Hematological and Biochemical Assessment of Two Species of Freshwater Mussels, Quadrula quadrula and Amblema plicata, Following Translocation

Abstract

Nondestructive, sublethal, and sensitive health monitoring tools are needed to assess the health of freshwater mussels (family Unionidae). Recent developments to standardize hemocyte characterization have assisted in the hematologic assessment of wild and captive freshwater mussels. In this study, preliminary baseline hematological reference ranges were established for wild mapleleaf mussels Quadrula quadrula (n = 14) and threeridge mussels Amblema plicata (n = 20) collected from the Muskingum River in Devola, Ohio. Mussels were collected from the wild, and hemolymph was sampled from each mussel in the field upon capture (baseline sample). They were then transported live to a propagation facility. Subsequent hemolymph samples were collected at 2 and 4 weeks and quarterly thereafter for 11 months following translocation. Hemocyte counts, hemocyte morphology, and hemolymph chemistry (Na , Cl , Mg , P , K , Ca , glucose, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase]) were measured from each sample on each sampling occasion. Hemocyte counts were consistently greater in Q. quadrula than in A. plicata following transfer to captivity. Baseline hemocyte morphology and hemolymph chemistry varied between species. This study provides a foundation of reference ranges for hemocyte characterization for Q. quadrula, and A. plicata and a preliminary understanding of how hemocyte character might be expected to change when wild mussels are translocated into captivity, and thus be a useful technique for monitoring the health of freshwater mussels.

Pathology and infectious agents of unionid mussels: A primer for pathologists in disease surveillance and investigation of mortality events

“…32,74 However, reference standards for hematologic and biochemical parameters are not available for all species, and developing reference ranges for healthy freshwater mussels is complicated because ranges are likely to vary by species, time of year, water quality, and physical habitat. 75,187 To collect hemolymph, mussel valves are opened slightly, for example, using a pediatric nasal speculum until a rubber stopper can be placed in a relatively anterior location in the opening between the shells. Up to 0.5 mL was drawn over 30 seconds using a small (28 gauge) needle and 1 ml syringe from 4 to 7 cm (50 g) Elliptio complanata (eastern elliptio) without negative impact on growth or survival.…”

The Status of Mussel Health Assessment and a Path Forward

“…Since the review by Newton and Cope (2006), advances have been made in several key areas of biomarkers and health assessment tools, namely, those characterizing health status by analysis of hemolymph constituents such as enzyme and ion levels (Gustafson et al 2005b;Burkhard et al 2009;Archambault et al 2013;Fritts et al 2015a, b;Steinagel et al 2018), behavioral endpoints such as mantle lure display and foot protrusion (Bringolf et al 2010;Hazelton et al 2013;Leonard et al 2014;Hartmann et al 2016), reproductive and endocrine endpoints (Morthorst et al 2014;Leonard et al 2017), and the use of -omics (e.g., metabolomics, proteomics, transcriptomics) techniques (Malecot et al 2013;Leonard et al 2014;Luo et al 2014;Roznere et al 2014;2017;Bartsch et al 2017). Recently, metabolomic studies of freshwater mussels have been used to identify shifts in key metabolites from stressors such as captivity and food limitation (Roznere et al 2014), relocation (Bartsch et al…”

“…Hemocyte count, phagocytic activity, natural killer-type activity, and lysozyme concentration were measured to assess immune responses of E. complanata (Gélinas et al 2013) and D. polymorpha (Juhel et al 2015) to cyanobacteria. Mahapatra et al (2017) followed the hemocyte count, phagocytic activity, and nitric oxide generation of L. marginalis during starvation, and Steinagel et al (2018) measured changes in hemocyte counts and morphology in response to translocation into captivity of Mapleleaf (Quadrula quadrula) and Threeridge (Amblema plicata).…”

“…Maintaining healthy individuals in culture facilities will depend on knowledge of potential pathogens, conditions that support immunocompetent animals, and the factors that favor optimal growth and health. Monitoring sublethal indicators, such as key metabolites (Roznere et al 2014) and hemolymph parameters (Steinagel et al 2018), could provide early warning of declining condition in captive mussels and help identify causes (e.g., nutritional deficiency, microbial imbalance, disease). Metagenomic analysis of gut microbiome and metabolomics could be used to compare responses of mussels to different diets and rearing conditions to optimize growth and production in propagation facilities (Roznere et al 2014;Aceves et al 2018).…”