Genetic evidence for the mating system and reproductive success of black sea bream (Acanthopagrus schlegelii)

Abstract

Understanding the mating system and reproductive success of a species provides evidence for sexual selection. We examined the mating system and the reproductive success of captive adult black sea bream (Acanthopagrus schlegelii), using parentage assignment based on two microsatellites multiplex PCR systems, with 91.5% accuracy in a mixed family (29 sires, 25 dams, and 200 offspring). Based on the parentage result, we found that 93.1% of males and 100% of females participated in reproduction. A total of 79% of males and 92% of females mated with multiple partners (only 1 sire and 1 dam were monogamous), indicating that polygynandry best described the genetic mating system of black sea bream. For males, maximizing the reproductive success by multiple mating was accorded with the sexual selection theory while the material benefits hypothesis may contribute to explain the multiple mating for females. For both sexes, there was a significant correlation between mating success and reproductive success and the variance in reproductive success of males was higher than females. Variation in mating success is the greatest determinant to variation in reproductive success when the relationship is strongly positive. The opportunity for sexual selection of males was twice that of females, as well as the higher slope of the Bateman curve in males suggested that the intensity of intrasexual selection of males was higher than females. Thus, male-male competition would lead to the greater variation of mating success for males, which caused greater variation in reproductive success in males. The effective population number of breeders (N b ) was 33, and the N b /N ratio was 0.61, slightly higher than the general ratio in polygynandrous fish populations which possibly because most individuals mated and had offspring with a low variance. The relatively high N b contributes to the maintenance of genetic diversity in farmed black sea bream populations. K E Y W O R D SAcanthopagrus schlegelii, Bateman gradient, multiple matings, parentage analysis, polygynandry

Parentage Analysis in Giant Grouper (Epinephelus lanceolatus) Using Microsatellite and SNP Markers from Genotyping-by-Sequencing Data

“…The higher producing male GM01 contributed to 62.23% of the offspring, and female GF01 contributed to all of the offspring. We also found the similar skew phenomenon in previous parentage research on orange-spotted grouper ( E. coioides ) [ 53 ]. This result is unexpected, since Bright et al [ 49 ] have described that, although a skew parental contribution exists in communally spawning giant grouper, all males and females successfully participated in production over the spawning period.…”

“…After filtering, the clean data of one paternal fish was chosen for microsatellite loci identifying using MIcroSAtellite identification tool (MISA) [ 52 ], with misa.ini file configured as: definition (unit_size,min_repeats): 1–10 2–6 3–5 4–5 5–5 6–5; interruptions (max_difference_for_2_SSRs): 100. Modified Primer3 scripts (p3_in.pl and p3_out.pl) were applied to design batch primers, which were subsequently screened by laboratory procedures which referred to our previously published work [ 53 ] with minor modifications. In brief, 10μL volume of polymerase chain reactions (PCRs) with subject primers were carried out, and afterwards inspected by agarose gel electrophoresis and polyacrylamide gel electrophoresis (PAGE).…”

Genetic Evaluation of Black Sea Bream (Acanthopagrus schlegelii) Stock Enhancement in the South China Sea Based on Microsatellite DNA Markers

“…As a result, in this study, sample collections were conducted in the northwest sea area of Daya Bay (Figure 1), where most of wild black sea breams inhabit with abundant seaweeds [27]. The black sea bream broodstock population (BP) comprised 29 males and 25 females collected from Daya Bay using trawl nets and transferred to the hatchery (Marine Fisheries Development Center of Guangdong Province, Huizhou, China) in January 2017 (Figure 1), reared in a concrete-walled pond with aquaculture setting [28]. After seed production, fertilized eggs were collected and incubated at 18-28 • C in a pond with seawater.…”

“…broodstock population (BP) comprised 29 males and 25 females collected from Daya Bay using trawl nets and transferred to the hatchery (Marine Fisheries Development Center of Guangdong Province, Huizhou, China) in January 2017 (Figure 1), reared in a concretewalled pond with aquaculture setting [28]. After seed production, fertilized eggs were collected and incubated at 18-28 °C in a pond with seawater.…”

“…Genotyping was performed using seven microsatellite loci developed in our previous research [28] (GenBank: No. MH782241-MH782243, No.…”