Comparison of Faunal Scavenging of Submerged Carrion in Two Seasons at a Depth of 170 m, in the Strait of Georgia, British Columbia.

Gail Anderson,Lynne Bell

doi:10.3390/insects8010033

Abstract

The taphonomy of carcasses submerged in the ocean is little understood, yet it is extremely important ecologically and forensically. The objectives of this study were to determine the fate of pig carcasses as human proxies in the Strait of Georgia at 170 m in spring and fall. Using Ocean Networks Canada’s Victoria Experimental Network Underseas (VENUS) observatory, two carcasses per season were placed under a cabled platform hosting a webcam and instruments measuring water chemistry. Two minutes of video were recorded every 15 min. In spring, Lyssianassidae amphipods and Pandalus platyceros were immediately attracted and fed on the carcasses, the amphipods removed the bulk of the soft tissue from the inside whilst the shrimp shredded the skin and tissue. The carcasses were skeletonized on Days 8 and 10. In fall, Metacarcinus magister was the major scavenger, removing most of the soft tissue from one carcass. Amphipods did not arrive in large numbers until Day 15, when they skeletonized the scavenged carcass by Day 22 and the less scavenged carcass by Day 24. Amphipods remained for some days after skeletonization. This skeletonization was very different from previous experiments at different depths and habitats. Such data are very valuable for predicting preservation, planning recoveries, and managing family expectations.

Highlights

The decomposition and insect colonization of carrion is well understood in the terrestrial environment and has been studied in a variety of habitats and geographic regions, globally [1,2], both for ecological value [3] and for medico-legal application or forensic entomology casework [4].the taphonomy of carrion in the aquatic world is much less studied
This work was performed in collaboration with Ocean Networks Canada (ONC)’s Victoria Experimental Network Underseas (VENUS) observatory, a cabled underwater observatory based at the University of Victoria on Vancouver Island, British Columbia (BC)
The shore station provides communication links between the instrument arrays and the University of Victoria, which houses a Network’s operation centre (NOC), which manages the functioning of the instruments and a data management and archive system (DMAS), which receives and processes the data which can be accessed by researchers anywhere in the world via the Internet [24]

Summary

Introduction

The decomposition and insect colonization of carrion is well understood in the terrestrial environment and has been studied in a variety of habitats and geographic regions, globally [1,2], both for ecological value [3] and for medico-legal application or forensic entomology casework [4].the taphonomy of carrion in the aquatic world is much less studied. The decomposition and insect colonization of carrion is well understood in the terrestrial environment and has been studied in a variety of habitats and geographic regions, globally [1,2], both for ecological value [3] and for medico-legal application or forensic entomology casework [4]. Some studies and case reviews have been conducted in freshwater environments [5,6,7,8,9,10]. Conducting carrion research in water is much more difficult than on land due to accessibility and safety issues; as well, changes in the physical and chemical environment can occur over just a few meters [11,12]. The marine environment is challenging as it is more complicated, expensive, and difficult to place and monitor carcasses.

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