I think we generally do our best to take care of the fish we catch. Still, there are lots of theories on how best to do it, and it can get pretty confusing.
Should we use ice or not? Should we add products to the water in the livewell? Is it better to lip the fish or hold them with two hands? I’m not a biologist, but through simple trial and error and observations over the course of my career I believe I have some ways to keep fish healthier.
It all starts with the hook set. There are some baits that fish are more prone to swallow, and others that are almost guaranteed to get the hook in the lip of the fish. There's not much we can do about it, but whenever possible early hook sets are better for the fish. If we allow a fish to choke a Carolina rig down to the gullet then set the hook, that fish is more apt to be injured. Although there’s no way to keep this from happening, just understanding that early hook sets help is a good start.
Landing the fish is when most of the damage is done. Keep the fish off the carpet of your boat at all costs. For fish that are big or tough to handle, I do my best to land them on a large sticker that I have in the center of my front deck. This sticker is plastic which is much better for the fish than carpet, especially hot, dry carpet.
When I swing a fish in the boat, I often catch the line and keep the fish from landing on the carpet. Most of the time I like to reach down and boat the fish by hand, thereby eliminating a lot of stress on the fish.
Once you have the fish in the boat, get the hook removed as fast and as non-invasively as possible. I like to hold the fish just about where the head and the body meet on the back while I remove the hook(s). I use my thumb, first and middle fingers and with a little pressure you can immobilize the fish while you hold them. You must have wet hands. As an alternative, lipping them isn't a bad way to hold them, and for bigger fish it's the only option. Then get the fish back in the water or into the livewell as quickly as you can.
Keep in mind — especially for fish caught on light line — they just got through fighting for their lives and are spent. Much like you or I after a workout, they need more oxygen. Getting them back into the water or into the livewell fast will increase their recovery chances.
If you add tags to your fish before you put them in the livewell there are some simple tricks to doing this in the best possible way. First, I sharpen all of my culling tag pins, this makes them go into the fish fast and easy and with as little of a tear as possible. Next put it as close to the tip of the fishes jaw as possible. The further back on the fish you insert the pin the bigger the hole. This affects the "vacuum" suction that a fish uses to inhale its food. I have caught a lot of fish with big holes, big enough for my finger to fit through, and it bums me out when I see that.
For livewell care, I don't recommend adding anything other than possibly ice and rock salt (which is non-iodized). However, there are some things you can do to make your livewell function better. First, be sure that your livewell has both the fresh and recirculating water entering from the top of your livewell. You want the surface water of the livewell to be as disturbed as possible because it increases the oxygen level for the fish. I re-plumbed mine a while back and since then my fish have been healthier than ever. This alone will increase the health of your fish.
Next, be sure that the bolts, screws or locking mechanisms on the underside of your livewell lids are protected. Adding rubber butt caps on them can help protect the fish from being injured especially in rough water. Lastly, be sure that you run your livewell on manual and that it’s bringing in fresh water all day. The only exception to this would be to run your livewell on recirculate when you are in a shallow or backwater type of area. Remember to switch it back to fresh water as soon as you leave that area.
When it comes to ice, I don't use it much anymore. Once I re-plumbed my livewells to bring the water in from the top I haven't needed much ice. However, I do use ice almost always when I am catching fish below 15 feet deep. Those fish are coming from cooler water and keeping them in similar temperature water is a good thing for their health.
Lastly, the tubs full of water and air stones in line for the weigh-in aren't there to help you hold the fish. They are there so you can give the fish fresh water. At B.A.S.S. tournaments, we have a double bagging system so once the fish get to the tanks they’re in mesh bags and getting completely fresh and well-oxygenated water, but other tournament circuits may not do this. If you’re fishing a circuit that forces you to keep your fish in solid bags in the weigh-in line, empty at least half the water from the bag and give them new water while you wait. If you’re there for more than 10 to 15 minutes, empty half the water and reload it again. This gives the fish fresh oxygen and takes very little effort.
Fish care really goes beyond the loss of weight for a penalty. We need to take care of what we catch so we can catch them again someday soon.
There’s a terrific page here on Bassmaster.com put together by the B.A.S.S. conservation team that will give you lots more great tips for keeping bass alive.
Good fishing to you all! Get 'em in the boat and take care of them.