*Article* **Comparative Biology of** *Daphniopsis tibetana* **from Different Habitats under Seawater Acclimation**

**Wan Zhang, Wen Zhao \*, Jingjing Zou, Jie Wei, Shan Wang and Dongpeng Yin**

Key Laboratory of Hydrobiology in Liaoning Province, College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China

**\*** Correspondence: zhaowen\_1963@163.com; Tel.: +86-159-4266-0511

**Abstract:** In this paper, we used experimental ecology methods and third-generation transcriptome sequencing to see the differences in growth, development, and reproduction of three strains of Daphniopsis tibetana Sars, 1903 from different locations in Tibet (Lake Namukacuo, NMKC; Lake Pengcuo, PC; and Lake Zigetangcuo, ZGTC). We also wanted to determine if the genes had changed after seawater-domesticated D. tibetana was reared in a laboratory. The results showed that at 15–16 ppt salinity and 15 ± 0.5 ◦C, the NMKC strain exhibited the highest survival rate of 26 d, and the ZGTC strain had the lowest survival rate at 53 days of culture. The body length was observed in NMKC (153.6 ± 12.1%), followed by PC (136.4 ± 16.1%), and then ZGTC (86.2 ± 7.6%). Combined, wild-type and seawater-acclimated D. tibetana produced 7252 DEGs, of which 4146 were up-regulated and 3106 were down-regulated. DEGs were subjected to gene ontology enrichment analysis. The DEGs were mainly enriched in single-organism localization, transporter activity, macromolecule localization, and organic substance transport. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis was also performed and revealed that the RNA transport, protein digestion and absorption, and protein processing in the endoplasmic reticulum pathways were highly enriched. The data mined can provide a reference for follow-up research.

**Keywords:** *Daphniopsis tibetana*; biology; different habitats; population growth parameters; thirdgeneration transcriptome sequencing
