KurauKing's Fishing Journal

Lunar Tides/Moonphase

Tides are periodic rises and falls of large bodies of water. Tides are caused by the gravitational interaction between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Since the earth is rotating while this is happening, two tides occur each day.

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The Sun’s Interaction with the Tides

Spring Tides

Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.

Neap Tides

Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.

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The eccentricity of the orbit of the moon in this illustration is greatly exaggerated.
The Proxigean Spring Tide is a rare, unusually high tide. This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) and in the New Moon phase (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years.

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Moonphase: observations of natural phenomena

The mating of Belankas (horseshoe crab):
I remember as a kid, seeing these blackish-green “alien-looking” creatures crawl up on the beaches. The female is larger and she is giving the smaller male a ride on her back. Normally on breeding season, there are hundreds of pairs and countless other singles crawling up the beach. I can’t remember exactly, but it is either on the full moon or new moon. Perhaps the mating season will co-incide with good / poor fishing days?

Sea lice:
Normally happens on neap tide days, although I’ve seen it happen at some badly infested areas during the period where there is no current flow at high tide. These are tiny yellowish creatures that will burrow through the bait if it is dead and devour it inside out. If you are diligent in checking your bait, you will find it swarming with these creatures and will start crawling out from the stomach cavities etc and it looks disgusting. Normally, when I encounter this, I either pack up and go home, or I anchor off in a safe, sheltered place and go to sleep.

Phosphorescent tide
Probably not related to moon phases, most often I noticed this happen after a rainy day, the sea will light up at night in a greenish-blue glow. The bow wave of the boat as well as the wash behind comes alight as the boat churns up the water. Sometimes, I see streaks shooting through the dark waters at night indicating fish swimming through.

On a dark moonless night at punggol pier, the water was very clear and each wash of the waves on the concrete steps of the pier brought on an explosion of amazingly beautiful light.

But beautiful as these things are, I noticed that on nights that the water fluoresce, i don’t catch fish, as it is an indicator of bad water condition. (Someone once told me it’s because of low pH in the water). What are your observations?

The green glowing stuff is bio-luminescence. Lots of sea creatures bio-luminese. The fireflies seen in swamps employ similar technology for their lights. There will always be plankton etc in the sea water at any one time which has bio-luminescent abilities and you can find one or two pin pricks of light, glowing in the water – that is normal.

But I’m talking here about the whole wave glowing. When you put your hand in and stir the water, your hand lights up the water.

This I notice happens normally a day or so after heavy rains. I believe freshwater, and runoff can stimulate an algal bloom, especially if there is NH3 or urea in the runoff (Most of our runoff will have that because of fertilisers from our roadside plants). And I guess marine dinoflagellates (a type of algae that is the cause of Red Tide) can bloom from this excess nutrient to cause this kind of glowing.

Those who keep fish will automatically know that the conditions I described here are what aquarists call “Poor Water parameters” – high NH3 and low O2, low pH – will kill fish. So how to expect fish to eat your bait under such conditions.

Corals spawn on the full moon. There is this marine forum http://www.sgreefclub.com/portal/ that tracks coral “hanky panky time” by tracking lunar phase.

Anyway, what are your observations/experience on a night where there is great phosphorescent seas. Do you experience a good catch?

Full moon
My Great-grand uncle used to tell us not to go fishing on the full moon. He’d say in Teochew “Moonlit night where got fish”. His probable reasoning is that on a moonlit night, fish can see your line and not bite (Thit is my guess because dunno why I never ask him “why not?” when he was alive, but instead chose to ignore the comment till now). However, my reasoning is if moonlit night fish can see line, daytime should be worst right?

By Ban_zai and LLCC

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