"Why in the world would you want to improve porcupine habitat?" This question is often asked by new members, or those unfamiliar with this type of structure. The "Porcupine" Crib gets its name from its appearance (see photographs below); it has nothing else to do with porcupines! It is a form of artificial fish habitat designed by Pennsylvania Fish & Boat Commission (PFBC) for use in lakes and reservoirs. The openings on a crib are only two inches high, thus providing baitfish and young gamefish protection from predators. These structures also make ideal spawning habitat for many species of fish.
There is very little cover or bottom structure in Allegheny Reservoir. Aquatic plants and weeds have difficulty establishing themselves due to seasonal water level fluctuation. Since 1994, KFWA has built and placed 1,289 "Porcupine" Cribs in the reservoir, in hopes of adding badly needed cover. Breaking this down, we've placed 831 Deep Water Cribs, 142 Shallow Cribs, and 316 Crib Juniors. For a look at the complete history of Crib projects, click here.
Each full size crib is constructed of 52 - 2"x2"x4' hemlock sticks, and 8 - 8" cement blocks. The cribs are built in two sections. When the lower section is completed, it is placed on special rollers on the barge, and the blocks are placed inside. The top section is nailed on, and a Mylar strap is fastened around the entire crib. The barge is finally maneuvered into position, and the crib is pushed overboard. Deep Water Cribs are generally placed in 50 feet of water at or around summer pool level.
In early spring and late fall, the water level in Allegheny Reservoir is very low. At this time, shallow water cribs can be built "on site" (on dry land that will be underwater during summer pool). Shallow water cribs are actually a full size crib that is placed in shallower water.
These structures are very similar to standard "Porcupine" cribs. They are 28" high, compared to 44" for a standard crib, and they use only 38 sticks. They were adapted from the standard crib design by PFBC for use in shallow water. Click here for plans, courtesy of PFBC.
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Last updated 10/11/01
