From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators
Abstract Background In the last decade, thousands of satellite-relayed data loggers (SRDLs) have been deployed, providing large datasets on marine predator movement patterns at sea and their diving behaviour. However, the latter is in a highly summarised, low-resolution form, from which it is diffic...
Main Authors: | , , , |
---|---|
Format: | Other/Unknown Material |
Language: | English |
Published: |
BioMed Central Ltd.
2015
|
Subjects: | |
Online Access: | http://www.animalbiotelemetry.com/content/3/1/42 |
id |
ftbiomed:oai:biomedcentral.com:s40317-015-0074-3 |
---|---|
record_format |
openpolar |
spelling |
ftbiomed:oai:biomedcentral.com:s40317-015-0074-3 2023-05-15T16:05:46+02:00 From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators Heerah, Karine Hindell, Mark Guinet, Christophe Charrassin, Jean-Benoît 2015-10-07 http://www.animalbiotelemetry.com/content/3/1/42 en eng BioMed Central Ltd. http://www.animalbiotelemetry.com/content/3/1/42 Copyright 2015 Heerah et al. Pinnipeds Argos tags Satellite-linked time depth recorders Foraging behaviour Dive profile Marine ecology Method Accelerometers Research 2015 ftbiomed 2015-10-11T00:08:36Z Abstract Background In the last decade, thousands of satellite-relayed data loggers (SRDLs) have been deployed, providing large datasets on marine predator movement patterns at sea and their diving behaviour. However, the latter is in a highly summarised, low-resolution form, from which it is difficult to make the sorts of important behavioural inferences that are possible from higher-resolution datasets (such as detection of likely foraging events). The main objective of this study was to develop a simple, but accurate tool to detect and quantify within-dive foraging periods in low-resolution dives. Method Two southern elephant seals were fitted with a head-mounted time depth recorder (TDR) (recording depth at 1 Hz) and an accelerometer (recording 3 axes of acceleration at 16 Hz) from which prey capture attempts were estimated (PrCA), and a Weddell seal was also fitted with a TDR (1 Hz).The resulting high-resolution dive profiles were used to: (1) calculate an accurate index of foraging effort based on the detection of vertical sinuosity switches (i.e. hunting highres time); (2) produce an SRDL-equivalent low-resolution dataset using a broken stick algorithm; and (3) from each low-resolution dive calculate a set of candidate foraging effort indices. Results Hunting lowres time, which is the total time spent in decreased vertical velocity segments of the dive, was the foraging effort index that best correlated with hunting highres time. Hunting highres mode of SES dives (highly sinuous parts of high-resolution dives) was associated with 77 % of total PrCA. In comparison, Hunting lowres segments of SES dives were associated with 68 % of PrCA as well as with four times more PrCA than transit lowres segments. Conclusion We found a low-resolution index which indicates foraging activity within a highly summarised dive profile and which identified most PrCA, despite degraded information transmitted by SLDRs. Used in combination with other measurements of the in situ environment, the hunting lowres index could be used in numerous integrated marine ecology studies, such as habitat use studies that are crucial to facilitate more effective conservation. Other/Unknown Material Elephant Seals Southern Elephant Seals Weddell Seal BioMed Central Weddell |
institution |
Open Polar |
collection |
BioMed Central |
op_collection_id |
ftbiomed |
language |
English |
topic |
Pinnipeds Argos tags Satellite-linked time depth recorders Foraging behaviour Dive profile Marine ecology Method Accelerometers |
spellingShingle |
Pinnipeds Argos tags Satellite-linked time depth recorders Foraging behaviour Dive profile Marine ecology Method Accelerometers Heerah, Karine Hindell, Mark Guinet, Christophe Charrassin, Jean-Benoît From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
topic_facet |
Pinnipeds Argos tags Satellite-linked time depth recorders Foraging behaviour Dive profile Marine ecology Method Accelerometers |
description |
Abstract Background In the last decade, thousands of satellite-relayed data loggers (SRDLs) have been deployed, providing large datasets on marine predator movement patterns at sea and their diving behaviour. However, the latter is in a highly summarised, low-resolution form, from which it is difficult to make the sorts of important behavioural inferences that are possible from higher-resolution datasets (such as detection of likely foraging events). The main objective of this study was to develop a simple, but accurate tool to detect and quantify within-dive foraging periods in low-resolution dives. Method Two southern elephant seals were fitted with a head-mounted time depth recorder (TDR) (recording depth at 1 Hz) and an accelerometer (recording 3 axes of acceleration at 16 Hz) from which prey capture attempts were estimated (PrCA), and a Weddell seal was also fitted with a TDR (1 Hz).The resulting high-resolution dive profiles were used to: (1) calculate an accurate index of foraging effort based on the detection of vertical sinuosity switches (i.e. hunting highres time); (2) produce an SRDL-equivalent low-resolution dataset using a broken stick algorithm; and (3) from each low-resolution dive calculate a set of candidate foraging effort indices. Results Hunting lowres time, which is the total time spent in decreased vertical velocity segments of the dive, was the foraging effort index that best correlated with hunting highres time. Hunting highres mode of SES dives (highly sinuous parts of high-resolution dives) was associated with 77 % of total PrCA. In comparison, Hunting lowres segments of SES dives were associated with 68 % of PrCA as well as with four times more PrCA than transit lowres segments. Conclusion We found a low-resolution index which indicates foraging activity within a highly summarised dive profile and which identified most PrCA, despite degraded information transmitted by SLDRs. Used in combination with other measurements of the in situ environment, the hunting lowres index could be used in numerous integrated marine ecology studies, such as habitat use studies that are crucial to facilitate more effective conservation. |
format |
Other/Unknown Material |
author |
Heerah, Karine Hindell, Mark Guinet, Christophe Charrassin, Jean-Benoît |
author_facet |
Heerah, Karine Hindell, Mark Guinet, Christophe Charrassin, Jean-Benoît |
author_sort |
Heerah, Karine |
title |
From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
title_short |
From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
title_full |
From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
title_fullStr |
From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
title_full_unstemmed |
From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
title_sort |
from high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators |
publisher |
BioMed Central Ltd. |
publishDate |
2015 |
url |
http://www.animalbiotelemetry.com/content/3/1/42 |
geographic |
Weddell |
geographic_facet |
Weddell |
genre |
Elephant Seals Southern Elephant Seals Weddell Seal |
genre_facet |
Elephant Seals Southern Elephant Seals Weddell Seal |
op_relation |
http://www.animalbiotelemetry.com/content/3/1/42 |
op_rights |
Copyright 2015 Heerah et al. |
_version_ |
1766401667144613888 |