The potential distribution of adult Antarctic krill in the Amundsen Sea

Antarctic krill is the key species of ecological system in the Amundsen Sea. At present, the suitable distribution is unobtainable by scientific surveys or data from the fishery. In this paper, the maximum entropy algorithm (Maxent) was used to obtain the potential distribution of adult Antarctic krill in order to provide useful information and reasonable reference for the policy on protecting potential krill habitats around the Amundsen Sea. Occurrence points and 17 environmental variables were used to simulate the distributions. Results show that the high and moderate suitable habitats lie between 65°S and 72°S in the Amundsen Sea. The high suitable habitat accounts for 8.1% of the total area of the Amundsen Sea. The sea ice persistence (ICE), total phytoplankton (PHYC), and the minimum value of dissolved iron (Fe_min) are the three dominant contributors to the model. Results from the response curves show that Antarctic krill preferred habitats with ICE of 0.42–0.93, PHYC of 2.48–2.77 mmol/m 3 and Fe_min of (7.10×10 −5 )−(9.45×10 −5 ) mmol/m 3 . Positive trends existed in the PHYC of the high and moderate suitable habitat, and a positive trend existed in the Fe_min of moderate suitable habitat. However, the probability of presence of Antarctic krill will decrease if the increase of the PHYC and Fe_min continues.