Tim � When I first read your post, I was impressed by the insight that you showed! Certainly, pond shape should be one of the primary factors that influences fish yield. Are you sure you are not some type of ecologist??
:-)
Wildlife biologists always look at the spacing and amount of various habitat types. In fact, one of my wildlife biologist friends always gives me a hard time. �Why the heck do you fish squeezers always talk about pounds of fish per acre of water? Why not pounds per cubic volume of water?�
I really had no �hard evidence� to give you for ponds, so I didn�t immediately respond. As usual, Bill responded, and with his typical thorough answer.
I have no doubt that you are right about pond shape. However, like Bill, I don�t know of any particular studies that focus on this topic for ponds. That doesn�t mean there are none, just that I haven�t seen them.
I think one reason for the lack of studies is simply that there are so many different factors that affect fish yield. One thing is certain: all ponds are NOT created equal, even when they are located close to each other. One pond may have higher water productivity (fertility) than another, and will support more pounds of fish than the other. One pond will be clear, while another will be muddy (that�s common even in fish hatcheries where side-by-side ponds are completely different). One pond will have few plants, another might have many. Types of plants present can vary between ponds. So, picking out just one factor in a study can be difficult.
Now, in reservoir studies, we actually do look at �shape� of the impoundment. We use an index called the �shoreline development index (SDI).� To get this number, you divide the shoreline length of the reservoir by the shoreline length of water body that is a perfect circle but of the same acreage. So, a reservoir that is perfectly round would have a SDI of 1.0. A reservoir that is long and narrow, with many arms and coves, will have a much higher value, often 10 or above. Whew! How�s that for wordy. Anyhow, we can clearly show increased fish abundance and sport fish yield in reservoirs with a higher SDI, if other factors (such as the fertility of the reservoirs) are similar.
Dave
