Detection of multiple paternity in green turtle clutches during a reproductive season at Khram Island, Thaiand

Organized by Graduate School of Informatics, Kyoto University ; JSPS Bangkok Liaison Office ; Japanese Society of Bio-logging Science ; Informatics Research Center for Development of Knowledge Society InfrastructureDecember 13-15, 2004, Imperial Tara Hotel, Bangkok, ThailandAlthough direct observations have been suggesting that multiple mating in green turtle (Chelonia mydas) may be quite common at Khram Island, Chonburi, Thailand, the number of successful males is still in question. Genetic analysis technique is a tool for investigation. We preliminary evaluated the proportions of successful breeding males and females of green turtle in a natural population at Khram Island, Gulf of Thailand, using two microsatellite markers. We analyzed genotypes of 77 tissue samples collected from 3 nesting females, and at least seven offsprings per clutch in three successive clutches within a reproductive season (total of nine clutches). We were able to detect multiple paternity of the hatchlings. For most clutches, at least two males successfully sired hatchlings within each clutch. Throughout a nesting season, at least three different males could mate with the same female and there were at least seven males successfully mating with this set of females. This study confirmed the effectiveness of microsatellite DNA markers in detecting multiple paternity within natural populations of green turtle. However, to reduce the confounding effects of mutations on allele assignment and to increase power to monitor individual's genetic contribution, we need additional variable genetic markers

Variasi DNA Mitokhondria dari Ikan kakap Putih Budidaya dan Dari Tangkapan Liar Di Thailand

Kakap Putih (Lates calcarifer Bloch) adalah salah satu ikan ekonomis penting yang benihnya dapat diproduksi Thailand. Data genetik merupakan salah satu aspek penting dalam mengatur pemijahan induk untuk pemuliaan, namun hingga saat ini informasi terkait keragaman genetiknya masih minim. Penelitian ini bertujuan mengkaji keragaman dan perbedaan genetik kakap putih pada tiga populasi hatchery dan dua populasi alam di Thailand dengan menggunakan metode gabungan antara Restriction Fragment Length Polymorphisms dan Polymerase Chain Reaction (PCR-RFLP) pada D-loop control region di DNA mitokondria. Ditemukan tujuh potongan endonuklease dari 268 sampel yang diamati. Populasi alami Chantaburi (CH) memiliki keragaman haplotipe dan nukleotida tertinggi (h = 0.6626, π = 0.0554) dibandingkan populasi lainnya: tiga populasi hatcheri yaitu Rayong (RA), Chonburi (CB) dan Nakhon Si Thammarat (NK) ) (h berkisar antara 0.2709 – 0.3227; π berkisar antara 0.0195 – 0.386) dan populasi alam Nakhon Si Thammarat (PN) (h = 0.172, π = 0.0091). Mismatch distribution analysis mengungkap kejadian bottleneck pada beberapa generasi sebelumnya di populasi alam PN dan seluruh populasi hatcheri. Analysis of Molecular Variance (AMOVA) menunjukkan 88.95% keragaman disebabkan perbedaan dalam populasi dan 11.05 % disebabkan perbedaan antar populasi. Perbedaan genetik yang signifikan terdapat pada perbedaan antar populasi alam (ΦST = 0.239, P<0.001), namun perbedaan antar populasi hatchery tidak signifikan, menunjukkan terjadi pencampuran genetik sekerabat antar satu dengan hatcheri lainnya. Hal ini karena minimnya masukkan indukan baru dari alam. Kedua hal tersebut dapat menurunkan keragaman dan perbedaan genetik pada setiap populasi hatchery dan antar populasi hatchery. Data awal penelitian ini dapat digunakan unt

Effects of landscape features on population genetic variation of a tropical stream fish, Stone lapping minnow, Garra cambodgiensis, in the upper Nan River drainage basin, northern Thailand

Spatial genetic variation of river-dwelling freshwater fishes is typically affected by the historical and contemporary river landscape as well as life-history traits. Tropical river and stream landscapes have endured extended geological change, shaping the existing pattern of genetic diversity, but were not directly affected by glaciation. Thus, spatial genetic variation of tropical fish populations should look very different from the pattern observed in temperate fish populations. These data are becoming important for designing appropriate management and conservation plans, as these aquatic systems are undergoing intense development and exploitation. This study evaluated the effects of landscape features on population genetic diversity of Garra cambodgiensis, a stream cyprinid, in eight tributary streams in the upper Nan River drainage basin (n = 30–100 individuals/location), Nan Province, Thailand. These populations are under intense fishing pressure from local communities. Based on 11 microsatellite loci, we detected moderate genetic diversity within eight population samples (average number of alleles per locus = 10.99 ± 3.00; allelic richness = 10.12 ± 2.44). Allelic richness within samples and stream order of the sampling location were negatively correlated (P < 0.05). We did not detect recent bottleneck events in these populations, but we did detect genetic divergence among populations (Global FST = 0.022, P < 0.01). The Bayesian clustering algorithms (TESS and STRUCTURE) suggested that four to five genetic clusters roughly coincide with sub-basins: (1) headwater streams/main stem of the Nan River, (2) a middle tributary, (3) a southeastern tributary and (4) a southwestern tributary. We observed positive correlation between geographic distance and linearized FST (P < 0.05), and the genetic differentiation pattern can be moderately explained by the contemporary stream network (STREAMTREE analysis, R2 = 0.75). The MEMGENE analysis suggested genetic division between northern (genetic clusters 1 and 2) and southern (clusters 3 and 4) sub-basins. We observed a high degree of genetic admixture in each location, highlighting the importance of natural flooding patterns and possible genetic impacts of supplementary stocking. Insights obtained from this research advance our knowledge of the complexity of a tropical stream system, and guide current conservation and restoration efforts for this species in Thailand

Effects of arachidonic acid supplementation in maturation diet on female reproductive performance and larval quality of giant river prawn (Macrobrachium rosenbergii)

The giant river prawn (Macrobrachium rosenbergii) is one of the most farmed freshwater crustaceans in the world. Its global production has been stalling in the past decade due to the inconsistent quality of broodstock and hatchery-produced seeds. A better understanding of the role of nutrition in maturation diets will help overcome some of the production challenges. Arachidonic acid (20:4 n-6, ARA) is a fatty acid precursor of signaling molecules important for crustacean reproduction, prostaglandins E and F of the series II (PGE2 and PGF2α), and is often lacking in maturation diets of shrimp and prawns. We examined the effects of ARA in a combination of different fish oil (FO) and soybean oil (SO) blends on females’ reproductive performance and larval quality. Adult females (15.22 ± 0.13 g and 11.12 ± 0.09 cm) were fed six isonitrogenous and isolipidic diets containing one of two different base compositions (A or B), supplemented with one of three levels of Mortierella alpine-derived ARA (containing 40% active ARA): 0, 1 or 2% by ingredient weight. The two base diets differed in the percentages of (FO and SO with diet A containing 2% SO and 2% FO and diet B containing 2.5% SO and 1.5% FO, resulting in differences in proportional contents of dietary linoleic acid (18:2n-6, LOA) and docosahexaenoic acid (22:6n-3, DHA)). After the eight-week experiment, prawns fed diet B with 1 and 2% ARA supplement (B1 and B2) exhibited the highest gonadosomatic index (GSI), hepatosomatic index (HSI), egg clutch weight, fecundity, hatching rate, number of larvae, and reproductive effort compared to those fed other diets (p ≤ 0.05). Larvae from these two dietary treatments also had higher tolerance to low salinity (2 ppt). The maturation period was not significantly different among most treatments (p ≥ 0.05). ARA supplementation, regardless of the base diet, significantly improved GSI, HSI, egg clutch weight and fecundity. However, the diets with an enhanced ARA and LOA (B1 and B2) resulted in the best reproductive performance, egg hatchability and larval tolerance to low salinity. These dietary treatments also allow for effective accumulation of ARA and an n-3 lcPUFA, DHA in eggs and larvae

Speaking their language – development of a multilingual decision-support tool for communicating invasive species risks to decision makers and stakeholders

Environmental changes due to non-native species introductions and translocations are a global concern. Whilst understanding the causes of bioinvasions is important, there is need for decision-support tools that facilitate effective communication of the potential risks of invasive non-native species to stakeholders. Decision-support tools have been developed mostly in English language only, which increases linguistic uncertainty associated with risk assessments undertaken by assessors not of English mother tongue and who need to communicate outcomes to local stakeholders. To reduce language-based uncertainty, the ‘ecology-of-language’ paradigm was applied when developing the Aquatic Species Invasiveness Screening Kit (AS-ISK), a decision-support tool that offers 32 languages in which to carry out screenings and communicate outcomes to stakeholders. Topics discussed include uncertainty related to language-specific issues encountered during the AS-ISK translation and the potential benefits of a multilingual decision-support tool for reducing linguistic uncertainty and enhancing communication between scientists, environmental managers, policy and decision makers

Speaking their language : Development of a multilingual decision-support tool for communicating invasive species risks to decision makers and stakeholders

Environmental changes due to non-native species introductions and translocations are a global concern. Whilst understanding the causes of bioinvasions is important, there is need for decision-support tools that facilitate effective communication of the potential risks of invasive non-native species to stakeholders. Decision-support tools have been developed mostly in English language only, which increases linguistic uncertainty associated with risk assessments undertaken by assessors not of English mother tongue and who need to communicate outcomes to local stakeholders. To reduce language-based uncertainty, the ‘ecology-of-language’ paradigm was applied when developing the Aquatic Species Invasiveness Screening Kit (AS-ISK), a decision-support tool that offers 32 languages in which to carry out screenings and communicate outcomes to stakeholders. Topics discussed include uncertainty related to language-specific issues encountered during the AS-ISK translation and the potential benefits of a multilingual decision-support tool for reducing linguistic uncertainty and enhancing communication between scientists, environmental managers, and policy and decision makers.Published version is available for viewing only. (See "Related URI")「関連URI」より出版社版の閲覧専用ページへリン

A global-scale screening of non-native aquatic organisms to identify potentially invasive species under current and future climate conditions

10.1016/j.scitotenv.2021.147868Science of the Total Environment78814786

A global-scale screening of non-native aquatic organisms to identify potentially invasive species under current and future climate conditions

The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium- and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a ‘very high risk’ of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate ‘rapid’ management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement