UNDERSTANDING THE IMPORTANCE OF BLEEDING SALMON
The Methods Defined and Used in the Alaskan Salmon Industry
A Narrative by Bill Webber
Understanding the importance of bleeding salmon is paramount to a wild Alaskan salmon harvester that has the desire to produce a quality product. There are three processes of bleeding salmon used by salmon harvesters in Alaska. Each requires a critical time-period to perform an “optimal” bleed-out to purvey a quality product. The amount of blood that can be removed from the salmon’s body varies with each process used depending on when the process is performed. These bleeding processes coupled with careful handling and immediate chilling of the salmon can produce a quantitative level of end quality that the harvester with a total quality mindset can adopt.
Outlined below are the three bleeding processes and subsets that can be used in harvesting wild salmon to produce a higher quality product.
This process is most commonly used in the Alaska salmon industry yet produces the least amount of expelled blood; it is better than not bleeding at all, however. This process is initiated by way of severing the gill rakers, the more gill rakers that are severed the better the bleed-out. It is also best done when the salmon is alive with a beating heart. Typically, in this bleeding process, the salmon is left to thrash on the deck to bleed-out after severance of the gills. The issue with this bleeding process is that the blood starts to coagulate within 20-30 seconds after it is exposed to air. This is a design by nature to stop the blood flow from the severed gills as to not let the body die. This is the primary reason dry bleeding salmon is the least effective. With this process, up to 25% of the blood can be expelled from the salmon’s venous and arterial systems depending on how much time passed since it was harvested and how much vigor and fight the salmon had left in it.
LIVE IMMERSION BLEEDING PROCESS
This process is initiated in the same manner as dry-bleeding, followed by immediately placing the live salmon in a tote of sea water. Although the salmon is in shock at this moment, this process is more beneficial as the salmon undergoes a less stressful death in bleeding out in its natural environment verses thrashing on the deck. When the salmon is lively and thrashing about, it is generating lactic acid and consuming adenosine triphosphate (ATP) in the muscle tissue which can influence a different result in the final taste verses the salmon that is not overly active in its new-found captivity. Some harvesters stun the salmon by way of a blow to the head allowing the salmon to still bleed-out but in a less active state. With this process, up to 75% of the blood can be expelled from the salmon’s venous and arterial systems depending on how much time passed since it was harvested and how much vigor and fight the salmon had left in it.
INTRAVENOUS PRESSURE BLEEDING PROCESS
With this process of bleeding salmon, the Dry and/or Live Immersion Bleeding process can be electively avoided. However, this process must be performed immediately at the time of harves in an onboard pre-rigor processing operation. An optimal pressure bleed-out is not achieved if it is done post-rigor as the congealing of the blood will have set in the severed vein which then does not allow an unobstructed flow of blood. The blood needs to be in a nearest-to-life consistency to achieve a full and proper bleed-out. Therefore, pre-rigor Intravenous Pressure Bleeding will produce the ultimate bled-out salmon.
There are three subsets of pressure bleeding, they are as follows:
A head-on intravenous process.
A head-off intravenous process.
A gilling and gutting process.
HEAD-OFF INTRAVENOUS BLEEDING PROCESS
As the title of this process states, the head is first removed from the salmon. This exposes the Dorsal Artery which lies between the Kidney (sometimes called the blood line) and the back bone. It can be hard to find as there is usually a lot of blood that obstructs the opening of this severed artery. Once found, a laboratory pipette with a low water pressure stream is inserted into the dorsal artery until the flow of blood 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 opening of the belly cavity, removal of the entrails, and spooning out the kidney follows. The last step of brushing out the remnants of the kidney meat is done for cleanliness and presentation followed by a thorough rinsing before putting on flake ice. This head-off process is best for a well setup on-board processing operation. With this process, up to 99% of the blood can be expelled from the salmon’s venous and arterial systems depending on how much time passed since it was harvested and how much vigor and fight the salmon had left in it.
HEAD-ON INTRAVENOUS BLEEDING PROCESS
This process is done just after the gills have been removed - an incision is made in a strategic location to gain access to the Dorsal Artery with the pipette. This process is typically used by the Alaskan hook and line or troll harvester. It is a more cumbersome, time-consuming, attended and totally hand manipulated process. Once a clear water stream is visualized, the pressurized water flow can be stopped, the belly cavity opened, and the entrails removed, followed by the same cleaning procedures used in the head-off process. With this process, up to 99% of the blood can be expelled from the salmon’s venous and arterial systems, depending on how much time passed since it was harvested and how much vigor and fight the salmon had left in it.
Below are weblinks depicting my early bleeding processes which I have developed and refined over the years.
GILLING & GUTTING BLEEDING PROCESS
This was probably the first pressure bleeding process used by the Southeast trollers. It was developed in the late 70’s or early 80’s. This process differs from the intravenous processes as it is not an intravenous process. The salmon is either processed head-on or head-off, the 5 bones near the back bone that lie above the anus are severed, and a low-pressure water stream from a water hose is hand manipulated over the area where the previously stated bones were severed. There are severed veins that connect to smaller capillaries that blood can be flushed out. Typically, in a salmon that has not been intravenously pressure bled, you will find blood in the smaller capillaries of the tail section. The post-processed bleeding process was discovered to help address this issue. With the post-processed process, up to 92% of the blood can be expelled from the salmon’s venous and arterial systems, depending on how much time passed since it was harvested and how much vigor and fight the salmon had left in it. This is a time-consuming process not desirable in a production operation.
AUTOMATING THE PROCESS
The percentage of expelled blood from a salmon using these intravenous pressure bleeding processes can vary depending on whether it has been pre-rigor or post-rigor processed. As previously stated, pre-rigor processing coupled with intravenous pressure bleeding will yield the best result in removing blood from the salmon providing a cleaner finish on the pallet to savor the rich oil and untainted taste of the flesh. Blood left in the post rigor commodity product can turn rancid, affecting the taste of the salmon.
Since the 2009 Copper River season, I have experienced great success, in developing and testing an electronic intravenous pressure bleed control system. Through my years of learning these processes, I have found that controlling two critical elements – time and pressure - are very important. They affect quality, food safety, and extension of shelf life. All the elements that this control system provides either meets or exceeds current Alaska DEC requirements.
The on-going development and product improvement of this electronic control system continues to evolve with each passing year in use. In the beginning of defining my quality specification, I designed a single processing station to perform these on-board processing procedures. In the 2016 season I tested two quad stations to help increase production, while maintaining the stringent quality specifications I have developed.
In closing, the level of quality that can be achieved using the electronic, intravenous pressure bleed control system in an at-sea processing operation are unrivaled in comparison to the traditional industry model. The wild salmon harvester owns the quality responsibility and can set the bar at a higher level using one of the bleeding processes, whether we work in the traditional industry or in a processed at sea model. This device will be made available for purchase to aspiring and enterprising harvesters through Webber Marine & Mfg., Inc. after the 2018 season.