The shoreline distribution and degradation of tilapia carcasses, Salton Sea, California: Taphonomic implications

The Salton Sea is a hypersaline, closed lake system in southern California, USA. Episodic fish kills led to bloating and floating fish bodies that were driven onto the shoreline by wind shear. The documented taphonomic destruction of the stranded fish carcasses includes the distribution of the fish parts after desiccation and disarticulation mainly by wave-induced transport with possible minor component of wind transport on the upper shoreface. Carcass decay is divided into five taphonomic categories 1 through 5. Category 1 represents whole pliable fish, recently washed onto the shoreline while category 5 incorporates longer-term destruction into ultimately single, isolated skeletal elements. High water, strand line deposits are delineated by the presence of categories 3 through 5 mixtures. The general trend, in 2012 was observed to be considerable bone disarticulation away from the shoreline because categories 1 and 2 were present in the swash zone; the influx of fresh fish carcasses recharged the shoreline. During 2013, the absence of new 1 and 2 categories arriving to the shoreline enhanced wave action to further break down categories 3 and 4 ultimately into category 5. In addition, isolated bone elements segregate according to density differences, typically on low-gradient beaches. Wave and wave-induced current action coupled with beach topography controls distribution of the various fish bones. As an actualistic model, the Salton Sea implies that shore-parallel complete to partial fish carcass concentrations are more shoreward and isolated skeletal elements more distal.