Bass Catchability as an Inherited Trait

Back to the science - think Thomas Dolby - "Science!". We've touched on this subject before in discussions, but a new piece of research, Selection for Vulnerability to Angling in Largemouth Bass by Philipp, Cooke, Suski, et. al., documents and proposes catchability of bass as an inherited trait. Of course the corollary of that means creation of uncatchable bass given enough selection pressure. This research actually dates back to the early 80's when it was first initiatied, and then subsequently carried out through the mid-90's. 

Anyway, fish were caught and segregated amongst ponds based on catchability and then off-spring reared, tracked, and again segregated out based on the same. Baits used were a white curlytail grub and jig, a 7-cm silver floating stick bait, a small chartreuse spinnerbait, and a 12-cm black plastic worm. Fish could be tracked by fin clipping as to the number of times a particular individual was (or wasn't) caught. Each successive generation of segregated fish created further lines of divergence between the groups.

The researchers summarize,

"These authors reported that both the direct effects of fishing (i.e., elevated mortality) and the indirect effects (i.e., changes in system properties and function) can indeed result in fisheries-induced changes in the fish populations themselves, suggesting that fishing does have an evolutionary effect."

The interesting wording there being the linking of "direct effects of fishing" to "elevated mortality". That basically means bass that were caught and released but died, but more especially those caught via tournaments that then subsequently perish via (delayed) mortality. This, arguably, then has a direct effect on trait inheritance by leaving less vulnerable fish in the population to reproduce. Interesting.

The authors also attempt to explain the biggest question in my mind, which is after decades of selective pressure on bass, why can we even still catch them? Shouldn't we have selected already for most of the aggressive fish, leaving nothing but hard to catch fish in our lakes and reservoirs? They surmise, though I'm not sure I agree:

"In light of this new evidence, one might ask why there are not more examples of fish populations in the wild showing such drastic responses to angling-induced selection or why there have not been widespread decreases in largemouth bass catch rates if the vulnerability to angling has in fact decreased. We speculate that the failure to observe such changes in angler catch rates is due to the tremendous increases in angling technology (e.g., the advent of better terminal equipment, the development of fish locating devices, and the improvement in boat design and handling characteristics). Another possible explanation is that supplemental stocking activities have masked potential changes by altering the composition of a given population. It could also be simply that we just really have not looked for decreases per se because of the almost universal lack of background data on angling vulnerability in any standardized format that could be used to assess such evolutionary changes in fish behavior."

Comments

[Rich Ziert]

Something for the pot.

Genetically "hard to catch" seems not to correlate with hungry fish and forage abundance. Basically, in times of less, if they don't eat, what they can when they can-even to go places and do things not normally associated with traditional habits, they die. That then equates to "easier to catch". In times of plenty all is reversed and the numbers skewed by random opportunity rather than concocted presentation. The ecosystem, parts of the overall lake/river/even larger pond domains, coupled with results from interplay of exponential numbers of unscheduled events, will always be an unknown. Fish that grow older/larger/isolated have simply been through more, have experienced more of life. Getting to that point is far more a part of fortune than it ever could be genetically induced. We should never make the assumption that all fish of a species are alike. The learning curves are always an individual experience. I read a rather long something out of Scientific America, or one of them “heady magazines” just yesterday while sitting in the lobby of my doctors office. More and more, behavioral scientists are coming to realize just how smart so called lower life really is; debunking the age old human superiority myth to the point where in some cases and in some ways, learning capacity and intelligence levels surpass human ability.

[Rich Ziert]

Steve Quinn just clued me into the following.

http://wfs.sdstate.edu/wfsdept/Pond%20Web%20Page/Largemouth%20Bass%20Angling%20and%20Catchability%20%20Mar.Apr%202006.pdf

[Big Indiana Bass]

Thanks for the link Rich. Thought it looked familiar and was able to dig up the answer. Had it posted to the site about 1.5 years ago (we're on top of our game here) in the following post:

http://www.bigindianabass.com/big_indiana_bass/2007/06/more_buzz.html

It's a great refresher though and glad that you posted it again for our readers. It's a very interesting piece and well worth reading. So much of the stuff gets "buried" back in the archives, never to be found except by the most adventurous perusers.

[bigmouth]

Bass have different variations of memory associated with different lures. For example, in plastic worms, their memory is shortest regarding the color, red shad. This was proven years ago by the Bass Professor, Doug Hannon.

Another inherited trait ... big fish spawn big fish, which is one of the best reasons for catch and release. That way, all of our offspring have the same opportunity to catch a trophy bass as we did.

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[Big Indiana Bass]

Thanks for dropping by the site and commenting! I've read Doug's book but can't recall if that little tidbit was in there or not. Might be time to reread. I have seen a piece that was similar, suggesting that specific bass tend to have certain "attractions" to certain baits, such that you might catch the same fish several times, each time on a worm and but never on a spinnerbait. Others reacted differently. Kind of interetsing.

The big fish spawning other big fish I think is pretty well accepted and makes sense in light of what we know and are learning all the time about genetics, but I'm not sure anyone has ever been able to document it in studies. I know Texas has been doing a lot of research in that area with their ShareLunker program. One day they might write a great piece on all that they've learned.

[Josh McDermott]

Im near 100 percent positive that there are many fish in the places we all fish that are simply uncatchable. They have all seen our presentaions over and over but simply will not eat any of those offerings. Im not sure if they are just that tuned in to a certain forage or they are just smarter than the other catchable fish. I know fish cant think per convensional wisdom, but they have to have some sort of process whether it be survival, spawing, foraging or comfort. I guess this is why I prefer to fish the way I do, catering to their instincts rather than a match the hatch or bigger, deeper, slower type of presentation.

[Paul Roberts]

“But why do we still catch them?”

Bass can learn. We know this. Keith Jones has said that when they test bass’ response to lures they must use new bass for each trial, because the bass become jaded to the (hookless) lures that are quickly known by the bass to be “not food”.

He also described research specifically on bass learning that showed that bass could remember certain lures for “the duration of the study” –three months if I remember correctly. Some lures, namely amorphous soft plastics were tougher for bass to remember, and presumably identify in the first place.

On the water, if you’ve had the chance to fish true virgin fisheries, there is no doubt bass learn and retain their experiences with angling. I can give a lot of examples, as many of you probably can too, (such as counting 130 bass before just stopping counting), but I’ll describe one -an un-fished pond a friend showed me that left an enormous impression: We weren’t allowed to fish it but he wanted to show me. He put a smallish garden worm on a snap swivel (that was already on his line) and tossed it in. Behind the slowly retrieved swivel and worm came a horde of bass all around 15-16inches. They followed like a parade for us to watch in amazement, until my friend finally let one suck in the worm, which it wrested off the swivel and took off with the horde chasing, pushing a wake over the pond. “They’ve never experienced a hook,” my friend said. “Just imagine...”
“Yeah, what a bore”, I thought.

Bass are individuals. There are some individual bass known to be highly vulnerable to angling (suckers for lures), including tagged bass in studies using angling as a sampling method. These individuals are caught repeatedly. There are also other individual bass in the same water bodies that have been labeled “immune to angling” by the researchers.

Also, from my own angling experience, and as Brian mentions, I’ve identified individual fish (bass, and pike) that showed a strong penchant for specific lures.

So...if angling can remove the “gullible” fish, why do we still catch fish?

Managers of the intensely groomed trout streams in the UK, shudder at the thought of C&R. It’s antithetical to their ideas on managing “good fishing” for their wealthy patrons. If you know brown trout, compared to brookies, cutts, and ‘bows you can see why. I’ve always wondered if the unique angling challenges browns bring doesn’t come from their much longer history of being angled for by hook and line. But, ‘bows and brookies can become jaded too, in hard fished waters.

C&R mortality may chip away at the “gene pool” but there are simply other over-riding factors. The real issue lies in the limitations of fish senses, and in the natural environment. Keith Jones research was conducted in a well lit laboratory under artificial conditions and circumstances. The real world is MUCH more complex in terms of its effect on bass’ senses, and motivations.

Two things have a major impact on bass’ perception of lures: visual obfuscation of the lure, (lighting and proximity to environmental elements), and competition within a bass group.

I’ll give an extreme example: Where would you rather pursue educated bass? In gin clear cover-less water under a mile high sky? Or in off-colored water, with broken cover, and a dark approaching front with a mild chop? Why? In attenuated light the food chain can become invigorated, bass gain an advantage over prey, and they simply can’t discern the fakeness inherent in lures as well.

Can we adapt to less than perfect conditions? You bet we can. But this is where the occasional “weekend” angler, maybe resting his hopes on the lure that killed ‘em last week, (or worse: red hooks or “Sexy Shad”), gets separated out from the more knowledgeable anglers.

Can the bass adapt? Apparently only so far, from what I’ve seen.

[Rick Vogelbacher]

"It's a great refresher though and glad that you posted it again for our readers. It's a very interesting piece and well worth reading. So much of the stuff gets "buried" back in the archives, never to be found except by the most adventurous perusers."

It was a nice refresher. I had forgotten about it. Thanks for bring back to our attention.