MỘT SỐ ĐẶC ĐIỂM SINH HỌC SINH SẢN CỦA LOÀI MÓNG TAY SOLEN THACHI COSEL, 2002 Ở ĐẦM THUỶ TRIỀU, KHÁNH HOÀ

Razor clam Solen thachi Cosel, 2002 is one of the high valuable species distributed at Thuy Trieu lagoon, Khanh Hoa. The aim of this paper was to examine some reproductive biology characteristics of razor clam. Samples of razor clam were collected monthly with a total of 822 inds. at Thuy Trieu lagoon and analysed at the laboratory of the Institute of Oceanography. Results of analysis showed that sex ratio was about 1:1. Spawning season was mainly between December and March of the following year, with the peak in December. The absolute fecundity was 1,048,893 ± 608,964 eggs per individual, while the relative fecundity was 146,349 ± 95,666 eggs/gram of body weight. Length of the first maturity was recorded at 69.6 mm of shell length. This paper provided baseline data for management and sustainable exploitation of marine living resources.Bài viết trình bày một số kết quả nghiên cứu đặc điểm sinh học sinh sản của loài móng tay Solen thachi Cosel, 2002 là loài có giá trị kinh tế ở đầm Thủy Triều, góp phần cung cấp cơ sở khoa học cho việc quản lý khai thác loài móng tay một cách hiệu quả và bền vững. Mẫu vật được thu hàng tháng trong chu kỳ 1 năm với tổng số mẫu là 822 cá thể. Kết quả phân tích cho thấy móng tay là loài phân tính, không phân biệt đực cái bằng mắt thường, tỷ lệ đực cái xấp xỉ 1:1. Tuyến sinh dục phát triển theo bốn giai đoạn. Mùa vụ sinh sản kéo dài từ tháng 12 đến tháng 3 năm sau, đỉnh cao vào tháng 12. Sức sinh sản tuyệt đối trung bình của móng tay là 1.048.893 ± 608.964 trứng/cá thể và sức sinh sản tương đối trung bình là 146.349 ± 95.666 trứng/gram khối lượng. Kích thước thành thục lần đầu 69,6 mm. Bài viết góp phần cung cấp cơ sở khoa học cho việc quản lý khai thác loài móng tay một cách hiệu quả và bền vững

THÀNH PHẦN LOÀI VÀ PHÂN BỐ CỦA THÂN MỀM VÀ DA GAI RẠN SAN HÔ TRONG CHUYẾN KHẢO SÁT TRÊN TÀU VIỆN SĨ OPARIN NĂM 2016–2017

A study on the species composition and distribution of Mollusca and Echinodermata on coral reefs from Quang Tri to Binh Thuan was conducted during the field survey between Vietnam and Russia on the AKADEMIK OPARIN RC vessel in 2016 and 2017 at 39 reef stations. 150 species were identified belonging to 100 genera, 50 families, 22 orders, 7 classes distributed on coral reefs. The species composition of mollusca and echinodermata was different between study areas.Nghiên cứu về thành phần loài và phân bố của động vật thân mềm, da gai trên rạn san hô khu vực từ Quảng Trị đến Bình Thuận được thực hiện trong chuyến khảo sát hỗn hợp Việt - Nga trên tàu Viện sĩ OPARIN trong thời gian từ tháng 11 đến tháng 12/2016 và chuyến khảo sát bổ sung từ tháng 5 đến tháng 7/2017 tại 39 trạm rạn thuộc 10 vùng nghiên cứu. Bằng phương pháp hình thái so sánh, nhóm tác giả đã xác định được 150 loài động vật thân mềm và da gai thuộc 100 giống, 50 họ, 22 bộ, 7 lớp phân bố trên rạn san hô. Thành phần loài thân mềm và da gai tương đối khác biệt giữa các vùng nghiên cứu

ĐÁNH GIÁ HIỆU QUẢ TẠI CÁC MÔ HÌNH DOANH NGHIỆP THAM GIA QUẢN LÝ RẠN SAN HÔ VÌ MỤC ĐÍCH DU LỊCH SINH THÁI Ở VỊNH NHA TRANG

The models of coral reef management for the development of ecological tourism were conducted under the coordination among the 3 businesses (Khanh Hoa Salanganes Nest Company, Vinpearl Nha Trang and Tri Nguyen Tourism), Institute of Oceanography and Khanh Hoa Department of Natural Resources Environment. The analysis of trends of coral cover, density of reef fishes and big size invertebrates at 3 sites allowed assessing effectiveness of 3 years’ management. The stability of hard coral cover, except the decline at southern Hon Tam due to impacts of the typhoon in Nov., 2017 indicated no increased damage to corals from human activities. However, the dominance of small size fish ( 10 cm in length), the decline of density of larger size fish and the poorness of large size invertebrate showed continuous overexploitation at these managed areas.Mô hình quản lý rạn san hô vì mục đích du lịch sinh thái được thực hiện với sự tham gia của Viện Hải dương học, Sở Tài nguyên và Môi trường Khánh Hòa và 3 doanh nghiệp bao gồm Công ty TNHH Nhà nước MTV Yến Sào, Công ty TNHH Vinpearl Nha Trang và Công ty Du lịch Trí Nguyên. Hiệu quả sau 3 năm quản lý được đánh giá thông quan phân tích xu thế biến động về độ phủ san hô, mật độ cá rạn và sinh vật đáy kích thước lớn. Sự ổn định độ phủ san hô ở khu vực Sau Sao - Vinpearl và Bãi Sạn - Hòn Miếu chứng tỏ san hô không bị suy thoái. Trong khi đó, độ phủ san hô ở Nam Hòn Tằm tăng rõ rệt trong giai đoạn 2015–2017 nhưng giảm đột ngột vào năm 2018 do bão số 12 diễn ra vào tháng 11/2017. Tổng mật độ cá rạn biến động không rõ rệt với ưu thế là nhóm cá có kích thước nhỏ hơn 10 cm, trong khi nhóm cá có kích thước lớn suy giảm đáng kể về mật độ. Mật độ động vật đáy kích thước lớn rất thấp và chủ yếu thuộc về các nhóm không có giá trị kinh tế. Phân tích này chứng tỏ rằng hoạt động quản lý đã ngăn chặn được tác động của con người gây suy thoái san hô nhưng chưa có hiệu quả với hoạt động khai thác nguồn lợi quá mức

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Ninh Hai waters (south Vietnam): a hotspot of reef corals in the western South China Sea

Vo, Si Tuan, DeVantier, Lyndon, Tuyen, Hua Thai, Hoang, Phan Kim (2014): Ninh Hai waters (south Vietnam): a hotspot of reef corals in the western South China Sea. Raffles Bulletin of Zoology 62: 513-520, DOI: http://doi.org/10.5281/zenodo.535434

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions