Time of Submergence Using Aquatic Invertebrate Succession and Decompositional Changes

Abstract

Pig carcasses were placed in pond and stream habitats in the Malcolm Knapp Research Forest in Maple Ridge, B.C. for approximately one year, to examine the development, species, and sequence of invertebrates associated with the carrion. An invertebrate successional database was created for pond and stream habitats for potential use in estimating time of submergence in water related death investigations. Analysis has shown that a predictable succession of invertebrates colonize the carrion. However, whether or not this succession is carrion dependent or seasonal is unknown. There is a difference in the species composition between pond and stream habitats. Habitats influence invertebrate fauna, therefore, species colonizing carrion are habitat-specific. In both habitats, no one organism can determine time of submergence alone. Decompositional descriptions from this research were compared with 15 freshwater related death investigations. Similarities were seen in the earlier decompositional characteristics including bloat, discoloration, and nail shedding; however, the human descriptions were so vague that they had little value in determining time of submergence and hence time of death.

Decomposition of carrion in the marine environment in British Columbia, Canada

“…This is consistent with that reported in many human cases in the marine environment [7,18], and also with the onset of adipocere in freshwater environments in B.C. [1,10,13,14,15]. However, a recent B.C.…”

“…Typical decompositional characteristics associated with aquatic habitats were observed including lividity, bloating, marbling, hair shedding, skin sloughing, scavenging, adipocere formation, flesh decaying, exposure of internal organs, algae accumulation, silting, disarticulation of bones, and algae staining on bones [1,10,13,14,15,16].…”

“…Decomposition would probably have been quite different had the remains surfaced. The position of a body in relation to the water line will affect the rate and sequence of soft tissue decomposition and eventual disarticulation of bones [1,10,13,14,15,16,17,18]. The formation of adipocere tissue was obvious on several of the marine carcasses around 40 days after submergence.…”

“…Table 1 Comparison of decomposition between carcasses submerged in the marine environment, still and running freshwater (modified from [15]) and those decomposed on land (modified from [12] dry or remains stages [12]. These stages were present but modified in freshwater experiments [13,14]. In the marine environment, clear decompositional stages were present, but different in duration and appearance from those seen in the previous environments (Table 1).…”

Upper Pleistocene blow flies (Diptera: Calliphoridae) trapped in fossilized crania of large mammals discovered from gravel pits in the Rhine rift valley from Hesse (Germany)

“…It is assumed that carcasses lay for a certain time on dry ground or were sitting by or in shallow water or sediments. Because a colonization of carcasses by blow flies, while floating at the water surface of the river might be possible, but is quite atypical and seldom occurs (Hobischak and Anderson, 2002;Anderson and Hobischak, 2004). In order to preserve the puparia inside the skulls, where they were protected against mechanical damage, mammal remains got shortly submerged after the emergence of blow flies, maybe caused by a river flooding, and were transported by running water until they were embedded.…”