In the thread: https://alantani.com/index.php/topic,36879.0.html (https://alantani.com/index.php/topic,36879.0.html)
we were debating about whether fish could detect and therefore respond to changes in atmospheric pressure. The subject started to wander into the full moon thing, specifically the commonly held belief that fishing during the full moon can be less productive. I was laid up for a day, and decided to dive into the scientific literature.
This full-moon-is-bad theory always bothered me a bit. First of all, it makes it harder to motivate my fishing buddies. Secondly, the moon phase change is gradual and consistent- not an on/off switch, so why wouldn't the story be that the bite gradually slowed down and then ramped up as the moon phase progressed (other then it being bad for the charter business)?
A more detailed version of this theory is that fish can feed under the moonlight and therefore would be less interested in feeding during the day when most fishermen were active. OK, this is a bit better, but still seems kind of weak, and still doesn't answer the ramp-up/ramp down question.
And there are lots of different types of predators, prey, and environments out there. It can't be the same for all of them.
I went to see what the scientific literature had to say. It turned out a lot! There is a ton of material of catch/effort rates based on environmental conditions for commercial fishing, and a bit for sportfishing as well.
I do want to limit the discussion a little. Moon phases will effect tides and therefore currents, but the big tides come with both new and full moons. Spawning cycles are often synchronized around full moon events, but they don't hasppen on each full moon cycle. Hopefully we can stick to what is unique and repeats with each full moon.
I am going to beak this up in a few chunks to make it more readable. If you want to skip the comments between the chapters:
Part 2 : How much extra light does a full moon make? https://alantani.com/index.php?msg=436256
Part 3: Vertical Migration vs. Thermoregulation . https://alantani.com/index.php?msg=436966
And the usual note that I am not trained in any of this stuff, just a science fanboy, so I would appreciate any corrections from the experts out there.
-J
Part 2 : How much extra light does a full moon make?
So lets start with the "just a day or two around the full moon" theory. I was sure that this was nonsense, but there is a sliver of science to support it.
A rough surface (like the surface of the moon) is a poor reflector of light, but will have a sudden jump up in effectiveness when the source of light is directly or nearly directly perpendicular to the surface . This is called the lunar opposition surge, and works for about four degrees or so on each side of the full moon. I have seen numbers between 20% to 40% brightness increase- but as a non-astronomer, I have no clue which is correct and under what conditions . Source: https://www.sciencedirect.com/science/article/abs/pii/S0019103596902250?via%3Dihub
But hold your horses: For reasons we can get into later, for many gamefish species, piscivorous feeding effectiveness (and therefore activity) peaks in a range of low light conditions – not too bright, and not to dark). This usually occurs right around sunrise and sunset. Sunlight is many orders of magnitude brighter than moonlight, so at sunset, the vast majority of the light is still coming from the sun. A full moon is essentially just stretching out that magic hour a bit, but on its own is not providing nearly enough illumination to keep the magic bite going without the help of the sun.
Furthermore, the sunlight reflecting off the moon is red shifted- so we are not getting as much of the higher frequency light waves that penetrate water more effectively- plus many (most?) saltwater gamefish species have no red vision- so red light doesn't do much for them.
That is not to say that for some species, especially in shallow fresh water, that there might be enough light (and red vision) to feed much farther into the night, but on the ocean side, I am still a skeptic. To support the believers, here is an interesting study on largemouth bass and feeding success at various light levels and water clarities. It supports the claim that bass can feed effeciently under a full moon in the right condtions: https://www.montana.edu/mcmahon/documents/LMB%20light.pdf
The bass study has a bit of a hack, as they used fluorescent light bulbs that were not adjusted simulate the frequencies of true moonlight.
(Side note: Low light can also occur due to cloud cover, but fish generally lack the ability to quickly adapt to light level changes, and the "night vision" switchover is usually driven by time of day and not available light).
Now this doesn't mean that a full moon is not a factor in oceanic fish feeding behavior. In fact, the catch/effort rates show moon phase based variation in the open ocean, where tides are not really much of a factor. But it is much more complicated than a bunch of species feeding by moonlight. More on this next.
-J
So you're telling me the science says they don't turn into werewolves?
Interesting discussion here about the full moon and also the thread on atmospheric pressure. My take on these things is probably a bit different from most of you guys who I gather fish on the West Coast. Around NY, my experience with fishing around the moons is that they most definitely affect the fishing. And not just the full moon, the new moon as well. It is because the current is significantly stronger for about two or three days before and after the moons. Doesn't mean it's always better or worse. It depends on the area, and the species. Better for some, worse for others.Don't think it has anything to do with the brightness of the moon. Kind of an impossible subject to generalize about in my opinion. For example; I have a spot where I usually hammer the bass around the moons and the fish reliably turn on at the max current, which runs about 3.5 kts. I have another spot about ten miles away where the fishing is also great around the moons. Except here the fish usually only hit for one hour on either side of slack water. Same fish, same moon, ten miles apart, opposite behavior. I think it's important not to psych yourself out about some reason you should not bother to go fishing. Just go.
John
I think this stuff is environmental and not regional. Fish don't know what coast they are on, just whether the water is moving, how well they can see, etc.
As to full moon/ new moon and tides. I don't think there is any debate that tide has a major effect, especially for inshore fishing. The tidal swings happen equally at both ends of the full moon/new moon cycle, so I don't consider the tidal effect as part of any potential full moon phenomenon. The open ocean is a good place to look, because tides have a much smaller effect on water movement.
But the catch/effort ratio is definitely affected by moon phase, even in the open ocean. I'll try to write some of this up next.
-J
Quote from: JasonGotaProblem on June 05, 2023, 11:16:32 AMSo you're telling me the science says they don't turn into werewolves?
They keep telling us that it is just shark attacks, but why should we believe a bunch of scientists? It has to be werewolves. Look at those teeth marks!
-J
Quote from: jurelometer on June 05, 2023, 04:20:20 PMI don't think there is any debate that tide has a major effect....
Yup
Quote from: JasonGotaProblem on June 05, 2023, 11:16:32 AMSo you're telling me the science says they don't turn into werewolves?
Come on now werewolfs do not have gills they are werewolf eels.
(https://alantani.com/gallery/37/1583-050623191823.jpeg)
;D I will throw my hat in the ring . Let`s put down the binoculars and start looking at the whole picture . Everything living thing on planet earth has a electric charge in it .
The earth is surrounded with magnetic fields . The moon phases change the flux line as well as other occurrences , such as solar flare ups .
Wild animals will feed at different times, Human behavior changes when the moon comes to full .
I believe all things are reacting the the surrounding electric charge .
Electric charge is for ever changing , air density ,hot and cold . Water temperature including the currents in water , the salinity of the currents
Humans are domesticated , fish are not . Fish have a lateral line and they use it , :d
,,??? ,,,,,,voodoo,,,,,, Wichcraft and folklore,,,,,,,a fish finder just makes me mad when I run over so many fish with the right bait and can't catch anything,,,,,,,,,
I'm certainly not a fish, but I can tell you that I sleep like $ hit for 5 days around, 2 days on either side of, and a full moon. >:D
Quote from: Midway Tommy on June 06, 2023, 04:54:16 PMI'm certainly not a fish, but I can tell you that I sleep like $ hit for 5 days around, 2 days on either side of, and a full moon. >:D
Definitely one of the signs of turning into a werewolf. Check for bristles under the tongue :)
-J
On the magnetic field theory: From a strictly science side, we would first have to find a magnetic phenomenon that was unique to just the full moon, then a reason why it might cause fish to eat differently, than an observation of fish actually behaving that way.
Marine biologists would agree with Joe that detection of the earth's magnetic field plays a direct role in the behavior of at least some fish species, but probably just for navigation. I haven't seen anything in terms of effecting cyclical feeding behavior. The tides do move seawater around, and seawater is a conductor, so the earths magnetic field is slightly affected by tides - but we would still have to have a theory about how small magnetic field changes would affect a fishes daily feeding habits. The moving water from tides is a more likely cause, as it improves predation success. And big tides are not unique to a full moon, they happen on a new moon too.
Magnetism seems to be useful for long range crude navigation. For example, they think that salmon imprint both magnetic signals and scents. To get back to the natal river to spawn, magnetic sensors are first used (they still haven't nailed down the biological mechanism yet), and once they are in the general vicinity, smell (taste?) takes over and leads them back to the river mouth and up to the spawning grounds.
On a side note on the comment on humans: For as far back as history goes and across many cultures, societies have always believed that full moon affects human behavior, but from what I have read, when the studies try to nail this down with hard data, the results are inconclusive. ER docs, cops and EMTs would probably disagree, but the numbers don't seem to support this belief.
-J
On the lateral line and magnetism: I do agree that we tend to over-focus on fish vision, and that is only one of the fishe's sensory systems.
The lateral line detects motion by detecting small changes in water pressure, not magnetism. Cilia (sort of like hairs) in special cells in the lateral line move enough to change the cell's electrical charge, which is detected and acted upon by the nervous system of the fish. Or something like that :)
The lateral line is used for detecting objects in the near vicinity of the fish (sometimes up to 30 feet, generally under 6 feet, closer is more accurate), and to maintain orientation.
OTOH, cartilaginous fish species (sharks, sturgeon, etc.) can have some sensitive electromagnetic sensors on their heads which are used to detect the faint electrical impulses from the nervous systems of prey, usually something up close trying to hide in the sand or weeds. Look up " Ampullae of Lorenzini" for more info.
Something to run with, but still a bit thin in my opinion.
-J
This is an interesting subject.
As a surf guy, I rely on tide and current charts. I've caught plenty of fish when the science says I shouldn't have. I'm not dismissing lunar influence because it's the primary tide engine. About light levels. You can't dismiss water clarity. I've seen trout come up late in the morning because of murky water. Some fishermen, who rely on the clock, would leave the spot instead of waiting for enough light to reach the lurking fish and stimulate them to rush the shallows. Sometimes the water is just too muddy and causes them to change patterns.
In my little world, I look at the tide charts and note the odd patterns that occur around the full moon. Not because of the light, but for the consistency of water levels covering the bottom structure I choose to fish. There's less tidal swing. In addition, I get to fish during multiple tide and current changes in a shorter period of time.
Now, I'm gonna spin some heads and talk about phosphorus. Based on my experience, when bait agitates the water during periods of high phosphorus, the agitated water glows green. Humans only see this at night and it's very cool. I have no proof, but I believe certain, or maybe all, saltwater fish "see" this in any light and have adapted to using it. I have thrown spoons in pitch-dark conditions and caught trout in the surf during these "glowing" conditions. I have found that daylight fishing is generally better in these conditions.
Based on these experiences where I fish, I believe light is a major factor, but water movement and structure are the first orders of business. The light change has to occur upon something that is holding bait.
Quote from: Midway Tommy on June 06, 2023, 04:54:16 PMI'm certainly not a fish, but I can tell you that I sleep like $ hit for 5 days around, 2 days on either side of, and a full moon. >:D
I am the same way , I took notice as a child the effect of the moon . And I will say their may be Two full moons a year that are not as strong . But for the rest , I am charged up , thought process , creative .and all around body energy goes up .
I want to say that we have to keep in mind fresh water fish , mainly pond fish , where there is no tides .
Yet they still feed on the Major and minor periods . Food can float for hours when they are not hungry ..
the local wisdom is the best time to fish for large walleye is at night, the full moons of March and April..
I do it every year and so far it hasn't worked ;-)
It does work for some, based on the pics they show..
Theory presumably is the walleye is a low-light hunter, the full moon extends the crepuscular light conditions to all night and they hunt longer into the night.
Sorry for abandoning this thread for awhile. I got sidetracked on ceramic bearings. You guys have been tempting me with too many sciency topics lately.
On the phosphorus glow- I thought that the glow as not from the phosphorous itself, but from the algae that consumes it. So an alternate explanation of more activity is that there is more plankton (eating algae) in the area, and more baitfish around to eat the plankton. But it is hard to tie any of this to the full moon...
On the walleye - yeah, walleye are optically evolved to feed in low light, but the magic hour argument with the full moon has the same problem mentioned earlier in this thread.
But if the walleye are found to feed more frequently after sunset under the full moon, but mostly in relatively clear water near the surface, I think we have an even better argument for the full moon theory.
The theory on why the magic hour (dawn or dusk) causes predators to feed more: Predators have better success chasing baitfish upwards- so this is how they tend to feed, and even how their vision is optimized. Coming from below makes it harder for the prey to reach cover(on the bottom), and can also trap prey at the surface. In periods of low light, it is easier to make out the silhouette of a fish above you than a fish below you. So the predator can see the prey more easily than the prey can see the predator in low light. But once the sun sets, the moonlight (even a full moon) is providing only a small fraction of light that was available at sunset- this advantage is gone. So a full moon might stretch the magic hour out a little bit, but it does not keep it going for hours.
-J
I never see algae bloom on the full moon!
Always on the new moon, and never once have caught a fish with fire in the water!
I have witnessed herring and shad feeding like crazy on the new moon on plankton!
I can not get them to hit anything, on the new moon for some reason!
Quote from: jurelometer on June 09, 2023, 01:39:42 AMThe theory on why the magic hour (dawn or dusk) causes predators to feed more: Predators have better success chasing baitfish upwards- so this is how they tend to feed, and even how their vision is optimized. Coming from below makes it harder for the prey to reach cover(on the bottom), and can also trap prey at the surface. In periods of low light, it is easier to make out the silhouette of a fish above you than a fish below you. So the predator can see the prey more easily than the prey can see the predator in low light. But once the sun sets, the moonlight (even a full moon) is providing only a small fraction of light that was available at sunset- this advantage is gone. So a full moon might stretch the magic hour out a little bit, but it does not keep it going for hours.
Okay, I know in other threads (mostly regarding fisherman's predilection to irrationally purchase expensive lures with "hot" color schemes (BTW I'm getting ready to go on my June 8 day and where in the H*** is my Katy Perry flatfall? anyhow) but there has been previous discussion about fish sensitivity (and insensitivity) to certain wavelengths of light due to their eye structure. And clearly in the early morning/sunset hours the spectral wavelengths of light that we are experiencing are totally different (part of why sunrises and sunsets are so beautiful? Only conjecture) so I wonder if the type of light also plays a factor in those "early/late" feeding patterns? And I will have to look at what the wavelength of moonlight is (since technically it is sunlight, but reflected off the moon and entering our atmosphere at a different angle).
This is a fun thread thanks for starting it - making me try to think....
Quote from: Brewcrafter on June 09, 2023, 06:38:37 AMQuote from: jurelometer on June 09, 2023, 01:39:42 AMThe theory on why the magic hour (dawn or dusk) causes predators to feed more: Predators have better success chasing baitfish upwards- so this is how they tend to feed, and even how their vision is optimized. Coming from below makes it harder for the prey to reach cover(on the bottom), and can also trap prey at the surface. In periods of low light, it is easier to make out the silhouette of a fish above you than a fish below you. So the predator can see the prey more easily than the prey can see the predator in low light. But once the sun sets, the moonlight (even a full moon) is providing only a small fraction of light that was available at sunset- this advantage is gone. So a full moon might stretch the magic hour out a little bit, but it does not keep it going for hours.
Okay, I know in other threads (mostly regarding fisherman's predilection to irrationally purchase expensive lures with "hot" color schemes (BTW I'm getting ready to go on my June 8 day and where in the H*** is my Katy Perry flatfall? anyhow) but there has been previous discussion about fish sensitivity (and insensitivity) to certain wavelengths of light due to their eye structure. And clearly in the early morning/sunset hours the spectral wavelengths of light that we are experiencing are totally different (part of why sunrises and sunsets are so beautiful? Only conjecture) so I wonder if the type of light also plays a factor in those "early/late" feeding patterns? And I will have to look at what the wavelength of moonlight is (since technically it is sunlight, but reflected off the moon and entering our atmosphere at a different angle).
This is a fun thread thanks for starting it - making me try to think....
I didn't see a request for any Jurelometer jigs. And are you even on my Pro-Staff list? ;D
I don't know what causes the color shift for sunlight reflected as moonlight. Maybe something to do with the composition of the moon's surface?
The reason for the reddish glow at sunrise and sunset up has to do with shorter wavelength light (blues) getting deflected more when traveling through the atmosphere, and when the sun is low, light travels through more of the atmosphere to reach the surface. Or something like that. I am not an astronomer.
But there is still blue light in the mix. And that is the light that carries the most energy, and will penetrate the water most effectively. The so-called "black and white vision" rod cells in a fishes eye is tuned to a wider range of frequencies, but is still centered on blues.
Since the predator is feeding upward in low light, your flatfall will appear as a a black profile (blocking light) against a slightly illuminated background. So black will work, red will work, purple will work, orange with pink polka dots will work. It's all black to the fish. But since most of the folks will be fishing Katy Perry, that will be considered the hot color, and you won't be able to find any at the tackle shops :)
Earlier in the magic hour, a light/reflective and dark combo might provide some benefit. One of my favorite all around/any time of day color schemes is white (or that holo stuff or bare metal) with some black on the shoulders. But rare to see this on commercial product. It doesn't work so well for catching humans at the tackle shop cash register.
-J
Quote from: jurelometer on June 09, 2023, 01:39:42 AMThe theory on why the magic hour (dawn or dusk) causes predators to feed more: Predators have better success chasing baitfish upwards- so this is how they tend to feed, and even how their vision is optimized. Coming from below makes it harder for the prey to reach cover(on the bottom), and can also trap prey at the surface. In periods of low light, it is easier to make out the silhouette of a fish above you than a fish below you. So the predator can see the prey more easily than the prey can see the predator in low light. But once the sun sets, the moonlight (even a full moon) is providing only a small fraction of light that was available at sunset- this advantage is gone. So a full moon might stretch the magic hour out a little bit, but it does not keep it going for hours.
so, why does dawn/dusk have same effect on bottom-feeding "grazers" (most cyprinids, catastomids, etc.)
Quote from: philaroman on June 09, 2023, 10:30:37 PMQuote from: jurelometer on June 09, 2023, 01:39:42 AMThe theory on why the magic hour (dawn or dusk) causes predators to feed more: Predators have better success chasing baitfish upwards- so this is how they tend to feed, and even how their vision is optimized. Coming from below makes it harder for the prey to reach cover(on the bottom), and can also trap prey at the surface. In periods of low light, it is easier to make out the silhouette of a fish above you than a fish below you. So the predator can see the prey more easily than the prey can see the predator in low light. But once the sun sets, the moonlight (even a full moon) is providing only a small fraction of light that was available at sunset- this advantage is gone. So a full moon might stretch the magic hour out a little bit, but it does not keep it going for hours.
so, why does dawn/dusk have same effect on bottom-feeding "grazers" (most cyprinids, catastomids, etc.)
The theory makes sense to me for piscavores. There can be other reasons for fish that fill other niches. And we don't know if the explanation for "why" is correct, but more active feeding with better success rates for piscavores during the magic hours is pretty well accepted.
I am not a sucker/carp guy myself, only did a couple sessions to see what the fuss was about. I thought that at least common carp feed all day and usually all night, but feed more when the water temps were just right, so more active early/late feeding occurs in some locales in the summer, but not maybe not in other seasons. Probably depends on the water temp variations where the food is at.
Otherwise, dunno. If you are a carp guy, maybe you can enlighten us.
-J
Everything has a factor,,,, ;) but food supply and when they are hungry,,,, :D that's the best place to be,,,,,, ;D
Quote from: Benni3 on June 11, 2023, 09:53:27 AMEverything has a factor,,,, ;) but food supply and when they are hungry,,,, :D that's the best place to be,,,,,, ;D
As usual, you hit the nail on the head, Bennie. You must go fishing a lot. ;D
If you only get to eat what you can catch with your mouth, you better hang out with the food. And unless you are absolutely too plugged to eat any more, don't turn down a meal.
This is the key to the whole full moon and feeding thing, and why the "tuna are harder to catch during a full moon because they feed all night" is not a very strong theory.
But there are feeding patterns that correspond to moon phases for some species, just not for the reasons that we read in the fishing magazines. And the actual moon phase and change in feeding varies by specie.
I will try to write this next part up soon for the final installment.
-J
I suspect a one sentence summary of this thread will ultimately be game fish DGAF about the moon, but some of their prey does care, and they follow them.
Do plankton change their behavior with the moon phase? If so that'll affect the bait fish behavior, and that's who the game fish are watching.
At least thats my idea. Or werewolves. That's still a possibility.
Quote from: JasonGotaProblem on June 12, 2023, 05:49:51 PMI suspect a one sentence summary of this thread will ultimately be game fish DGAF about the moon, but some of their prey does care, and they follow them.
Do plankton change their behavior with the moon phase? If so that'll affect the bait fish behavior, and that's who the game fish are watching.
At least thats my idea. Or werewolves. That's still a possibility.
Getting warmer... As always in nature, there is more than one thing happening at a time.
The problem with a one sentence explanation is that there is not enough detail to change anybody's mind. The problem with a full explanation is that not too many folk are going to read it. Lots of useful information waiting for us out there if when we are willing to digest something larger than a tweet sized bite of knowledge.
-J
Dave: if you can explain it in a 4 second tic tock video then I may be able to make it all the way through it. ::)
Cheers:
Todd
I think I can make it through a long-inclusive explanation, but only if you write it as though it were for a 5yr old. Use some simpler more child-like synonyms for example. Keep reminding me every sentence or two what we were talking about. Throw in some bathroom humor...
My 2c:
There are too many uncontrolled variables to draw meaningful conclusions about such things. It seems that a lot of fishing "truths" are the product of repetition of anecdotes rather than hard data.
I believe there are too many factors to fish being switched on that we either can't reliably measure or may not even know exist, and this severely complicates trying to establish the influence of a single factor. Even if you created a controlled environment where you were only varying one factor, the absence of the other factors would likely have an influence that was impossible to quantify.
I think the one factor that is near-universally agreed on for saltwater angling is that current has a large influence on fish behaviours, although it is different from species to species, with some feeding most actively when there is very little current and some feeding aggressively when the tide is at maximum flow.
>:D I wanted to quote the last 7 post , but that would have defeated the one sentence that i usually post.
Look at the time of the year and water temperature . What is being flushed in the tides ? :fish :fish
Quote from: jurelometer on June 12, 2023, 05:42:20 PMQuote from: Benni3 on June 11, 2023, 09:53:27 AMEverything has a factor,,,, ;) but food supply and when they are hungry,,,, :D that's the best place to be,,,,,, ;D
As usual, you hit the nail on the head, Bennie. You must go fishing a lot. ;D
If you only get to eat what you can catch with your mouth, you better hang out with the food. And unless you are absolutely too plugged to eat any more, don't turn down a meal.
This is the key to the whole full moon and feeding thing, and why the "tuna are harder to catch during a full moon because they feed all night" is not a very strong theory.
But there are feeding patterns that correspond to moon phases for some species, just not for the reasons that we read in the fishing magazines. And the actual moon phase and change in feeding varies by specie.
I will try to write this next part up soon for the final installment.
-J
One factor I came up with is oxygen,,,, ;) I see trout coming up to get air for there blatter I,,,,,? and marlo said no Benny they need oxygen in the water that's where they go not a food source,,,,,,, ;D
Quote from: jurelometer on June 10, 2023, 01:32:36 AMI thought that at least common carp feed all day and usually all night, but feed more when the water temps were just right, so more active early/late feeding occurs in some locales in the summer, but not maybe not in other seasons. Probably depends on the water temp variations where the food is at.
this is correct.. carp are mostly feeding by senses other than sight, so light conditions aren't that important. Clear water and bright light of course will send them into the deeps like any other fish, and may produce more nocturnal feeding.
Last week I was trying to flyfish for some carp, could see the mud plumes from their feeding but not the fish. What surprised me was several groups of pelicans hanging out around the carp, but not feeding on the carp, nor did the carp seem at all perturbed by the nearby predators.
Quote from: DougK on June 14, 2023, 05:56:58 PMQuote from: jurelometer on June 10, 2023, 01:32:36 AMI thought that at least common carp feed all day and usually all night, but feed more when the water temps were just right, so more active early/late feeding occurs in some locales in the summer, but not maybe not in other seasons. Probably depends on the water temp variations where the food is at.
this is correct.. carp are mostly feeding by senses other than sight, so light conditions aren't that important. Clear water and bright light of course will send them into the deeps like any other fish, and may produce more nocturnal feeding.
Last week I was trying to flyfish for some carp, could see the mud plumes from their feeding but not the fish. What surprised me was several groups of pelicans hanging out around the carp, but not feeding on the carp, nor did the carp seem at all perturbed by the nearby predators.
Ooh, interesting.
Only caught one carp on a fly rod. The guy I was with said that they don't take flies easily, so of course the first carp that I cast to ran down that critter fly like a starving bonefish :) . I read somewhere that carp will focus on either a grazing vegetarian mode or more actively hunting invertebrates, so it might pay to watch how a particular group is feeding.
Do you think the mudding is from grazing, or hunting mode? I know that in saltwater, there are often gamefish trailing rays around, looking to snatch any stray critters that the ray rooted up. Maybe the muds are from rooting for invertebrates, and the pelicans were hanging around for a similar reason. Dunno.
If moon phase affects shallow freshwater invertebrate behavior, that might be of interest to fly fishers targeting carp. Maybe not so much for the bait guys.
-J
Quote from: Benni3 on June 14, 2023, 03:11:15 AMQuote from: jurelometer on June 12, 2023, 05:42:20 PMQuote from: Benni3 on June 11, 2023, 09:53:27 AMEverything has a factor,,,, ;) but food supply and when they are hungry,,,, :D that's the best place to be,,,,,, ;D
As usual, you hit the nail on the head, Bennie. You must go fishing a lot. ;D
If you only get to eat what you can catch with your mouth, you better hang out with the food. And unless you are absolutely too plugged to eat any more, don't turn down a meal.
This is the key to the whole full moon and feeding thing, and why the "tuna are harder to catch during a full moon because they feed all night" is not a very strong theory.
But there are feeding patterns that correspond to moon phases for some species, just not for the reasons that we read in the fishing magazines. And the actual moon phase and change in feeding varies by specie.
I will try to write this next part up soon for the final installment.
-J
One factor I came up with is oxygen,,,, ;) I see trout coming up to get air for there blatter I,,,,,? and marlo said no Benny they need oxygen in the water that's where they go not a food source,,,,,,, ;D
True dat. When the dissolved oxygen decreases towards a lower threshold for a species(I ?think? about 5ppm for trout), they head for where the O2 is. Maybe a plunge-pool ina river? Deeper colder water in a lake?... the surface to gulp air when it get's really bad?
Full moon, full moon! Hopefully we can mostly stay on topic.
If we divert on every environmental factor that might affect the bite, the discussion will get too unwieldy.
Alright, alright, Dave. I got practically nothin for this'n. But it is real interesting. My experience with no real empirical data, is trolling the reef in the dark with the full-moon in the west and it "seems" not as good'a fishin.
Quote from: jurelometer on June 14, 2023, 08:34:48 PMFull moon, full moon! Hopefully we can mostly stay on topic.
If we divert on every environmental factor that might affect the bite, the discussion will get too unwieldy.
Ok let's stay on topic,,,,, ;) full moon is a thing but some other things has factors on it,,,,, :D oxygen,,,food source,,,water temperature,,,lighting storms,,,,biosphere,,,cloud cover,,,polushion,,,,,predators,,,what fly to use on the hatch,,,,,, >:( where to fish when to fish,,,,, :( moonshine is good and one day we can figure it out add all the factors then in maybe we got a better grasp on it,,,,,,, ;D
Quote from: jurelometer on June 14, 2023, 08:34:48 PMFull moon, full moon! Hopefully we can mostly stay on topic.
If we divert on every environmental factor that might affect the bite, the discussion will get too unwieldy.
I don't chuck moons anymore... neither full, nor partial
when I did, I wasn't looking for a bite :P
Part 3. Vertical Migration vs. Thermoregulation
In the end, yes, the moon phase (independent of tides) affects the bite on the ocean, but not as strongly as key environmental factors such as temperature, current strength, visibility, and salinity (Boon's point). And not all species, and not at the same phase. So if you are worried about the full moon affecting your fishing... meh.
I am covering the open ocean here, but there is probably some useful stuff to glean for inshore salt and freshwater environments.
First of all, lets talk about plankton and vertical migration.
There are two general categories of plankton. Phytoplankton- the plant stuff – relies on photosynthesis- so it lives near the surface where sunlight penetrates well. Zooplankton- the critter stuff- often feeds on the phytoplankton. Baitfish (this is shorthand, also includes important prey like squid and argonauts) diet often consists of zooplankton, and those little buggers are not very fast or agile, so they are pretty easy to run down in the daylight - being in deeper (and therefor darker) water makes it harder to be seen. So the zooplankton slowly (remember that they are not very speedy) migrate daily up and down through the water column between the surface (night) and down 300 feet or more (day). [Update: the complete story is a bit more complicated: This migration works more like a complex nutrient conveyor belt that extends several thousand feet, with the participating species having different ranges of daily migrations].
When the moon is full, the zooplankton, and therefore the baitfish don't migrate quite as high in the water column. Presumably this is due to the extra light from a full moon. In the arctic winter where there is next to no sunlight, this vertical migration still happens, but reversed from sunlight driven to moonlight driven- the zooplankton migrate downward as the moon rises.
Now let's talk about thermoregulation.
Most fish species are ectotherms (cold blooded) with their internal temperature matching the surrounding water. There is an ideal temperature for a specie, where its internal bodily functions perform optimally (warmer is better within limits), but water temperature drops with depth. So when a baitfish is cold, it is not seeing as well, or capable of moving as fast, but ectotherms are very efficient in terms of not burning off calories to warm themselves.
An adaption that has evolved independently in some predatory fish species (billfish, tunas, opahs, some sharks) uses heat energy from muscle contraction to warm the blood in some areas of the body, making them endotherms (warm blooded), at least for parts of the body. This burns off a lot of calories, but gives them an advantage over prey in colder water. How predators thermoregulate determines how and when they can take advantage of the vertical baitfish migration.
Tuna are the most extreme endotherms, and the larger the individual, the more extreme the thermoregulation. So the tuna have a greater speed advantage over prey at depth, and have no problem following the baitfish on the vertical migration. During a full moon, the tuna are feeding all day where the bait is hanging out, which might be a bit deeper than normal. This is especially true of bluefin and bigeye tunas. But the tuna are not out of reach for the sportfishers, just possibly shifted a little lower than normal.
Marlin just warm the region around the eyes and brain, improving their already strong low light vision. This saves some calories compared to tuna. Marlin spend most of their time near the surface, diving to as deep as around 250 ft to feed, and then back to the surface to warm up. There is some sportfishing catch/effort data that shows better success in the full moon (but not always), and it is attributed to marlin being more hungry/willing to bite in the full moon when the prey is deeper. But the sportfishing studies data set is not really complete enough to inspire my confidence.
Now at the other extreme, mahi mahi are ectotherms (cold blooded). They also thermoregulate, but have to do it behaviorally. They like to stick to a narrow temperature band, usually staying near the surface with a bit of deep diving, but not as often or as deep as the marlin. Mahi have excellent day vision, but not as good night vision as marlin, so they feed more during the day. But mahi can't really follow the vertical migration. Maybe this is why they are such enthusiastic daytime feeders once we find them. There is some pretty good evidence that mahi will spend more time at relatively greater depth at night if the water temps are warm enough, so it may be that they are taking advantage of the peak of the vertical migration that they are able to reach. It could also be to avoid billfish predation, or some combination of the two..
I will post one more followup with links to some of the scientific papers that are available without subscription. They are worth taking a look at, especially the one on smart-tagged mahi (dolphinfish) behavior.
Hope you folk found this useful.
-J
Quote from: jurelometer on June 14, 2023, 07:46:59 PMOnly caught one carp on a fly rod. The guy I was with said that they don't take flies easily, so of course the first carp that I cast to ran down that critter fly like a starving bonefish :) . I read somewhere that carp will focus on either a grazing vegetarian mode or more actively hunting invertebrates, so it might pay to watch how a particular group is feeding.
Do you think the mudding is from grazing, or hunting mode? I know that in saltwater, there are often gamefish trailing rays around, looking to snatch any stray critters that the ray rooted up.
about one day in a hundred fly fishing for them, I find carp actively hunting.. typically it's a crawfish bite, though I have heard of them taking young shad in the shallows, never seen it.
mudding is definitely browsing/grazing. A couple of times I've caught smallmouth bass while trying to present a fly to the mudding carp, suspect the bass might be following them around..
fascinating detail in your post on the temp regulation evolutions in saltwater, thank you. I knew about the warm-blooded tuna, not the marlin and mahi-mahi..
Many of the references are behind paywalls, but these are useful and free:
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Remote Predictions of Mahi-Mahi (Coryphaena hippurus) Spawning in the Open Ocean Using Summarized Accelerometry Data.
Don't let the title fool you. Lots of good data about mahi movement and water temps.
https://www.frontiersin.org/articles/10.3389/fmars.2021.626082/full (https://www.frontiersin.org/articles/10.3389/fmars.2021.626082/full)
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Lunar landings—Relationship between lunar phase and catch rates for an Australian gamefish-tournament fishery
Almost 400 tournament-days worth of catch/effort data by moon phase. Way too many variables at play to take the results as gospel, but still very interesting.
https://moscow.sci-
hub.se/1657/03b96a4ffc6b350f8e83222b530eb66c/lowry2007.pdf (https://moscow.sci-hub.se/1657/03b96a4ffc6b350f8e83222b530eb66c/lowry2007.pdf)
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Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter
Stuff on vertical migration of Zooplankton and how it changes in the arctic winter
https://www.cell.com/current-biology/fulltext/S0960-9822(15)01432-3 (https://www.cell.com/current-biology/fulltext/S0960-9822(15)01432-3)
Ok but when and where to fish that's the question we all have,,,,,, 8)
Quote from: Benni3 on June 16, 2023, 05:45:24 AMOk but when and where to fish that's the question we all have,,,,,, 8)
That's easy. Go whenever you can, wherever you can. But you already knew this :)
-J
Quote from: jurelometer on July 12, 2023, 05:45:07 AMQuote from: Benni3 on June 16, 2023, 05:45:24 AMOk but when and where to fish that's the question we all have,,,,,, 8)
That's easy. Go whenever you can, wherever you can. But you already knew this :)
-J
So true! I've never caught much, other than boredom, sittin' on the couch watchin' TV. ;) ;D
Benni has the street cred of not just once, but a few times tuning in for the Saturday Zoom and then catching a fish on air. And I want to say there was also a bunch of young ladies on the bike path cheering for him? - john
Quote from: Brewcrafter on July 13, 2023, 02:24:53 AMBenni has the street cred of not just once, but a few times tuning in for the Saturday Zoom and then catching a fish on air. And I want to say there was also a bunch of young ladies on the bike path cheering for him? - john
Thanks my freinds,,,,, ;) it's time for me to go fishing again,,,the heat is bad but just got to make it happen,,,,,, ;D