I climbed up on my catch & release soap box recently, again, http://outdoornebraska.ne.gov/blogs/2011/12/hitting-ice-winter/ , now let me talk about some fish handling specifically for the ice season.
With the coldest water of the year, fish are VERY releasable when caught through the ice. However, there are some special circumstances that must be kept in mind. First of all, of course, would be the air temperature. When pulled through an ice hole, the fish come out of water that will be above freezing, 32 degrees F, but once they are exposed to the air, fish may be exposed to temperatures that are much colder than 32 degrees. Fins, eyes and gills can be especially vulnerable to cold temperatures. If you are fishing on a day with cold air temperatures, way below freezing, you need to do everything you can to keep fish that are going to be released from having frost burn or freeze damage. At the coldest temperatures, a person may have less than a minute to get fish back into the water.
I have augered holes partially through the ice and then filled them with water to be used as ice “livewells” or a person can take an empty bucket and put some water in it. If you are not going to release a fish immediately, say you want to get the camera ready for some pictures, or you need to find some tools to remove hooks, slip ‘em into one of those ice livewells or buckets of water. Another option I have employed is the use of a mesh laundry bag; a fish can be placed inside that bag and then it can be slipped down a hole into the water.
Even if you choose to selectively harvest some fish while on the ice, throwing those fish on the ice is a good way to keep them, but not the best way. You do not want your harvested fish to freeze; keeping them cold and ALIVE is the absolute best handling that will provide the best quality and freshest fillets on the table.
On days when the air temperature is not extremely cold, near freezing or above, the ice surface itself is not too damaging to fish. Certainly the frozen surface of ice is a lot easier on fish and their slime coat than letting them flop on the bottom of a boat, ice shack floor, or on the sand and gravel of a bank. However, if there is snow on the ice, it is best not to let fish that are to be released flop around in the snow as that will remove slime from the side of the fish. Removal of the slime coat or mucus from the skin of a fish will make them more vulnerable to infections after release.
Tools for hook removal are essential for all fishing. During the winter relatively small baits and jigs are used especially for panfish and at times even panfish can suck small baits deep into their mouths. In my opinion the best tool for removing those hooks would be a pair of forceps.
I will almost always have a pair of forceps clipped to my bibs while I am on the ice catching panfish.
For bigger fish and larger hooks there are a variety of needle-nose pliers or hook-out tools that will do the job. Choose your favorite; I like extra long nose pliers myself, http://www.cabelas.com/product/Fishing/Fishing-Tools/Pliers-Grippers-Hook-Removers%7C/pc/104793480/c/104720580/sc/104505480/Cabelas-Advanced-Anglers8482-Pro-Series-Fishermans-Tools/701680.uts?destination=%2Fcatalog%2Fbrowse%2Ffishing-fishing-tools-pliers-grippers-hook-removers%2F_%2FN-1100396%2FNs-CATEGORY_SEQ_104505480%3FWTz_l%3DSBC%253Bcat104793480%253Bcat104720580&WTz_l=SBC%3Bcat104793480%3Bcat104720580%3Bcat104505480 .
Put a lanyard of some type on the handle and attach your pliers or hookout tool to a belt, bucket or to your bibs. That way you will have them handy when you need them and you can keep them from getting kicked down an ice hole.
If you do any ice-fishing for northern pike, and a lot of Nebraska anglers do, then you absolutely need a set of jaw-spreaders as well. Here are probably the best ones I know of, http://www.muskyshop.com/modules/cart/products.php/nav_id/28/page/1/id/2704/name/TyrantTackleJawSpreaders .
Jaw spreaders have often been very handy for me when removing the hooks from other large fish as well. They are a necessity for the big toothies, but if you catch and release any large predator fish you should have a pair. Absolutely make sure you tie a lanyard or cord to your jaw spreaders and attach them to something solid. You do not want to lose them down an ice hole and you do not want a fish to accidently slip from your grip with the jaw spreaders still in their mouth!
The catch & release of any fish provides no benefits if those fish do not survive. Fortunately, with some care, fish caught through the ice can be released with an excellent chance of survival. As always my motto for catch & release is to land ‘em as quickly as possible, keep ‘em in the water and handle ‘em as little as possible, and then get ‘em back in the water from which they were caught as soon as possible!
And remember so support them horizontally, especially big fish!