Methods for biomass estimation of Antarctic krill(Euphausia superba): a review

Antarctic krill (Euphausia superba) is a key species in the Antarctic marine food web, which plays an important role in the southern ocean pelagic ecosystem. History of krill research has 90 years, the information of biomass and its distribution has been the focus of krill research, and the study methods have constantly been developed. From the early zooplankton dry weight method, then replaced by the conversion factors of production to biomass method (consumption of predators, primary production, larval abundance of krill), nets sample method, and now widely used acoustic method. This review analyses the advantages and disadvantages of each method, puts forward some suggestions for improvement of the current acoustic biomass assessment method from the five aspects of in-situ measurement of krill target strength model parameters, krill detection from the acoustic data, calculation of the krill nautical area scattering coefficients, correction of the krill fishery CPUE based on fishing vessel acoustic data, study on the krill swarm and fishery ground based on fishing vessel acoustic data which could provide a scientific basis for our country's Antarctic krill biological resources development and management.