02-12-2003, 07:09 PM
Somehow you hear of "full moon: high tide at midnight in Boston". This isn't precisely correct but sure is useful (obviously you add or subtract to make it useful for your fishing location).
And you realize, or are told, that the tides reverse every week. Again, not exact but useful.
Sharing the issue of having way too much time to ponder such things at this season, I checked the extent to which the tides repeat every other week. I expected to see a smooth slope as the time of the tides gradually moved. In fact, over a significant portion of the year two bi-weekly tides may occur at virtually the same time. Two weeks later the time will shift significantly, followed by another near match. Apparently this is the result of the daily shift in time between tides changing significantly with major peaks in sync with lunar phase and minor peaks at the mid point. Doesn't matter why, it just may be useful to know that it does happen. If you want to repeat a great day fishing it may be useful to know whether the times will match, make a big jump, or just slide in two weeks.
Of course, some of the Forum members probably have all of the minus tides from June to October memorized by now and who knows what else they have stored away.
Current flow in estuaries is hard to get data on, never mind figure out (height of tide apparently is an important factor). There is a tidal creek near Area 61 that I suspect has been an object of study, but I haven't seen any data on this. Maybe when Penguin gets back from the Miami Boat Show he can comment.
Definitely true that the tide patterns at certain times of the year are remarkably regular for certain areas, particularly in New England from year to year.
These extreme tides have a major influence on fish behavior, but also fish-ability of spots in terms of the time you can exploit the available real estate.
The bad news is that bait movements and population fluctuations play a comparable role on where the fish are going to be most active and prevalent once migration cools down and even on perfect logistic tides the fish could be somewhere unexpected. That is also the good news - they could be hot to trot on tides that are "no good" by humanly expected tides.
The one thing tide does do is put water moving a certain way at certain times in certain places. If you familiarize with such places and they are in the feed routines of fish, the combined fishability and presence of forage can result in some of the best days of the season.
There is nothing I enjoy more than a good day when it wasn't supposed to happen according to the charts.
It's also wild that some places on earth have only one high / one low in a day due to the tilt of the earth on it's axis if I recall correctly.
02-13-2003, 12:08 PM
The folks who publish the Eldridge guide have a cool software product which inlcudes graphic display of tidal heights at different locations - inlcuding the major estuary/tidal rivers where there are stations. You can get a visual display of how the state of tide varies with, say, New York Battery Park versus the Troy dam on the Hudson river.
Explaining tides is a tricky concept at best, in fact the text I use for my Geog 12 class at high school handles it by omission! As far as I'm aware there are always 2 high and 2 low tides, it is just that the difference between them is less in some tropical locales.
The tilt of the Earth on its axis remains constant (parallelism of the axis) so it will not effect the tides. The moon's orbit however, is 5 degrees off the equatorial axis of the Earth. What this means is that there are only 2 times during the lunar month when the moon is directly over the equator, the rest of the times it varies as much as 5 degrees away from the equator.
The effect of this is the difference between the height of the 2 daily tides (diurnal). When the moon is furthest north in its orbit it causes the tidal bulge to cross the rotating Earth at different latitudes. The effect is that one high tide will be the high high tide and the next the low high tide ( this is where people get lost - a model or diagram really helps). This difference changes as the lunar month progresses and the pattern continually evolves as the earth-moon relationship changes.
This of course gets further complicated by the shape of the coastline as well as the sun-moon-earth positions - I guess I see now why my text just leaves well enough alone! :eyecrazy: .
For fishing, the best advice I can give someone trying to figure out when is best, is to start a log book and get out lots so you can rack up the data - when you get it figured - write a book!
02-14-2003, 04:37 AM
This is one of the best teatments I've come across so far .....
Adrian and Juro,
Thank's I've saved the links for use at school. However, even Adrian's simple model (let alone the link Juro posted) demonstrates how complicated the relationships that result in tides are!
Without a doubt, tides effect our fishing success, but like I said before, I think the best way to understand tides is to just go fishing! Keep track as best you can of what spots produce at various stages of various tides and hope that eventually you can discern a useable pattern!
02-15-2003, 06:52 PM
Thanks Adrian and Juro for the links!
Kush probably provided the key to why the bi-weekly tides usually repeat: when you revisit the same site two weeks later you are visiting at the OTHER tide, for example if you were on the high high tide two weeks later you will be on the low high tide. If there is a slight time difference between these tides it will add on one bi-weekly tide and subtract on the next bi-weekly tide. Apparently this is what creates the common pattern of match then jump in bi-weekly tide times on the Cape (there are periods where this does not happen due to all of those other complications). (so Kush can even teach old dogs...).
I have a copy of Eldridge and "The Fisherman's Ocean" but some of these things are obviously useful only if you have a good sized boat. IF you use a Pungo or canoe your world is quite different. I think I can paddle against most currents in Chase Garden Creek (a small tidal stream draining into Cape Cod Bay), but I doubt that I could make it upstream against the current in Bass River at the railroad bridge when there is a pretty good "lump".
Tomorrow I may get down to the Cape but with the very cold temperatures lately may not see familiar water but ice. The last time I was down the ice flows in the Cape Cod Canal covered about 30% of the surface. There may be some "scouts" at the Bourndale herring run but, if so, they will surely be winter crazed fishermen staring at the run, not herring.