What do you do with deeply hooked fish?
Response by Ralph Mann - Dated 07/23/04

Deep Hooks: In or Out?

    Those of us who try to share the findings of scientific study with non-scientists are often frustrated. It seems very difficult to get the word out. We write about some important discovery, but find anglers, particularly the influential professional and TV bass anglers, either don't read the new information or dismiss the new scientific insights because they conflict with beliefs the anglers already hold.

    Professional and TV anglers aren't the only ones to be slow in learning and applying the latest "word" from scientists. Biologists, particularly state fisheries workers are often too busy with their own assigned tasks to read all of the literature produced by other scientists. They continue to advise anglers to handle fish using outmoded procedures.

    The recommendation that anglers cut the leader close to the hook when bass are "deep-hooked" is a good example. It is hard to find a publication on catch-and-release (C&R) techniques that doesn't pass on this poor advice. Yet, recent research on release techniques strongly suggests there is a better way.

    Some years ago, Doug Hannon noted that most magazine articles and state publications recommend leaving hooks in bass and other fish to "rust" out. He reported that hooks don't rust fast enough, even in salt water; and suggested that the shank of a hook pointing up the throat of a bass acts like a lever or trap door that prevents swallowing. Bass can die of starvation while waiting for normal body processes to eject the hook. Food coming down a bass' throat will bypass a hook-shank, IF the shank lies tightly against the side of the throat where the barb is lodged. However, if the shank protrudes into the throat, food coming down can push the shank across the esophagus, blocking it. Deep-hooked bass may even feel pain as the food rotates the barb and regurgitate the food.

    Recently, Hannon's observations have been scientifically verified. John Foster, Recreational Fisheries Coordinator for the Maryland Department of Natural Resources, studied striped bass at Chesapeake Bay. His researchers held throat-hooked stripers between 16- and 28-inches long for observation in half-strength seawater so that hooks had ample opportunity to rust away. Size 1/0 and 2/0 stainless steel, bronzed, nickel, tin, and tin-cadmium plated hooks were hooked in the top of each fish's esophagus, with an 18-inch length of line connected to the hook.

    After four months, 78 percent of the hooks were still imbedded. Cadmium coated hooks poisoned 20 percent of the fish, and production of these hooks has been stopped. Bronzed hooks were less likely (70%) to be retained than tin-cadmium (80%), nickel (83%), or stainless steel hooks which were all retained (100%).

    In a second test, the line was clipped either at the eye of the hook as advised by most existing C&R guides, or well outside the fish's mouth, . One-hundred percent of the stainless hooks were again retained, while 56 percent of tin, 76 percent of bronze, 84 percent of tin-cadmium, and 88 percent of nickel hooks remained. Fish mortality was greater when all line was trimmed. Foster suggested that the lengths of line hanging from a fish's mouth kept the hook-shank flat against the side of the esophagus and allowed food to pass. Without the line, food could move the hook and close the throat.

    Hooks rusted slowly in stages, and the bend and barb became smaller very gradually. Stripers formed scar tissue around imbedded hook points, a typical reaction of body tissue to foreign matter. Foster noted, however, that once the tough scar tissue formed, hooks became more, not less, difficult to remove. Months after fish were hooked, infections sometimes developed around points, causing some deaths.

    Based on this research, Foster recommended anglers carefully remove even deeply imbedded hooks. If a hook can not be removed, then it seems better to leave about 18 inches of line attached. Perhaps, someday, these findings will reach C&R anglers, the biologists who are researching C&R and publish C&R guidelines, and TV anglers who teach by their example.

    Removal is usually best for a released bass. But, the hook should be easily reached. A back up option is to carry a specially designed, slim-necked tool called the D-Barb to reach and cut off barbs and points of any hooks you can not rotate out.. To be strong enough to cut or crush down the barbs of heavy hooks like True-Turn Brutes, the tool usually must have heavy jaws and long handles but not be too wide.. Forcing large wire-cutters into the gullet of small bass can do as much damage as leaving a hook in place.

    Best for the fish is using barbless hooks. They greatly reduce hook damage to all mouth tissues and rotate out easily. (See the through-the-gills comments below).

    Texas researchers compared the mortality of largemouth bass hooked with live bait and artificial lures. Their main finding: "there is no biological justification to regulate use of live bait to catch bass" has been widely publicized. Their other findings may help anglers make appropriate adjustments in technique.

    In two separate tests, largemouth bass in a private water were landed by TPWD anglers using Carolina-rigged scented plastic worms, crankbaits with multiple treble hooks, and live carp fished with either a Carolina rig or a float. To simulate normal fishing conditions, anglers with different levels of expertise were used.

    While fishing with floats, anglers were instructed to delay hooksets until floats went completely under, simulating the way typical amateur anglers fish with unattended rods. Under all other conditions, anglers were to strike immediately upon feeling a hit. Captured bass were immediately examined to identify hook-related injuries. When bass were hooked deep in the throat, the line was cut and hook left in place. (TPWD did not identify whether the cut was made in the traditional way near the hook, or with line remaining outside the fish's mouth.) Bass were then kept in a large holding net over a 72-hour observation period to determine short-term mortality rates. Sixty bass were taken using each method. Tests were made in August, when water was warm and stress and mortality are normally high.

    The average mortality under these worst-case conditions was 22 percent. Carolina rigs with flavored worms caused the highest mortality, followed by live carp used under floats, crankbaits, and Carolina-rigged carp minnows.

    TPWD biologists concluded that the timing of the hookset appeared more critical than the type of bait used in the determination of short-term death rates. The data show bass hooked in the throat had poor survival odds. Evidently, largemouth bass took both lures and live bait fully into their mouths almost immediately. The bass pros' advice to strike without delay is important to reduce mortality. Angling techniques that delay hooksets should be avoided.

    Carolina-rig and worm combos likely killed more fish because the lengthy leaders prevented immediate detection of some strikes and flavored worms are quickly and easily swallowed. Eighteen percent of bass taken on Carolina rigs with worms were throat-hooked.

    In contrast, Carolina rigs with live bait and live baits under floats caused less mortality, likely because live preyfish are often held in a bass' mouth for a few seconds, killed, and turned to be swallowed headfirst. This gives anglers a few seconds more to detect hits before baits are ingested. The decision to delay hits when live baits were used with floats and to strike immediately with Carolina-rigged baits likely caused the different mortality rates of these two techniques. Nevertheless, 10 percent of bass hooked on Carolina-rigged live baits were hooked in the esophagus. It is no surprise that crankbaits are less likely to be swallowed, as their artificial nature is immediately detectable to fish.

    When fisheries are managed primarily for C&R or trophy bass production, it may be appropriate to ban use of multiple rods to reduce delayed hooksets, or to limit lures to items unlikely to be swallowed. In any case, C&R sportsmen will want to avoid techniques that delay hooksets, like fishing with unattended rods.

    The TPWD study showed that bass hooked in the tongue and esophagus had about a 50 percent chance of dying, while bass hooked in the lips mouth, jaw, roof of mouth had 25 percent or less mortality. Interestingly, only 12.5 percent of gill hooked fish died. This finding suggests anglers who kill and eat or mount gill-damaged bass because "they are unlikely to live" are in error.

    TPWD also compared the survival of bass when they were bleeding and when leaders were cut and hooks left in the fish. Removing hooks improved bass survival when bass were not bleeding. But there was little difference in mortality when bass were bleeding or hooks were left in the fish.

    When I read that some anglers removed hooks by working through the gill slits several years ago, I reacted negatively, assuming excess damage would occur. But, upon reflection on the normal function and resistance of gills to external damage, I decided to test the procedure for myself. In a private pond with barbless hooks I've now made over 950 gill-slit removals of barbless hooks without any observed fish deaths or apparent bleeding or gill damage. Several individual bass with identifying marks have been caught again and again. Although some unobserved delayed deaths are likely, if the procedure was exceptionally hazardous I likely would have seen several floaters.

    Despite their fragile appearance, the gills of bass are one of the strongest and most disease resistant structures of the bass, equivalent in resistance to skin of the lower jaw that we grasp so handily. After all, the gills are constantly exposed to outside influences. The prey the bass eats brush against them, and many prey are caught because they are sick and carrying diseases. Prey with spines cut and stab bass in the gill areas. With food, bass often ingest goop and disease laden muck from the bottom. Moreover, each breathing gill movement brings whatever bacteria, viruses, and dirt is in the water over the filaments. To function, gills must be tough. light contact isn't likely to damage gills or introduce disease. They are as resistant as the fish's skin to light contact.

    Still caution is needed. Gill filaments, the red comblike elements, are not reversible. Like a flag, they naturally stream with the flow. They never should be forced back toward the mouth by a tool or by reverse water pressure. Swishing a bass or any other fish back and forth to "revive it" can do more harm than good. If the fish need to be revived by more oxygen, move it slowly forward through the water. But, do not force water down its throat by moving it rapidly into a current.

    By using barbless hooks that reverse easily, an entry through the gill slit can often be used when entry through the mouth is impractical or impossible with typical tools. A small, narrow pair of long-nosed pliers should be used, so the tool can be rotated without putting pressure on the gill arches. If an angler is particularly clumsy, or careless, the procedure could cause significant damage, making leaving a hook and long leader in the bass a better option with higher odds of survival.

    Anglers practicing C&R rather than eat legal bass or legally abiding with a slot limit might note these findings. Fish caught with only superficial wounds are likely to survive release. Small, deeply-hooked, bleeding, and legal bass likely should be eaten, rather than released to die later. Slot bass must be released in as healthy a condition as possible. And lunker bass larger than 24 inches are so rare and valuable in any fishery that they should be immediately released, even if they are bleeding or deeply-hooked. Remove the hook if possible, but leave an 18-inch leader if you can not remove the hook.


This article is protected by copyright, and may be reprinted for public use only with my written permission. However, I want the information in this article to get maximum exposure to other anglers, so reprinting of this specific article is encourage when permission is obtained. (

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