “[t]he traditional pond system typically produces 4,500–5,500 kg/​ha of catfish with a maximum of 7,000 kg/​ha (Brune, 1991; USDA, 2006). However, today, many farms in Alabama produce more than 10,000 kg/​ha, and the amount of aeration provided is not adequate to consistently maintain minimum dissolved oxygen (DO) concentrations above 3 mg/​L (Boyd and Hanson, 2010).” (Brown (2011), p. 72)

E.g, “For catfish, one of the major causes of significant die-offs is low oxygen, while oxygen levels are something that can be feasibly controlled.”

E.g., “Caged salmon companies have reported over 760 mass deaths to the Scottish Government in the last three years.” This article reports that oxygen shortages are a frequent killer.

E.g., The report linked in the OP estimates pre-slaughter mortality rates of 15%-80% for commonly farmed fish over the entire production cycle.