scholarly journals Relationships between the distributions of marine avian predators and their prey, Euphausia superba, in Bransfield Strait and southern Drake Passage, Antarctica

1989 ◽  
Vol 58 ◽  
pp. 3-16 ◽  
Author(s):  
D Heinemann ◽  
G Hunt ◽  
I Everson
Keyword(s):  
Drake Passage ◽  
Euphausia Superba ◽  
Bransfield Strait ◽  
Avian Predators

Synchronous moulting of krill, Euphausia superba , in the Bransfield Strait (Antarctica)

Polar Biology ◽  
2004 ◽  
Vol 27 (6) ◽  
pp. 380-382
Author(s):  
G. Rotllant ◽  
J. B. Company ◽  
X. Busquets ◽  
F. Buchholz
Keyword(s):  
Euphausia Superba ◽  
Bransfield Strait

scholarly journals Variability of Salpa thompsoni population structure in the Drake Passage in summer season 2010

2015 ◽  
Vol 36 (4) ◽  
pp. 391-404 ◽  
Author(s):  
Angelika W. Słomska ◽  
Anna A. Panasiuk-Chodnicka ◽  
Maria I. Żmijewska ◽  
Maciej K. Mańko
Keyword(s):  
Population Expansion ◽  
Thermal Conditions ◽  
Drake Passage ◽  
Euphausia Superba ◽  
Horizontal Distribution ◽  
Summer Season ◽  
South Shetland Islands ◽  
The West ◽  
Climatic Fluctuations ◽  
West Antarctic

AbstractDynamic climate changes have become noticeable in recent decades, especially in the vulnerable region of the West Antarctic. The relatively simple food web of this area relies on krill –Euphausia superba. Presumably, as a result of climatic fluctuations, a decrease in the number of this crustacean has been recorded, followed by an increase in the population of the gelatinous zooplankterSalpa thompsoni. In the research presented herein, population and morphometric analyses ofSalpa thompsonihave been conducted. Specimens for this research were collected from the Drake Passage, using a Bongo net in the summer season of 2010. It has been found that the horizontal distribution of this gelatinous zooplankter was significantly irregular (Kruskal-Wallis test, p < 0.001). In the northern part of the investigated area, both blastozooids and oozooids were recorded, which confirms the dynamic development of this species. The central part of the Drake Passage was characterized by the dominance of blastozooids, with embryos found at different stages of the development. Only in the region of the South Shetland Islands, the salpid population was characterized by reduced or even stopped reproduction. The immense reproductive efficiency observed in theSalpa thompsonipopulation was mostly induced by the favourable thermal conditions. These observations may suggest that the ongoing climat changes in the West Antarctic will promote the population expansion of this species.

scholarly journals Geophysical models of Drake passage and Bransfield strait crustal structure

2008 ◽  
pp. 9-14
Author(s):  
S. P. Levashov ◽  
◽  
N. A. Yakymchuk ◽  
I. N. Korchagin ◽  
V. G. Bakhmutov ◽  
...  
Keyword(s):  
Crustal Structure ◽  
Drake Passage ◽  
Bransfield Strait

scholarly journals Glider-Based Estimates of Meso-Zooplankton Biomass Density: A Fisheries Case Study on Antarctic Krill (Euphausia superba) Around the Northern Antarctic Peninsula

2021 ◽  
Vol 8 ◽  
Author(s):  
Christian S. Reiss ◽  
Anthony M. Cossio ◽  
Jennifer Walsh ◽  
George R. Cutter ◽  
George M. Watters
Keyword(s):  
Antarctic Peninsula ◽  
Antarctic Krill ◽  
Spatial Scales ◽  
Euphausia Superba ◽  
Acoustic Energy ◽  
Alternative Methods ◽  
Small Scale ◽  
Biomass Density ◽  
Bransfield Strait ◽  
Cape Shirreff

We compare estimates of krill density derived from gliders to those from contemporaneous and previous ship-based surveys. Our comparisons cover several temporal and spatial scales within two strata around the northern Antarctic Peninsula (off Cape Shirreff on the north side of Livingston Island and in the Bransfield Strait). Our objective is to explore the feasibility of using gliders to supplement or replace vessel-based surveys of fishery resources. We deployed two long-duration Slocum G3 gliders manufactured by Teledyne Webb Research (TWR), each equipped with a suite of oceanographic sensors and a three-frequency (38, 67.5, and 125 kHz, each single-beam) Acoustic Zooplankton Fish Profiler. We used the acoustic data collected by these gliders to estimate biomass densities (g⋅m–2) of Antarctic krill (Euphausia superba). The two gliders were, respectively, deployed for 82 and 88 days from mid-December 2018 through mid-March 2019. Off Cape Shirreff, glider-based densities estimated from two repeat small-scale surveys during mid-December and January were 110.6 and 55.7 g⋅m–2, respectively. In Bransfield Strait, the glider-based estimate of biomass density was 106.7 g⋅m–2 during December–January. Contemporaneous ship-based estimates of biomass density, from a multi-ship broad-scale krill survey (Macaulay et al., 2019) restricted to the areas sampled by the gliders, were 84.6 g⋅m–2 off Cape Shirreff and 79.7 g⋅m–2 in Bransfield Strait during January. We compared two alternative krill-delineation algorithms (dB differencing and SHAPES); differences between biomass densities estimated by applying these algorithms were small and ranged between 4 and 7%. Alternative methods of sampling krill length-frequency distributions (LFDs) (nets or predator diets), which are required to convert acoustic energy to biomass density, also influenced the glider-based results. In Bransfield Strait, net-based estimates of biomass density were 6% less than those based on predator diets. Off Cape Shirreff the biomass density of krill estimated from a net-based LFD was 20% greater than that based on predator diets. Development of a variance estimator for glider-based biomass surveys is ongoing, but our results demonstrate that fisheries surveys using acoustically-equipped gliders are feasible, can provide density estimates to inform management, and may be conducted at lower cost than ship surveys in some cases.

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