Approach On The Status Of Fishery Resource At The Guinea Bissau Fishing Ground

Guinea Bissau fishing ground is one of the earliest developed fisheries in the West African country of China.Double rig method and stern trawl are the main operation modes.In recent years,the number of fishing boats are aboult 20,and the annual catch are about 18000 tons.Guinea Bissau fishing ground is a traditional fishing ground for the company.This paper is based on the CNFC transshipment data,which from the fishing boats at Guinea Bissau fishing ground.And combined the environmental data from the U.S.National Oceanic and Atmospheric Administration(NOAA)Ocean Watch(http://oceanwatch.pifsc.noaa.gov/las/servlets/dataset).This paper analyzed the relationship between the change of fishery resources and the environmental factors in Guinea Bissau fishing ground.The main results are as follows:1)There are two fishing seasons in Guinea Bissau fishing ground,respectively the first quarter(1 ~3 months)and fourth quarter(10 ~12 months),the first quarter of the highest yield in February,the fourth quarter of the highest yield in October.2)According to the different ways of operation,the main fishing species are also different.Double rig method is used to catch demersal fishand pelagic fish,stern trawl is used to catch mollusks.The proportion of other fish production is very low,such as crustaceans and cartilaginous fishes.Every first and fourth quarter,the main operating mode isdouble rig method,the highest yield in October;and every second and third quarter,the main operating mode is stern trawl,the highest yield in9.3)2011~2015,The major fishing areas of China National Fisheries Corporation in Guinea Bissau fishing ground was concentrated from10°30′N,16°10′W to 11°45′N,17°00′W,the catch in the coastal area more than the area away from the coast significantly.4)According to the biological characteristics of main fishing species,analyse Trachurus trachurus,Cynoglossus senegalensis and Arius hendelotii,have been found increased the proportion of small individual phenomenon,but CPUE still showed a rising trend,that amount is still in the growth of fishery resources in Guinea Bissau fishing ground.5)The center of gravity of the fishing fleet in the sea area of Guinea Bissau,latitude gradually shifted to the north every year after April,and gradually shifted to the south in November,and gradually shifted to the West on the longitude of 1~7 months,and then transferred to the East in July.The variation of gravity center is related to climate change,and the composition of main fishing species is affected.6)The GAM model was used to analyze the environmental factors affecting 3 species(pelagic fish,demersal fish,animal software)of CPUE,found that SST has an important influence on the ten black horse Bayu refers to CPUE,Chla has the same effect on the CPUE CPUE,basically a rising trend with the increase of Chla;the time factor of deviation on the green mackerel CPUE greater impact;environmental factors,only Chla of CPUE has a significant effect.Effect of Chla on green mackerel CPUE fluctuated trend,but in the Chla is about 10mg/m3 the biggest influence;influence of Octopus vulgaris CPUE.Octopus CPUE decreased with the increase of SST,increased with the increase of SSH,but decreased with the increase of Chla,low Chla favors the emergence of high CPUE.7)Selected the typical fish(middle fish,bottom fish)to calculate the corresponding fatness,fatness on behalf of the feeding conditions and maturity of the species,analysis of the impact of the environment on the fatness of different species of.Correlation between bothid and latent small chin SST was not obvious(P>0.05),but in May each year,when SST began to increase the fatness of the small chin also began to flounder potential increased rapidly,and began to increase in 8-9 in the annual temperature,fatness microgenia latent flounder began to decline rapidly fatness index;Mackerel and SST have a significant negative correlation(R=-0.559,P<0.05),the basic annual 3-5 month when the water temperature is low,SCAD the fatness of the highest.A negative relation exists between the small chin bothid and Chl-a potential(R=0.478,P<0.05),generally speaking,when the Chl-a is higher,the fatness of the small chin latent flounder is low,low Chl-a when its value increased;in contrast with the small chin latent flounder,fatness index of bamboo.Fish and Chl-a showed a significant positive correlation(R=0.5536,P<0.05),whose value changes with the consistency of Chl-a waters.The results showed that the bottom fish was significantly lower than that of the pelagic fish because of the deep water layer,and the effect of Chl-a on the two species was completely opposite to that of the SST.Based on the CNFC transshipment dataand combined the environmental data,explore the changes of fishery resources in Guinea Bissau fishing ground,the research results can provide reference for understanding the fishery resources exploitation and utilization in Guinea Bissau fishing ground,but also provided a scientific basis for the ship scheduling of the fishery fleet of China National Fisheries Corporation and the representative office at Guinea Bissau.