Advances in Gametogenesis and Quality Assessment of Teleost Fish Gametes

Dear Colleagues,

In 2022, global aquaculture production reached a historic high, with farmed aquatic animal production amounting to 94.4 million tons. This output surpassed capture fisheries production for the first time, accounting for 51% of the total global production of aquatic animals and providing approximately 15% of animal protein for the global population. The healthy and sustainable development of the aquaculture industry relies on a sufficient and stable supply of fish fry. The quality of gametes in farmed fish directly impacts embryonic development, as well as the survival and growth of larvae and juveniles, making it a critical factor closely linked to efficiency in aquaculture. 

Fish gametogenesis is a highly coordinated process that occurs alongside gonadal development. Typically, the migration of primordial germ cells into the genital ridge (which develops into the gonad) and their subsequent mitosis and differentiation mark the onset of gametogenesis. The direct outcome of gametogenesis is the production of mature gametes; therefore, the normal progression of this process is a prerequisite for fish reproduction. Its regulation involves multiple levels, including environmental factors, hormonal signals, and molecular networks.

Current standards for the assessment of gamete quality in fish can be broadly categorized into three types: direct production indicators such as fertilization rate, hatching rate, survival rate, and malformation rate; composite indicators reflecting specific gamete characteristics, such as sperm density, motility, and structural features in semen, and egg diameter, transparency, surface glossiness, buoyancy, and oil droplet morphology in oocytes; and microscopic and molecular indicators, including the biochemical composition of gametes, molecular markers, sperm plasma membrane integrity, mitochondrial function, and DNA damage. 

A deeper understanding of the characteristics of fish gamete quality and the biological principles governing gametogenesis is not only crucial to fulfill the demands of fish propagation and farming but also pro-vides essential technical support for the development and selective breeding of new fish varieties. 

This Special Issue aims to compile the latest research findings and reviews in this field. Topics of interest include, but are not limited to, the following: 

1. Regulatory mechanisms of sperm and oocyte development in fish (genetic, endocrine, and environmental factors). 
2. Novel assessment methods and standardized indicator systems for gamete quality. 
3. Advances in low-temperature and cryopreservation techniques for gametes (sperm, oocytes) and embryos. 
4. Studies on the correlation between gamete quality and subsequent embryonic development, larval survival, and growth. 
5. Key factors affecting gamete fertility (e.g., nutrition, stress, and disease). 
6. Fish breeding and reproductive management strategies based on gamete quality assessment. 
7. The role of primordial germ cell migration and differentiation in gametogenesis. 
8. Research on the biochemical composition, molecular markers, and functional integrity of gametes. 

We invite researchers to submit original research articles, reviews, or short communications to jointly advance knowledge in the field of teleost reproductive biology and its applications in aquaculture.

Dr. Fangzhou Hu
Dr. Chang Wu
Guest Editors

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