Combining genotypic and phenotypic variation in a geospatial framework to identify sources of mussels in northern New Zealand

Abstract

The New Zealand green-lipped mussel aquaculture industry is largely dependent on the supply of young mussels that wash up on Ninety Mile Beach (so-called Kaitaia spat), which are collected and trucked to aquaculture farms. The locations of source populations of Kaitaia spat are unknown and this lack of knowledge represents a major problem because spat supply may be irregular. We combined genotypic (microsatellite) and phenotypic (shell geochemistry) data in a geospatial framework to determine if this new approach can help identify source populations of mussels collected from two spat-collecting and four non-spat-collecting sites further south. Genetic analyses resolved differentiated clusters (mostly three clusters), but no obvious source populations. Shell geochemistry analyses resolved six differentiated clusters, as did the combined genotypic and phenotypic data. Analyses revealed high levels of spatial and temporal variability in the geochemistry signal. Whilst we have not been able to identify the source site(s) of Kaitaia spat our analyses indicate that geospatial testing using combined genotypic and phenotypic data is a powerful approach. Next steps should employ analyses of single nucleotide polymorphism markers with shell geochemistry and in conjunction with high resolution physical oceanographic modelling to resolve the longstanding question of the origin of Kaitaia spat.

Expansion of shellfish aquaculture has no impact on settlement rates

“…Green-lipped mussels are broadcast spawners and have a pelagic larval duration between 4 and 6 wk. Depending on connectivity and water currents, larvae can travel anywhere from just a few km to hundreds of km over this duration (Gardner et al 2021). Larval mussels then undergo settlement, typically attaching onto filamentous surfaces like macroalgae before eventually transitioning to adult mussel reefs or other hard surfaces (Buchanan & Babcock 1997, Alfaro & Jeffs 2002.…”

Population connectivity and genetic diversity population connectivity of Rabbitfish (Siganus canaliculatus) among Bangladesh, China and Indonesia

“…Genetic distance shows the degree of difference in genes (genomic differences) between a population or species [25]. Genetic data that reduce genetic diversity are genetic drift variability and natural selection, whereas mutations and migrations result from spatial and temporal variability in low-level [26]. This relatively close geographic location between China and Bangladesh allows the genetic structure of the Baronang Fish to tend to be similar and in the same group.…”

“…Given distance estimates are usually inferred from genome sequences and probabilistic models [32]. Neighbor Joining is a phylogenetic analysis method that refers to the value of the evolutionary distance (p-distance) from the Operational Taxonomy Unit (OTU), which assumes that each branch evolves at a different distance [26].…”

Bottlenecks and barriers: Patterns of abundance in early mussel life stages reveal a potential obstacle to reef recovery

“…Successful natural mussel reef recovery relies on the ability of existing populations (either remnant or restored) to produce larvae and for those larvae to grow into adults, which is a complex multi‐step process. Mussels are broadcast spawners with a pelagic larval duration that varies between species from a few weeks to many months (Bayne, 1976; Widdows, 1991; Jeffs et al, 1999), during which time they can travel from a few kilometres to hundreds of kilometres (Gardner et al, 2021; Atalah et al, 2022). Following this pelagic period, larval mussels undergo metamorphosis and primary settlement into a range of habitats (McGrorty et al, 1990; Hunt & Scheibling, 1996; Navarrete et al, 2015).…”