Tides, why do we have them?

I feel lost in this section seeing as I don't sea fish any more, but I have a question that some on here may be able to answer....

Well, the answer to the topic I do already know (that was a teaser). The reason we have tides is because the Moon causes a bulge of water (it tries to flatten the earth as well causing a bulge, bit like a rugby ball) on the nearest side to the Moon and on the opposite side of the Earth. Each time the Earth spins through the bulge we get a high tide. That I understand, two tides per 24 hours (almost).

Now this was demonstrated with a new graphic on the BBC programme last night entitled 'Orbit'. However, they showed (and I also understood this to be so) the bulge of water strongest in the middle of the Earth. Yet, they went to a point on the coast of Canada, very north, and showed how great the tides can be with one of the greatest tide differences on Earth.

Now, I'd have thought that the greatest difference between high and low water on a spring tide would be around the equator and that the tides closer to the poles would be more negligible. Isn't that normally the case?

That's your starter for 10 and for your bonus question, why do spring tides fish better for some species and neap tides fish better for others?

I always thought it was a government directive to swill all the c r a p away that people leave on the beaches Jeff

I think this is right: The equator is closest to the sun, but not to the moon, which has it's own orbit, quite different from the one which relates the Earth/Sun.

Well, for the bonus question, some species (most notably Cod) thrive in the stronger currents generated during Spring tides. It also (I guess) gives them access to more food that's scoured out of the bottom and is washed into the sea as it hits the highest point of the beach.

Some fish (like thornback rays) prefer smaller tides as, IMO, they can feed more easily without a fierce tide run. Also, a neap tide doesn't go as far out so fish that like shallower water don't have to retreat so far out on a neap.
That's my thoughts anyway

murv said:

Some fish (like thornback rays) prefer smaller tides as, IMO, they can feed more easily without a fierce tide run.

Click to expand...

I'll go with that, Murv. When I did go sea fishing we always had better ray catches on a neap tide.