Assessing the stock status of Atlantic bumper, Chloroscombrus chrysurus, Linnaeus 1766, from the coastal waters of Ghana

The main objective of this study was to examine the growth, mortality, and exploitation rate of Chloroscombrus chrysurus from the continental shelf of Ghana, West Africa between July 2018 and June 2019. This study provided results on fishery dynamics parameters to contribute to estimating the stock assessment of these fish species. Monthly length-frequency data were collected from 697 samples and analyzed using fisheries models fitted in TropFish R. The von Bertalanffy growth parameters were utilized to analyze the population dynamics of these species using ELEFAN Simulating Annealing. The estimated asymptotic total length (L∞), coefficient of growth (K), and growth performance index (Φ′) was 24.9 cm, 0.84 year-1, and 2.72, respectively, with a Response surface (Rn) value of 0.79. The total mortality (Z), natural mortality (M), and fishing mortality (F) rates C. chrysurus from the continental shelf of Ghana were 3.27 year-1, 1.31 year-1, and 1.96 year-1, respectively. The exploitation rate (E) estimated was above the optimum level of 0.5 which indicates that the species is overexploited. Based on the Emsy (0.69) value, analyses show that the exploitation rate has exceeded the sustainable limit and hence the need for proper fisheries management measures

Assessment of Agricultural Drought Vulnerability Based on Crop Growth Stages: A Case Study of Huaibei Plain, China

Abstract Climate change can lead to and intensify drought disasters. Quantifying the vulnerability of disaster-affected elements is significant for understanding the mechanisms that transform drought intensity into eventual loss. This study proposed a growth-stage-based drought vulnerability index (GDVI) of soybean using meteorological, groundwater, land use, and field experiment data and crop growth model simulation. The CROPGRO-Soybean model was used to simulate crop growth and water deficit. Four growth stages were considered since the sensitivity of soybean to drought is strictly related to the growth stage. The GDVI was applied to the Huaibei Plain, Anhui Province, China, with the goal of quantifying the spatiotemporal characteristics of soybean drought vulnerability in typical years and growth stages. The results show that: (1) The sensitivity of leaf-related parameters exceeded that of other parameters during the vegetative growth stage, whereas the top weight and grain yield showed a higher sensitivity in the reproductive growth stage; (2) A semi-logarithmic law can describe the relationship between the drought sensitivity indicators and the GDVI during the four growth stages. The pod-filling phase is the most vulnerable stage for water deficit and with the highest loss upper limit (over 70%); (3) The 2001 and 2002 seasons were the driest time during 1997−2006. Fuyang and Huainan Cities were more vulnerable to drought than other regions on the Huaibei Plain in 2001, while Huaibei and Suzhou Cities were the most susceptible areas in 2002. The results could provide effective decision support for the categorization of areas vulnerable to droughts