Louisiana's wetlands and crops are presently under invasion by Pomacea maculata (Perry, 1810). Insight into the physiology of ampullariids is vital to informing threat assessment, developing effective control measures, and enhancing our understanding of the physiological adaptations that facilitate successful introductions of invasive species. This paper addresses the respiratory physiology and heart rate of P. maculata submersed in water, during initial and extended (aestivation) emersion in air. Invasive P. maculata in Louisiana possess fully functional lungs and gills, permitting survival in air without access to water, and reciprocally, survival in water with no access to air. The aquatic respiration rate measured as V^̇ O₂ (∼19 µL/g/h) was significantly lower than the initial aerial respiration rate (∼ 63 µL/g/h) for P. maculata, while the heart rate was similar in both water (∼37 bpm) and during initial emersion in air (∼34 bpm). Small snails (< 10 g) consistently exhibited significantly higher respiration and heart rates in both air and water compared to medium (10–60 g) and large (> 60 g) snails. A substantial reduction in heart rate (86%), body weight (24%), and V^̇ 0₂ (94%) was observed in P. maculata after 58 days of aestivation in air. Periodic changes in the rate of oxygen uptake and cardiac arrhythmia were regularly observed in snails during emersion in air.

Understanding the relative times of gametogenesis and spawning of gametes in bivalves provides crucial insight on how a species may be influenced by environmental factors, in addition to the potential impacts a species of bivalve has on the ecosystem as a whole. The focus of this study was on gametogenesis and times of spawning in Rangia cuneata (G. B. Sowerby I, 1831), an infaunal estuarine bivalve inhabiting Johnson Bayou, Pass Christian, MS, and how salinity gradients may influence spawning. Specimens were collected monthly in 2016 from three sites along an established salinity gradient (0–16 ppt) within Johnson Bayou. Using standard histological methods and a quantitative method to estimate both the abundance of gametes and spawning times, this study showed that over the course of one year the rate of gametogenesis and times of spawning differed among sites. Clams of both sexes in the site closest to the opening of the bayou (lower site) produced gametes and spawned earlier (June) than those collected from the middle and upper sites (October–November). Interestingly, two separate spawning events are likely to have occurred by clams collected from the lower and middle sites. There was a positive correlation between increasing water temperature and mean percent gonadal tissue in all sites with a significant correlation at the middle and upper sites. In contrast, no correlation was found between salinity levels and mean percent gonadal tissue in clams from the lower site, while a weak positive but non-significant correlation was seen with clams from the middle and upper sites. There was a weak negative correlation between salinity levels and mean percentage of ripe gametes from the lower and middle sites, but a weak positive correlation from the upper site. The results indicate that the same species can vary the amount of gametes and spawning times in the same estuarine system, presumably due to the effects of abiotic factors, namely water temperature and salinity.

Freshwater mussels (order Unionida) are a historically abundant component of North American freshwater ecosystems, yet are among the most imperiled faunal groups. Understanding the underlying genetic structure and how it relates to historical geographic changes is critical for development of effective conservation strategies. Here we analyze mitochondrial gene fragments (COI) and 6 microsatellite loci of the freshwater mussel Lampsilis cardium (Rafinesque, 1820) in the Great Lakes and Mississippi River drainages to assess phylogenetic structure. The mitochondrial phylogeny shows geographic structure, with one divergent clade found exclusively in the Maumee and Wabash River. Phylogenies created using the COI sequences indicate divergence between two distinct clades of putative L. cardium (uncorrected p distance = 5.22%). Results from the microsatellite analyses suggest two genetically distinct populations corresponding to at least two glacial refugia, similar to the genetic structure observed for some other freshwater mussels in the region and are largely consistent to the results of mtDNA dataset. Three COI sequences from putative L. ovata (Say, 1817) were obtained from other published studies and included the phylogenetic analysis, these rendered the sequences from putative L. cardium generated in this study non–monophyletic. This suggests that more work is needed to determine whether L. cardium and L. ovata represent two distinct species or represent two divergent populations. Despite the highly divergent COI haplotypes in two monophyletic clades, nuclear microsatellite markers failed to detect differences in allele frequencies between individuals from these two clades in regions where they co–occur (F_ST = 0.004). These data aid in conservation strategies for unionids, providing guidance of best practices for maintaining natural genetic structure.

We investigated nonmarine gastropod fauna on Ulleung Island, an oceanic island in South Korea. Surveys were conducted in June and September 2018, which newly recorded four terrestrial gastropod species (Paludinellassiminea cf. japonica (Pilsbry, 1901), Vallonia costata (Müller, 1774), Meghimatium cf. bilineatum (Benson, 1842) and Ambigolimax sp.) and two freshwater snails (Galba truncatula (Müller, 1774) and Physella acuta (Draparnaud, 1805)). All records of nonmarine gastropods obtained from Ulleung Island so far were compiled as well.

Five new records are presented on the presence of two rare cephalopod species (Argonauta argo (Linnaeus, 1758) and Ocythoe tuberculata (Rafinesque, 1814)) in the waters of the Autonomous Region of Madeira, Portugal. Increased collaboration with fishermen has made it possible to significantly add to the number of records in the region, and further collaboration may provide key insights into the ecology of these rare cephalopod species.