EATS — Ike Jime and Eating Quality

Ike Jime and Eating Quality

Many years ago in the 1970s, I watched a black and white documentary on television of a tuna hunt by Japanese fishermen. Their bait was elaborately prepared from Flying Fish. After the tuna is subdued and brought on board, I saw they did some procedure of driving a spike through the head of the giant Yellowfin Tuna. Then in a few quick strokes, they cut the jugular, the tail, let out blood at the lateral line and inserted a length of monofilament line into the hole that was made into the head by the spike. At that time, I was more in awe of the huge sizes of fish they caught than on the procedure of Ike Jime and its ramifications. After all, I am first a sport angler, and I release all the fish I catch except those that I’m unable to successfully revive.

Later, I came to realise that I can’t be doing that all the time, unless I am fishing on my own boat. In such a situation, the skipper’s decision is final. But there were times when I’m fishing as a guest on so and so’s boat, or I’m on a fishing charter, and everyone on that charter is nursing hopes of taking home a feed of freshly caught snappers. Releasing the snapper I caught on such a charter is considered extremely bad form, and can earn me the privilege of walking the plank because it’s be believed that once a snapper escapes, it will return to the school and alert its brethren and the school will go off the bite.

So my catches on such trips are placed on ice, to be taken home as a hunting trophy at the end of the trip. As a consequence, it piqued my interest in dressing my catch. English is a strange language. When I remove my clothes, it’s called undressing. But when I remove the scales, skin and guts from my fish, it’s called dressing. So odd; but I digress. It was from dressing my fish, that I observed how the meat from my fillets are always coloured and cloudy. Nothing like the white, almost transparent flesh presented in the sashimi menu, or in the Sampuru displays at a sushi restaurant. I began to search out why, sashmi fish is capable of almost crystal clear flesh, and how I can achieve the same quality.

Bleed and Ice This Areolate Grouper (Epinephelus areolatus) was brain spiked, bled and iced. Although the flesh was firm and fresh, there are still signs of colour in the meat.

My first introduction to administering the final stroke of Coup de Grâce was in my book of Whales by Jacques Cousteau. I didn’t relish what I read, as a 13-year old schoolboy and that night, lost my appetite for dinner. But by the early 90s, I was involved in a fishing magazine called SEA Fishing World. One article on achieving the highest quality for Spanish Mackerel spoke about spiking the brain “which is found behind a soft spot between the eyes”, bleeding the fish and quickly chilling it in a slurry of ice and sea water. I attempted to do so on the mackerel we landed on Razak’s wooden trawler, after he had gaffed it aboard and priested it with his truncheon. But without clear instructions, I broke the tip of my knife trying to look for that “soft spot between the eyes”. Everything was all hard bone, and trying to insert a knife into the head of a semi-conscious fish with razor sharp dentition on a rolling deck was not the most ideal classroom lesson I had.

Bleeding was easier to do, and so was lowering the temperature quickly. Even so, we thought we had succeeded in achieving the “highest quality” by what we did for the mackerel, as it was much more than what we had customarily done in the past, which was to leave it flopping on the deck till the feeding frenzy is over. Then, the fish are collected and kept in the eskee. It was not until the age of the internet, that I got more knowledge about this very Japanese attitude to death, mercy and the cherishing of nature.

In 2006, I was given a picture of an ohanami party in front of Himeji Castle at Hyogo, for the cover picture of the June-July issue of Frequent Traveller magazine. From Google, I found that the cover photo was not suitable as the sakura blossoms would have fallen by the time the magazine appear on the news stands. I also learned about the beauty and transience of life and to cherish nature’s beauty as all are born to die. I somehow got sidetracked in my googling and chanced upon the term Ike Jime.

Ike Jime
I read that the Japanese commercial fishermen would drive an icepick between the eyes of fish as the Coup de Grâce, slit the gills to drain blood, then destroy the spinal chord with a length of wire. I was fascinated, thinking that finally, I had found the trick to getting those translucent, clear sashimi fish that I had failed to achieve when I applied western methods and western reasoning. But it wouldn’t be till several years later, that I followed up on this, because I’m primarily a catch and release angler, so I had no compulsion to learn Ike Jime. 

Ah Boy is looking forward to eating the Sawara belly sashimi

On 1 August 2008 at 1325h, I did my first Ike Jime when a buddy called Nimo landed a Spanish Mackerel at Rompin. Armed with the theory of Ike Jime but lacking on practice, I managed to brain spike the mackerel and bleed it while keeping all my body parts free from cuts and scratches. But in the excitement, I forgot to destroy the spinal chord. Even then, we had a delicious sashimi appetiser of Sawara 鰆. A fish that didn’t have to trash out it’s final moments really does leave behind better quality meat.

So other than the humane element of quickly putting fish out of their misery, what does Ike Jime really do to preserve the eating qualities of fish? Not very much information can be found on Google in English language. But when I started looking in Japanese language sites, a wealth of information started to show up. A summary of which are as follows:

Swiftly killing fish immediately after capture by spiking the brain will delay the process of physical breakdown called rigor mortis. When compared to slower methods of Coup de Grâce, e.g. bleeding, ice slurry chilling or priesting (a blow to the head), destruction of the brain is the most effective method of humanely putting a fish down and at the same time, stopping any further struggle from the fish. It is the struggling that depletes energy reserves called Adenosine triphosphate (ATP) in the tissue.

So putting down a fish in the shortest time, retains the greatest amount of ATP. By further destroying the spinal chord, the muscles are put into a kind of limbo since there is no nerve impulse to activate them. ATP in the cells can convert into Inosine monophosphate (IMP) or Inosinic acid. (By the way, IMP is a known flavour enhancer. Although it does not have an umami taste, it strongly enhances other flavours, reducing the need for more salts and flavour enhancers. You might see it listed in your food ingredient as E630). No wonder, fish that had been through Ike Jime appear so good and taste great.

On the other hand, fish that had been killed by either bleeding, chilling or simply struggling till it succumbs will have used most of its ATP energy. Even though the heart may have stopped or drained of blood, the nerves continue to function, independent of the brain and heart. Muscles tense up consuming ATP which changes the pH value of the cell. When all ATP is consumed, the muscles literally die which result in the body becoming most rigid – the state of Rigor Mortis.

After the body had time to resolve, it begins to loosen. Flesh breaks down into amino acids which eventually lead to decomposition. If the fish is not bled effectively, blood which carries by-products of lactic acid and ammonia will further hasten the breakdown process as well as become a medium for bacterial breakdown.

This may sound like a lot of chemical mumbo-jumbo. At least it does to me. But it also explains beyond the aspects of morals and religion, why Ike Jime works in a scientific way.

Here’s more reading if you are interested to dig deeper. The first three links are to Japanese language sites, the third one is about parasites, which may be a possibility if the fish is consumed raw.

Let’s go kill a fish!

Bernard is trying to brain spike a Coral trout (Plectopomus leopardus)

Finding the brain is the the most difficult first step for anyone starting to do their first Ike Jime. It is a tiny spot on an angry fish, thrashing with all its teeth and spines primed to inflict maximum hurt on you. To make matters more complicated, some fish are very flat and have a great big hump of bone at their forehead, e.g. the Ebek (Alectis ciliaris) It is very difficult to push a spike in at the forehead without incurring a great risk to self. 

After many trials and errors, I’ve come to establish this simple way of locating the brain. From the picture above, locate the Lateral line from tail to head of fish — the spinal chord generally runs along this line. And since the spinal chord is connected to the brain, the end of the lateral line should also be where the brain is. 

The right half of this halved mackerel head, clearly shows how the spinal chord is connected to the brain

If you are right-handed, lay the fish on its side, facing your right. Hold your Ike Jime spike in your right hand and take aim, starting between the eyes on the forehead (pink arrow), towards where the lateral line ends (green line in the picture). With a piece of cloth, cover the body of the fish as well as the eyes. This will calm the fish down reduce struggling, and the cloth gives you a safe and efficient way to hold a slimy, spiny fish. If the fish has sharp teeth, cover the mouth with cloth too.

Insert the spike into the brain. Some fish have very hard bones (e.g. Cobia and catfish) and need some twisting of the spike to penetrate the skull. Others (e.g. Mackerel, Mahi Mahi) have a softer bone and is easy to poke through. It is easier to push the spike from the mouth into the brain for fish with a hard bony forehead e.g. Ebek.

When the spike had pierced the brain, you will feel the fish give a shudder, the fins will flare, mouth and gills open and all it’s colours will come back in a last blaze of glory, and the fish doesn’t move anymore.

Bleeding the fish

The next step is to bleed the fish. Note that at this point, the fish may be brain dead. However, involuntary organs such as the heart is still working for a few more moments. Use a knife cut the membrane that links the gills to the body to start the bleeding. If you have a sharp and strong knife such as the Deba in the picture above, you can cut the spine behind the head and at the caudal peduncle to sever the artery for more effective bleeding.

The more effective the bleeding, the cleaner the flesh will be, so you want to make special effort to ensure you get the blood out. Because the heart is still beating, it will serve as a pump to drain out blood from the fish. Immersing the fish in a bucket of cooled sea water will help in ejecting blood effectively.

Do not place ice directly into the sea water as it will dilute the water and cause osmosis problems. Instead, freeze a couple of plastic bags/bottles of water. Use these frozen bags/bottles to cool down the sea water. Putting in effort to remove blood clots from forming at the cuts will also help in effectively evacuating blood from fish.

If you have a bilge pump, running sea water through the gills or mouth also help to speed up the evacuation of blood. 

When you cut the caudal peduncle, take care not to cut the whole tail off. What you want is to cut through the spine, leaving a piece of flesh and skin on the other side intact. This way, you have a handle of sorts to hold the fish when you fillet it. Fish like cobia, ebek, snappers and groupers have a hard skeleton. You need a sharp and hard knife to cut through the spine. Fish like mackerel and Mahi Mahi have soft bones. It is very easy to sever the whole tail if you are not careful in cutting the spine.

Spinal Chord Destruction

After the fish had been soaking in chilled sea water for ten to fifteen minutes, all blood that could be bled off will have done so. Choose the biggest mono wire that will fit the spinal canal, and insert into the hole in the head. The wire will be funnelled by the skull into the spinal canal.

As your wire comes in contact with the spinal chord, you can feel parts of the fish start squirming. Since the fish had been dead for a while, this squirming is proof of the need for spinal chord destruction as muscles are still responsive to nerve input. Push your wire till the spinal chord comes out at the cut tail end and all squirming ceases.

If your wire is not long enough to come out at the tail, you can also reinsert the wire from the tail end to finish the job. Note that the spinal column is the tiny hole at the top of the spine. The bottom hole carries the blood, so be sure to insert your wire into the correct hole.

If you have compressed air on board (dive boat), you can shoot a blast of air into the spinal canal at the cut tail end. You will find a whitish translucent, stringy-like spinal chord getting blown out at the cut in the gills or from the hole in the head. If you are squeamish to handle a squirming fish, compressed air makes doing the deed quick and insulates you from the squirming.

The spinal canal is in proportion to the size of the fish. The bigger the fish, the thicker the wire you need to push out the spinal chord. You can even use a length of fluorocarbon line for very large fish. Some fish however, have very fine spinal canals. Groupers especially, need a fine wire to be able to thread through, so I have a few sizes of wire in my Ike Jime kit.

After spinal chord destruction, I’d clean off any slime and blood from the fish, place into a waterproof bag, then using a short water hose, suck out the air so it is vacuum packed, tie off the bag, and bury in the ice, to keep the fish chilled. Do not place your fish on the ice without a bag, even if the ice is a sea water ice. That’s because fresh water from the meltwater will get sucked into the flesh by osmosis. This degrades the meat and puts to waste, all your efforts at Ike Jime. Even if it is sea water ice, the salt will melt off first, and a higher concentrated brine will conversely suck out all the juices from your specially prepared fish. So always invest in a few good strong bags to keep your fish separate from the ice, and suck out the air from the bags as air act as an insulator to prevent your properly Ike Jime’d fish from chilling effectively.

How I carry my Ike Jime stuff

This is my Ike Jime kit. I have a high flex, long fillet knife for skinning, a medium flex fillet knife for general cutting work, a stainless steel deba for cutting the spine (because salt water and carbon steel knives do not mix); a stainless steel awl which I got from Daiso serve as the spike (a tako yaki needle works well too) and different sizes of mono wire.

I find that for the very fine wire sizes, a titanium-nickel (NiTi) fishing wire works best because it always straightens itself up when uncoiled.

That hot pink device by the way, is my wife’s Ike Jime spike for squids and cuttlefish.  I’ll talk about ike jime for cephalopods in another story.

The different pieces are bundled in individual pockets of a sewn cotton duck cover and secured with tie straps. There are canvas merchants at King George’s Avenue and Horne Road where you can get yours sewn.

The proof of Ike Jime’s effect is in the eating

This Blacktip Grouper (Epinephelus fasciatus) was caught on 4 April 2015, the same day as the Areolate Grouper in the first picture. Ike Jime with spinal chord destruction was done to this fish, while the Areolate Grouper only got a spike to the brain and then bleeding.

Both were kept on ice till the end of the day, then individually bagged and left in a deep freezer till the end of our trip. The frozen blocks of fish was brought home, with guts intact, and stored frozen for 10 days till 14 April when I had time and energy to attend to them. They were moved from freezer to refrigerator to thaw on 14 April.

On 15 April, it was used to make a Gyotaku print, then the ink washed away, and it was gutted, and again stored wrapped in blood absorbing cloth in the refrigerator. On the evening of 16 April, this fish was taken out, filleted and served as sashimi. It had aged 3 days in the refrigerator, not counting the days it had been deep frozen.

Finally, what happens to all your effort in doing Ike Jime? This アカ ハタ sashimi is the result. The flesh was pearly-white and translucent, and it was flavourful, tender and sweet when eaten with a dab of that green ball, even without any soy sauce!

I hope you will also Ike Jime the fish you intend to bring home to eat and release the rest. The whole process of Ike Jime require you to pause and be deliberate in what you choose to take home, so you only bring back the best, instead of bagging everything.

Above all, I wish you bon appetit!

Dozo omeshi agari kudasai!


©Lawrence Lee
All Rights Reserved
If you want to use any content for your own publication/web/blog, please write me @


18 responses to “EATS — Ike Jime and Eating Quality

  1. Hi..I’m aware that flash freeze kills the bacteria/ parasites..but how do we do it without having to buy a top grade freezer, and is it safe to eat our catches in our waters in Singapore/ Malaysia as sashimi?
    I’ve seen horrible photos of with parasites in the brains/ stomachs from eating ‘unclean’ sashimi..

    Appreciate your thoughts in this..

    • I’ve only used my eyes to inspect the organs for parasites when I dress the fish. If worms etc are seen, the meat is immediately relegated for cooking and I salt the fillets to draw out water. This also draws out the parasites and I look out for them.

      If none appear, I’d happily eat them on the boat. It’s risky activity, but my other hobby is mountaineering and rock climbing so I’m not averse to taking calculated risks.

      Having said this, I also recommend that you not eat fish you catch immediately, as they don’t taste as good as after some aging. Grouper sashimi taste best after 7days in the freezer + 4-5 days aging in the chiller. Give it time to mature and the umami flavour really comes out. I encourage everyone to try the first piece of fish without soyu or wasabi to taste the original flavour. You can really appreciate matured fish if you do this. Wasabi brings out the sweetness while soyu is only to disguise imperfections.

      Fish I bring home are frozen in my normal fridge for a week before I thaw and age the meat. I figure that for warm water fish like ours, spending a week frozen in ice will have destroyed the cysts and eggs of parasites.

      That’s what I do. And I’m also known to taste the food from the same ladle that I stir the soup so that’s my Best Practices for what’s it’s worth. Hahaha.

      Enjoy your fishing. And enjoy your feasting.

      • Hi Lawrence..
        Yes I agree with your comments.
        The Koreans, though like their sashimi slightly chewy..freshly killed, sliced and served..
        For the aging in the chiller, that is in the fridge section right? Wouldn’t it go bad or become not fresh after 4-5days?

        p.s. Probably not going kayak fishing at Changi this weekend..USS Theodore Roosevelt coming into Singapore tomorrow.

      • 1) yes the fridge.

        2) No. After ike jime, you will find the meat to be quite lasting. Keeping it wrapped in plastic and in the fridge it will get to mature. In the freezer, it just stays immature.

  2. Hi, do you think this method can be applied to fishes caught in our local Pasir Ris pond? Maybe not sashimi but to make it more palatable…

  3. Hi, interesting read, do you think this method can be applied to fishes caught in our local Pasir Ris pond? Maybe not sashimi but to make it more palatable…

    • Yes, it will give you better meat quality than if you were to keep it on ice. Try one with and one without to prove to yourself.

      The difference is gonna be your motivation why it’s worth setting aside the time to ike jime when the fish are biting.



  4. Hi Lawrence, thanks for this interesting read on the ike jime method. Its the most detailed and informative material that I find on the internet. Really appreciate your time and effort to explain it. Happy fishing!

  5. Hi,
    Particularly to the prmp scenario.
    If we’re to ike jime the fish at the pond, do you think it’s safe (bacteria, parasite, etc) to put the fish back into the net in the pond until end of the trip? The quality of the water in the pond sometimes looks quite bad…
    Or if there’s any other recommended methods to keep the fish until of the day? Ideally doesn’t require too many gears, ice, boxes, etc.


    • No. After Ike Jime, you are to keep the fish on ice and wrapped up away from water (fresh or saltwater regardless)

      Moreover, you should be wary of higher levels of microbes in a farmed situation such as a pond than out at running waters at the ocean

  6. So after Ike Jime, you’d not want your fish to contact with the pond waters anymore, as the microbes can now get directly into the open cuts and holes made by Ike Jime in the meat.

  7. Ah, got it.
    Then that will lead to difficulties to bleed the fish at a pond scenario. Was thinking of cutting, and put into pond to release blood, then bring back up for storage.
    Seems like it’s not easy to ike jime at pond without bringing many boxes, pails, etc…
    Thank you so much for your write-up and reply!

    • You can bring a small pail (I reuse the engine oil packaging) to hold some clean water to do so. But do ask the pond management for permission to do that. In the late 90s the PRMP management prohibit gutting and bleeding at the pond as it polluted the water and cause ants and flies on land.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s