First Record of Coralline Lethal Orange Disease on the Reefs of Belize

Abstract

Crustose coralline algae (CCA) are important to reef integrity by cementing coral reef structures together (Littler and Littler 1984) and serving as recruitment substratum for coral larvae (Harrington et al. 2004, Price 2010, Ritson-Williams et al. 2016), yet little is known about the distribution, ecology, or pathogenesis of CCA diseases (Vargas-Ángel 2010, Weil and Rogers 2011, Williams et al. 2014). Coralline lethal orange disease (CLOD) is a bacterial disease of reef-building crustose coralline algae (Littler and Littler 1995) that has been found in the Indo-Pacific (Littler and Littler 1994, 1995, Vargas-Ángel 2010), Red Sea (Aeby et al. 2017), and the Indian Ocean (Aeby et al. 2015). It has been reported from a few areas within the Caribbean, but little is known about CCA diseases in this region (Weil and Rogers 2011). Here, we report the first observations of what looks like typical CLOD signs at four out of nine sites surveyed at Carrie Bow Cay, Belize (see photograph and Online Fig. S1). In the Pacific, CLOD is readily transmitted among different species of coralline algae and causes significant mortality in the dominant algal ridge builderPorolithon onkodes (Littler and Littler 1995), but little is known about the etiology, ecology, or pathology of CLOD in the Caribbean. The Caribbean has been experiencing massive coral mortalities since the early 1980s, including the ongoing stony coral tissue loss