The holding power of your anchor is dependent on many factors, the most important being what kind of underwater environment you encounter. One thing to remember is that when you want to leave, your anchor should be readily recoverable, which is not always easy.
The mushroom anchor
This is one of the most common anchors used by sport fishermen on lakes and rivers with slow currents and muddy bottoms. It is lightweight yet relatively effective. You simply throw the anchor overboard and allow the current to drag you away, until you have achieved about four to 10 times the depth in distance from the anchor. That is called the scope of the anchor.
If you are just fishing and the current remains the same, in other words, you have no ebb and flow from tidal influences, this type of anchor is tolerable. To continue your journey, you just run forward over the anchor or pull the scope back onboard, pulling up a heavy, mud-filled mushroom, and head to shore for the fish fry.
The mushroom anchor is a very basic, specific ground-purpose anchor, probably the least desirable choice amongst sailors and motor boaters who operate in offshore waters.
Some anchoring techniques
Unless you are just the recreational fisherman operating in shallow, muddy waters, there are some absolute musts to be observed while you are throwing out your anchor. First and foremost amongst them are that you do not attach a rope directly to your anchor.
Take the length of you boat and use that as a basic measure of how much fairly heavy chain you should attach to your anchor before switching to a suitable type of rope for the rest of the length.
The anchor chain lying at the bottom will act as a buffer between swells lifting you boat and the anchor buried in whatever surface you are hooked into. Avoid anchoring in coral unless it is an emergency, as you will terminally damage the coral and in all likelihood sacrifice your anchor, unless you are prepared to dive for it, which can be a problematic situation when you are the only person on board.
Winds, currents and tides
The ocean is a very wicked thing that, once you are aware of what it may do, is simple to work with. Always be aware of the weather forecast, paying particular attention to winds and the tidal forecast. Every six hours or so, your boat will swing about in a 180-degree arc, so you must assure that you are not anchored too close to other boats or obstacles.
If high winds are forecast, make sure you put your best anchor out, something like a plow anchor or a CQR, and it never hurts to have a secondary anchor at the ready, as many times your primary anchor may drag with a change in wind or tidal direction.
So what is the least desirable anchor?
As stated earlier, the mushroom anchor is a temporary situational anchor, and you should not rely on it to save your boat or lives on it. If you are in a lake and a storm kicks up, there is nothing like a plow, with a secondary plow anchor on hand in case the wind shifts 180 degrees and unseats your primary anchor. If you have only one anchor, you should not be out there in the first place, as your primary anchor could become fouled and you may have to cut the rope. When at sea, you always have to think ahead and have a secondary plan. Before setting out it is also advisable to file a float plan with someone, so if you go missing, they will know where and how many people to look for.