Introduction

The decomposition of a body on land and the interaction between the body and its insect fauna have been well studied, and predictable insect development and colonization patterns have been described from many countries, geographical regions, habitats and seasons (reviewed in Anderson 2009). However, despite the oceans' vast area, little is known about human or animal decomposition and the associated faunal dynamics in the marine environment. Knowledge of the effects of body submergence is important as many homicide victims are disposed of in the ocean in an effort to get rid of the body and a much greater number of people are lost in the marine environment to drowning, boating or airplane accidents. In all these cases, it is important to the investigators and to family members to understand what has happened to the decedent from the time they were last seen alive, to the time of discovery. This has been particularly highlighted recently when six individual feet, shod in running shoes, washed ashore along the Southern British Columbia, Canada coastline, with a seventh found a few kilometres south in the US' San Juan Islands.

Forensic entomology can be of value in many parts of a death investigation, but its' primary purpose is to estimate the time elapsed since death. This is important in any death investigation but is of paramount value in a homicide, supporting or refuting an alibi, and allowing the investigators to understand the victim's timeline prior to death. However, estimating elapsed time since death is difficult (Chorneyko and Rao 1996; Teather 1994; Wentworth et al. 1993; Lawlor 1992; Mant 1960) or even impossible after a body has been submerged for a period of time (Wentworth et al. 1993; Picton 1971). In most cases when a body is recovered from the marine environment, the elapsed time since death is based on when the victim was last seen alive (Wentworth et al. 1993). This may be perfectly valid when the victim is, perhaps, a person who was last seen alive on a

G.S. Anderson

School of Criminology, Simon Fraser University, Burnaby, British Columbia, Canada

J. Amendt et al. (eds.), Current Concepts in Forensic Entomology, 223

DOI 10.1007/978-1-4020-9684-6_12, © Springer Science + Business Media B.V. 2010

fishing vessel and was expected back shortly. It is much less likely to be valid when a person has been murdered, as witness statements as to last time seen alive may not be truthful (Anderson 2008).

There have been very few studies on decomposition of either human or animal remains in aquatic environments (Sorg et al. 1997), and those that have been conducted are mostly from freshwater (O'Brien and Kuehner 2007; Petrik et al. 2004; Hobischak and Anderson, 1999, 2002; Hobischak 1998;O'Brien 1997; O'Brian 1994; Kelly 1990; Dix 1987; Tomita 1976; Payne and King 1972). Most of our knowledge of the marine taphonomy of a body is anecdotal, based on case studies of recovered bodies and known drownings (Dumser and Türkay 2008; Ebbesmeyer and Haglund 2002; Haglund and Sorg 2002; Kahana et al. 1999; Boyle et al. 1997; Ebbesmeyer and Haglund 1994; Haglund 1993; Davis 1992; Giertson and Morild 1989; Donoghue and Minnigerode 1977). The most valuable reviews are from Sorg and colleagues (1997) and Teather (1994), a Royal Canadian Mounted Police (RCMP) Officer who was an investigative police diver and published the book 'Encyclopedia of Underwater Investigations'. Some research has been conducted in the more accessible intertidal regions (Davis and Goff 2000; Lord and Burger 1994) but these primarily describe colonization by terrestrial insects until the remains were submerged, when bacterial decomposition became prominent (Davis and Goff 2000). Large carcass falls, such as those of whales, have been observed since the 1850s. These do provide interesting information on the ecology related to large nutrient injections into normally nutritionally poor environments (Baco and Smith 2003). However, these are extremely large animals and usually are found at great depths (~4,000 m or more) (Smith and Baco 2003; Witte 1999) so do not relate well to a recovered human body.

Decomposition in the ocean is impacted by a large number of interacting variables including water temperature and salinity, tides, currents, depth in the water column, substrate type, season, body covering, water chemistry and the species and numbers of colonizing animals (Anderson and Hobischak 2002, 2004; Sorg et al. 1997; Teather 1994; Keh 1985; Polson and Gee 1973; Mant 1960). A body, whether human or animal, provides a sudden input of nutrients. Sorg and colleagues describe the four ecological roles of such a carcass on the seafloor. They state that, depending on depth, substrate type and other factors, the remains may become food for many vertebrate and invertebrate scavengers, may provide shelter for other species, may attract secondary scavengers and the bones may eventually provide a source of minerals and act as a substrate for bacterial grazers (Sorg et al. 1997).

The lack of research from marine environs is hardly surprising as the oceans cover such vast territory and are mostly inaccessible. Marine decompositional research requires boats, divers, or deep sea equipment, often making it prohibitively expensive. In an effort to fill this gap, this author has been conducting a number of studies in the Pacific Ocean, in the coastal waters of Southern British Columbia. The first set of experiments was conducted in shallow, well oxygenated waters in Howe Sound. The second set of experiments is being conducted in the deeper and much more anoxic waters of the Saanich Inlet. Pig carcasses were used as models for humans as pigs have been shown to decompose in a manner very similar to that of humans (Catts and Goff 1992).

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