Population genetics and otolith strontium/calcium ratios analysis of marble goby Oxyeleotris marmoratus in Southeast Asia for aquaculture application

Ha, Hou-Chew (2014) Population genetics and otolith strontium/calcium ratios analysis of marble goby Oxyeleotris marmoratus in Southeast Asia for aquaculture application. In: Bulletin of the Fisheries Laboratory of Kinki University. Fisheries Laboratory of Kinki University, Japan, pp. 25-75.

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Abstract

The marble goby Oxyeleotris marmoratus belongs to the suborder Gobioidei in the order Perciformes. It has partial flattened body with snake-like head, symmetrical patterning on the dorsal surface and rounded, outstretched round pectoral fin, two dorsal fins, rounded caudal fin and separated pelvic fins. It is a popular freshwater fish in Southeast Asia for its fine texture and delicious taste. In the wild, it feeds on small fish, shrimp, molluscs and crustaceans. It can grow to a maximum size of approximately 65 cm standard length. Fish farmers would like to culture the marble goby, but the seed supply is still mainly dependent on natural sources. In 2008, the seed production of marble goby has been succeeded in Sabah of East Malaysia. Although it is a freshwater fish, 10 psu diluted seawater is the best for the larval survival of marble goby in Sabah. It showed the possibility of different populations is existed in Southeast Asia. Thus, three experiments were conducted to better understanding of its population structure and early life history in salinity in nature would aid more effective broodstock management in the hatchery for seed production. Chapter 1 This study was conducted to investigate the population structure of the marble goby in Southeast Asia. A total of 85 fin samples were collected from 3 regions (the mainland, the peninsula, and the islands) for mitochondrial DNA (mtDNA) analysis. Sampling locations that were geographically close were pooled and treated as a single population. Partial mtDNA control regions were amplified, sequenced, and analyzed. Fourteen haplotypes were detected among all the samples. Hap-5 was the most widespread haplotype among the six populations, comprising of 29.4% of all samples. Both the non-significant values of Tajima’s D and Fu’s FS suggested that all 6 populations were at equilibrium. Analysis of molecular variance (AMOVA) revealed significant differences among and within populations, and no variance was due to regional site (FCT= - 0.1498, P>0.05). In pairwise comparisons of FST, Ayutthaya, Dong Nai and Sabah showed significant values (P<0.05) between the all populations. The non-significant values of FST showed that Sarawak, Indonesia, and West Malaysia are less genetically different. This suggests that the marble goby in Ayutthaya, Dong Nai and Sabah may be genetically differentiated populations compared to the other populations in Southeast Asia. However, the relationship between population and water salinity where they inhabited was still unclear. Chapter 2 Therefore, the next study was carried out to investigate the population divergence of landlocked and river marble goby in West Malaysia (WM) and East Malaysia (EM). The term of “landlocked” is used to indicate the marble goby from pond, where entirely isolated and surrounding by land. The term of “location” is used to indicate the sampling place of the marble goby. According to their geographical features, locations were combined into two regions, as pond and river. Fins of wild marble goby were collected from freshwater ponds and along rivers. A total of 120 fin samples were collected from four locations for mtDNA analysis. The samples were collected from Ipoh pond and Kundang river in WM; Kuching pond and Kimanis river in EM. DNA was extracted from the samples, then partial mtDNA control region were amplified, sequenced and analyzed. Both the non-significant values of Tajima’s D and Fu’s FS suggested that the all populations from each location were at equilibrium. Among the twenty haplotypes, eight were same with the results in the Chapter 1; the twelve newly detected haplotypes were labelled from Hap-15 to Hap-26. Only Hap-5 was shared in four locations, and it comprised 12.5% of all samples. It is same results in Chapter 1 that Hap-5 is the most widespread haplotype among the locations and the most common among the control region sequences. Hap-6 and Hap-14 were the only distinct haplotypes, which detected in this study and in both chapters. This is further proven that the Hap-6 and the Hap-14 can be used as DNA marker to identify the indigenous marble goby population in Sarawak and Sabah respectively. AMOVA revealed significant differences among and within locations, and no variance was due to regional site (FCT= - 0.1735, P>0.05). The significant FST values (P<0.05) of pairwise comparison among the four locations, ranged from 0.1500 to 0.4864, showed that the marble goby from ponds and rivers of WM and EM were different from each other. Although phylogenetic tree showed no obvious genealogy among the marble goby with no significant genealogical branches or clusters of samples corresponding to sampling locations, genetic analyses of AMOVA and pairwise comparison FST in the both studies succeeded to differentiate the four populations significantly. Yet, early life of the marble goby in pond and river is not been clearly defined. Furthermore, there is no proof to show that the larval surviving of wild marble goby in brackishwater. Chapter 3 Lastly, this study was conducted to investigate the fish individual life history in landlocked and river marble goby in WM and EM. The otoliths from 10 fish were sampled from the same locations in Chapter 2 for the investigation of strontium/calcium (Sr/Ca) ratios to trace the water salinity where the larva previously survived. The otolith samples were cleaned, and embedded in epoxy resin. The embedded otoliths were ground transversely by grain sandpapers and ultra-fine films until core of the otolith was exposed. Strontium and calcium concentrations in the otolith were measured from the core to the edge of the otolith at intervals of 5µm by electron probe microanalyzer. The otolith Sr/Ca ratios indicated that all samples from four locations survived in freshwater only, except two individuals (Kim8 and Kim10) from Kimanis river showed clear evidence of shift in the water salinity from brackishwater into freshwater at early life. These 2 individuals had the same distinct haploypte Hap-14, which only detected in Sabah population. However in this study, Hap-14 was detected as well in Kim2 and Kim5, which showed life history in freshwater habitat only. According to the theory of maternal inheritance of mtDNA, Kim2, Kim5, Kim8 and Kim10 were from the same maternal ancestor. Thus, the maternal ancestor with Hap-14 might have the genetic factor of possibility to survive in both freshwater and brackishwater at early life in the wild. However, Senoo et al. (2008) reported that marble goby larvae in Sabah only survived in 10 psu water. This can be explained by the paternal genetic contribution mating with the female. The way to determine the genotype, which affects to the salinity tolerance, is unknown, however, the mating might has a possibility to produce three types of offspring, which could survive in freshwater only, survive in brackishwater only, and able to survive in both. This inference could explain the survival in different salinity even the fish have the same haplotype. The otolith growth patterns from different the sampling locations were investigated using spectral analysis of Fast Fourier Transform (FFT). The FFT results were represented in the form of a magnitude plot for each sample. Two highest magnitude signals represent high Sr/Ca ratios detection at an interval along transect from core to edge of otolith, and then the observed intervals were group into ranges for comparison among locations. It showed same growth pattern between Ipoh pond and Kundang river; Kimanis river showed unique pattern and Kuching pond showed randomly growth. The marble goby in Kuching pond are always dwelling in enclosed freshwater pond. Compared to the marble goby in Kuching pond, Kim8 and Kim10 in Kimanis river had been migrated from brackishwater to freshwater and, which need to consume more energy for the osmoregulation. Consequently might affect the unique growth patterns in the otoliths in the Kimanis river. This study revealed the different marble goby populations in the Southeast Asia based on the geographical distribution, and the differences of the population genetics. Although marble goby is regarded as a freshwater fish, the otolith Sr/Ca ratios analysis showed the Kimanis river marble goby (Sabah) shift of water salinity from brackishwater enter into freshwater. Therefore, broodstock management in hatchery should be carried out carefully based on the population and environmental differences, which require different salinities for seed production.

Item Type: Book Section
Keywords: Population genetics, otolith, marble goby, Oxyeleotris marmoratus
Subjects: Q Science > QH Natural history > QH426 Genetics
S Agriculture > SH Aquaculture. Fisheries. Angling
Faculty / Institute: Faculty of Bioresources & Food Industry
Depositing User: Dr Hou Chew Ha
Date Deposited: 15 Oct 2014 10:09
Last Modified: 15 Oct 2014 10:09
URI: http://erep.unisza.edu.my/id/eprint/1673

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