The Point of Hooks

[PeterSL]

It's easy to pick and choose research studies that support your own beliefs on catch and release mortality, barbed vs barbless hooks etc. but here's a summary by a reputable scientist of 107 related studies that I just received from KeepEmWet Fishing https://www.keepemwet.org/ Figured it would be of interest to many on this forum.

THE POINT OF HOOKS
By Sascha Clark Danylchuk

Hooking damage is the number one cause of mortality for fish that are caught-and-released. That’s not a surprising statement since hooks are the only commonality for all fish caught by recreational anglers. But what that statement doesn’t address is how and why fish die from hooking damage. If every fish that is landed has a hook wound, what is it that makes some fish die and others live? How much damage do hooks actually cause? Does it matter what type of hook you use? What other factors come in the play to determine if a fish lives or dies after being hooked?

This paper looks at hooks and specifically hooking mortality in many different studies. It’s called a meta-analysis, which is a statistical analysis that combines the results of multiple scientific studies. It’s also a great introduction to Dr. Robert Arlinghaus, our newest science ambassador. Robert’s work is often based a social-ecological systems approach, which means that he looks at fisheries issues through the lens of both fish ecology and social science.

What did they do?

Looked at hooking mortality studies for fishes that are important in European freshwater recreational fisheries. All species in a genus were included, even if the species were not found in Europe. Studies conducted anywhere in the world were included in the study.

• 107 studies on 8 European species and an additional 10 species from the same genus.

• Extracted what caused mortality from each study:
Water temperature
Fish length
Hook type (singe vs. treble)
Existence of a barb (barbed vs. barbless)
Type of bait (natural vs. artificial)

What did they find?


Across all studies and species:

• Mean hooking mortality was 15.9%, with a range of 0 to 88.5%.

• Half of the studies reported hooking mortality of less than 10%. Only a few studies reported mortality levels over 50%.

• Factors that are important for hooking mortality:
Water temperature (higher water temperatures lead to higher mortality rates).
Bait type (average mortality for artificial baits was 11.4%, average mortality for natural bait was 25%)
Existence of a barb (average mortality for barbless hook was 8.2%, average mortality for barbed hooks was 14.6%).

For Salmonids:

• Results for trout and salmon species was similar to the overall results.

• Factors that were important for hooking mortality:
Water temperature (higher water temperatures lead to higher mortality rates).
Bait type (average mortality for artificial baits was 11.6%, average mortality for natural bait was 27%)
Existence of a barb (average mortality for barbless hook was 8.6%, average mortality for barbed hooks was 15.1%).

Takeaways:

• The good news is that most of the reported hooking mortality rates were very low (less than 10%).

• High mortality was most often due to deep hooking or when fish were caught at high water temps.

• There are several reasons why barbed hooks could lead to higher mortality rates than barbless hooks: barbed hooks have been known to cause more injury and bleeding, they also take longer to remove which often increases handling time and air exposure (both things known to lead to worse outcomes for fish), and either or both of these could increase stress levels in fish which also leads to poorer outcomes for fish after release.

• Despite the fact that in this study hook type (single vs. treble hooks) did not turn out to be significant, the authors think that hook type is a species specific issue and likely dependent on hook size as well as the mouth morphology of the fish, and the type of fishing. All these factors could not be teased out in the present study, but are likely important on a species by species basis.

[bobalong]

I see this study is on European waters. Having fished walleye tournaments on the NAWT now the WCWT for over 2 decades my observation was that catch and release numbers were substantially better in the Alberta lakes. Back in the late eighties and early nighties tournaments were new, as was keeping fishing healthy, and adopting good catch and release techniques....all had to be learned and were constantly being improved.

Temps were checked in livewells, no fish were bagged, all went from livewell to weigh tub, delayed mortality studies were also done. F/W gave seminars and helped with the handling techniques, livewell techniques and release techniques all evolved and improved over time. Instead of bringing fish to shore to weighed and released in warm shallow water, at first release boats were utilized moving fish to deeper water before being released.

Eventually pontoon/weigh boats were used being moved to deeper water and anchored. Fish were observed in a holding tank on the pontoon boat which was oxygenated and then fish were released directly into the lake. On the very hot days ice was used on the Pontoon holding tank and angler boat livewells to insure that heat/oxygen levels were kept at an acceptable level. Over time most tournaments were allowed only in May, June and September the cooler months of the summer.

I was one of the members of the WCWT (now called) involved when the F/W approached the ( now) WCWT to assist with a best practices for walleye tournaments. This involved all rules and regs from licensing up to and including all aspects of a CFE (competitive fishing event). These new "best practices" were finalized in August 2006. From Sept 1, 2006 the "best practices forms became the rules and regulations for hosting a CFE. CFE had different categories based on the number of anglers and prizes/payouts and these categories had different rules and regs.

The new CFE license became official Sept 1,2006 and I applied for and received the first CFE license in Alberta for our "Last Cast" tournament on Pinehurst lake in Sept of 2006 .

Although F/W did not agree with everything we initially presented and changes were made much of that first draft with some safety and other modifications was accepted and is still the basis for the current CFE license.

Some of the tournament walleye were measured by F/W biologist and staff from the ACA at a few of our tournaments. Our techniques, water temps were all monitored and I remember walleye mortality being measured in single digit numbers rather than percentages.

I competed in some tournaments on the Southern and Sask Walleye Trail but am not familiar with their techniques or mortality rates.

[AK47]

I have seen similar studies where there was no difference between barbed or barbless hooks although it was for pike and walleye. Obviously salmonids are much more susceptible to hooking mortality so barbed or barbless when fishing for them could make a small difference.