I have always bonked fish to stun them, slit the gills to bleed them, and popped them in the cooler with ice. When I go with one of my fishing buddies in his boat, he bonks them several times, puts them in an uninsulated fish box, fills the fish box with water, and leaves them all day.

Any suggestions/or info I can share with him to consider a different system? It seems like his system results in partially "boiled" unbled fish. He is pretty set in his ways, so any tech info that provides the food handling basis for something different may be helpful. thx.

Maybe you should ask him to bring a serving or two of fish to your place and you can do a side by side comparison taste test with fish that you have properly cared for......

Like you, I stun, bleed, and put on ice. I like to keep my fish cold and dry, so I put them in a large plastic bag on the ice blocks. I use the 5 liter box wine containers for my ice blocks. Easy to re-freeze and re-use. Cleaning the fish as soon as practicable is also a good idea. Fish have strong digestive juices. Left uncleaned, they will start breaking down internally. I think the commercial term is "belly burn". Not good for quality eats.

+1

I'm amazed at how many people I see (who spend big $$ on gear bait gas boat etc...) who can't justify taking 3-5 minutes to bonk, bleed, clean and get a fish on ice as soon as it's landed.....especially in the warmer summer and fall months. It's almost like they'll leave no rock unturned to land a fish and then when they do land one, thumb their noses at the fish with no regard for the table quality they're destroying.

I'll admit it's not always feasible to clean a fish at the time of landing but absolutely, there's no excuse for not bleeding and getting it on ice.

I think one of the hottest fish is actively feeding chinook.....and should be cleaned asap. Pinks also, which tend to be soft anyway. The bleeding aspect is made a big deal out of today, but wasn't much concern in days gone by, and I can't say the taste was affected one way or another. The fillets look better, however, when bleeding takes place, and I always do it.

I'm sometimes guilty of not cleaning a salmon right away, but I always pop a gill and then throw it in the cooler.

If you carry some large trash bags, you can cut the gill and put the fish in the bag on ice. The blood stays in the bag. Easier to clean the cooler at the end of the day or bring along an extra 5 gal bucket, fill it about 1/3 or so with water, cut the gill and let the fish bleed out in the bucket and then clean it or put it on ice until you can clean it.

It always blows me away when beach fishing for coho that someone will catch a coho and throw it up on the gravel unbleed and uncleaned and let it bake in the sun. Asked a guy one time if he would let a $15 rib steak bake in the sun like that, he just didn't get it. Bleed, clean and ice immediately.

exactly

This will be a long post, but I have pasted in an except from article for Fish Alaska Magazine I did a few years back.

KEEPING THEM FRESH

Use a few extra minutes to care for your fish in the field and you’ll have a much better product for the dinner table.
This applies to any fish you may catch for the table, be it salmon, pike, halibut, trout, char, rockfish, lingcod or others.
Here are some methods and tools that will make your catch more tasty while providing longer shelf live in the refrigerator or freezer.
W.B.I.----Whack, bleed and ice are steps that may sound unpleasant to some. But they are crucial steps to preserving quality of fish taken for the table.,
The first step to quality table fare is a good fish club.
A sharp whack on the head will stun the fish. This quickly puts the fish out of any perceived misery it may be suffering. After a fish is decommissioned by stunning with a fish cub, the heart muscle will continue to beat. This is important as removing as much blood from the fish as soon as possible will make a major improvement in flavor and shelf life.
Blood is the first thing that bacteria breaks down in a dead fish.
Bleed a fish immediately by cutting a single gill arch . Reach inside the gill plate at the back of the fish’s head to cut a single gill arch.
Cutting a gill results in most of the of this blood being pumped out of the flesh.
Use a sharp knife or a pair of kitchen shears.
A word of caution here, some anglers will break a gill arch with their finger. It works OK on some fish, but others like lingcod or pike have sharp gill rakers that will result in a nasty cut on your index finger. This can ruin a day’s fishing, so use the proper tools.
Bled fish will last under refrigeration for about five days. If they are to be kept longer it should be frozen as soon a possible.
Keeping your catch cold is the next and a most necessary step. Icing fish as soon as possible will keep your catch firm and fresh. The colder the better.
If you are planning a extended fishing trip and can pack an ice chest for the trip, shaved ice is the very best choice. It however is not always readily obtainable.
Cubed ice melts more quickly. Fish floating in melted ice water will go soft more quickly that that kept packed in ice in layers.
To keep fish in better condition on ice, it is a good idea to build a rack for the bottom of an ice chest for the water to drain. Other methods include layering the bottom of the ice chest with frozen one-quart milk bottles or using block ice. Either method will take up more space than a draining rack.
A sheet of plywood with drain holes drilled through it set on a couple of two by two slats works well for keeping fish from soaking in melted ice water. Layer the rack with ice before fishing so your catch will be kept cold on both sides. As you catch additional fish, add a layer of ice between each layer of fish.
If you can’t ice your fish immediately, then evaporation is you next best cooling technique. Long used by commercial trollers, fish stored in an open fish box can be kept cooler by placing a wet burlap bag over the catch.
On most charter boat operations your catch will be tossed in a hold or fish box, most likely without refrigeration. Some skippers and deck hands will bleed a fish, others won’t. If you are concerned about the quality of your catch by the time it reaches the table, you might consider asking if they will bleed your fish for you once it is in the fish box. Understand that when fish are coming over the rail in rapid succession that this may not be one of their priorities.
Once your is cut in the round, or filleted, keep it well packed in ice while transporting it home.
When freezing,, spread packages of fish out on the freezer shelf so that it will freeze quickly. Don’t make the mistake of piling package after package on top of each other, as some packages fill not freeze properly. The quicker a fish is frozen the quicker it is preserved.

Fresh fish smells fresh. If your fish smells fishy, it will be poor table fare. Oftentimes people say they do not like fish. I have had more than one quest change their mind after having well prepared, carefully handled fish that is fresh or was frozen properly.
All the sauces, lemons, and seasoning you can use to disguise the flavor of poorly handled fish will never take the place of fresh or fresh frozen fish that has been taken care of from the moment it is taken from the water.
If you are going to freeze fish for prolonged storage, vacuum packing is far superior to just freezing in a plastic bag. If you cannot vacuum pack. freezing the fish in water so it is encased in ice is the next best, if not somewhat space demanding method.
Some fish keep better and longer than others. On some white meated fish you will notice a reddish layer of flesh along the middle of the fillet on the skin side. The flesh tends to have the strongest flavor and in some fishes is best removed from the fillet, particularly if the fish is to be frozen more than a couple of months. Salmon have this same strip of flesh, but it is usually a brownish color.
The best way to have the finest table fare is to fish often, keep only what you will eat in a reasonable amount of time and be sure to follow the simple rules of WBI, whack, bleed, and ice.
Your dinner guests will appreciate the effort without ever knowing how this particular fish dinner came to be so tasty.