Lunar/Solar Gravitational Effect on Fish

[Beweav]

I have heard some talk in the bass fishing world about using gravitational cycles as a way to predict bass feeding activity. It just hit me today that I have never even heard this mentioned on this forum. I was wondering if you all have seen any possible correlation between the wildlife activity predictors(available in app, online, or in old school forms) and trout activity? It seems reasonable to think that something as consistent as moon/sun cycles would have an impact on wildlife. There seems to be something that coordinates insect hatches, coral spawning and things like that beyond just light/dark cycles. If there is some level of predictability in fish feeding behavior then knowing or tracking it would be a helpful part of a successful fly fishing outing. I found this older study that seem to point to them not being very accurate but, to me the study could have been improved in a number of ways and given more clarity.
Does anyone have any thoughts or more info on this topic? I’d love to hear.
-Study-

 

[jifigz]

My insight comes from personal experience in many years of being a hardcore bass angler (and any fish, really) through many hours of angling, studying books, theories, magazines, fish behavior videos, blah blah blah...... It's not predictable enough to put any faith in. I don't believe it. I've had bad fishing on the supposed "great" fishing days and great fishing on the "poor." Good fishing on full moons and bad fishing on full moons.

I really think it is kind of a sham, hocus pocus thing as just one more thing to fill your new month's issue of In-Fisherman.

 

[troutbert]

When I was a kid many publications carried John Alden Knight's solunar tables.

But I think it is more productive to pay attention to factors like water levels, temperatures, amount of light, hatches etc. to figure out when the best fishing times will be.

 

[wildtrout2]

In short, I think it's a crock.

 

[dryflyguy]

In short, I think it's a crock.

Agree.

I remember reading many places that the best times to fish at night, were during the new - or no - moon.
Total darkness being the best - although I guess if it's overcast, that goes out the window.

I've fished many hatches late under a bright full moon, with fish rising all over the place

 

[Fish Sticks]

I think its a crock in general but I will say moonlight definitely affects night fishing. The bright moons fish poorer mote frequently but not as an absolute rule but noticeable for sure. Nothing to do with gravity just light which we already know affects trout. This is why when moons out i am often trying to side arm under a tree branch like its mid day but at 2am.

 

[krayfish2]

I have heard some talk in the bass fishing world about using gravitational cycles as a way to predict bass feeding activity. It just hit me today that I have never even heard this mentioned on this forum. I was wondering if you all have seen any possible correlation between the wildlife activity predictors(available in app, online, or in old school forms) and trout activity? It seems reasonable to think that something as consistent as moon/sun cycles would have an impact on wildlife. There seems to be something that coordinates insect hatches, coral spawning and things like that beyond just light/dark cycles. If there is some level of predictability in fish feeding behavior then knowing or tracking it would be a helpful part of a successful fly fishing outing. I found this older study that seem to point to them not being very accurate but, to me the study could have been improved in a number of ways and given more clarity.
Does anyone have any thoughts or more info on this topic? I’d love to hear.
-Study-

Sir,
When you get Pcrayd in a little bit, just realize you brought it on yourself 🤣🤣

 

[krayfish2]

There's been several similar threads on here regarding barometric pressure, lunar phase, etc.

I have long standing position on barometric pressure and hatches. I always felt that a drop in pressure could be picked up by the insect larvae and might help hatch success if there was the slightest drop in pressure on the water surface. I then received a 500+ word Pcraying explaining that barometer drop couldn't be sensed under water and also virtually no difference in surface tension. I still think that it does impact most hatches. Exception would be high up on a tailwater like South Holston or WB where you can have blue bird skies, high pressure and sulphurs still pour off in the middle of the day. Fish might not respond but the hatch still happens.

In my experience, pressure rises and falls seems to bother bass more than trout. I also found clear skies and full moon to be not as great as it was talked up to be. It's got to be like a flashlight in the fishes eye.

 

[Beweav]

There's been several similar threads on here regarding barometric pressure, lunar phase, etc.

I have long standing position on barometric pressure and hatches. I always felt that a drop in pressure could be picked up by the insect larvae and might help hatch success if there was the slightest drop in pressure on the water surface. I then received a 500+ word Pcraying explaining that barometer drop couldn't be sensed under water and also virtually no difference in surface tension. I still think that it does impact most hatches. Exception would be high up on a tailwater like South Holston or WB where you can have blue bird skies, high pressure and sulphurs still pour off in the middle of the day. Fish might not respond but the hatch still happens.

In my experience, pressure rises and falls seems to bother bass more than trout. I also found clear skies and full moon to be not as great as it was talked up to be. It's got to be like a flashlight in the fishes eye.

Interesting, I was under the impression that the lateral line in fish could detect pressure changes. But I didn’t consider whether or not barometric pressure had any effect under water.
As I was looking that up, I found this interesting study about the lateral line.
I thought some of you may be interested.
Study
Section 7 is really interesting. When I thought about fly choice and presentation I was always thinking in terms of the fish “seeing” the fly. But this would seem to indicate that a fish can tell if it should eat what lands on the water just by the way something hits the water.

 

[Kevin82]

I have an app on my phone, and alot of calendars have best fishing days.
I havent noticed any affect on trout fishing, but in my experience it did seem to be kinda accurate for salmon fishing in NY. If it said the best times were 7:00-9:00 it seemed like the salmon would be moving better then. No concrete eveidence, just something I've noticed. Could be a placebo effect, haha.

Just fish when you can/want to.

 

[wildtrout2]

Interesting, I was under the impression that the lateral line in fish could detect pressure changes. But I didn’t consider whether or not barometric pressure had any effect under water.
As I was looking that up, I found this interesting study about the lateral line.
I thought some of you may be interested.
Study
Section 7 is really interesting. When I thought about fly choice and presentation I was always thinking in terms of the fish “seeing” the fly. But this would seem to indicate that a fish can tell if it should eat what lands on the water just by the way something hits the water.

That is interesting. Thanks for sharing the info.
I was aware that the lateral line could pick up ground vibrations streamside, but I wasn't aware that they can tell a trout about food possibilities/opportunities.

 

[Beweav]

I would assume they use the info from their lateral line and also their eyes, which could be part of the reason they refuse a fly at the last second?
Also this would make fly size, composition and casting pretty high on the priority list. I would say a lot of peoples experience would hold true to this. Sometime a size up or down can induce an eat.

 

[redietz]

When I was a kid many publications carried John Alden Knight's solunar tables.

I was about to post that John Alden Knight may have been right about the efficacy of a Micky Finn, but was completely off base witThere's no correlation that I've been able to discern in 60 years of fly fishing.

 

[Bamboozle]

The only gravitational effect I've seen with fish is that it keeps them in the water instead of floating off in space...

It keeps me grounded too!

 

[JeffK]

My number one prompt to go fishing is when I have time. All that other stuff is secondary.

I have done a fair amount of angler surveys and the one thing that seems to turn off fish reliably is a sudden drop in water temperature whether from snowmelt, cold front or dam release. Seems fish like need about three days of consistent weather to feed best.

IMHO, there might be something to Solunar tables, but it is secondary to stream flow, water clarity, temperatures, brightness, etc and not all that important.

 

[JimKennedy]

I'm glad JeffK mentioned the old Solunar tables. As a kid I was always kind of intrigued by them, but the reality was then and still is that I go fishing when I can get out, regardless of the weather and regardless of what the Solunar tables say. Sometimes I can do no wrong and catch a mess of fish. Sometimes I have to really work for a few hits. And, of course, sometimes the skunk refuses to leave. It's like they say about the bear, sometimes you get the bear ...

 

[pcray1231]

The point of me "pcraying" was that yes, fish can sense pressure, but pressure underwater. The difference of like 1/8 of an inch in depth under water far outweighs the variations in atmospheric pressure. In a riffle with chaotic water above you, in terms of pressure, is like a dump truck being repeatedly and rapidly slammed on top of you, and asking if adding or removing a feather from the top of that truck makes a difference. Technically, yeah, but the natural variations of how that truck is slammed on you far outweigh anything you're gonna feel from the feather.

But of course atmospheric pressure absolutely affects atmospheric weather, and weather has a strong effect in multiple ways. Temperature, direction of change of temperature, amount of light, wind causes ripples and blows junk into the water, rain and flow changes, humidity affects how a hatch progresses, etc. etc. etc. I'm by no means saying pressure has no effect on fishing, I just very much doubt a direct effect. Same with lunar cycles. Does the difference in gravity affect fish? Probably not. But how bright the moon is does, and that's at least in part due to lunar cycles (as well as clouds and such). And in coastal areas, the tide certainly affects life by changing the water depth, and lunar cycles determine how strong the tide is.

 

[krayfish2]

I haven't really noticed the impact of atmospheric pressure on trout. I'm all ears for an explanation on the impact on hatches. Too many times to count, I've been on the river in nice weather and encountered a hatch. Low is on it's way to the area at some point during the day. As the the rain shield ahead of the low reaches us, the hatch intensity increases and you often have a second or third hatch join the party. As high pressure enters the area, you often have hatches peter out or shuts off abruptly.

You could use the argument for cloud cover being the main factor but it's already cloudy well in advance of the low pressure front. Any explanation is appreciated.

For me, the crappier the weather, the better the hatch / fishing. Not 100% accurate but it has been accurate enough for me to go out in some pretty awful conditions.

 

[DomR]

For me, the crappier the weather, the better the hatch / fishing. Not 100% accurate but it has been accurate enough for me to go out in some pretty awful conditions.

Hell yeah, nice, bluebird days are for yard work, long walks, and grill/chill on the deck. To me good fishing weather is the kind of days and conditions that my friends and family (non-fishing variety) think I'm a lunatic for wanting to be outside in.