Silver pomfret (Pampus argenteus) is an economically important mariculture species. However, little is known about the genetic parameters of its commercially important traits. In order to determine whether continuous progress can be achieved by selection for growth, we took the body weight trait of East China Sea P. argenteus as the target trait of mass selection. The realized heritability of P. argenteus from the selected group and control group was analyzed at the three growth times (60, 90, and 120 days). The results showed that the growth performance parameters of the selected group in the third month post hatching were higher than those in the control group, but the opposite results were found in the fourth month. The morphological traits highly correlated with the body weight of P. argenteus were found by Pearson correlation analysis and path analysis, which were body length and tail length, respectively. On the 60th, 90th, and 120th days after hatching, the genetic gains of body weight trait in the selected group were 9.44%, 17.64%, and 15.18%, respectively, and the mean values of realized heritability were at moderate level. Nevertheless, in the selected group, the genetic variation values of the two morphological traits significantly related to body weight were all below 10%, and the genetic gains were relatively low and stable, but the genetic variation values of body weight trait in the selected group were above 20%, and genetic gains were relatively high. These implied that it is possible to obtain considerable genetic gains by selecting for body weight trait, and the results provide supportive evidence for the continuity of the P. argenteus-selective breeding program.

The silver pomfret (Pampus argenteus) is a widely distributed and economically important marine fish in the Indo‐Pacific. In this study, we acquired the second generation of wild P. argenteus by artificial breeding and further studied the testicular development and ultrastructure of spermatogenesis. The results of gonadosomatic index (GSI) showed the spawning period of this marine fish was from April to June. Besides, through morphological analysis, we found that P. argenteus had an anastomosing tubular testis surrounded by a layer of tunica albuginea, in which spermatogenesis occurred in cysts where the synchronous germ cells were completely surrounded by the cytoplasmic projection of Sertoli cells. Meanwhile, based on submicroscopic characteristics, the germ cells are classified into nine different types. During the ontogenesis of testis, both the early stage of spermatogenesis and sperm were observed in P. argenteus. At sperm maturation stage, different types of spermatozoa and activation of sperms occurred non‐synchronously in the tubules. Cytoplasmic bridges also were observed among synchronous germ cells within the cysts, suggesting an interrelated and differentiated relationship among these germ cells.

The parasitic dinoflagellate Amyloodinium ocellatum (AO) is known to cause lethal outbreaks at aquaculture facilities, resulting in nearly 100% mortality events in just a few days (Byadgi et al., 2021;Nozzi et al., 2016). Consequently, in recent years, AO has become a major concern in marine fish farming (Francis-Floyd & Floyd, 2011). AO can infect many types of fishes, such as the gilthead bream (Sparus aurata Linnaeus) and seabass (Dicentrarchus labrax) (Alvarezpellitero, 2008;Paperna, 2010). Mature trophonts detach from the host and form motile dinospores. Briefly, reproduction occurs via binary fission, and actively swimming dinospores were released to infect new fish hosts (Diansheng et al., 2015). Considering the impact of parasites on aquaculture, AO is considered to be the most pathogenic protozoan parasite, affecting the culture of marine and brackish water fish (Woo, 2006).

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Silver pomfret (Pampus argenteus) performs a significant appetite for jellyfish, and amino acids are common components of the natural prey of fish, so we investigated the effect of aspartic acid, glycine and cysteine (high‐content amino acid in jellyfish) on olfactory‐related receptors regulating appetite in silver pomfret. The fish showed significant attractant responses to these amino acids in water, which were also observed to improve the ingestion rates of the fish. Next, we conducted transcriptomes of the olfactory epithelium (OE) and identified 34 olfactory‐related receptor genes were including olfactory receptors, trace amine‐associated receptors and vomeronasal receptors genes, and we examined these genes in the OE and appetite‐related genes (ghrelin and leptin in gut/stomach and neuropeptide Y, agouti‐related protein and proopiomelanocortin in brain) by qRT‐PCR. The olfactory‐related receptor genes significantly expressed in amino acid groups, and the expression level of appetite‐related genes was highest in aspartic acid group. Thus, olfactory‐related receptors induced by amino acids might regulate appetite in fish through the OE–brain–gut and stomach axis. Using these data, we identified some effective amino acid phagostimulants which could be supplied in silver pomfret diet, and the results improved our understanding of the mechanism of olfactory‐related receptors regulating appetite in fish.