Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) infection on Betta rubra Perugia, 1893 (Anabantiformes: Osphronemidae) from Aceh Province, Indonesia / Infecção por Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) em Betta rubra Perugia, 1893 (Anabantiformes: Osphronemidae) provenientes da província de Aceh, Indonésia

Abstract Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish samples were obtained from the Cot Bira tributaries, Aceh Besar District, Indonesia from January to December 2020. The results showed that the parasite infected 6 out of 499 samples in August and September, with a prevalence and intensity rate of 1% and 2 parasites/fish, respectively. The eyes and pectoral fins were the common infection sites. Despite B. rubra is not an optimal host (small size) for the parasite, this parasite might serve as additional threatening factors for the endangered B. rubra fish population.

Resumo Betta rubra é um peixe de água doce ornamental endemico da região norte Sumatra, Indonesia. A população de Betta rubra diminuiu ao longo dos anos, sendo classificada como espécie em extinção na Lista Vermelha da IUCN. Este estudo tem como objetivo relatar pela primeira vez infecção por L. cyprinacea em B. rubra coletados na região de Aceh Besar na Indonésia. As amostras de peixes foram obtidas nos afluentes Cot Bira, distrito de Aceh Besar, Indonésia de janeiro a dezembro de 2020. Os resultados mostraram que o parasito infectou 6 das 499 amostras em agosto e setembro, com uma prevalência e taxa de intensidade de 1% e 2 parasitas/peixes, respectivamente. Os olhos e as nadadeiras peitorais foram os sítios de infecção mais comuns. Apesar de B. rubra não ser um hospedeiro ideal (pequeno tamanho) para o parasita, este parasita pode servir como fator de ameaça adicional para a população de peixes B. rubra, ameaçada de extinção.

Effect of cryoprotectant on the motility, viability, fertilization, and DNA integrity of naleh fish Barbonymus sp. (Cyprinidae) sperm / Efeito do crioprotetor na motilidade, viabilidade, fertilização e integridade do DNA no sêmen de peixes naleh Barbonymus sp. (Cyprinidae)

Naleh fish Barbonymus sp. is a commercial freshwater fish, which is indigenous to Aceh, Indonesia. The population of this species has declined over the years as a result of habitat perturbations and overfishing. Hence, the crucial need to develop a cryopreservation method to support breeding programs. This involved the use of a cryoprotectant as an important component. The objective of this study, therefore, was to explore the best cryoprotectant for naleh fish spermatozoa, and a total of five types were tested. These include the DMSO, Methanol, Ethanol, Glycerol, and Ethylene Glycol at a similar concentration of 10%, which were individually combined with 15% egg yolk, and every treatment was performed in three replications. Conversely, Ringer's solution was adopted as an extender, and the sperm was cryopreserved in liquid nitrogen for 15 days. The results showed significant influence on sperm motility and viability, as well as egg fertility of naleh fish (P <0.05), although the DMSO provided the best outcome, compared to others at 47.17%, 50.13%, and 45.67%, respectively. Furthermore, DNA fragmentation had not occurred in the fresh and cryopreserved sperm samples, indicating the protective effect of tested cryoprotectants. It is concluded that the 10% DMSO and 15% egg yolk is the best cryoprotectant for naleh fish spermatozoa.(AU)

O peixe naleh Barbonymus sp. é um peixe comercial de água doce, originário de Aceh, Indonésia. Durante vários anos, as perturbações provocadas no seu habitat e a pesca predatória determinaram o declínio da sua população, cuja preservação deve apoiar-se em um programa de reprodução controlada, com o emprego de espermatozoides criopreservados. O presente trabalho realizou um estudo comparativo de cinco crioprotetores: dimetilsultóxido, metanol, etanol, glicerol e etileno glicol. Todos os crioprotetores foram testados na concentração de 10%, combinados a 15% de gema de ovo. Cada tratamento foi efetuado em triplicatas. A solução de ringer foi utilizada como extensor e o esperma foi criopreservado em nitrogênio líquido por 15 dias. Os resultados obtidos revelaram a existência de influência significante (P<0,05) na viabilidade e motilidade espermática bem como na fertilidade dos ovos do peixe naleh, em que o dimetilsulfóxido apresentou o melhor resultado com os valores de 47,17%, 50,13% e 45,67%, respectivamente. Por outro lado, a fragmentação do DNA não ocorreu nas amostras de esperma fresco e criopreservado, indicando o efeito protetor dos crioprotetores testados. A conclusão obtida foi que o dimetilsulfóxido e 15% de gema de ovo foram o melhor crioprotetor para os espermatozoides do peixe naleh.(AU)

Bacterial diversity on wild shrimp post larvae in a mangrove biodiversity hotspot

Aims@#This study aims to assess the impact of anthropogenic activities on shrimp microbiome in a biodiverse mangrove forest ecosystem, along the Merbok River, Kedah, Malaysia.@*Methodology and results@#To assess the impacts, a microbiome study of wild post larvae shrimps along the river was conducted as a health indicator of the shrimp hosts which in turn would reflect the river conditions. A 16S rRNA gene amplicon sequencing of the wild post larvae shrimp microbiomes sampled across areas of varying human activities was conducted. Samples were obtained from four sites ranging from upstream river habitat to downstream brackish water towards the marine coast. Individuals detected from the sequence were then counted and their relative abundance of bacterial diversity were compared. All abundances are up to 100% and the diversity indices were calculated using proportions of each species. The Operational Taxonomy Unit (OTUs) were obtained by using USEARCH and UPARSE software. Twenty-eight bacterium phyla were detected, dominated by phyla Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes at each site. Eighteen families were dominant at each site with Streptomycetaceae being the major abundant. At the genus level, the most abundant genera were Streptomyces sp., Mesorhizobium sp., Rhizobium sp., Bacillus sp. and Pseudomonas sp.@*Conclusion, significance and impact of study@#In general, the diversity of opportunistic and coliform bacteria was low. Thus, despite being exposed to various levels of human activities, the Merbok River and its mangrove surroundings still serve as a good spawning and nursery sites of shrimps and presumably other inhabitants.

Genetic structure of the snakehead murrel, Channa striata (channidae) based on the cytochrome c oxidase subunit I gene: influence of historical and geomorphological factors

Nucleotide sequences of a partial cytochrome c oxidase subunit I gene were used to assess the manner in which historical processes and geomorphological effects may have influenced genetic structuring and phylogeographic patterns in Channa striata. Assaying was based on individuals from twelve populations in four river systems, which were separated into two regions, the eastern and western, of the biodiversely rich state of Perak in central Peninsular Malaysia. In 238 specimens, a total of 368-bp sequences with ten polymorphic sites and eleven unique haplotypes were detected. Data on all the twelve populations revealed incomplete divergence due to past historical coalescence and the short period of separation. Nevertheless, SAMOVA and F ST revealed geographical structuring existed to a certain extent in both regions. For the eastern region, the data also showed that the upstream populations were genetically significantly different compared to the mid- and downstream ones. It is inferred that physical barriers and historical processes played a dominant role in structuring the genetic dispersal of the species. A further inference is that the Grik, Tanjung Rambutan and Sungkai are potential candidates for conservation and aquaculture programmes since they contained most of the total diversity in this area.

Isolation and multiplex genotyping of polymorphic microsatellite DNA markers in the snakehead murrel, Channa striata

Seven polymorphic microsatellite loci were isolated and characterized for the snakehead murrel, Channa striata (Channidae), a valuable tropical freshwater fish species. Among 25 specimens collected from Kedah state in Malaysia, the number of alleles per locus ranged from 2 to 7. Observed and expected heterozygosities ranged from 0.120 to 0.880 and 0.117 to 0.698, respectively. A single locus (CS1-C07) was significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction. These novel markers would be useful for population genetic studies of the C. striata.

Evidence of geographical structuring in the Malaysian Snakehead, Channa striata based on partial segment of the CO1 gene

Channa striata, locally known as "haruan", is economically important in fisheries and aquaculture industries in several Asian countries. DNA sequencing, based on a partial segment of the Cytochrome oxidase c subunit 1 (CO1) gene, was used to determine genetic variation in C. striata samples from four different populations on the west coast of Peninsular Malaysia. The highest nucleotide and haplotype diversities were observed in the Linggi population (π = 0.0067, h = 0.835), and the lowest in the Timah Tasoh population (π = 0.0008, h = 0.286). Apart from Kajang-Linggi, which was insignificant, F ST values were significant (p < 0.05) in all pairwise-population comparisons. Consequently, it is inferred that genetic structuring C. striata populations in this region was largely shaped by a common origin, with secondary influences from geographical factors and isolation.