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Understanding the Importance of bleeding salmon

Updated: May 5, 2018

A Narrative by Bill Webber

Understanding the importance of bleeding salmon is paramount to a wild Alaskan salmon harvester who has a desire to produce a quality product. There are three methods of bleeding salmon used by salmon harvesters in Alaska. Each presents a critical time period to be performed for an “optimal” bleed out to purvey to the marketplace a quality product. This is coupled with careful handling of each salmon which there are many handling techniques that the harvester with a total quality mindset can adopt.

Outlined below are the three bleeding techniques and a few subsets of one.


This method is the most commonly used method and provides for the least amount of blood to be expelled from the fish. It is however better than not bleeding. This process is initiated by way of cutting or tearing multiple gills, the more the better. It is also best done when the fish is alive. Typically the salmon is put on the deck and left to bleed out after this. The issue with this bleeding method is that the blood coagulates within 20-30 seconds after it is exposed to air. This is a design by nature to stop the bleeding or blood flow from the severed gills to not let the body die. This is the primary reason dry bleeding salmon is the least effective. With this technique one can realize up to 25% of the blood expelled from the fish’s venous and arterial system.


This method or process is initiated in the same manner as dry bleeding but the salmon is immediately placed in a tub or tote of sea water, its natural environment. Although the salmon is in shock at this moment there is another unseen benefit to this. When the fish is lively and thrashing about, it is generating lactic acid in the muscle tissue and this can affect a different result if the fish was not overly active while in its new found captivity. Some harvesters stun the fish by way of a blow to the head. The fish can then still bleedout in a less active state. The primary reason why Live Immersion Bleeding is better than dry bleeding is the fact the fish is placed back in a tote of seawater after the gills have been severed, this tends to flush the blood away from the severed gills and encourage an unobstructed flow of blood for a better and more thorough bleed out. With this technique one can realize up to 75% of the blood expelled from the fish’s venous and arterial system depending on how long it has been captured from whatever method of harvest and how much vigor and fight the fish has left in it.


With this method of bleeding salmon the dry and/or Live Immersion bleeding process can be electively avoided. However this process is best done by the harvester in an onboard pre-rigor processing operation. An optimal pressure bleed out is not achieved if it is done post-rigor as coagulation will have taken place in the exposed or severed vein and not allow a clear and unobstructed blood flow to occur. The blood needs to be in a nearest-to-life consistency to achieve a full bleed out and this is why pre-rigor pressure bleeding will produce the ultimate bled out salmon product.

There are three subsets of pressure bleeding and they are as follows:

A head-on intravenous method

A head-off intravenous method

A Post processed method.

Below is an outline of the basic procedures for each of these methods.


As the title of this method states, the head is first removed from the salmon. This exposes the Dorsal Artery of the salmon which lies between the Kidney (sometimes called the blood line) and the back bone of the salmon. It can be hard to find as there is usually a lot of blood that tends to hide the opening of the severed artery. Once found a laboratory pipette with a low water pressure stream is inserted into the dorsal artery and pressurized with water until the flow of blood being expelled from the Post Cardinal Vein runs clear. This is the vein that the heart was attached to and removed during severance of the head. The next step is the opening of the belly cavity and removal of the entrails, then spooning out the kidney. The last step of brushing out the remnants of the kidney meat is done for cleanliness and presentation finished by a thorough rinsing just before putting down on flake ice. This head-off method is best for a high production processing operation. With this technique one can realize up to 99% of the blood expelled from the fish’s venous and arterial system.


This method is done just after the gills have been removed and an incision made in a strategic location to provide an entry point into the dorsal artery with the pipette. This method is typically used by the Alaskan troll harvester. It is a little more cumbersome and time consuming method and is a totally hand-manipulated performance. Once the clear water stream is evidenced then the belly cavity can be opened up and the entrails removed. The same cleaning procedures are used as stated in the head off method. With this technique one can realize up to 99% of the blood expelled from the fish’s venous and arterial system.




This was probably the first pressure bleeding technique. It was developed in the late 70’s or early 80’s. This process differs from the intravenous methods and is not a full intravenous process. The salmon is either processed in a head on or head off product form first and then the 5 bones near the back bone that lye above the anus are severed and a low pressure water stream from a low pressure wash hose is manipulated into the area where the previously stated bones were severed. There are also severed veins in that area that connect to some smaller capillary veins that blood can be flushed out. Typically a fish that has not been pressure bled, will find a small amount of blood in the flesh in the tail section. This first pressure bleeding technique was discovered to help address this issue from a harvester quality stand point. With this technique one can realize up to 92% of the blood expelled from the fish’s venous and arterial system and is also a laborsome process not really desired in a production processing setting.

The degree or percentages of expelled blood from a salmon using these pressure bleeding techniques can vary depending on whether it is has been pre-rigor or post-rigor processed. As previously stated, pre-rigor processing and pressure bleeding yield the best result for removal of the blood from the venous and arterial system for a cleaner finish on the pallet to savor the rich oil and taste of the flesh.

I have developed and tested with great success an electronic intravenous pressure bleed control system starting in the 2009 Copper River season to present. Through my years of learning these processes, I have found that controlling two critical elements in this process that are very important that deals with not only producing and maintaining quality but also food safety and extension of shelf life of a properly intravenous pressure bled salmon. I have also experimented with the use of a certified fresh water source as my water source for the head-on intravenous method that I use in my at sea processing operations. All of the elements that this device provides for either meet or exceed current Alaska DEC requirements.

In short, the level of quality that can be achieved using these techniques in an at sea processing operation are unrivaled in the traditional industry model. The harvester owns the quality responsibility and the harvester can set the bar at a higher place whether we work in the traditional industry model or in a processed at sea direct model. This device will be made available for purchase by Webber Marine & Mfg., Inc. to salmon harvesters in the 2019 season. A U.S Patent has been applied for.

The importance of pressure bleeding salmon can be seen in this clean, blood-free salmon flesh
A Pressure Bled Salmon

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