Individual variability in sub-Arctic krill material properties, lipid composition, and other scattering model inputs affect acoustic estimates of their population

Lucca, Brandyn M; Ressler, Patrick H; Harvey, H Rodger; Warren, Joseph D

doi:10.1093/icesjms/fsab045

i

Individual variability in sub-Arctic krill material properties, lipid composition, and other scattering model inputs affect acoustic estimates of their population

2021
By Lucca, Brandyn M ; Ressler, Patrick H ; Harvey, H Rodger ; ...

Details

Journal Title:

ICES Journal of Marine Science
Personal Author:

Lucca, Brandyn M ; Ressler, Patrick H ; Harvey, H Rodger ; Warren, Joseph D
NOAA Program & Office:

NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center)
Description:

Target strength model inputs including morphometry, material properties, lipid composition, and in situ orientations were measured for sub-Arctic krill (Euphausia pacifica, Thysanoessa spinifera, T. inermis, and T. raschii) in the eastern Bering Sea (EBS, 2016) and Gulf of Alaska (GOA, 2017). Inter-species and -regional animal lengths were significantly different (F1,680 = 114.10, p < 0.01), while animal shape was consistent for all species measured. The polar lipid phosphatidycholine was the dominant lipid, comprising 86 ± 16% (mean ± SD) and 56 ± 22% of total lipid mass in GOA and EBS krill, respectively. Krill density contrasts varied by species and region rather than with morphometry, lipid composition, or local chla fluorescence. Mean in situ krill orientation was 1 ± 31°, with 25% of observed krill within ±5° of broadside incidence. Modelled target strength sensitivity was frequency independent for variations in material properties but was primarily sensitive to morphometry and orientation at lower (38 kHz) and higher (200 kHz) frequencies, respectively. Measured variability in material properties corresponded to an order of magnitude difference in acoustic estimates of biomass at 120 kHz. These results provide important inputs and constraints for acoustic scattering models of ecologically important sub-Arctic krill species.
Keywords:

Krill
Source:

ICES Journal of Marine Science
DOI:

https://doi.org/10.1093/icesjms/fsab045
Document Type:

Journal Article
Place as Subject:

Alaska, Gulf of (Alaska) ; Bering Sea
Rights Information:

Other
Compliance:

Submitted
Main Document Checksum:

urn:sha256:b181b1b6192d1438b5f62a8021255526ae8f6cfed18e817ef4788e5037364a20
Download URL:

https://repository.library.noaa.gov/view/noaa/29585/noaa_29585_DS1.pdf
File Type:

[PDF - 1.52 MB ]

ON THIS PAGE

Details

The NOAA IR serves as an archival repository of NOAA-published products including scientific findings, journal articles, guidelines, recommendations, or other information authored or co-authored by NOAA or funded partners. As a repository, the NOAA IR retains documents in their original published format to ensure public access to scientific information.