I don't have access to the whole paper, but the abstract leaves me with lots of questions. 

The net of it is that they conclude it is better to cut the line that do the through-the-gills, which I have a hard time believing based how on easily the hook usually pops out. 

 

https://www.sciencedirect.com/science/article/abs/pii/S0165783622000996

 

Highlights

•We evaluated the use of the “through-the-gill” method to remove hooks from the gullet of deeply hooked fish.

•Hook removal via the gills increased the chances of sublethal outcomes, particularly for barbed hooks.

•The highest mortality (24%) occurred for fish that had barbed hooks removed using the through-the-gill method.

•When anglers use barbed hooks and encounter a deeply hooked fish, cutting the line poses the least risk to the fish.

Abstract

Sustainable catch-and-release fisheries are based on the assumption that most fish survive an angling event. The adoption of best practices has become important to help mitigate post-release injury, behavioral impairment and mortality. However, in any catch-and-release fishery, a proportion of fish will become inadvertently deeply hooked (e.g., in the gullet) and numerous studies have shown this to be a major driver of mortality.

 

Although available science suggests that cutting the line tends to yield better outcomes than removing hooks in the gullet, there has been interest within the angling community with removing hooks using the “through-the-gill” method where the hook shaft is turned outwards into the gill region and then the hook is removed by pulling anteriorly by gripping the outside bend of the hook. Here, we tested the efficacy of removing barbed and barbless hooks though the gill opening from experimentally deep-hooked Smallmouth Bass (Micropterus dolomieu) relative to leaving the hooks in place.

 

Using a control group and four experimental treatment groups (barbed and removed through the gills; barbless and removed through gills; barbed and left in; barbless and left in), we evaluated handling time, presence of bleeding, incidence of gill or esophageal injury, reflex impairment, incidence of hook shedding (for the left in treatment groups), and survival across a 24-hour monitoring period.

 

Collectively, our results suggested that when hooks were barbed and removed through the gills, fish condition and survival were lower. In addition, barbed hooks were more likely to cause bleeding, gill damage, esophageal tearing, and impair reflexes. When hook removal was done through the gills, the chances of all sublethal outcomes across all categories were more likely to occur. While short-term mortality was not statistically linked with any treatment group, the greatest percentage of mortality (24%) occurred for fish that had barbed hooks removed using the through-the-gill method. These data suggest that when anglers use barbed hooks and encounter a deeply hooked fish, cutting the line poses the least risk to the fish.

It’s almost always the tiny ones that are hooked in the throat for me with smallies, I have to cut the line sometimes. Aggressive little boogers 

I've got the full paper and a couple others that have been done in reference to the "through-the-gills" hook removal method over the years. I wrote a short piece about it (one of the papers) several years back for another site:

 

Watching anglers remove hooks from the jaw of a largemouth bass can be pretty enlightening. Seems everybody has their favorite technique. Some reach for the long-nose pliers, while others do that fancy “pop the hook with the palm of your hand” thing. You’ve seen it done – just don’t know who in the hell invented it - brilliant though. We’re all kind of like pseudo-dentists, minus the 10 years of advanced medical training necessary to perform our extraction magic on other people.

 

Well, a very cool study was recently published concerning largemouth bass hook removal technique and effects. Effects of Four Hook Removal Techniques on Feeding, Growth, and Survival of Deeply Hooked Largemouth Bass by DeBoom, et al. took a scientific look at several common hook removal methods. What makes the study so neat is the intentional inclusion of the "through the gills" removal technique made popular by a Ralph Manns piece back in 2002 in In-Fisherman magazine and revisited again by Doug Stange some years later. The study authors even went so far as to use the exact same hook style in their testing as was done in the original publication piece.

 

The study techniques involved a control set of fish that were hooked in the oral cavity (that’s science geek talk for "the mouth"), but not deep, as well as the deeply hooked fish that were given 4 treatment types:

 

> barbless method - through the mouth with hemostats

> standard method - through the mouth with hemostats

> through the gill method- the IF technique with hemostats

> hook in method -  left the hook in the mouth with 1" or less of cut line attached

 

After all the testing was complete, fish were placed back into ponds and checked in both the summer and the fall for feeding and growth. Results included:

 

• Hook removal method has no influence on survival of deeply hooked largemouth bass angled using these gear types.
• The authors found no evidence that deeply hooked largemouth bass suffer reduced growth compared with fish hooked in the oral cavity or among deeply hooked fish subjected to various hook removal techniques.
• No method for removal of deep hooks in largemouth bass was found to be advantageous in terms of growth or survival.
• Necropsies of eight surviving fish that originally had hooks left in revealed that all of the fish had shed their hooks by the end of the experiment.
• Although air exposure varied among treatments (ave. 8-60 sec.), these patterns were not consistent with measures of feeding recovery, suggesting that the observed periods of air exposure had little negative effects.

 

So get the darn hook out of your fish’s mouth with whatever tool you’d like, or no tool at all. Just be quick about it.

 

Just now, Team9nine said:

We’re all kind of like pseudo-dentists

 

Just now, Team9nine said:

So get the darn hook out of your fish’s mouth with whatever tool you’d like, or no tool at all. Just be quick about it.

 

Thanks for posting that study! One of my biggest questions about the first one was what about long-term mortality?

13 minutes ago, txchaser said:

 

Thanks for posting that study! One of my biggest questions about the first one was what about long-term mortality?

 

The study you cited is a newer one that questions to some degree the findings in the one I wrote about. However, the key finding (IMO) is the final two sentences of this newer study, especially: "short-term mortality was not statistically linked with any treatment group," meaning they basically came to a similar overall end result in that respect as the initial study, though they have some concerns based on their specific data showing higher occurrence of possible damage/death based on outright numbers in their study for the barbed "hook through the gills" method.

I wonder how they performed the "through the gill" hook removal process? I mean someone with years of experience probably has much better results then a newb.

 

I also wonder why the barb matters. It seems like it wasn't an issue the few times I've done it. I did stick one with the hook point though. But the barb?

14 hours ago, schplurg said:

I wonder how they performed the "through the gill" hook removal process? I mean someone with years of experience probably has much better results then a newb.

 

I also wonder why the barb matters. It seems like it wasn't an issue the few times I've done it. I did stick one with the hook point though. But the barb?

 

They performed as originally written and published by In-Fisherman, as well as shown in a couple videos by TPWD, *** and TB. They claimed at least some experience with the removal technique. As for the barbed part, from the full study:

"This study revealed that barbed hooks that were removed from the esophagus of SMB using the through-the-gill method took more than twice as long to remove than barbless hooks. Moreover, barbed hooks were more likely to cause esophageal tears and bleeding. No matter if the hook was barbed or barbless, removal through-the-gills had the potential to damage the gills. All of the sublethal outcomes that we assessed were worse for fish that had hooks removed than those that were left in place. Removal of hooks from the esophagus has the potential to damage vital organs and vasculature."

The through the gill method is quick and easy with just a little practice and the right tools. Learn to do it and don't leave hooks in fish. I've caught too many paper thin fish with hooks in their throats to believe that leaving the hook in is the best option. 

Very true.........Kill & give the fish to someone who will eat it.

Starting to think about just cutting the hook on bigger fish. I carry cutters with me in the boat, and I'd trade a hook for better survival. Some of my big heavy hooks also have big barbs. Might not make any difference after I'm fiddling around in the throat with a big pair of cutters though.