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Announcing Version 2 of our Welfare Standard

Updated: Feb 9, 2023

After reviewing Version 1 of our welfare standard, we concluded that we could be having a greater impact in improving the lives of fish. Over the past 12 months, we conducted primary and secondary research in order to find a welfare standard that can:

  • Improve on Version 1’s impact on welfare.

  • Improve on Version 1’s implementability at scale.

  • Teach us more about the most important aspects of aquaculture systems.

Our Version 1 consisted of a stocking density cap and FWI staff evaluations of welfare at farm sites. Version 2 adds to this a feed management protocol, which is designed to control phytoplankton blooms and prevent poor oxygen levels.

Specifically, our Version 2 Standard consists of:

  • A stocking density cap of 2,500–3,000 fish/acre (as in Version 1).

  • A fortnightly FWI staff evaluation of welfare at the farm site and possible corrective actions provided (as in Version 1, though streamlined).

  • Feed management:

    • Fish feed on phytoplankton only (with no supplemental feed) for 3 consecutive days each month, in order to re-stabilize phytoplankton levels.

    • Further phytoplankton-related corrective actions if flagged in the staff evaluation.

We will continue testing and developing Version 2 via the Alliance for Responsible Aquaculture, and we expect to make minor adjustments to it and its delivery mechanism throughout the year.

Picture of Euglena, a class of phytoplankton. Our research this past year has found unbalanced phytoplankton to be the leading cause of poor oxygen levels, which is the main welfare issue fish face. Photo credit: Sinhyu.


Across the 2 years that FWI has spent in the field in India, we have developed our understanding of the welfare issues that Indian major carp (the species that we predominantly work with) face, as well as the practical realities of reducing their suffering.

Through a needs assessment and welfare infringements evaluation for Indian major carp (which we plan to publish soon), we have decided to prioritize dissolved oxygen levels as the main welfare concern.

In brief, dissolved oxygen refers to the amount of oxygen in the water that is available in water for fish to breathe. Low dissolved oxygen levels can lead to perpetual stress for fish as they struggle to breathe. However, too-high levels of dissolved oxygen (“hyperoxia”) can also be stressful for fish, as can rapid changes in oxygen levels.

Dissolved oxygen is one of the most important water quality parameters for the welfare of farmed fish. In our data set, we have seen that fish farm ponds are outside of ideal dissolved oxygen levels most of the time; during summer and the monsoon seasons (when water quality tends to decrease), critical oxygen levels (outside of our required levels) are a frequent occurrence.

Graph showing the percentage of measurements here dissolved oxygen is within our required (blue) and ideal (orange) ranges by month.

Often, in earthen pond systems (including the farms we work with in India), uncontrolled phytoplankton is the predominant cause of dissolved oxygen level issues. Phytoplankton are microscopic organisms that live in the water column and both produce and consume oxygen. If the phytoplankton population become too large, oxygen balances become destabilized, leading to extreme highs and lows, which in turn cause distress to the fish in the system.

A farmer using a Secchi disk (a device that helps assess phytoplankton levels). Most farmers do not monitor water quality regularly. Part of Version 2 aims to train farmers to take simple measurements such as this.

Most farmers we work with in India do not regularly assess their phytoplankton or dissolved oxygen levels, nor take sufficient steps to mitigate the influence of these parameters on fish. As such, fish are often forced to suffer in inhospitable conditions (in the worst farms, this occurs for the majority of the year).

Version 2

Feed management

There are many potential avenues to control phytoplankton’s effect on dissolved oxygen (including aeration, pond preparation, and water exchange). Perhaps the most promising, is controlling feed inputs in order to prevent phytoplankton from over-producing. In their natural environment, Indian Major Carp feed on phytoplankton (alongside other organisms in the pond). However, farmers want fish to grow faster than natural. Because of this, semi-intensive and intensive farmers add supplemental feed to their farm ponds. When delivered, this supplemental feed typically leaches nutrients into the water. These introduced nutrients can significantly stimulate phytoplankton growth.

Thus, stopping excess supplemental feeding to control phytoplankton levels is one of the most important improvements for dissolved oxygen and, thus, for improving fish welfare.

Below is our protocol for controlling phytoplankton levels through feed management.

Flowchart of FWI’s feed management protocol. Green circles represent directly impactful steps;blue boxes represent intermediary steps.

Fish feed on phytoplankton only (no supplemental feed) 3 days per month

Every farmer will be expected to stop applying supplemental feed for 3 consecutive days at the start of every month. This will act to prevent phytoplankton blooms by ensuring every fish farm pond has a substantial break from nutrient input, and will encourage fish to consume phytoplankton instead. Breaks of supplemental feed do not negatively affect the welfare of Indian major carp, as these species will naturally consume phytoplankton. There are papers showing that Indian major carp seem to be either unaffected or to benefit from periods of no feed (see here, here, and here).

Phytoplankton evaluation & corrective actions

Once every two weeks, an FWI representative will visit each farm within the ARA to measure the following:

  • Turbidity

  • Water color

  • pH

  • Temperature

Our data analysis has indicated that these parameters have a strong correlation (~0.8) with chlorophyll-a (the predominant proxy we use for phytoplankton). These parameters will be considered in concert with other important factors, such as the pond’s history and the time of year.

For every alternate measurement, a more in-depth analysis will be performed at the farms. (See corrective actions below).

Pond scum at an Indian fish farm pond. Pond scum is usually composed of phytoplankton and can be an indicator of imbalanced phytoplankton populations. Part of Version 2 will regular checks for signals of phytoplankton-related problems.

If a problem is detected during these field measurements, FWI staff will suggest a future course of action. For phytoplankton blooms, these suggestions may include:

  • Increasing the number of days where fish feed on only phytoplankton (no supplemental feed).

  • Introducing aeration devices to the system.

  • Additional training and support for farmers to take and respond to measurements.

  • Stopping fertilization.

It will be up to the discretion of the respective FWI staff member to decide what exact corrective action to assign. However, we plan to build a more specific protocol as we gain more experience with farmers implementing these improvements.

Farmer training

We also plan for each ARA farmer to receive training in what phytoplankton is, why it is a critical issue for fish health and welfare, and how to detect issues like phytoplankton blooms. Each farmer will be provided a Secchi disk (a small tool used to measure turbidity—an indicator of phytoplankton levels) and be encouraged to take measurements at least once a week. If farmers notice any concerning issues, they can have an FWI representative perform an early phytoplankton evaluation.

In summary, our feeding protocol will have farmers letting fish feed on phytoplankton only (no supplemental feed) for 3 consecutive days every month in order to help reduce phytoplankton levels and prevent subsequent blooms. FWI will measure each farm once every 2 weeks to evaluate phytoplankton-related issues and assign corrective actions as needed. Further, farmers will be trained to understand why phytoplankton is a concern and how to identify the issue using simple equipment and observations (which they can then use to flag issues to FWI representatives).

Other aspects

The additional components of Version 2 are roll-over aspects from Version 1, including:

Stocking densities

Stocking densities refer to the number of fish divided by the amount of space available to those fish. Stocking densities that are too high negatively affect the lives of fish by degrading water quality, increasing occurrences of injury, and adding psychological stress.

Our requirements are:

  • Grow-out stocking (later life-stage fish) will not exceed 2500–3000 fish/acre and 80,000 shrimp/acre.

  • Breeding stocking (earlier life-stage fish) will not exceed 50,000 fish/acre.

Corrective actions

Alongside the phytoplankton evaluation, our field staff will perform a full evaluation during every alternate farm visit. This will include more measurements (such as checking for signs of disease) and the use of our more advanced equipment by trained staff. If problems are identified, corrective actions will be assigned to farmers (see our current document on corrective actions).

We plan to do this more intensive measurement protocol only once a month, as many of our problems with scaling come from the use of complex and cumbersome equipment. As such, our goal is to assess our phytoplankton evaluation as a simplified measuring system that can capture similar value, and thus will only need to be occasionally supplemented with more in-depth analysis.

Why is this better than Version 1?

Version 2 is better than Version 1 in a few key ways:

More impactful

Over 2022, we have been refining our understanding of the key welfare issues within Indian farms and their causes. By focusing more attention on dissolved oxygen, we are able to weigh our resources more heavily on the main welfare issue that fish are facing.

We also believe that our mixture of preventative measures (3-day breaks where fish feed only on phytoplankton) and regular check-ins and assignment of further action if needed is a strong balance that can stand to significantly reduce the issue of oxygen imbalance.

More scalable

Often, dissolved oxygen problems are more concentrated across a few farms and a few months of the year. However, Version 1 currently distributes our resources evenly across all farms. This means that resources are being used inefficiently; thus it will be harder to achieve impact at scale.

Version 2 solves this by implementing a blanket preventative measure (3-day breaks during which fish feed only on phytoplankton), while allowing the flexibility for more attention and further actions to be taken in the places that need it.

Version 2 also stands as our first large-scale trial of farmers performing their own measurements, which, were it to be successful, could massively increase our ability to scale our project.

Higher learning value

In focusing our attention on the worst issues, and testing new strategies, such as farmer education, we are transitioning away from learning about the welfare of the systems more broadly and toward learning more about the specific issues present and the potential delivery mechanisms we can adopt for fixing them.

Conclusion & Plans for 2023

We created Version 2 of our welfare standard with the intention of having a bigger impact at scale than with Version 1. We believe that what we have outlined in this document will succeed at this. However, the reality of work in a novel field such as Indian Major Carp welfare is that it will likely take us many iterations to find a sufficiently impactful and scalable standard. For this reason, we have already set a goal for updating to a Version 3 by the end of 2023.

Version 2, we hope and believe, will target the worst welfare issue (dissolved oxygen) and make a significant, cost-effective, and scalable change. We also believe that, along with our progressing corporate and government work, Version 2 will propel more intensive improvements to fish welfare in India.

Over the next year, we will evaluate Version 2 of the standard as we slowly roll it out through the ARA. We plan to introduce Version 2 fully around mid-2023. Until then, we will implement it in a smaller section of farms and refine the standard. We will also continue to investigate other promising options for improving the lives of fish, including and apart from improving dissolved oxygen.


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