Effect of voluntary restriction zone on Antarctic krill fishery and 

fishing ground distribution in the Antarctic Peninsula

DONG Sisong1,2, ZHU Guoping1, 2, 3, 4

(1. College of Marine Sciences, Shanghai Ocean University, Shanghai201306; 2. Center for Polar 

Research, Shanghai Ocean University, Shanghai201306; 3. Polar Marine 

Ecosystem Lab, Key Laboratory of Sustainable Exploitation of Oceanic 

Fisheries Resources, Ministry of Education, Shanghai Ocean University, Shanghai201306; 

4. National Engineering Research Center for Oceanic Fisheries, Shanghai201306)

Abstract: Antarctic krill (commonly refers to Euphausia superba) is a key species in the Southern Ocean ecosystem. Its huge biomass has tremendous potential for fishery exploitation. With the development of krill fishery, the total catch has exhibited an increasing tendency, and the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) conventional area subarea 48.1, a hotspot for the krill fishery, has been closed in recent years due to reaching the trigger level. The areas around the Antarctic Peninsula are also inhabited for protection of vast numbers of penguins and seals. To better conserve krill resources and the predators depending on krill for food, the Association of Responsible Krill Harvesting Companies (ARK), a group of 90% of the world’s krill fishery companies, has agreed to and implemented voluntary restriction zones (VRZs) for krill fisheries in this area, starting in 2019. The VRZ requires krill fishing vessels to voluntarily restrict fishing activities in some areas during the summer and to reduce their access in other seasons, except for a failed searching for krill resource outside the VRZ, to reduce the potential impact of krill fishing activities in the areas around the Antarctic Peninsula due to competition between fishing and penguins for krill in the area. The implementation of the VRZ has had a significant impact on krill fishery and the distribution of fishing ground, and this change is bound to have an unpredictable impact on the sustainable development of krill fishery, as well as further affecting the decisionmaking of krill fishery companies. To understand the impact of the VRZ establishment and the potential future trend of VRZ enlargement on krill fishery and fishing ground selection, based on the existing VRZ, this study defines the boundary of the simulated restriction zone by extending 20 km, 30 km, and 40 km from the shoreline off the Antarctic Peninsula and the South Shetland Islands, respectively. The Bransfield Strait region is divided into four areas near the Antarctic Peninsula: AP20 (from the Antarctic Peninsula shoreline to the 20 km simulation line), AP30 (from 20 km to 30 km off the Antartic Peninsula), AP40 (from 30 km to 40 km off the Antarctic Peninsula), and BS (40 km off the Antartic Peninsula). The South Shetland Islands VRZ is divided into SSI20 (from the South Shetland Islands shoreline to the 20 km simulation line), SSI30 (from 20 km to 30 km off the South Shetland Islands), and SSI40 (from 30 km to 40 km off the South Shetland Islands), and NSSI (the open waters north of the restriction zone of the South Shetland Islands). The trawling locations and catch of krill trawler Furonghai owned by Liaoning Pelagic Fisheries Corporation around the Antarctic Peninsula from January to May 2017—2020 is used for the analysis in this study and the catch per unit effort (CPUE) is calculated to be an indicator of the vessel’s fishing efficiency. The area with high fishing efficiency can be considered as the core fishing ground. The fishing grounds in CCAMLR subarea 48.1 is divided into eight simulated restricted zones (MRZ). The spatial and temporal distribution and changes in fishing catch and fishing efficiency in different areas before and after the establishment of VRZ are analyzed.Results show that most of the fishing locations are concentrated in the BS near the Antarctic Peninsula north shelf during these four years, while the number of nets near the South Shetland Islands is low. With the establishment of the VRZ, the number of nets in the inshore off the South Shetland Islands declines significantly, while the number of nets in the NSSI but outside the VRZ increases. Following the establishment of the VRZ, krill fishery’s core fishing grounds shift to the BS, and the fishing efficiency in the BS is higher than that in other areas near the South Shetland Islands. There is an overall decreasing tendency of fishing efficiency and a greater negative influence on the seasonal catch peak in January and February. To reduce the impact of the VRZ on fishing grounds selection, no fishing vessel visits the Antarctic Peninsula in January and February, instead moving to the South Orkney Islands to launch the new fishing season. The VRZ and MRZ already cover a large portion of the Gerlache Strait, the northwest and north area off the South Shetland Islands, and parts of the Bransfield Strait, where krill fishery is much efficient. Krill fishing vessels will have less time available to fish in subarea 48.1 during summer if fishery management develops with the assumed MRZ, and the fishing grounds will be less selective. If conservation measures are implemented around the years in the future, subarea 48.1 will be too low in revenue for the fisheries to be exploitable. The transport mechanisms of krill stock is not generally known, and the potential impacts of krill fishery on predators are not fully demonstrated. The krill fishery has provided the CCAMLR with a wealth of basic scientific data for the development of conservation measures and has contributed to the study of the Southern Ocean environment, although overly harsh management of fishery may have a negative effect on subsequent scientific research. The current VRZ has led to an overconcentration of krill fishery in the Bransfield Strait for a short period, and this highdensity fishing behavior in small areas might lead to excessive fishing effort in hotspots, which in turn can have a greater impact on krill and their predators. To cope with more stringent fisheries management in the future, it’s suggested to develop professional krill fishing vessel with continuous pumping technology to improve fishing ground exploitation and increase fishing efficiency, while lowering operation costs. It’s also suggested to strengthen scientific research and international cooperation to enhance our position in krill fisheries internationally.