This study aimed to understand the gonadal development and reproductive characteristics of the black scraper (T.modestus) before and after spawning.From November 2021 to March 2022,the parent fish were collected for five times,with three males and three females at each time.The total length,body weight,hepatopancreas index and gonadosomatic index were measured every time.At the same time,paraffin-embedded sections and hematoxylin-eosin staining were used to observe the gonadal development.The results showed that under artificial temperature control,the gonad weight and gonadosomatic index of the female and male parental T.modestus reached the maximum in February,and entered the peak period of sexual maturity,which was significantly higher than that in other months (P<0.05),suggesting that the parent fish reached the peak of maturity in February under the condition of artificially controlled water temperature.The spawning type of T.modestus was asynchronous and batch spawning,and the ovarian development of T.modestus could be divided into six phases,which was peri-nucleolus,yolk vesicle,primary yolk,secondary yolk,teritary yolk,and ripe stage,respectively.The testis development of T.odestus could be divided into five phases,which was spermatogonium,primary spermatocyte,secondary spermatocyte,spermatid and spermatozoa,respectively.In conclusion,this study investigated the morphological characteristics,organizational structure and developmental rules at different gonadal development stages of T.modestus,which may enrich the basic data of reproductive biology and provide scientific basis for artificial breeding and seed production of T.modestus.

To understand the changing laws of net fouling biological communities in the Leizhou Bay and provide a scientific basis for cage anti-fouling and green farming,the annual hanging net experiment divided into upper and down water layers carried out at the southeast wharf of Leizhou Bay from June 2020 to June 2021.The results showed that a total of 35 species of fouling organisms were detected, belonging to 11 phylums, 28 families and 35 genus.The spatial characteristics were the total number of species (29~32), Shannon-Wiener index (H', 0.985~2.010), Pielou index (J, 0.539~0.852), and Margalef index (d,0.539~2.856) in the upper and lower water layers.The abundance was higher than that in the lower water layer (8.50 ind·cm^-2), and the biomass was higher than that in the lower water layer (0.01 g·cm^-2), which showed that the fouling organisms in the upper water layer were larger in fouling and body size.The seasonal variation was characterized by the least species in winter (7 species).Using Excel and SPSS, the diversity and univariate analysis of 56 net samples were carried out respectively.The results showed that Shannon-Wiener index (H') and Margalef index (d) in winter were lower than those in other seasons, but evenly there was no difference in the Pielou index (J); compared with time accumulation, the most types of nets were attached throughout the year, then could conclude that the longer the time, the richer the species diversity.The RDA analysis showed that temperature affects the structure of the fouling biological community.The main groups of net fouling organisms in the waters of Leizhou Bay include Arthropoda, Molluscs and Chlorophyta.Spatially, there was little difference in biodiversity between upper and lower water layer.The biodiversity in spring, summer and autumn was larger than that in winter, while temperature (average contribution rate: 44.95%) and salinity (average contribution rate: 31.90%) were the main environmental factors affecting the community structure.