Fish Fertilizer is Damaging the Environment

Home » Blog » Fish Fertilizer is Damaging the Environment

Robert Pavlis

I always thought that fish fertilizer was an acceptable product. As a nitrogen source it is very over priced as explained in Fish Fertilizer – Is It Worth Buying? but at least the fertilizer is being made from a resource that is a waste product, namely fish guts (offal) , bones and heads. It seemed like a good use for this waste product.

But a comment left on my other post, by Cynthia E. Olen, June 12, 2016 made me rethink things. Thank you Cynthia.

Did you know that companies are harvesting whole fish to make the fertilizer? I didn’t believe it myself, but is is true.

Catching fish to make fish fertilizer
Catching fish to make fish fertilizer

Raw Materials for Fish Fertilizer

Fish fertilizer is made from two different types of ingredients; either fish waste (guts , bones and heads) or whole fish caught specifically for the purpose.

Microbe Science for Gardeners Book, by Robert Pavlis

A fish called menhaden is not used for human consumption. It is harvested, ground up, processed and some of it eventually is used to make fish fertilizer.

In a documented letter from Alaska Fish Fertilizer (ref 1), a leader in supplying fish fertilizer, they confirm that almost all of their fertilizer is made from whole menhaden fish. Ironically, this company called Alaska Fish Fertilizer gets it fish raw material from the Atlantic and Caribbean Oceans.

Here is a video showing the process of grinding up the fish. You can clearly see whole fish are used.

YouTube video

If the above link does not work, click here:

It is important to point out that not all fish fertilizer is made from whole fish.

Fish Fertilizer is Damaging the Environment

So why is this a concern? After all they are ‘useless’ fish – right? Wrong!

According to Wikipedia (ref 2), “menhaden are an invaluable prey species for many predatory fish, such as striped bass, bluefish, mackerel, flounder, tuna, Drum (fish), and sharks. They are also a very important food source for many birds, including egrets, ospreys, seagulls, northern gannets, pelicans, and herons.” By harvesting the menhaden and turning it into fertilizer companies are removing an important food source for other species. They are damaging the environment!

Wikipedia goes on to say “In 2012 the Atlantic States Marine Fisheries Commission declared that the Atlantic menhaden was depleted due to over fishing.” The current website for ASMFC says “Atlantic menhaden are neither over fished nor experiencing over fishing. ”

Fish Fertilizer is Not a Renewable Resource

The letter from Alaska Fish Fertilizer (ref 1) goes on to say that they use just 20 rail cars per year of the ‘fish solubles’ (one rail car is approximately 20,000 gallons). The company supplying this, Zapata Haynie Corp, can manufacture about 20 rail cars per day.  The rest of their production is used for animal feed and pet food.

So it would be incorrect to say that the manufacturers of fish fertilizer are responsible for depleted stocks of menhaden, but they are certainly contributing to the problem.

It has become clear for many years that fish stocks in our oceans are dwindling. It is no longer a renewable resource unless fishing stops.

Which Brands Use Whole Fish?

I checked on a number of brands of fish fertilizer and it was never easy to tell which brands use whole fish. They like to use terms like “fresh fish”, as if that is important when you are making fertilizer!

Whole fish are processed into three separate components; fish meal (solid parts), fish oil and fish emulsion. Fish emulsion is what is left after the meal and oil have been removed (ref 3). Wikipedia defines fish emulsion as ” the fluid remains of fish processed for the fish oil and fish meal industrially”.

Based on this definition you might conclude that any fish fertilizer made from ‘fish emulsion’ is made from whole fish. But …. advertisers have a different point of view. I guess the term fish emulsion has become popular and is seen as a ‘good thing’ . I found several manufacturers that promote their product as fish emulsion,  but in small print somewhere on their web site, they say made from fish remains, or fish viscera. The term ’emulsion’ is not a reliable term for determining the source of the fish.

I was not able to find the % of fish fertilizer that comes from whole fish. If you find such a value, let me know in the comments below.

Fish Fertilizer Made From Carp

Some companies are catching invasive species like the carp and using them as a source for making fertilizer. This is a good practice and should be encouraged. If you Google ‘fish fertilizer made from carp’ you will find these companies. I found some in both the USA and Australia.

Is Fish Fertilizer Organic?

I will deal with most of this topic in another post, but for now lets assume that fish fertilizer is organic. Gardening organically is a good thing – it should be environmentally friendly.

If you use fish fertilizer that is made from whole fish – you are not being environmentally friendly, and in my opinion you are not gardening organically. Organic certification organizations disagree – as long as you follow their rules, even if you are damaging to the environment you are gardening organically. I disagree.

Feel free to use fish fertilizer – your plants will like it. But make sure the product is made from fish waste products, or carp and not whole fish.


  1. How a Fish Becomes Fertilizer – letter from Alaska Fish Fertilizer;
  2. Menhaden;
  3. The Principal Method of Processing Fish;
  4. Photo source; Ra Boe


If you like this post, please share .......

Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

18 thoughts on “Fish Fertilizer is Damaging the Environment”

  1. Misleading. The article should say Fish fertilizer is good to the environment- but not when you harvest fish to be manufactured for pure fertilizer. Most use fish scraps like fish guts, which I do is very beneficial to my garden. Badly written article.

    • Most commercial fish fertilizer is NOT made from fish scraps – but if you have data to show this is wrong – lets see it.

      Most people who use fish fertilizer do NOT make their own.

  2. If you buy Charlie Carp liquid fertiliser from Australia; its made from pest carp taken from our inland rivers. They are a pest and hunt native fish so the more fertiliser you buy the better for our environment.


Please leave a comment either here or in our Facebook Group: Garden Fundamentals