There’s Air Guitar, Air Surfing and Air Dancing, but Air Stripping? For this you can leave your hat on; air stripping is a method of removing eggs from a female carcass without drawing blood. Like any technique, it has pros and cons. There are also some tricks to the practice.

Air stripping is the injection of air, or other inert gas into the celoem (body cavity) of the female spawner in order to propel the eggs out the ovipositor (the little pink thing where eggs come out). The idea sounds absurd at first, but the reasons for the practice are grounded in reason.

The practice of air stripping came from making kelts of male and female grilse. Hatchery operators in the UK and to some extent North America, didn’t want to terminally spawn two-year fish, instead, they wanted a method where they could purge the eggs from female grilse and return the fish alive to the stream. This was for two reasons: first, the hatchery wanted the eggs and second, egg-bound females usually die or have low reproductive success in subsequent years. Instead of squeezing eggs out of fish akin to getting the last bit of toothpaste out of a tube, the technicians needed and kinder, gentler way.

After several Guinness, pickled onions, oysters and pickled eggs, the technicians were still at an impasse. It was not until the next morning that idea game: build up pressure behind the eggs and push rather than squeeze them out.

Like traditional methods of stripping, the fish has to be ripe and running to get the eggs. All the signs of ovulation are the same: the eggs are fluid in the body cavity, the fishes’ colour is correct, and the ovarian fluid is abundant. A partially ovulated female will only gum up the works when air is injected. In general, you must induce all your fish with Ovaplant, repeat: use Ovaplant on all your spawners. Buy more than you need, share with your friends. After the fish are determined to be ready, the initial procedures for air stripping are the same for lethal stripping: bonk and bleed as normal, hang the fish tail up and rinse the saltwater off, dry her down. Some Chilean farmers hang the fish and wash off the blood then dry them as shown in the photo. These fish are spawned from fresh water.

There is a debate about clamps. Clamps are used to prevent eggs and fluid from escaping from the dead and bled females. Some use paper clamps, some even use battery terminal clamps (that part makes me wince). If the fish is hung tail up until just before air injection, there should be little need for clamps. The downside of clamping off the ovipositor is that it can crush and egg or cause tissue damage and bleeding. The prime objective of air spawning a dead fish is to not mix blood in the eggs and ovarian fluid. If the clamp causes bleeding, the objective is lost. Hanging the fish tail up until injection also keeps the fish in a relatively clean environment. Fish should not be laid on the ground.

To air spawn, you need not use oxygen, but some feel it is better for the eggs – this is pure conjecture. Air is a heck of a lot safer too. Before spawning, place the egg receptacle close to the fish. Hang the dry fish (no dripping blood or water) by the gills or head or jaw as in the photos. Insert the needle midline, just below the pectoral girdle, insert on a downward 45 degree angle to avoid hitting any tissues or eggs.

Start the flow. This is the tricky part - watch for the flow of eggs to begin. You want a steady stream, not a machine-gun expulsion of eggs. Don’t let the eggs make a drumming sound in the container; after all, they’re eggs. Regulate the flow to about 10 PSI or less, the better systems have a valve on the needle, but this makes it heavy, so you have to hold it the whole time. If the needle (10G and 10cm long) is attached to the hose by finer tubing, it need not be held in place and your hands are free to do other things - it takes fewer people.

Keep your eyes open for broken eggs or broken bits of ovary or tissue. Avoid making the hen look like a zeppelin. This serves to either spew eggs in a manner akin to projectile vomit from a three-year-old or explode like a pizza-pop on max power in a microwave. In any event, it's funny to watch but hell to clean up.

The eggs should make a pleasant plopping sound as they are expelled. This should be in a constant and steady stream. Near the end of the egg supply, the hen will start to fart and you should slack off on the pressure or wiggle the needle to let out pressure. Take the egg catching container out from under the fish and give the fish a shake by the tail. Put the needle back in and the container back under and apply a bit more pressure. Before undesirable stuff comes out, stop the flow and get the eggs out of there. Then take you samples after you open the carcass.

At any time if the flow is interrupted, back off on the flow and give her a wiggle. A partial ovulated female will cause the most trouble. Gravity and pressure are working against you here. Sometimes you have to take her down and invert her a couple of times before resuming the egg take.