Liew, J. H. | Search bioRxiv

bioRxiv2025

Highlighting the species diversity, pricing trends, and conservation concerns in a major ornamental fish hub

The global ornamental fish trade presents significant challenges to conservation of biodiversity. Here we explore patterns in the freshwater ornamental fish market in Hong Kong, a major wildlife trading hub. Weekly surveys over three-months in the primary aquarium district documented 540 freshwater fish species from 73 families. We found that species occurrence in the market was largely price-driven, and minimum retail price was the strongest predictor of their frequency of occurrence. Along the occurrence-price gradient, we found that potentially undescribed species dominated the rare/expensive end of the market, potentially influenced by the anthropogenic allee effect. Alarmingly, 86 species (16%) were potentially undescribed, while 38% were either not evaluated or classified as Data Deficient by the IUCN. While common/cheaper species dominate the market, the substantial number of little-known species being sold is of conservation concern, underscoring the need for more extensive monitoring at the risk of losing them to unregulated exploitation.

zoology↗

bioRxiv2023

The reference genome of the paradise fish (Macropodus opercularis)

Over the decades, a small number of model species, each representative of a larger taxa, have dominated the field of biological research. Amongst fishes, zebrafish (Danio rerio) has gained popularity over most other species and while their value as a model is well documented, their usefulness is limited in certain fields of research such as behavior. By embracing other, less conventional experimental organisms, opportunities arise to gain broader insights into evolution and development, as well as studying behavioral aspects not available in current popular model systems. The anabantoid paradise fish (Macropodus opercularis), an "air-breather" species from Southeast Asia, has a highly complex behavioral repertoire and has been the subject of many ethological investigations, but lacks genomic resources. Here we report the reference genome assembly of Macropodus opercularis using long-read sequences at 150-fold coverage. The final assembly consisted of {approx}483 Mb on 152 contigs. Within the assembled genome we identified and annotated 20,157 protein coding genes and assigned {approx}90% of them to orthogroups. Completeness analysis showed that 98.5% of the Actinopterygii core gene set (ODB10) was present as a complete ortholog in our reference genome with a further 1.2 % being present in a fragmented form. Additionally, we cloned multiple genes important during early development and using newly developed in situ hybridization protocols, we showed that they have conserved expression patterns.

genomics↗