Application of Gray Metabolic GM (1,1) Model in Prediction of Annual Total Yields of Chinese Aquatic Products

To predict the annual total yields of Chinese aquatic products in future five years ( 2011-2015) ,based on the theory and method of gray system,this paper firstly establishes a conventional GM ( 1,1) model and a gray metabolic GM ( 1,1) model respectively to predict the annual total yields of Chinese aquatic products in 2006-2009 and compare the prediction accuracy between these two models. Then,it selects the model with higher accuracy to predict the annual total yields of Chinese aquatic products in future five years. The comparison indicates that gray metabolic GM ( 1,1) model has higher prediction accuracy and smaller error,thus it is more suitable for prediction of annual total yields of aquatic products. Therefore,it adopts the gray metabolic GM ( 1,1) model to predict annual total yields of Chinese aquatic products in 2011-2015. The prediction results of annual total yields are 55. 32,57. 46,59. 72,62. 02 and 64. 43 million tons respectively in future five years with annual average increase rate of about 3. 7% ,much higher than the objective of 2. 2% specified in the Twelfth Five-Year Plan of the National Fishery Development ( 2011 to 2015) . The results of this research show that the gray metabolic GM ( 1,1) model is suitable for prediction of yields of aquatic products and the total yields of Chinese aquatic products in 2011-2015 will totally be able to realize the objective of the Twelfth Five-Year Plan.

Heterosis and combining ability evaluation for growth traits of blunt snout bream(Megalobrama amblycephala)when crossbreeding three strains

The blunt snout bream(Megalobrama amblycephala)is a major aquaculture species in the Chinese freshwater polyculture system.In this study,complete diallel crossing of three strains(i.e.,Liangzi[LZ],Poyang[PY]and Yuni[YN])was used to evaluate the combining ability and heterosis effect of intraspecific crossbreeding on the growth performance(i.e.,body weight,total length,body length,body height,and Fulton’s coefficient of condition).The offspring produced from the three strains were reared in a communal pond for 20 months,and nine microsatellites were used to assess their pedigree.Of the749 offspring,708(94.53%)could be assigned directly to a single parental pair.Significant differences were observed in body weight(BW)among the different combinations,indicating that the combining ability of BW from each strain was significantly different.The general combining ability(GCA)of BW from the sire was much higher than that from the dam.The GCA for the dam and sire of the LZ and YN were the largest and the smallest,respectively.The special combining ability of YN$9 PY#was the largest,and YN$9 PY#showed significantly positive heterosis effects on all F1growth traits,except for Fulton’s condition coefficient(K)(P\0.05).In addition,significant positive linear correlations were found between the mean BW of corresponding progeny and the H E of the parental generation(y=600.7x-29.472,r=0.8651,P=0.0026),H O(y=1206.9x-518.14,r=0.7436,P=0.0216),and the polymorphism information content(y=1021.3x-331.31,r=0.8245,P=0.0063)as determined by a correlative test.The findings obtained from the study will be important for future considerations of M.amblycephala stock improvement programs.

Impact of anthropogenic activities on changes of ichthyofauna in the middle and lower Xiang River

With the population increasing,fish communities,as important components in the river system,were inescapably impacted by human activities.To investigate these impacts,we characterized the fish community’s composition by environmental DNA metabarcoding in the urban and suburban sites along Xiang River in central China.The results showed that 32 species were identified,and most species were from Cypriniform.The analysis indicated no significant differences in fish communities among the three urban areas.However,significant differences were observed between the bank solidified and non-solidified areas,which indicated that the channelization significantly influenced the biodiversity and abundances.An alien species,Clarias gariepinus,was discovered in all examined sites,and it was negatively associated with ten native species.Furthermore,human populations and acidification were also negatively related to diversity.Our findings clearly showed that the consequences of anthropogenic activities shaped ichthyofauna and caused biodiversity loss in the urban river.