Tuesday, May 20, 2014

How Weather Affects Fish: Research Series #2

Mornin' Folks,

I found this great article on weather.com about how the weather and the solar and lunar phases affect fish and game activity. I figured I'd post it here, in its entirety, for you guys to look over and to make it easy for me to find again!

Tight lines!


How Weather Affects Fish Activity

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    Want to increase your catch? 

    You're not alone.
    Every angler is interested in catching larger fish, faster. Every angler also knows that the best fishing times are when the fish are feeding, which is typically at dusk and dawn. But there are other factors to consider, too. Here's more ...
    A History of Solunar Tables
    The quest to determine the best times to hunt and fish is not a recent project. For hundreds of years people that made their living hunting and fishing recognized that there were certain times when wildlife was more abundant. The lives of most Native Americans were completely dependent on knowing the best times to hunt and fish. People who base their existence on the ocean or lakes have long understood that solar and lunar influences help determine the best times to fish.
    What is generally known and almost universally accepted is that fish and game are more active at certain times of the day, most noticeably at dawn and dusk. It is also generally agreed that many game species are more active during certain phases of the moon as well as when the moon is in certain positions in the sky each day. All of these influences have an individual effect that can be observed and in some instances measured.
    Much of the early research and understanding of solar and lunar influences was pioneered by John Alden Knight. In 1926 Knight began his studies of various influences that affect wildlife activity. This research resulted in his publication of tables that illustrated periods in each day of major activity and minor activity. To substantiate his research and theory, Knight analyzed data for over 200 record catches of fish. His analysis concluded that 90% of the catches were made while in the effect of the new moon and while in a "solunar period".
    Additional proof of Knight's theory was provided by a biologist at Northwestern University. Dr Frank A. Brown had live oysters flown in to his lab in Chicago, Illinois. Oysters open their shells at each high tide. Dr. Brown wanted to see if this opening and closing was the actual result of the changes in water flow from the tides or from lunar influences. Dr. Brown discovered that after about a week the oysters had changed their opening and closing to correspond to the times that the moon was directly overhead and underfoot for Chicago.
    Solunar tables have been used in some form since 1936. Since that time, the most significant improvement in our understanding of influences on wildlife activity has come with more recent capabilities to calculate and observe the combined effect of multiple solar and lunar influences. The days and times of these combined influences result in periods of significantly increased activity, which are shown in Weather and Wildlife Charts.
    Solar Influence
    The sun is the largest body in our solar system and some would say exerts the greatest influence in our daily lives, as well as that of wildlife. The primary solar periods that are factored in Weather and Wildlife charts are dawn, dusk, midday and midnight. Each of these periods is determined based on the exact time of sunrise and sunset for that specific location and date.
    The sun has its greatest influence when it is at its zenith or most directly overhead. That point occurs around June 21st each year in the northern hemisphere. Even though the solar influence on wildlife within each day is significant, the day-to-day and even the week-to-week change resulting from this solar influence is incremental and not very noticeable.
    Lunar Influence
    The moon is also a large factor in the day-to-day lives of people as well as wildlife. Some of the lunar influences are obvious while some are not. The most obvious and measurable affects of the moon on the earth are seen with tides. The gravitational force of the moon is one of the primary influences in the rise and fall of tides. The period that the moon exerts its greatest influence at any specific location on earth is based on the relative position of the moon, the distance the moon is from the earth, and the angle of the moon above a certain location at that specific time.
    Most evidence and conventional wisdom indicate that the periods of greatest lunar influence on wildlife are when the moon is most directly overhead and then again when it is most directly underfoot (opposite side of the earth). These two positions are usually referred to as "major" activity periods or in other charts as "excellent" activity periods. There are two other daily periods of lunar influence that occur halfway between the overhead and underfoot positions, and they are usually called "minor" or "good" activity periods.
    When the moon is at perigee (closest to earth) all other lunar influences are magnified. This is also the case when the moon is at its highest declination or so called high moon. The moon phase has also been shown to indicate, if not directly cause, certain heightened periods of activity.
    Weather and Wildlife Charts
    What determines why one specific day is a better day to fish than another? Why are you more likely to find fish feeding at certain times of the day than others? These are good questions that anyone is likely to have when looking at a solunar table.
    Virtually all wildlife repeats certain activities each and every day. All fish and animals must eat and rest to sustain life. The movement necessary to accomplish these basic needs is what provides all of us with the opportunity to observe and to harvest more game and fish. Our ability to understand how these solar and lunar influences affect feeding activity has made hunting and fishing more predictable. Weather and Wildlife charts are a simple way to graphically combine the solar and lunar influences discussed above and illustrate the results in a clear and easy to read format.
    Best Time of the Day or Peak Activity Time
    During each day the sun and moon exert their individual influence on each and every hour. Each hour and day will have a different combination of these influences. The Best Time of the Day Chart shows the entire day graphically so that you can quickly determine the peak activity times for fishing at your specific location. Times that show a higher rating have a greater combination of solar and lunar influence and thus a higher probability of heightened wildlife activity. Sunrise and set, the two most significant solar periods, are also indicated on the chart. All Weather and Wildlife charts are generated for the specific latitude and longitude from the data entered. The Best Time of the Day Chart can also be viewed for a total of ten days including the current date.
    Declination and Diurnal Inequality
    Anyone who has used solunar charts or tables (sun and moon) to predict wildlife feeding activity is probably familiar with the terms "major" and "minor" period. As discussed earlier they are also often referred to as "excellent" or "good" times. These major times occur when the moon is directly overhead or underfoot and the minor times follow the major times by approximately 6 hours. The lunar event from which each of these times are calculated is called "transit", or the daily point that the moon passes the meridian at that specific location. Transit occurs sometime between moonrise and moonset, but not always halfway between.
    The other two lunar events that affect the intensity of the feeding activity periods are "perigee" and "high moon". High moon is another name for the monthly point of maximum lunar declination.
    To understand the "high moon" effect it is important to understand that the lunar orbit is not on the same plane as the earth's equator. The moon's orbit is tilted in two different planes 28.5 degrees off the earth's equator. At some point in its orbit, the moon will be 28.5 degrees above the equator and approximately two weeks later it will be 28.5 degrees below it. The moons orbit varies between these two positions during the month, appearing to advance to the north and then retreat back to the south. This advancing and retreating is what is called lunar declination. The highest declination or "high moon" is determined when the moon is at its highest altitude angle.
    Diurnal inequality is what causes one of the "major periods" to be less intense or weaker than the other major period during the same day. This is also why the two high tides during the same day are almost never equal. Most solunar tables are based entirely on daily transit times. A few tables include a "high moon" effect with no consideration of declination. Only Weather and Wildlife charts incorporate all the above-mentioned factors to provide the most accurate ratings possible.
    Game Fish
    Understanding the affects of the sun and moon on wildlife is only one part of the complex puzzle that helps predict when game animals and fish are most active. First and perhaps most important to putting together the puzzle is a good understanding of the individual species being pursued. Most game fish species are carnivores and will eat a wide variety of foods, but quite frequently they feed on other smaller fish. Fish are opportunistic feeders and will feed ravenously when hungry, and when food is readily available. However when full they may totally ignore the food source. There is an extremely large number of different species of fish that are sought after in both fresh-water and salt-water. Weather and Wildlife charts rate the lunar and solar events that generally affect all fish. However, each species has certain specific habits and diet that requires specific knowledge and individual study in order to understand their feeding tendencies.
    Weather is the single most significant factor that affects wildlife activity. Every one that has spent time fishing knows that changing barometric pressure or frontal activity can bring fishing activity to a halt even in peak activity times. Weather and Wildlife Charts are based on steady fair weather. Changing weather may result in activity levels less than what is shown in the chart. It is also true that knowing when weather will stabilize is equally important to predicting heightened feeding activity.
    Understanding the impact of weather on the individual species of fish you are pursuing as well as other factors including depth fished, water temperature and clarity are also important factors in your success. Perhaps the most important reason for viewing and understanding weather as a factor in your fishing plans relates to safety. High winds and cold temperatures can be a deadly combination when you are unprepared. There is a great deal of information available on the Internet for people who want to learn about the anatomy, habits, diet, reproduction and many other facts about various game animals and fish.


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