The Truth About Hooks & Lures
New Jersey Freshwater Fishing
The Truth AboutHooks&LuresBy Scott Collenburg, Fisheries BiologistThe prevalence of catch-and-release fishing among today’s anglers—coupled with increased restoration efforts for struggling species such as trout—has renewed some age-old debates about hooks and lures. In the realm of fishing, facts on which hook types are the most ethical (barbed versus barbless, treble versus single) and which hooks will have minimal impact— from the fishes perspective—have been debated since the 1930’s when Fred Westerman, while Chief of Fisheries for the Michigan Department of Conservation, conducted one of the earliest studies. Over 80 years and numerous studies later, the dispute about hooking mortality continues.
Conservative approaches to managing fisheries resources have been implemented over time in an effort to protect vulnerable species such as trout. Knowledge of what practices are most effective is essential. In New Jersey Division of Fish and Wildlife’s 2012 trout angler survey, 64 percent of trout angler respondents indicated they released most, or all, trout caught—an 11 percent increase from 2003 when the same question was asked. In a 2016 online survey of anglers who fish for wild trout, 74 percent either moderately, or strongly, supported catch-and-release-only regulations on wild trout streams.
When the conservative catch-and-release approach spread among anglers, so did an increased interest in restricting the use of specific gear types. As a result, requests for regulations implementing barbless hook restrictions, banning of treble hooks or banning bait have increased steadily in recent years. The ultimate success of catch-and-release angling (either by regulation or by angler choice) undoubtedly rests with ensuring high survival rates of the released fish.
Scientist, Neil deGrasse Tyson once stated, “The good thing about science is that it’s true whether or not you believe in it.” But what if the science isn’t so clear? Like an angler in a stream, let’s wade through the myriad of—often contradictory— scientific literature about hooking mortality.
Do barbless hooks cause more mortality than barbed hooks? Are treble hooks more dangerous to fish than single hooks? Are timing restrictions beneficial such as no wading or fishing during spawning?
Hooks: Barbed vs. Barbless
Fish mortality from barbed versus barbless hooks seems intuitive. No barb makes removing a hook easier. There’s less stress and, naturally, less mortality, right? Surprisingly, no. A majority of scientific studies on trout, a species intolerant of any level of mishandling, have shown that mortality from either barbed or barbless hooks is not significantly different (Mongillo 1984; Schill and Scarpella 1997; Dubois and Dubielzig 2004; Dubois and Pleski 2007.)* This suggests there is scant biological basis for restricting barbed hooks.
Since unhooking a fish is easier when no barbs are used, why don’t more studies reveal a higher mortality with the longer handling time using barbed hooks? Dubois and Dubielzig (2004) explain that “…barbless single hooks were quicker to remove than other hooks, but the difference was insufficient to reduce mortality.”
In fact, handling time is taken into account in each of these studies. Post-release mortality is often monitored by retaining fish for a 48-hour period after being caught. Still, in many cases, no mortality difference is documented between barbed or barbless hooks. Some studies suggest that a barbless hook causes higher mortality through what is called the “stiletto effect,” where single hooks tend to penetrate deeper (Behnke et al 2007).
In addition, researchers have theorized that even if a difference in hooking mortality is documented, the effect on the overall population is negligible because natural mortality rates for wild trout are so much higher, commonly ranging from 30 percent to 65 percent of the population annually. Although research indicates little protection is afforded to trout populations through the use of barbless hooks from the mortality aspect, two studies do document a decreased rate of injury with their use. (DuBois and Dubielzig 2004; DuBois and Pleski 2007).
Contrary to research results there is strong social support among New Jersey wild trout anglers for implementing barbless hook restrictions. In Fish and Wildlife’s 2016 online wild trout survey, anglers were asked if they support or oppose a barbless hook-only restriction. Results: 68 percent either strongly or moderately supported such a restriction. This would not come without cost. Bloom (2013) documented a 13 percent decreased angler efficiency in landing trout using barbless hooks. (Mean capture efficiency of 76 percent for anglers using barbed flies vs. 63 percent using barbless flies.)
Only marginal benefits of reduced injury to individual fish were realized using barbless hooks. Overall, requiring the use of barbless hooks is not beneficial to trout populations and can reduce angler catch rates. In the end, with the lack of strong scientific support, the best option may be to let anglers continue to decide for themselves.
Hooks: Single vs. Treble
The safety of single versus treble hooks is about as straightforward as it gets. The logic is simple: more hooks, more injury, therefore increased mortality, right? Again, not true. On treble hooks, research is just as conclusive as the barbed vs. barbless question. However, deviations exist when we delve into variables related to size of fish and temperature.
The data is based on two major scientific papers which reviewed multiple studies; Taylor and White (1992, review of 18 hooking studies); and a review by Mongillo (1984). Both concluded that the number of hooks did not show a statistically significant relationship to hooking mortality. Mongillo (1984) concluded that little justification exists for gear restrictions for artificials and data even indicates that the practice of using single hooks on lures may actually cause higher mortality than treble hooks.
A study by Titus and Vanicek (1988) also found no significant difference with mortality (using either gear type) at less than 1.5 percent when water temperatures were low. Surprisingly, when temperatures were higher, single barbless hooks actually caused the highest mortality (59 percent).
A more recent study by DuBois and Dubielzig (2004) also demonstrated that hook types did not differ statistically in causing mortality. A higher mortality rate from treble hooks was documented with larger trout. Larger fish have a larger gape enabling them to fully engulf a treble hook (Nuhfer and Alexander 1992). However, many investigators fail to discover this relationship because test fish, like many of our wild trout, are typically small, less than 12 inches.
Interestingly, the inverse relationship is sometimes found with smaller salmonids, where single hooks are found to be more lethal than treble hooks (Klein 1965; Warner 1976). This was a result of treble hooks being more difficult to engulf for smaller salmonids.
Research shows little justification to restrict treble hooks based on fish mortality although one study reviewed by Dubois and Dubeilzig (2004) documented a significantly greater rate of jaw injury in brown trout using treble hooks with spinners than with other hook types. No differences were evident with rainbow trout nor when assessing serious injuries to eyes or gullet. It should be noted that the study design could not determine if jaw injuries occurred from previous capture events, an inherent problem with this type of research.
While treble hooks pose no greater impact to trout populations than single hooks and can even be beneficial with larger fish, there is evidence of increased jaw injury. Although the injury may not result in mortality because of the prevalence of catch-and-release, is it in the best interest of the resource for measures to be taken to reduce injury? Anglers may think so as 77 percent of New Jersey wild trout anglers responded that they strongly or moderately opposed the use of treble hooks in wild trout streams.
Bait, Lures and Flies
The use of bait causes significantly higher mortality than the use of artificial lures or flies and can be expected to range from 20-50 percent of fish caught on bait (Mongillo, 1984). Many studies have reached the same conclusion. For comparison, Mongillo concluded that all artificials induce a mortality of less than 10 percent, results consistent with other literature (Taylor and White 1992).
Recent research suggests baitfishing mortality is lower than the earlier studies of the 60s, 70s and 80s indicate. Schill (1996) documented only 16 percent baitfishing mortality of wild rainbow trout. Lower still, DuBois and Kuklinski (2004) found that when using an active baitfishing technique, mortality was no higher than 7 percent. The hook type and technique employed by the individual angler may be responsible.
A study by High and Meyer (2014) found that using baited circle hooks caused only 7 percent mortality in trout, compared with dry flies at 4 percent and treble hook spinners at 29 percent. It is important to note that the treble hook mortality rate seen in this study was much higher than those seen in single- versus multiple-hook studies. They suggest the use of circle hooks instead of J-hooks when baitfishing to reduce deep-hooking and mortality.
A practice that may be common among catch-and-release anglers using bait is the use of barbless hooks, again, to reduce effects of deep hooking. Schill and Scarpella (1997) noted there may be merit to using barbless hooks when fishing with bait but this is based on only two trials in the study by Fred Westerman in 1932.
There is significant variation between study conclusions on mortality from baitfishing, but in most cases lures and flies are the safest for trout. When using bait, anglers should employ methods that help reduce mortality including the use of circle hooks plus active fishing rather than a passive technique.
In some states, closures during trout spawning season are utilized to protect redds and to avoid further strain on trout already stressed due to spawning activities. Few such studies have been conducted due to the ethical dilemma of deliberately destroying trout redds for research purposes. However, as shown by Robert and White (1992), damage done by anglers wading through redds is a valid concern in areas that receive significant fishing pressure. Evidently, twice-daily wading (very heavy wading in a controlled, man-made channel) throughout the egg development period destroyed up to 96 percent of eggs and pre-emergent fry. Even a single wading just prior to hatching destroyed 43 percent of eggs. In areas where spawning habitat is limited and intensive angler wading occurs, restrictions on wading would appear well-justified.
Another study by Kelly (1993) found that wading-related mortality—in a natural environment, documented by anglers—of Yellowstone cutthroat trout ranged from less than 10 to 26 percent for eggs and pre-emergent fry. Kelly (1993) indicates that in a stable population where less than 1 percent of trout survive from egg to spawning adult anyway, wading-related mortality would not affect the population.
In fisheries that receive a significant amount of fishing pressure, restrictions during spawning may be beneficial. For healthy populations where only moderate fishing pressure occurs, negative effect of wading or fishing during spawning times appears to be negligible. Perhaps of greater concern is mid- to late-summer fishing pressure because the already-increased stress of higher temperatures and low flows are documented to cause high mortality (Titus and Vanicek 1988). As a result, some states have seasonal closures to protect specific fisheries during these times.
While specific gear types—aside from the use of bait—may have little effect on survival of released fish, an angler’s technique can be significant. Regulations aside, the following angler practices have been shown to reduce fish mortality:
- Keep handy at all times a small pair of pliers or forceps for quick and efficient hook removal.
- Reduce play time. Land fish as quickly as possible to minimize stressing the fish. Extended play time can exhaust the fish causing sub-lethal stress, reducing growth, impairing reproductive success and increasing susceptibility to disease or pathogens (Casselman, 2005).
- Keep the fish in the water as much as possible; minimize handling.
- Avoid fishing during very hot temperatures. Multiple studies have shown increased mortality under such conditions regardless of gear used.
- For an engulfed hook that’s deeply imbedded, cut the line and leave the hook. Numerous studies demonstrate that fish have the ability to shed the hook. For example, Mason and Hunt (1967) examined the effect of hook removal on the survival of rainbow trout up to four months after release. Fish released without hook removal had a 66 percent survival rate while only 11.5 percent of fish whose hooks were removed survived. Of those that survived with hooks left in place, more than half had shed the hooks.
When choosing bait:
- Actively fishing the bait—instead of passive fishing—decreases the chance the fish will engulf the hook.
- Use circle hooks. Although variation is seen among species, Cooke and Suski (2004) found that using circle hooks reduced mortality by about 50 percent.
*Literature citations are available with this article’s online version at http://www.njfishandwildlife.com/pdf/fwfisheries/hooksandlures.pdf.