Voyage 11 portrays the ramifications in the Chesapeake Bay of weather events far away. A huge hurricane causes an enormous rainfall in the Susquehanna Valley, resulting in flood waters filled with debris and dirty-filled fresh water.
To understand what was happening, one must visualize the bay as carefully structured in three distince dimensions. From north to south the waters of the bay were meticulously graduated according to their salt content...the bay was also divided into a bottom and a top. The lowest area contained deep, cold, very salt water, often deficient in oxygen...On top rested the less salt, less heavy, warmer water replenished by the sun and containing a good oxygen content...There was a final division, this one between the western half of the bay and the eastern...the western half of the bay (was) much less saline than the eastern, more silty, more filled with accidental non-marine vegetation, and in general more active.
In this complex ecosystem of interrelated temperatures and saline and oxygen levels, oysters were unable to flee the weight of the silt settling on them as the flooding waters slowed their motion upon entering the bay. The oyster beds of Devon Island were smothered.
Jimmy the blue crab, however, was able to attempt to voyage to more suitable water when the floodwaters began to radically impact the conditions in the bay. He was in the process of moulting when the fresh water dropped the salt content of the bay. Jimmy's body required a specific level of salinity; he was forced to move away from the protection of Turlock Marsh and its quiet water during the time when his body was unprotected, while the new shell hardened.
Once Jimmy's new, larger shell was hardened, natural instinct led him to locate a female crab. Jimmy carried her in his claws and legs as she moulted, which allowed the two to mate, and then until her new shell had hardened. Then they separated, and Jimmy attempted to follow his instincts back "to the northerly areas to spend the winter in the deeps" of Chesapeake Bay. Both crabs, however, were killed by the massive amounts of manure, sewage, and industrial waste that was carried into the Chesapeake by the floodwaters from the Susquehanna.