Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period

The growth rates of postlarval krill (Euphausia superba) were measured across a wide range of environments in the Scotia Sea and around South Georgia using the Instantaneous Growth Rate (IGR) method. Each IGR experiment determined the intermolt period (IMP) and growth increment at molt (GI) of an av...

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Main Authors: Tarling, Geraint A., Shreeve, Rachael S., Hirst, Andrew G., Atkinson, Angus, Pond, Dave W., Murphy, Eugene J., Watkins, Jon L.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Society of Limnology and Oceanography 2006
Subjects:
Online Access:http://nora.nerc.ac.uk/id/eprint/137/
http://aslo.org/lo/pdf/vol_51/issue_2/0959.pdf
id ftnerc:oai:nora.nerc.ac.uk:137
record_format openpolar
spelling ftnerc:oai:nora.nerc.ac.uk:137 2024-06-09T07:40:29+00:00 Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period Tarling, Geraint A. Shreeve, Rachael S. Hirst, Andrew G. Atkinson, Angus Pond, Dave W. Murphy, Eugene J. Watkins, Jon L. 2006 http://nora.nerc.ac.uk/id/eprint/137/ http://aslo.org/lo/pdf/vol_51/issue_2/0959.pdf unknown American Society of Limnology and Oceanography Tarling, Geraint A. orcid:0000-0002-3753-5899 Shreeve, Rachael S.; Hirst, Andrew G.; Atkinson, Angus; Pond, Dave W.; Murphy, Eugene J. orcid:0000-0002-7369-9196 Watkins, Jon L. 2006 Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period. Limnology and Oceanography, 51 (2). 959-972. Zoology Publication - Article PeerReviewed 2006 ftnerc 2024-05-15T08:39:04Z The growth rates of postlarval krill (Euphausia superba) were measured across a wide range of environments in the Scotia Sea and around South Georgia using the Instantaneous Growth Rate (IGR) method. Each IGR experiment determined the intermolt period (IMP) and growth increment at molt (GI) of an average of 120 individuals incubated for 5 d in through-flowing ambient, filtered seawater. We examined the results from 51 IGR experiments involving 5,927 animals ranging between 25 mm and 62 mm. Animals were collected from an area that covered a latitudinal range of 108 and surface temperatures of between -0.85°C and 4.75°C. The measurement of IMP has rarely been achieved in IGR experiments because synchronous molting biases estimates. We overcame this by applying a binary logistic regression model to our data. This related IMP to temperature, body length, and maturity stage. Food did not influence IMP. Our model estimated that krill within our experiments had IMPs ranging from 9 d to 57 d. Temperature affected the IMP of females more than that of males. The IMPs of females were shortest around 2°C and increased at lower and higher temperatures. IMP increased with body size and altered according to gender, with male IMPs being 50% longer than those of equivalently sized females. One of the main assumptions of the IGR method is that the GI measured in the first few days reflects the in situ conditions experienced by krill in the previous intermolt period. However, we found that the GIs declined immediately and rapidly after capture, particularly when growth was initially high. Thus, conditions at time of molt also influence GI. We developed a method of correcting measured GIs to natural growth in field conditions. These refinements to IGR methodology (IMP and GI estimation) enable more accurate and precise predictions of krill growth rates in summer to be made. Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Euphausia superba Scotia Sea Natural Environment Research Council: NERC Open Research Archive Antarctic Scotia Sea
institution Open Polar
collection Natural Environment Research Council: NERC Open Research Archive
op_collection_id ftnerc
language unknown
topic Zoology
spellingShingle Zoology
Tarling, Geraint A.
Shreeve, Rachael S.
Hirst, Andrew G.
Atkinson, Angus
Pond, Dave W.
Murphy, Eugene J.
Watkins, Jon L.
Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
topic_facet Zoology
description The growth rates of postlarval krill (Euphausia superba) were measured across a wide range of environments in the Scotia Sea and around South Georgia using the Instantaneous Growth Rate (IGR) method. Each IGR experiment determined the intermolt period (IMP) and growth increment at molt (GI) of an average of 120 individuals incubated for 5 d in through-flowing ambient, filtered seawater. We examined the results from 51 IGR experiments involving 5,927 animals ranging between 25 mm and 62 mm. Animals were collected from an area that covered a latitudinal range of 108 and surface temperatures of between -0.85°C and 4.75°C. The measurement of IMP has rarely been achieved in IGR experiments because synchronous molting biases estimates. We overcame this by applying a binary logistic regression model to our data. This related IMP to temperature, body length, and maturity stage. Food did not influence IMP. Our model estimated that krill within our experiments had IMPs ranging from 9 d to 57 d. Temperature affected the IMP of females more than that of males. The IMPs of females were shortest around 2°C and increased at lower and higher temperatures. IMP increased with body size and altered according to gender, with male IMPs being 50% longer than those of equivalently sized females. One of the main assumptions of the IGR method is that the GI measured in the first few days reflects the in situ conditions experienced by krill in the previous intermolt period. However, we found that the GIs declined immediately and rapidly after capture, particularly when growth was initially high. Thus, conditions at time of molt also influence GI. We developed a method of correcting measured GIs to natural growth in field conditions. These refinements to IGR methodology (IMP and GI estimation) enable more accurate and precise predictions of krill growth rates in summer to be made.
format Article in Journal/Newspaper
author Tarling, Geraint A.
Shreeve, Rachael S.
Hirst, Andrew G.
Atkinson, Angus
Pond, Dave W.
Murphy, Eugene J.
Watkins, Jon L.
author_facet Tarling, Geraint A.
Shreeve, Rachael S.
Hirst, Andrew G.
Atkinson, Angus
Pond, Dave W.
Murphy, Eugene J.
Watkins, Jon L.
author_sort Tarling, Geraint A.
title Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
title_short Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
title_full Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
title_fullStr Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
title_full_unstemmed Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period
title_sort natural growth rates in antarctic krill (euphausia superba): i. improving methodology and predicting intermolt period
publisher American Society of Limnology and Oceanography
publishDate 2006
url http://nora.nerc.ac.uk/id/eprint/137/
http://aslo.org/lo/pdf/vol_51/issue_2/0959.pdf
geographic Antarctic
Scotia Sea
geographic_facet Antarctic
Scotia Sea
genre Antarc*
Antarctic
Antarctic Krill
Euphausia superba
Scotia Sea
genre_facet Antarc*
Antarctic
Antarctic Krill
Euphausia superba
Scotia Sea
op_relation Tarling, Geraint A. orcid:0000-0002-3753-5899
Shreeve, Rachael S.; Hirst, Andrew G.; Atkinson, Angus; Pond, Dave W.; Murphy, Eugene J. orcid:0000-0002-7369-9196
Watkins, Jon L. 2006 Natural growth rates in Antarctic krill (Euphausia superba): I. Improving methodology and predicting intermolt period. Limnology and Oceanography, 51 (2). 959-972.
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