Willson, A.,Baldwin, R.,Cerchio, S,Collins, T.,Findlay, K.,Gray, H.,Godley, B.J.,Al Harthi, S.,Kennedy, A.,Minton, G.,Sucunza, F.,Zerbini, A. N.,Witt, M.J.
Research update on satellite tagging studies of the Arabian Sea humpback whales in the Sultanate of Oman Technical Report
no. 500, 2016.
Abstract | BibTeX | Tags: Distribution, feeding, humpback whales, megaptera novaeangliae, Oman, photo identification, Satellite telemetry, seasonal change
@techreport{,
title = {Research update on satellite tagging studies of the Arabian Sea humpback whales in the Sultanate of Oman},
author = {Willson, A.,Baldwin, R.,Cerchio, S,Collins, T.,Findlay, K.,Gray, H.,Godley, B.J.,Al Harthi, S.,Kennedy, A.,Minton, G.,Sucunza, F.,Zerbini, A. N.,Witt, M.J.},
year = {2016},
date = {2016-01-01},
journal = {Report presented to the Scientific Committee meeting of the International Whaling Commission},
number = {500},
pages = {23},
publisher = {IWC},
abstract = {Three surveys focusing on Arabian Sea humpback whales (Megaptera novaeangliae) were conducted from
two field sites off the southern coast of Oman between February 2014 and December 2015. We present a
summary of boat-based survey data and satellite telemetry activities generated by these surveys. Our
findings provide insight into the spatial ecology of Arabian Sea humpback whales (ASHW) and salient
threats to the population. Ninety hours of on-effort vessel-based surveys resulted in 29 sightings of ASHW
groups. Analysis of fluke and dorsal fin images indicates that these sightings involved 40 different
individuals. Tagging efforts resulted in successful deployment of nine satellite tags, six of which provided
data on dive behaviour and vertical distribution within the water column. Tagged whales that were
resighted (n = 5) during subsequent surveys exhibited signs of healing following tag rejection. Satellite
tracking data reveals whales ranging within a 1,150 km corridor along the southern coast of Oman and
northern Yemen, the first transboundary movement recorded for this population. Individuals spent an
average of 83% (SD = 17%) of their time engaged in localised or ‘area restricted search’ (ARS) that is
likely associated with foraging, breeding and resting behaviour. Tracked individuals spent much of their
time over the continental shelf with 73% of satellite-derived locations attributed to waters <200 m depth.
Gathered dive data reveal that tracked whales spent 83% of time in the top 20 m of the water column, most
frequently (39%; SD = 11%) engaged in dives with durations between 5 and 10 minutes. The average
maximum depth recorded by the tags was 199 m (SD = 95 m). Further spatial analysis indicated that 35%
of location points in the study were within the Gulf of Masirah, habitat that co-occurs with emerging
industrial activity and existing artisanal fisheries. Dive behavior in offshore waters beyond the continental
shelf also likely indicates foraging activity. The growing knowledge base for this population supports need
for on-going research and putative mitigation measures to address a wide spectrum of anthropogenic threats
for humpback whales in Oman and the wider region.},
keywords = {Distribution, feeding, humpback whales, megaptera novaeangliae, Oman, photo identification, Satellite telemetry, seasonal change},
pubstate = {published},
tppubtype = {techreport}
}
Three surveys focusing on Arabian Sea humpback whales (Megaptera novaeangliae) were conducted from
two field sites off the southern coast of Oman between February 2014 and December 2015. We present a
summary of boat-based survey data and satellite telemetry activities generated by these surveys. Our
findings provide insight into the spatial ecology of Arabian Sea humpback whales (ASHW) and salient
threats to the population. Ninety hours of on-effort vessel-based surveys resulted in 29 sightings of ASHW
groups. Analysis of fluke and dorsal fin images indicates that these sightings involved 40 different
individuals. Tagging efforts resulted in successful deployment of nine satellite tags, six of which provided
data on dive behaviour and vertical distribution within the water column. Tagged whales that were
resighted (n = 5) during subsequent surveys exhibited signs of healing following tag rejection. Satellite
tracking data reveals whales ranging within a 1,150 km corridor along the southern coast of Oman and
northern Yemen, the first transboundary movement recorded for this population. Individuals spent an
average of 83% (SD = 17%) of their time engaged in localised or ‘area restricted search’ (ARS) that is
likely associated with foraging, breeding and resting behaviour. Tracked individuals spent much of their
time over the continental shelf with 73% of satellite-derived locations attributed to waters <200 m depth.
Gathered dive data reveal that tracked whales spent 83% of time in the top 20 m of the water column, most
frequently (39%; SD = 11%) engaged in dives with durations between 5 and 10 minutes. The average
maximum depth recorded by the tags was 199 m (SD = 95 m). Further spatial analysis indicated that 35%
of location points in the study were within the Gulf of Masirah, habitat that co-occurs with emerging
industrial activity and existing artisanal fisheries. Dive behavior in offshore waters beyond the continental
shelf also likely indicates foraging activity. The growing knowledge base for this population supports need
for on-going research and putative mitigation measures to address a wide spectrum of anthropogenic threats
for humpback whales in Oman and the wider region.
two field sites off the southern coast of Oman between February 2014 and December 2015. We present a
summary of boat-based survey data and satellite telemetry activities generated by these surveys. Our
findings provide insight into the spatial ecology of Arabian Sea humpback whales (ASHW) and salient
threats to the population. Ninety hours of on-effort vessel-based surveys resulted in 29 sightings of ASHW
groups. Analysis of fluke and dorsal fin images indicates that these sightings involved 40 different
individuals. Tagging efforts resulted in successful deployment of nine satellite tags, six of which provided
data on dive behaviour and vertical distribution within the water column. Tagged whales that were
resighted (n = 5) during subsequent surveys exhibited signs of healing following tag rejection. Satellite
tracking data reveals whales ranging within a 1,150 km corridor along the southern coast of Oman and
northern Yemen, the first transboundary movement recorded for this population. Individuals spent an
average of 83% (SD = 17%) of their time engaged in localised or ‘area restricted search’ (ARS) that is
likely associated with foraging, breeding and resting behaviour. Tracked individuals spent much of their
time over the continental shelf with 73% of satellite-derived locations attributed to waters <200 m depth.
Gathered dive data reveal that tracked whales spent 83% of time in the top 20 m of the water column, most
frequently (39%; SD = 11%) engaged in dives with durations between 5 and 10 minutes. The average
maximum depth recorded by the tags was 199 m (SD = 95 m). Further spatial analysis indicated that 35%
of location points in the study were within the Gulf of Masirah, habitat that co-occurs with emerging
industrial activity and existing artisanal fisheries. Dive behavior in offshore waters beyond the continental
shelf also likely indicates foraging activity. The growing knowledge base for this population supports need
for on-going research and putative mitigation measures to address a wide spectrum of anthropogenic threats
for humpback whales in Oman and the wider region.
Piontkovski, SA,Al-Gheilani, HMH,Jupp, B,Sarma, YVB,Al-Azri, AR
The relationship between algal blooms, fish kill incidents, and oxygen depletions along the Omani coast Journal Article
In: International Journal of Oceans and Oceanography, vol. 6, no. 429, pp. 145-177, 2012, ISBN: 0973-2667.
Abstract | BibTeX | Tags: Arabian Sea, fish kill, Gulf of Oman, Harmful Algal Bloom, mass mortality, oxygen minimum, Sea of Oman, seasonal change, Sultanate of Oman
@article{,
title = {The relationship between algal blooms, fish kill incidents, and oxygen depletions along the Omani coast},
author = {Piontkovski, SA,Al-Gheilani, HMH,Jupp, B,Sarma, YVB,Al-Azri, AR},
issn = {0973-2667},
year = {2012},
date = {2012-01-01},
journal = {International Journal of Oceans and Oceanography},
volume = {6},
number = {429},
pages = {145-177},
abstract = {A persistence of hypoxia is a common feature for the Sea of Oman, and the
western Arabian Sea. By using historical data complemented by ongoing
measurements, the relationship between the frequency of harmful algal
blooms, fish kill incidents, and oxygen depletions, was investigated. In the Sea
of Oman, the seasonal pattern exhibited a tendency of fish kill incidents to
increase, from January to November. In the western Arabian Sea, the pattern
was different- maximal occurrence of fish kill incidences was observed in
December and January. In 1988-2011, the number of harmful algal blooms
accompanied by fish kills was 4 times higher for the Sea of Oman (N= 91)
compared to the Arabian Sea coast (N= 22), whereas the total number of fish
kill incidents was about the same (22 versus 25). This means that the Arabian
Sea coast faced more frequent harmful blooms than the Sea of Oman. The Sea
of Oman coastal time series of the dissolved oxygen concentration implied a
steady decline throughout the year, from January to December. The fish kill
incidents in this region were mainly driven by oxygen depletions, whereas in
the Arabian Sea these incidents were mediated by the harmful algal blooms
along with the oxygen depletions. In analyzing the Omani coast as a whole,
the Ridge Multiple Regression Analysis implied the dissolved oxygen
concentration and monthly occurrence of algal blooms as the two variables
explaining 75% of the seasonal variations in fish kill incidents.},
keywords = {Arabian Sea, fish kill, Gulf of Oman, Harmful Algal Bloom, mass mortality, oxygen minimum, Sea of Oman, seasonal change, Sultanate of Oman},
pubstate = {published},
tppubtype = {article}
}
A persistence of hypoxia is a common feature for the Sea of Oman, and the
western Arabian Sea. By using historical data complemented by ongoing
measurements, the relationship between the frequency of harmful algal
blooms, fish kill incidents, and oxygen depletions, was investigated. In the Sea
of Oman, the seasonal pattern exhibited a tendency of fish kill incidents to
increase, from January to November. In the western Arabian Sea, the pattern
was different- maximal occurrence of fish kill incidences was observed in
December and January. In 1988-2011, the number of harmful algal blooms
accompanied by fish kills was 4 times higher for the Sea of Oman (N= 91)
compared to the Arabian Sea coast (N= 22), whereas the total number of fish
kill incidents was about the same (22 versus 25). This means that the Arabian
Sea coast faced more frequent harmful blooms than the Sea of Oman. The Sea
of Oman coastal time series of the dissolved oxygen concentration implied a
steady decline throughout the year, from January to December. The fish kill
incidents in this region were mainly driven by oxygen depletions, whereas in
the Arabian Sea these incidents were mediated by the harmful algal blooms
along with the oxygen depletions. In analyzing the Omani coast as a whole,
the Ridge Multiple Regression Analysis implied the dissolved oxygen
concentration and monthly occurrence of algal blooms as the two variables
explaining 75% of the seasonal variations in fish kill incidents.
western Arabian Sea. By using historical data complemented by ongoing
measurements, the relationship between the frequency of harmful algal
blooms, fish kill incidents, and oxygen depletions, was investigated. In the Sea
of Oman, the seasonal pattern exhibited a tendency of fish kill incidents to
increase, from January to November. In the western Arabian Sea, the pattern
was different- maximal occurrence of fish kill incidences was observed in
December and January. In 1988-2011, the number of harmful algal blooms
accompanied by fish kills was 4 times higher for the Sea of Oman (N= 91)
compared to the Arabian Sea coast (N= 22), whereas the total number of fish
kill incidents was about the same (22 versus 25). This means that the Arabian
Sea coast faced more frequent harmful blooms than the Sea of Oman. The Sea
of Oman coastal time series of the dissolved oxygen concentration implied a
steady decline throughout the year, from January to December. The fish kill
incidents in this region were mainly driven by oxygen depletions, whereas in
the Arabian Sea these incidents were mediated by the harmful algal blooms
along with the oxygen depletions. In analyzing the Omani coast as a whole,
the Ridge Multiple Regression Analysis implied the dissolved oxygen
concentration and monthly occurrence of algal blooms as the two variables
explaining 75% of the seasonal variations in fish kill incidents.
Ashjian,C.J.,Smtih,S.L.,Flagg,C.N.,Idrisi,N.
Distribution, annual cycle, and vertical migration of acoustically derived biomass in the Arabian Sea during 1994-1995 Journal Article
In: Deep-Sea Research Part II, vol. 49, no. 299, pp. 2377-2402, 2002.
Abstract | BibTeX | Tags: acoustic, Arabian Sea, diel, Distribution, history, life history, migration, myctophids, Oceanic, Oman, predation, seasonal change, stocks, Upwelling, zooplankton
@article{,
title = {Distribution, annual cycle, and vertical migration of acoustically derived biomass in the Arabian Sea during 1994-1995},
author = {Ashjian,C.J.,Smtih,S.L.,Flagg,C.N.,Idrisi,N.},
year = {2002},
date = {2002-01-01},
journal = {Deep-Sea Research Part II},
volume = {49},
number = {299},
pages = {2377-2402},
abstract = {The distinguishing characteristic that sets the Arabian Sea apart from other oceanic regions is the regular oscillation of monsoonal atmospheric conditions that produces predictable periods of upwelling or convective mixing, with associated biological response, during the Southwest and Northeast monsoons, respectively. This oscillation is also evident in cycles of standing stocks of zooplankton and micronekton. The vertical distribution and spatial pattern of zooplankton and micronekton biomass were estimated using an acoustic Doppler current profiler along a 1000-km transect extending from the continental shelf of Oman to the central Arabian Sea during ten cruises on the R/V Thomas G. Thompson (November 1994-December 1995). The influence of the Southwest Monsoon, and accompanying upwelling and enhanced acoustically derived biomass, was the dominant feature in the spatial-temporal distributions of both zooplankton and micronekton near the Omani coast. The diel vertical migration of predators (myctophids, pelagic crabs), and the seasonal changes in the strength of this signal, was the most significant pattern observed in the vertical distribution of biomass and imparted a strong day-night signal to the integrated upper water-column biomass. Significant differences in the magnitude of integrated upper water-column biomass, both zooplankton (day) and migrator-zooplankton (night), were seen between inshore and offshore of the atmospheric Findlater Jet. A station located in the central Arabian Sea demonstrated seasonal changes in biomass over the year, despite being quite far from the influence of the monsoonal oscillations. Predation pressure was greater offshore of the Findlater Jet than in the region inshore of the Jet or in the central Arabian Sea. The pelagic community of the Arabian Sea may have evolved life history strategies to coincide with the predictable monsoonal cycle},
keywords = {acoustic, Arabian Sea, diel, Distribution, history, life history, migration, myctophids, Oceanic, Oman, predation, seasonal change, stocks, Upwelling, zooplankton},
pubstate = {published},
tppubtype = {article}
}
The distinguishing characteristic that sets the Arabian Sea apart from other oceanic regions is the regular oscillation of monsoonal atmospheric conditions that produces predictable periods of upwelling or convective mixing, with associated biological response, during the Southwest and Northeast monsoons, respectively. This oscillation is also evident in cycles of standing stocks of zooplankton and micronekton. The vertical distribution and spatial pattern of zooplankton and micronekton biomass were estimated using an acoustic Doppler current profiler along a 1000-km transect extending from the continental shelf of Oman to the central Arabian Sea during ten cruises on the R/V Thomas G. Thompson (November 1994-December 1995). The influence of the Southwest Monsoon, and accompanying upwelling and enhanced acoustically derived biomass, was the dominant feature in the spatial-temporal distributions of both zooplankton and micronekton near the Omani coast. The diel vertical migration of predators (myctophids, pelagic crabs), and the seasonal changes in the strength of this signal, was the most significant pattern observed in the vertical distribution of biomass and imparted a strong day-night signal to the integrated upper water-column biomass. Significant differences in the magnitude of integrated upper water-column biomass, both zooplankton (day) and migrator-zooplankton (night), were seen between inshore and offshore of the atmospheric Findlater Jet. A station located in the central Arabian Sea demonstrated seasonal changes in biomass over the year, despite being quite far from the influence of the monsoonal oscillations. Predation pressure was greater offshore of the Findlater Jet than in the region inshore of the Jet or in the central Arabian Sea. The pelagic community of the Arabian Sea may have evolved life history strategies to coincide with the predictable monsoonal cycle