First detection of gas bubble disease and Rickettsia‐like organisms in Paphies ventricosa, a New Zealand surf clam

Abstract

Gas bubble disease (GBD) is a non‐infectious condition in aquatic organisms caused by supersaturated levels of total dissolved gas (TDG) in water (Bouck, 1980). GBD is analogous to “the bends” (decompression sickness) in human scuba divers (Barratt, Harch, & Van Meter, 2002). In fish, the disease can manifest externally as bubbles on the eyes, opercula, fins, body and mouth regions, and internally as bubbles in the blood and on gill arches (Espmark, Hjelde, & Baeverfjord, 2010). GBD has also been reported in invertebrates, including in shrimp, blue crab, oysters and clams (Johnson, 1976; Lightner, Salser, & Wheeler, 1985; Malouf, Keck, Maurer, & Epifanio, 1972). The effects of GBD can range from mild to lethal depending on the level of TDG supersaturation, the species affected, life history stage, animal health, depth distribution and water temperature (Beeman et al., 2003; Johnson, 1976; Smiley, Drawbridge, Okihiro, & Kaufmann, 2011)...