Whale carcass leachate plumes in beach groundwater: A potential shark attractant to the surf?

Mar Pollut Bull. 2019 Mar;140:219-226. doi: 10.1016/j.marpolbul.2019.01.043. Epub 2019 Jan 28.

Abstract

With the recovery of whale populations, carcass strandings on beaches are growing. Beach burial is a common management option for stranded carcasses. However, communities fear shark attraction following leachate transport to the ocean via submarine groundwater discharge. Here, a sediment column mesocosm experiment indicated that carcasses can be a localised source of dissolved organic carbon (DOC), phosphate and ammonium to groundwater. The spatial reach of the leachate plume was <2.5 m, while the temporal stabilisation occurred over 100-300 days. No significant chemical signals were observed under a beach-buried carcass, implying effective attenuation of decomposition plumes. For beaches with conditions similar to our one-directional, fast-flowing sediment experiment generating extreme groundwater contamination, it is unlikely that any leachate from a whale carcass would reach the ocean if buried >25 m onshore. Therefore, carcass leachate plumes would only potentially attract sharks to the surf under specific conditions not experienced during our experiments.

Keywords: Attenuation; Biogeochemistry; Cetacean; Coastal management; Marine pollution; Permeable sediments; Subterranean estuaries.

MeSH terms

  • Animals
  • Australia
  • Bathing Beaches*
  • Geologic Sediments / chemistry*
  • Groundwater / chemistry*
  • Models, Theoretical
  • Mortuary Practice
  • Oceans and Seas
  • Predatory Behavior / physiology*
  • Refuse Disposal
  • Seawater / chemistry
  • Sharks / physiology*
  • Water Pollutants, Chemical / analysis*
  • Whales*

Substances

  • Water Pollutants, Chemical