The Effects of Fish Processing Bio-waste on the Ocean’s Organisms and Nutrients

The effect fish processing bio-waste has on surrounding environments, habitats, and organisms is highly controversial. Although it is a natural pollutant, fish bio-waste has the ability to affect oxygen levels, salinity, temperature, pH levels, and the overall abundance of organisms in sea water.


The effect fish processing bio-waste has on surrounding environments, habitats, and organisms is highly controversial. Although it is a natural pollutant, fish bio-waste has the ability to affect oxygen levels, salinity, temperature, pH levels, and the overall abundance of organisms in sea water. The infiltration of this waste also affects the food web of surrounding marine environments, especially when present in large amounts. Fish processing facilities, like those in Kodiak, Alaska, dump millions of metric tons of fish waste into the ocean every year. Marine environments surrounding these sites are at risk for anoxia (oxygen depletion), harmful algae blooms, and other harmful effects. Alternatives such as thermal de-polymerization process (TDP) could help alleviate the problems associated with bio-waste dumping at fish processing facilities.


“Fish processing waste, especially from shore-based facilities, can cause serious harm to the marine environment in the surrounding area,” said Edward Kowalski, EPA Director of Compliance and Enforcement in Seattle. (1) Our paper will focus on several aspects: What procedures, limits, and regulations guide fish processing facilities? The differences between the naturally decaying salmon compared to the ground up fish paste that the fish processing facilities discharge. This paper also covers some of the major nutrients that are important factors for the growth of the organisms at the base of the food chain, and what occurs when an over abundance occurs within an ecosystem. We conducted a study on a local fish processing plant that has impacted the natural state of the area due to the substances deposited by the plant. Lastly, we address some possible alternatives to dumping bio-waste back into the ocean in Kodiak and similar Alaskan communities. To avoid the excreting of fish offal, Changing World Technologies has created a plan that can change the way that waste is handled.


To aid our research we have extensively used internet search engines such as Google. We conducted several in-person consultations with experts, including: Tim Blott, plant manager of Ocean Beauty Processing Kodiak, AK (10/29/10); Robert Foy, laboratory director and program manager of the RACE Division’s Shellfish Assessment Program at the Kodiak Fisheries Research Center (11/04/10); and Harry Heiberg, supervisor, Kodiak Waste Water Treatment plant (11/05/10). We also conducted a quantitive analysis of plankton in several locations associated with our research.

Results and Discussion

Fish Processing Facilities’ Regulations, Processes, and Limits

Fish processing facilities have various regulations and systems to follow that should ensure safe and environmentally stable conduct. For example, International Seafood’s of Alaska Incorporated (ISA), of Kodiak, was caught violating the Clean Water Act in 2005. (2) ISA exceeded its discharge limits for certain pollutants including oil and grease. (2) Fish wastes from these facilities go through various filters that filter out the solids and anything bigger than 0.5mm. From there, the remaining water is discharged back into the surrounding waters.

Locally and globally, the seafood industries produce large quantities of fish waste. According to the Food & Agricultural Organization of the United Nations, in approximate terms, over 100 million metric tons of fish waste or discard is generated worldwide annually, with only a small portion used in the production of fishmeal and fish oil. (5) In the year 2000 85% of the 1.0 million metric tons of fish waste produced in Alaska was discharged offshore. Which is legal under the Clean Water Act and EPA’s NPDES permit.

“The Clean Water Act (CWA) is the cornerstone of surface water quality protection in the United States”. (3) The part of the Clean Water Act, that is pertinent to our research, is the reduction of direct pollutant discharges into waterways. Through maintaining and restoring the chemical, physical, and biological integrity of our nation’s water the Clean Water Act is ensuring “the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water.” (3)

EPA’s National Pollutant Discharge Elimination System (NPDES) permit is required by federal law to be obtained by any functioning fish processing facility. As authorized by the Clean Water Act, the NPDES permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. (6) All seafood processing facilities in Kodiak have been required to treat seafood processing wastes by screening the effluent, to recover the waste solids, and to send the waste solids to a by-product reduction facility since 1986. (4) Under the permit, the owners and operators of the shore based seafood processing facilities engaged in the processing of seafood in Kodiak, Alaska, are authorized to discharge seafood processing wastewaters to St. Paul Harbor and Near Island Channel, in accordance with effluent limitations, monitoring requirements and other conditions set forth in the permit. (4)

Kodiak shore based facilities discharge a pollutant waste load consisting of biochemical oxygen demand (BOD) five-day, total suspended solids (TSS); including floating, suspended, and settle-able residues, and seafood oils and residual disinfectants such as chlorine. (4) These substances then have the ability to affect pH levels, salinity, and temperature. Wastewaters are discharged back into the surrounding harbor and channel and the solid seafood wastes are conveyed to a waste holding area, collected and transported by truck to Kodiak’s fish meal plant; which also discharges waste into Gibson Cove. (4) This system of discharge may cause multiple effects on organisms that influence the food chain dynamics and in turn pose a threat to the ecological balance of local ecosystems. (5) Periodic abundance of nutrients in seawaters is also well known for producing toxic algae and plankton blooms, which may cause mass scale fish mortality. (5) (Figure 1 and 2)

Natural Decomposition vs. Fish Waste Disposal

In this section the natural effects of salmon carcass decomposition in rivers will be discussed, and related to the processes unnaturally introduced into the ocean at the fish processing plant’s dump sites. Looking at the natural effects of decomposing salmon is important in discussing this topic because there have been many more studies on these natural ecological effects than the effects in areas with fish processing facility discharges. Many ecological processes in the ocean are still not understood and the extent of unnatural effects may possibly never be fully known. Usually though, in a stable ecosystem, there are definite processes by which nutrients, and energy are recycled and used in most levels of the food web.

This section will discuss the two processes through which nutrients are passed through ecosystems naturally and relate them to the likely pathways in a fish processing facility dump area. Direct consumption by other consumers is one of the processes, and the easiest to observe. The other process is decomposition accomplished by bacteria, and fungi, which is much harder to observe. There are a few small differences between the naturally occurring decomposition of salmon in streams, compared to the human impacted decomposition occurring in unorthodox environments. One difference is that most of the salmon decompose as whole carcasses in nature. Whereas, fish processing facilities grind what is not processed down to a specific size before releasing the waste where it doesn’t naturally belong. Another variable is the total amount of bio-waste. Even though there can be annual runs of salmon in the millions, fish processing facilities discharge about 120,000 kg of fish waste daily. (Figure 3)

Figure 1 is very relevant to the decomposition of salmon. The diagram shows what processes release what nutrients, and the potential effects of these processes. The part that includes direct consumption describes other animals, such as bears and birds, consuming the body of the salmon. The other side of the chart names the processes and describes what nutrients are released.

When relating the decomposition of these salmon in nature to fish processing facilities’ discharge, there are a few differences to consider. For instance, the fish processing facilities process a lot of the muscle tissue so most of the salmon is not released into the ocean; however, all of their bio-waste is organic animal remains. So refer back to the table and know that the canneries almost skip the early and part of the mid portions of the table. Another difference is the consumers. For instance, there are no bears underwater; however, there are quite a variety of fish that eat the fish chunks as they spew from the shoots. I know this for a fact because I have fished in these areas and there are definitely an unnatural abundance of grey cod, pollock, halibut, skates, and various sole and flounder.

Grey cod, pollock, halibut, and possibly some sole and flounder have other types of meals in their diets. For example, in the past I’ve found shrimp, crabs, and other small fish in halibut I’ve caught. The diets of some of these fish are based a good amount on the amount of plankton in the water. This over abundance causes a threat to the organisms that require a stable environment. One hypothesis in that this may be why there is no more king crab or shrimp around Kodiak. There is also a noticeable impact on the seagulls who, in thousands have colonized a rock very close to one of these bio-shoots. All of this is relevant to what the table says on the right side, which is increased (population) densities, biomass growth, and change in community structures.

The other half of the chart represents the recycling of nutrients through decomposition done by bacteria, algae, and plankton. The water is a very different place compared to up here on land. Not many people know there are microscopic organisms in a majority of the ocean at all times. Therefore under water in certain areas, there is usually a larger amount of organisms per cubic foot than on land, so it is possible that the effects of these nutrients in the near shore oceanic environment can effect greater populations of organisms. The table shows that phosphorous (P) and nitrogen (N) are major nutrients released by salmon remains. There nutrients are the main limiting factors for bacteria, plankton and algae. As the amount of algae and bacteria increase, they are providing more food for predators, as well as increase respiration, and pp levels which is when they use up lots of the oxygen in areas and replace it with CO2. Good thing there are tides and currents, otherwise this could cause a variety of harmful effects.

Harmful Algae Blooms and other effects of Fish Processing Bio-Waste

The organic waste discharge consisting of fish oils and fish products is rich in nutrients. This nutrient rich biomass can result in a rapid increase of organisms feeding on this new food supply. Some of these organisms require oxygen to use the nutrients and may quickly deplete the available dissolved oxygen in the seawater, which results in anoxic waters. When this happens, the animals or organisms that need oxygen to survive simply cannot live because this blocks out all the oxygen required for the flora and fauna to live (15).

Additionally, some of the wastes are turned into gases. Carbon dioxide may be formed which dissolves into the water producing carbonic acid. This raises the pH or acidity of seawater affecting marine life (16).

Scientists are also concerned that we may see increased algae and bacteria feeding on the fish waste. Some of these algae may produce harmful toxins to fish and marine mammals as well as humans. Kenneth R Weiss in his Los Angeles Times article, “A Primeval Tide of Toxin” refers to this as a returning to the seas of hundreds of millions of years ago, where bacteria and algae are the predominant life forms (16).

Harmful algae blooms (HABs) are microscopic, single-celled plants that live in the sea. HABs is a term used to describe a proliferation, or “bloom,” of single-celled marine algae called phytoplankton. Most species of algae or phytoplankton are not harmful and serve as the energy producers at the base of the food web. While there are thousands of algae species in existence, only a few dozen are known to be toxic. These few toxic species produce potent neurotoxins that can be transferred through the food web where they affect and even kill the higher forms of life such as zooplankton, shellfish, fish, birds, marine mammals, and even humans that feed either directly or indirectly on them.

Our concern for algae blooms in Kodiak is nutrients. Our biowaste plant releases nitrogen, phosphate, along with many others that can lead to a harmful epidemic in algae and plankton. An excessive of any nutrient especially phosphates or nitrates can lead to conditions where the most rapidly growing algae will flourish causing an imbalance in the food chain. Over population in algae can lead to anoxic water.

Plankton abundance comparison between fish waste site and control site

We performed a study by taking plankton tows in an area of fish processing facility discharge, and in an area not as close to the discharge sites. The purpose of this study was to test if there is greater productivity in areas where the salmon waste is discharged.

On board the school vessel Ki-Hi-C, our group went to Gibson Cove, Kodiak, where Biodry is located, and we took four plankton tows. We then took samples at a distance from the dump area for natural data readings. The samples were transported back to the lab and kept at five degrees Celsius over night, then counted the following day. We used a Folsom plankton splitter to split the samples. The Gibson samples were split into 8ths and the other samples into 4ths. For our study we used a 20″ diameter 7′ long plankton net at 18 feet deep which gave us a sample of 725.34 m3.

In the Gibson subsample, 80 copepods were counted, a total of 640 copepods per m3. In the control sample 48 copepods were counted for a total of 192 copepods per m3. All plankton encounted in the subsamples were copepods of the genus Pseudocalanus.

This difference in copepod abundance clearly shows the possibility that more plankton were attracted to the waste plant area. More samples would have to be taken to conduct a full study, but this still indicates the possibility. (Figure 4, 5, and 6)

Alternatives to dumping

Whenever it is economically feasible, some of the fish processing waste is reclaimed. Typical examples are the grinding and freezing of salmon cannery waste solids for later conversion to fish or mink food, oil extraction from heads, and use of eggs for caviar by the Japanese (15). Research is ongoing on how to reduce filter and reduce the discharge from the fish processing facilities. Fish processing facilities remain an important part of our heritage and economy, so it is important we find a way to address these issues.

There are many ways to divert the disposal of bio waste from Alaska’s fish processing facilities into the ocean. Many different kinds of fish such as salmon and herring are very oily and energy rich.

Changing Worlds Technologies (CWT), a corporation striving for a cleaner and better environment has been searching for ways to convert fish oil into a profitable product. In 1998, CWT discovered and started developing a new technology that is capable of transforming products varying from fish waste to old computers into oil, minerals, and fertilizers. This remarkable new technology is called the thermal de-polymerization process (TDP). (12)

The TDP is based on the process that has been making gas and oil from hydrocarbon-based waste. The oil coming out of the ground is mainly from decomposed plants and animals that have died millions of years ago and have been broken down by subduction. The polymers inside the objects get turned into short chain petroleum hydrocarbons resulting from substantial heat and pressure created by the earth. The few differences in this process are that the material is heated at a higher temperature and pressure and processing time. (11) (Figure 7)

The TDP can convert a remarkable amount of waste very efficiently and in a reasonable amount of time. For example, the process using animal offal is 85% efficient using only fifteen British thermal units (btu) for every hundred btu generated. (13)

The substances subject to transformation go through five different phases. First they go through a grinder, which mixes the substances with water to create slurry, a liquid form of mixed solids. The next stage is the first reactor that heats up the material to about 500 degrees Fahrenheit and is pressurized to about 600 pounds. In this process the slurry is partially broken down to molecular chains. The third step brings it to the flash vessel which decreases the pressure dramatically and frees 90 percent of the water. The second reactor, the fourth step heats up the slurry to 900 degrees Fahrenheit. The chemical decomposition of the long molecular chains is continued in this step. Lastly, the liquid runs into distillation tanks which separate the different components of the sludge. The gasses run into the top of the tanks first then the light oils, then the heavier oils, then water, and lastly powdered carbon. The finished oils are stored at the facilities to operate the whole system and the rest of the products are sold.

The benefits of a TDP plant in Kodiak

A TDP plant on Kodiak Island would be very beneficial since Kodiak has such a strong fisheries industry it produces massive amounts of fish offal. This offal could be used in the plant to produce bio-diesel fuel that fisherman in Kodiak could use. This plant would cut down on garbage that would otherwise be dumped in the garbage dump. This would be a great solution in an upcoming problem.

  • Positive impact on Kodiak’s economy. It will change how many companies spend their money and it would bring more jobs to operate the plant. This plant can change the way Kodiak deals with waste.
  • Cheaper garbage removal for Kodiak’s residents. The garbage removal for residents would be cheaper because the processing plants would collect the garbage and instead of having it dumped in the dump it could go to the plant.
  • Efficient way to get rid of fish and human waste such as garbage or even sewage. This would get rid of having a garbage dump and it would help the environment.
  • Fish processing facilities wouldn’t have to spend money on grinding down the fish waste. Fish canneries could give the plant its waste to be processed.
  • Oil could be sold to fisherman for eight to ten dollars and would go down in time. In 2004, the U.S. imported 4.2 billion barrels of petroleum (U.S. Department of, 2010) and if all the agricultural waste went through the thermal de-polymerization process it would produce almost four billion barrels of diesel.


In conclusion, we have shown that although fish processing bio-waste is a natural pollutant, it remains a pollutant nonetheless. In large amounts or in a concentrated area, fish processing bio-waste has the ability to effect surrounding marine environments and ecosystems by changing natural chemical levels and affecting food chain relationships. When fish processing facilities’ discharge their waste back into the ocean two things happen. First the increase of nutrients causes an increase in algae blooms; which aren’t necessarily negative. Then, the increase of phytoplankton causes an increase in zooplankton. This can either result in too much organic matter at one time; which can result in anoxia in inert waters. Or, a bigger food source for a growing fish population. Either way, it is a concern that needs to be monitored, studied and addressed with emerging technologies when possible. It is a shame we are still dumping all this nutrient rich waste into the ocean. After all, we have the technology to turn this waste into something use. Even though it may take a little extra effort and mo=ney, it should be worth it.


We would like to thank Bev Malley, Robert Foy, Tim Blott, Harry Heilberg, Jan Haaga, Switgard Duesterloh, Jane Eisman, and Martha and Michael Barnett for their time, support, expertise, and insight.

Figures and Tables

fish processing effluent in Sitka

Figure 1. Fish processing facility’s effluent in Sitka. (1)

fish processing effluent in Kodiak

Figure 2. Fish processing facility’s effluent in Kodiak. (Google Maps)

process to recycle nutrients through consumption and decomposition

Figure 3. The process by which certain nutrients are recycled through direct consumption and decomposition. (9)


Split Samples

Total Amount per Meter

Gibson Cove

80 copepods (0.125 of a sample)

640 copepods

Control Site

48 copepods (0.25 of a sample)

192 copepods

Figure 4. Sampling results

sampling sites

Figure 5. Sampling sites (left Gibson cove) (right control)


Figure 6. Copepod like the ones we found in our samples. (Google images)

thermal conversion process

Figure 7. Thermal Conversion Process (Google Images)


  2. EPA, . “Inaccurate Water Pollution Reporting Results in $20,000 Fine Against International Seafoods.” Green Environment News. N.p., Tuesday, November 1st, 2005. Web. 7 Nov 2010.
  3. “Introduction to the Clean Water Act.” U.S Environmental Protection Agency (Watershed Academy Web). EPA, Friday, September 12th, 2008. Web. 12 Nov 2010.
  6. “U.S Environment Protection Agency.” National Pollutant Discharge Elimination System (NPDES). N.p., March 12, 2009 11:32 PM . Web. 12 Nov 2010.
  7. Harry M. Heilberg, City of Kodiak Alaska Water and Wastewater Treatment Plant Head Supervisor.
  8. Robert Foy, Laboratory Director and Program Manager of the RACE Division’s Shellfish Assessment Program at the Kodiak Fisheries Research Center
  10. Tim Blott, plant manager of Ocean Beauty Processing Kodiak, AK.
  11. Lemle, B. (2003). Anything into oil., 24(5), Retrieved from
  12. What solutions does cwt offer?. (2010). Retrieved from
  13. Trounson, J. (2004, March 31). Energy-crisis solution. Retrieved from
  14. U.S. Department of Energy Office of Science, Office of biological and environmental research . (2010). Biofuels for transportation Retrieved from
  15. Nakatani, R., and D. Beyer. (1973). The effects of salmon cannery waste on juvenile salmon in a closed system. Proceedings of the National canners association (pp. 1-36). Seattle, WA: Fisheries Research Institute.
  16. Weiss, K. (2006, July 30). A primeval tide of toxins. Los Angeles Times, pp. 1-12.

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The Effects of Fish Processing Bio-waste on the Ocean’s Organisms and Nutrients

The effect fish processing bio-waste has on surrounding environments, habitats, and organisms is highly controversial. Although it is a natural pollutant, fish bio-waste has the ability to affect oxygen levels, salinity, temperature, pH levels, and the overall abundance of organisms in sea water.

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