Culturing echinoderm larvae through metamorphosis

Abstract

Echinoderms are favored study organisms not only in cell and developmental biology, but also physiology, larval biology, benthic ecology, population biology and paleontology, among other fields. However, many echinoderm embryology labs are not well-equipped to continue to rear the post embryonic stages that result. This is unfortunate, as such labs are thus unable to address many intriguing biological phenomena, related to their own cell and developmental biology studies, that emerge during larval and juvenile stages. To facilitate broader studies of post-embryonic echinoderms, we provide here our collective experience rearing these organisms, with suggestions to try and pitfalls to avoid. Furthermore, we present information on rearing larvae from small laboratory to large aquaculture scales. Finally, we review taxon-specific approaches to larval rearing through metamorphosis in each of the four most commonly-studied echinoderm classes-asteroids, echinoids, holothuroids and ophiuroids.

Symbiotic Life of Echinoderm Larvae

“…Specifically, Strongylocentrotus purpuratus larvae cultured under traditional laboratory settings associate with bacterial communities that are less diverse in total taxa and the phylogenetic breadth of those taxa, and retain ∼40% of the OTUs harbored by "wild-type" counterparts (Schuh et al, 2019). This implies that studying larval-associated bacterial communities is most accurately performed at near-natural conditions, such as by filtering ambient seawater to 5-µm to remove most debris and planktonic predators while retaining the environmental microbiota (Carrier and Reitzel, 2018;Hodin et al, 2019).…”

Population structure, habitat preferences, feeding strategies, and diet of the brittle star Ophiopholis aculeata in nearshore and offshore habitats of the northwest Atlantic

“…This selectivity was also reported in sea cucumbers (Hamel & Mercier, 1996) and sea urchins (Lambert & Harris, 2000) from the same location. In fact, crustose coralline algae are well known to induce metamorphosis and provide early habitat for many echinoderms worldwide (Hodin et al, 2019). Results of the present study suggest that rhodoliths are central to the life cycle of O. aculeata, and disturbance of rhodolith beds could have greater impacts on populations than disturbance of other habitats like rock fields.…”

Cell size asymmetries in the sea star embryo

“…Adult Patiriella regularis were collected off the coast of Tasmania (Australia) and held in aquaria at a temperature of 20C. Sea star gametes were obtained as previously described (Hodin et al, 2019). Briefly, ovaries and spermogonia were dissected via a small incision on the ventral side of adults.…”