Any discussion of fishing hooks should begin with the understanding of hook sizes and the recognition of several hook types. Hook sizes are broken down into two numbering sets or series and where one series size end the next begins. The first series relates to the smaller hooks and uses a numbering system generally ranging from 32 to 1. Within this series the larger the number the smaller the hook, for example, a number 3 hook is smaller than a number 2, with the number 1 being the largest in the series.
For fishing hooks larger than the number 1 a transition into the "aught" series begins and generally relates to larger hooks. The "aught" series is a number followed by a backslash and zero. For example, 1/0, 2/0, 3/0, here the larger the number the larger the hook therefore, the hook size breakdown from smaller to larger is 3, 2, 1, 1/0, 2/0, 3/0. Hook sizes range from the very small number 32 to the very large 20/0, however most retail store carry only the most common used sizes ranging from about number 8 to the 7/0 and odds are your hook selection will fall within this range.
There are dozens of fishing hooks types being manufactured, here are examples of the four most relevant types.
The aberdeen is the most commonly used freshwater hook, made from shaped wire which will bend before breaking, this allows the aberdeen to be bent back into shape several times before the hook loses strength.
The circle hook is the hook for catch and release, it generally sets in the fish jaw not the gut and often will hook without the need for setting action. The circle hook is our recommended hook for most outings.
The o'shaughnessy is a very strong, thick, forged hook which does not bend easily and is excellent for offshore fishing.
The kahle is used mainly for live and natural bait, especially with larger shiners when bass fishing. This hook can be easily swallowed making it very effective but unsuitable for catch and release.
From these types many modified styles have been created like the bait keepers which has additionally barbs on the shank and weedless hooks which has a wire clip designed to prevent snagging. There are true-turns, trebles, duals, and barbless - well you get the idea.
The important things to keep in mind when selecting fishing hooks are; the size of the fish to be caught, how large or small the bait to be used, matching the line strength and diameter with the hook, and the structure in the waters where you are fishing.
Fish size may or may not relate to how large the mouth of the fish is. For example, the channel catfish have a relatively small mouth as compared to the same size flathead catfish. This same comparison can apply to the bait size used to catch these fish, where a larger hook would be needed to fish a six inch bream as bait for flatheads, the channel cat becomes a bait stealer because of its small mouth.
If fishing with equipment that does not allow for drag setting, the line strength versus hook strength is a consideration. Also the line diameter is a factor because if the hook eye is too small the uses of the best knot could be impossible. Lastly, structure is a consideration because of the possibility of becoming snagged. Is it better to break or bend a hook than lose hook, line and sinker? Could a weedless hook be used? Using 80 pound test braided line with a 7/0 hook is very hard to pull loose when snagged but this will hold one very big fish.
Remember not to mix used fishing hooks with new one, keep hook in a sealed container until ready for use otherwise corrosion becomes an issue.