Fig 1.
Spatio-temporal patterns in the length distribution of Antarctic krill (Euphausia superba) across five subareas of the Antarctic Peninsula region.
Top left: CCAMLR statistical subareas around Antarctica, highlighting Subarea 48.1. Top right: Management units in 48.1 subarea considered in this study: Bransfield Strait (BS), Elephant Island (EI), Gerlache Strait (GS), Joinville Island (JOIN), and the Southwestern South Shetland Islands (SSWI).). Bottom: Annual krill length composition (2001–2020) for each management unit. Red line is length recruit (36 mm). Base map data from Natural Earth (public domain).
Table 1.
Antarctic krill SPR estimates from CCAMLR(1) Subarea 48.1, by management strata and year (parentheses represent the standard deviation). BS = Bransfield Strait, EI = Elephant Island, GS = Gerlache Strait, JOIN = Joinville Island, SSWI = Southwest.
Fig 2.
Krill intrinsic productivity (SPR) by management strata and by year.
The green dashed line represents 75% SPR (reference target) and the red line is 20% SPR (reference limit). BS = Bransfield Strait, EI = Elephant Island, GS = Gerlache Strait, JOIN = Joinville Island, SSWI = Southwest.
Table 2.
Antarctic krill LBSPR estimates from CCAMLR Subarea 48.1 by management strata in relation to a range of theoretical krill growth parameters, including eleven asymptotic lengths and three growth rate coefficients (low = 0.2, medium = 0.7, and high = 1.2) (parentheses represent the standard deviation). In bold, the values of the parameters currently used in management (Maschette et al, 2020). BS = Bransfield Strait, EI = Elephant Island, GS = Gerlache Strait, JOIN = Joinville Island, SSWI = Southwest.
Fig 3.
Sensitivity analysis in SPR estimation by management strata in relation to the scenario of a range of Von Bertalanffy asymptotic length values for Antarctic krill.
The green dashed line represents 75% SPR (reference target), and the red dashed line is 20% SPR (reference limit). Red boxes represent current parameters used in krill management. BS = Bransfield Strait, EI = Elephant Island, GS = Gerlache Strait, JOIN = Joinville Island, SSWI = Southwest.
Fig 4.
Sensitivity analysis to SPR estimation by management strata in relation to a range of growth coefficients (k) representing three different Antarctic krill growth rates (low = 0.2, medium = 0.7, and high = 1.2).
The green dashed line represents 75% SPR (reference target) and the red dashed line is 20% SPR (reference limit). Red boxes represent current parameters used in krill management. BS = Bransfield Strait, EI = Elephant Island, GS = Gerlache Strait, JOIN = Joinville Island, SSWI = Southwest.
Fig 5.
Overall results of SPR estimation and sensitivity scenarios of Antarctic krill for Subarea 48.1.
A) SPR values in time series (2000-2020), B) scenario comparisons with VB asymptotic length values and C) SPR variability for growth rates scenario.