Zeehan Jaafar

Fishes Out of Water: Biology and ecology of mudskippers

Mudskippers, particularly species of the genus Periophthalmus, are renowned for their inter- and intraspecific interactions while out of water. Displays include those for courtship (Townsend and Tibbets 2005; Brillet 1980a) and maintaining territorial boundaries (e.g., Clayton and Vaughan 1982). Although other areas of mudskipper research have progressed (e.g., Sakamoto et al. 2015; Quan et al. 2012; Kanemori et al. 2006) since the literature was reviewed (Clayton 1993), the understanding of social behavior has not. Indeed, with few exceptions, there is little available information to distinguish between the description of territorial and courtship displays.

Cryopreservation of Fish Spermatogonial Cells: The Future of Natural History Collections

As global biodiversity declines, the value of biological collections increases. Cryopreserved diploid spermatogonial cells meet two goals: to yield high-quality molecular sequence data; and to regenerate new individuals, hence potentially countering species extinction. Cryopreserved spermatogonial cells that allow for such mitigative measures are not currently in natural history museum collections because there are no standard protocols to collect them. Vertebrate specimens, especially fishes, are traditionally formalin-fixed and alcohol-preserved which makes them ideal for morphological studies and as museum vouchers, but inadequate for molecular sequence data. Molecular studies of fishes routinely use tissues preserved in ethanol; yet tissues preserved in this way may yield degraded sequences over time. As an alternative to tissue fixation methods, we assessed and compared previously published cryopreservation methods by gating and counting fish testicular cells with flow cytometry to identify presumptive spermatogonia A-type cells. Here we describe a protocol to cryopreserve tissues that yields a high percentage of viable spermatogonial cells from the testes of Asterropteryx semipunctata, a marine goby. Material cryopreserved using this protocol represents the first frozen and post-thaw viable spermatogonial cells of fishes archived in a natural history museum to provide better quality material for re-derivation of species and DNA preservation and analysis.