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that sunfish are not well adapted to present conditions in

south Florida. Drainage has caused a general lowering of

the water table, increasing the duration and frequency of

drought. The sizeable number of sunfish in Mud Lake Pond

during the 1974-75 season was probably due to the nearness

of Lake Trafford, which served as a reservoir for

colonists. The comparatively low population of sunfish in

Mud Lake Pond during the 1975-76 season probably resulted

from the delay in summer rains, which shortened the growing

time for recruits that were the product of spawning by

migrants from Lake Trafford.

 Crayfish may recolonize marshes more quickly than fish

because their migration is only a few feet and in a

vertical direction. Crayfish burrow to escape dry

conditions, and, unlike fish and prawns, dq not concentrate

in ponds where they could be subjected to crowded, hypoxic

conditions. Survival rates of crayfish during the dry

season probably exceed that of fish because crayfish can

burrow at least 5 ft (1.5 m) to reach water (M. Duever,

pers. comm.). An abrupt decline in the number of crayfish

several months before the marsh had totally dried suggested

that they go into their burrows before low water forces

them to do so.


 Effects of Natural Storage and Impact of Drainage

 Although the years 1970 through 1975 were unusually

dry in south Florida, results of the water model (Model in