Skeletal myopathy in juvenile barramundi, Lates calcarifer (Bloch), cultured in potassium‐deficient saline groundwater

Abstract

Saline groundwater is being pumped from a number of locations in rural Western Australia to prevent secondary salinity impacting farmland, rural infrastructure and areas with high conservation value. Aquaculture may offset the costs of groundwater pumping, and the suitability of groundwater for finfish aquaculture is being assessed through bioassays. There are marked spatial variations in the ionic composition of saline ground water in Western Australia and this paper describes two bioassays investigating a saline, potassium-deficient water source that resulted in mortalities in juvenile barramundi, Lates calcarifer (Bloch). Histopathological examination revealed severe degeneration and necrosis of skeletal muscles, marked hyperplasia of branchial chloride cells and renal tubular necrosis. Clinical chemistry findings included hypernatraemia and hyperchloridaemia of the blood plasma and lowered muscle potassium levels. It is concluded that the principal cause of death was skeletal myopathy induced by low water potassium levels.

Fortification of an Aquafeed with Potassium Chloride Does Not Improve Survival of Juvenile Australian Snapper Pagrus auratus Reared in Potassium Deficient Saline Groundwater

“…Our observations are reflective of reports on teleosts where K + had been accidently omitted from artificial seawater [29] and mirror those reported by Fielder et al [5]. Our results are consistent with studies on other euryhaline species such as mulloway [3] and Barramundi reared in KDSGW [28]. In the case of Barramundi, transfer to KDSGW caused the degeneration and necrosis of skeletal muscle, hyperplasia of mitochondria rich cells (MRC or ionocytes), and renal tubular necrosis.…”

“…Numerous studies have indicated that extreme imbalances in the ionic composition of water effect hydromineral balance in fish and shrimp resulting in low survival and poor health [3,[26][27][28][29][30]. When a K + deficiency occurs, fish display symptoms such as poor growth, elevated food conversion ratio (FCR), anorexia, convulsions, tetany, and weakness or failure of skeletal, cardiac, and respiratory muscles [11,31].…”

“…These responses indicate a clear dependency on K + for regulating body fluid homeostasis and salt secretion, see [13,16,[32][33][34][35]. Fielder [5], Partridge and Creeper [28], and Doroudi et al [3] have already demonstrated that morbidity and mortality of euryhaline/marine species such as snapper, Barramundi Lates calcarifer, and mulloway Argyrosomus japonicus reared in KDSGW can be overcome by the direct addition of KCl to the water, achieving near optimal growth when the [K + ] of water was elevated above 60% the concentration of equivalent salinity seawater.…”

Larval rearing of barramundi (Lates calcarifer) in saline groundwater

“…Partridge and Creeper (2004) showed that mortality of juvenile barramundi in potassium-deficient, hyperosmotic groundwater was the result of unsustainable buffering of blood plasma with potassium from skeletal muscle, the body's major store of intracellular potassium. Moreover, demonstrated that such buffering also occurs in fish at near-isosmotic salinity.…”

“…The effects of this deficiency on juvenile barramundi have been described (Partridge and Creeper, 2004;Jain et al, 2006;, however, the effect on larvae is unknown. This paper describes the production of barramundi larvae in potassium-deficient groundwater with a salinity of 14‰.…”