Black Bass Diversity: Multidisciplinary Science for Conservation

Common Diseases of Black Bass: Implications for Conservation and Management

Jeffrey S. Terhune and Benjamin H. Beck

doi: https://doi.org/10.47886/9781934874400.ch28

Abstract.—Disease issues relevant to black bass populations arise from infectious as well as noninfectious etiologies. While disease outbreaks can occur via direct means, as is the case with primary pathogens, mortality events can also be linked to factors that disrupt the delicate balance between the environment, host, and pathogen. Indeed, black bass are found in a variety of geographies and habitats, and irrespective of their locale, fish are subject to environmental fluctuations, such as changes in dissolved oxygen, temperature, and water quality, as well as physical affronts, such as handling and confinement. These and other associated stressors can disrupt homeostasis and result in physiologic perturbations that are central to the pathophysiology of disease in black bass. Many pathogens that affect black bass are ubiquitous and opportunistic and commonly have limited impacts on populations as a whole unless a degradation of environmental conditions occurs that predispose fish to disease or exacerbate disease development. Examples include common aquatic bacterial pathogens (e.g., Aeromonas sp. and Flavobacterium columnare) and fungal and parasitic infestations, especially commensal protozoan parasites. In recent years, viral pathogens have been linked to large-scale fish mortalities in extensive, natural habitats as well as managed recreational impoundments. The underlying mechanisms behind these outbreaks remain largely undefined, yet significant concerns regarding biosecurity practices have surfaced due to the tremendous economic impacts that black bass fisheries support. Additionally, some grossly obvious phenotypic alterations of unknown etiologies (e.g., neoplasms and hyperpigmentation) may be indicative of environmental concerns that warrant further exploration.