In order to assess effects of Summer Fishing Moratorium (SFM) in Daya Bay, variations in stock density, fish diversity, fish species composition, fish body length and weight, and bio-environments during the pre-SFM (May in 2015) and post-SFM (August in 2015) in Daya Bay were analyzed, based on trawl survey data. Results showed that the average stock density in the post-SFM was 5.65 times of that in the pre-SFM, and the average species numbers in the post-SFM was 1.76 times of that in the pre-SFM. Analysis of fish body length and weight indicated that fish grew faster during the SFM, and body weight was more uniform in the post-SFM. In the post-SFM, the Shannon-Wiener diversity index and Pielou evenness index increased by 0.36 and 0.14, respectively, indicating that the fish biodiversity and community structure improved. SFM alleviated fishing intensity, recovered and conserved coastal fish resource. In order to improve efficiency and impacts of SFM and to promote sustainable development of coastal fish resource, prolonging the time of SFM, reducing the number of coastal fishing boats and enforcing the conservation of fish resources were suggested.

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Dapeng Bay is a typical offshore fisheries area in the South China Sea (SCS). In order to understand the fishery resources, seasonal variations of species composition, dominant species composition, standardized catch per unit effort (SCPUE) and community diversity of fishery resources in Dapeng Bay, China were analyzed based on trawl survey data in spring (March) and summer (May) of 2013 as well as autumn (August) and winter (December) of 2012. Results demonstrated that there are 113 fishery species, which belong to 78 categories, 50 families, 14 catalogues, 3 classes. There are the most species in summer (61 species) and about 56 species in other seasons. In all four seasons, fish and crustacea are dominant species, and there are the fewest cephalopoda. High values of SCPUE occur in spring and autumn, reaching 5.65 and 5.33, respectively. SCPUE is generally low in summer, ranging between 0.52 -0.96. Fish biodiversity is the highest in summer and the lowest in winter.Among biodiversity, Shannon-Wiener diversity index, Margalef diversity index and Pielou evenness index vary in the same trend. They are decreasing from summer, spring, autumn to winter successively. Therefore, there are violent seasonal variation of species composition, quantity and structure of fishery resources in Dapeng Bay. The community structure and function are highly stable in summer, but they have poor stability in autumn and winter. This research can provide scientific references for protection and sustainable use of fishery resources in typical offshore fisheries area in the SCS.

The performance of a portable near-infrared (NIR) spectrometer to determine organic carbon (OC) in marine sediments was evaluated. The NIR reflection spectra of 180 samples in the range 950 -1650 nm were acquired using an ultra-compact spectrometer. NIR spectroscopy combined with the partial least squares (PLS) regression and Savitzky-Golay (SG) smoothing was successfully applied to rapid and reagent-free determination of OC. Using the PLS-SG model with 1 nd order derivative, 2 th polynomial and eleven smoothing points, the root-mean-square errors (RMSEP M ) and correlation coefficients (R P,M ) of prediction for modeling were 0.073% and 0.894, respectively, the root-meansquare errors (RMSEP V ) and correlation coefficients (R P,V ) of prediction for validation were 0.075% and 0.883, respectively. Results showed that the small portable NIR instrument achieved well prediction effect for the analysis of OC in marine sediments, which had advantages of rapid, easy to carry and operate suitable for large-scale applications to analyze marine sediments.

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