Predicting changes in the Antarctic krill, Euphausia superba, population at South Georgia

first_imgVariability in the Southern Ocean is frequently reflected in changes in the abundance of Antarctic krill Euphausia superba and subsequent effects on dependent predators. However, the nature and consequences of changes in krill population dynamics that accompany fluctuations in its abundance are essentially unknown. A conceptual model, developed from quantitative measures of krill length in the diet of predators at South Georgia from 1991 to 1997, allowed predictions to be made about the abundance and population structure of krill in 1998 and the consequences for predators. Consistent with model predictions, in 1998 there was a serial change in krill population structure, low krill biomass and low reproductive performance of predators. The change in the modal size of krill, from 56 mm in December to 42 mm in March, was apparently a result of the transport of krill into the region. This is the first occasion when the future status and structure of the krill population at South Georgia has been successfully predicted. By representing local krill population dynamics, which may also reflect large-scale physical and biological processes, predators have a potential key role as indicators of environmental variation in the Southern Ocean at a range of spatial scales.last_img read more

Navies test submarine search and rescue skills off Australia

first_imgThe six-nation submarine search and rescue exercise Pacific Reach 2019 has concluded off the coast of Western Australia.Held at Fleet Base West and in the Western Australian Exercise Area, the drill involved assets from Australia, Japan, Malaysia, the Republic of Korea, Singapore and the United States.Australian Minister for Defence, Senator the Hon Linda Reynolds CSC said the exercise was vital to developing interoperability and trust with partner nations.“During Exercise Pacific Reach the Royal Australian Navy’s submarine force and our regional partners demonstrated readiness and the ability to respond to the unlikely event of a submarine incident at sea,” Reynolds said.“Each nation’s submarine search, escape and rescue organisations took part in simulated rescues.“HMAS Sheean and ROKS Lee Sun-sin, both successfully transferred participants while submerged using the James Fisher Submarine Rescue System submersible LR5, with support from rescue units from Japan and the United States.“Joint maritime exercises like Exercise Pacific Reach strengthen the already deep relationship that exists between Australia and our partners.”Exercise Pacific Reach is a triennial multinational event and was last held in the Republic of Korea in 2016. View post tag: ROK Navy View post tag: Submarine rescue View post tag: JMSDF View post tag: RAN View post tag: Exercise Pacific Reachcenter_img View post tag: RMN Photo: Capt. Patrick Friedman, commander, Submarine Squadron 11, pilots the Royal Australian Navy submarine rescue vessel, LR5, during Exercise Pacific Reach. Photo: US Navy View post tag: RSN Share this articlelast_img read more