Ingrid N Visser - Academia.edu (original) (raw)

Papers by Ingrid N Visser

Endangered Species Research, 2014

Conservation initiatives are typically constrained by economic circumstances, a factor certainly ... more Conservation initiatives are typically constrained by economic circumstances, a factor certainly true for marine mammal conservation in New Zealand. Most research in this field has been conducted following concerns over anthropogenic impacts on populations and has therefore been funded and/or driven by stakeholder interest. Bottlenose dolphins Tursiops truncatus are classified as 'Nationally Endangered' in New Zealand waters. Here, we present the first study on occurrence, site fidelity and abundance of this species off Great Barrier Island (GBI), a previously overlooked region within the home range of the North Island population. Dedicated boat-based photo-identification surveys were conducted monthly from 2011−2013, resulting in 1412 sighting records of 154 individuals. Dolphins were recorded during all months of the year, with a higher probability of encounter in deeper waters during summer and shallower waters during winter and spring. Group sizes (median = 35, mean = 36) were higher than previously reported for this population in other regions. Individual re-sighting patterns were variable; however, overall site fidelity was high (mean monthly sighting rate = 0.33). A Robust Design approach resulted in seasonal fluctuations in abundance and temporary emigration. Based on a super-population estimate, 171 dolphins (CI = 162−180) visited the area during 2011−2013. Our data suggest that GBI is a potential hotspot for bottlenose dolphins of the North Island population rather than a corridor to reach other destinations. We highlight the need for researchers, managers and funding agencies to consider the entire range of a population when conducting or funding research.

Aquatic Mammals, 2008

The common dolphin (Delphinus sp.) is the most frequently observed cetacean species in the Haurak... more The common dolphin (Delphinus sp.) is the most frequently observed cetacean species in the Hauraki Gulf, a large shallow body of water on the northeastern coastline of North Island, New Zealand. Herein, we present the first data relating to the occurrence and distribution of common dolphins in this region and assess the possible effects of abiotic parameters on the demographics of this population. The presence of associated marine species is quantified, and differences in the occurrence and demographics of single and multi-species groups are examined. Sightings data were collected between February 2002 and January 2005 during boat-based surveys. We recorded 719 independent encounters with common dolphins, involving 1 to > 300 animals. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups made up of < 50 animals. Larger aggregations were most frequent during the austral winter when nutrient upwelling typically leads to increased prey availability within the region. Over 70% of groups encountered contained immature animals and 25% of groups included neonates. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Month, season, depth, and SST significantly affected group composition. Common dolphins were observed in association with four cetacean and eight avian species, most frequently with the Australasian gannet (Morus serrator) and the Bryde's whale (Balaenoptera brydei). The distribution of dolphin-only groups differed significantly from that of dolphin-whale groups, with mono-specific groups found on average in waters that were 3.6 m shallower and 3.1ºC warmer. The year-round occurrence and social organisation of common dolphins in Hauraki Gulf waters suggest this region is important both as a calving and nursery ground.

Aquatic Mammals, Jun 1, 2011

Forty-nine species of cetaceans have been recorded in the literature with cookie cutter shark (Is... more Forty-nine species of cetaceans have been recorded in the literature with cookie cutter shark (Isistius sp.) bites. The first record of a cookie cutter shark bite mark on orca (Orcinus orca) was from New Zealand waters in 1955. We present 37 unpublished records of cookie cutter shark bite marks on orca in tropical to cold waters; a further six published records were collated, and additionally 35 individuals with bite marks were noted in photo-identification catalogues. A total of 120 individuals and 198 bite marks were recorded, with the northernmost at 70° 44' N and the southernmost at 77° 14' S. We provide the first healing rate of a cookie cutter shark bite mark on an orca in New Zealand waters, with a maximum of 150 d between open wound and healed scar. Longevity of scars is considered, with one particular bite mark still visible as a dark grey oval/elliptic mark 1,158 d post photographing the open wound. Open cookie cutter shark bite marks were not observed on orca photographed in Antarctic waters, despite the majority of bite marks being recorded on Antarctic orca. This suggests a high level of movement outside the Antarctic cold water regions as the known distribution of cookie cutter sharks is in warm temperate to tropical waters. Supporting evidence for these movements is given by records of Antarctic orca in New Zealand waters with open cookie cutter shark bite marks.

Killer whales of ecotype C (Orcinus orca, TCKW) were studied in McMurdo Sound, Antarctica, during... more Killer whales of ecotype C (Orcinus orca, TCKW) were studied in McMurdo Sound, Antarctica, during Dec 2014-Jan 2015 by dart biopsy sampling and photo-identification (photo-ID). We collected 33 dart biopsy samples including 27 samples from killer whales (26 type C, 1 type B) and 6 samples from Antarctic minke whales (Balaenoptera bonaerensis). With the exception of 7 type-B killer whales (TBKW; 5 adults, 2 calves), all killer whales sighted in the McMurdo Sound region were TCKW. By combining images from our 2013/14 and 2014/15 with an existing catalogue compiled by the Orca Research Trust ('AKWIC') and photos submitted by 'citizen scientists', we have created an expanded photo-identification catalogue for Antarctic killer whales that is scheduled to go online in 2015. Preliminary analysis of the database provides evidence for long-distance migrations of TCKW between the Ross Sea and New Zealand waters: (a) One adult female TCKW has been re-sighted in both New Zealand ...

Anomalous pigmentations have been recorded in many cetacean species. However, typically only one ... more Anomalous pigmentations have been recorded in many cetacean species. However, typically only one variation is reported from a population at a time (e.g., an albino). Here we record a spec- trum of pigmentation from common dolphins (Delphinus sp.) off northern New Zealand. All- black, dark-morph, pale-morph, and all-white individuals, as well as variations between these have been recorded. Pale-coloured pectoral

Marine Mammal Science, 2008

observed a group of seven killer whales (Orcinus orca) conduct a coordinated attack on a crabeate... more observed a group of seven killer whales (Orcinus orca) conduct a coordinated attack on a crabeater seal (Lobodon carcinophaga) by creating a wave to wash the hauled-out seal off floating ice. Since then a number of similar events have been witnessed along the Antarctic Peninsula. The increased tourist ship traffic in this area has provided an opportunity for many observers equipped with cameras and video recorders to document a number of these. Given that it is often difficult to gain an accurate description of events involving a number of killer whales moving quickly and typically under water, in an ice-filled environment, the availability of good quality video recordings is often the best way of documenting such a fast-moving incident. The vantage point is of importance and those observations from the bow of a large ship, which can maneuver to within a short distance of the animals, are of significantly better quality than those at water level. Still photography, in addition to video, is of particular importance in any attempt to identify individual whales or groups.

Killer whales (Orcinus orca) interact with longline fisheries around the world, however they have... more Killer whales (Orcinus orca) interact with longline fisheries around the world, however they have not previously been reported taking fish off longlines in New Zealand waters. Two new killer whale prey species (school shark, Galeorhinus galeus and blue-nose, Hyperoglyphe antarchia) have been recorded. A great deal of effort has been applied, world wide, to reduce killer whale-fishery interactions, but few methods are successful. Fishers in New Zealand have used 'tuna bombs' and shooting.

Marine Mammal Science, 1999

New Zealand Journal of Marine and Freshwater Research, 2004

Reports of anomalously pigmented cetaceans, including melanistic (all-black) individuals are infr... more Reports of anomalously pigmented cetaceans, including melanistic (all-black) individuals are infrequent. We observed four melanistic southern right-whale dolphins (Lissodelphis peronii) including a calf, off Kaikoura (42°34¢S, 173°50¢E), New Zealand. We also compiled records of melanistic individuals from five other species of cetaceans. The ecological context of melanistic pigmentation of cetaceans is not well understood; however, it may increase heat absorption, affect ability to capture prey, impair visual/social communication, and/or increase conspicuousness to predators.

Aquatic Mammals, 2008

... Ingrid N. Visser,1 Matt P. Drennan,2 Richard W. White,3 Stephen F. MacLean,4 Lisa C. Lagerstr... more ... Ingrid N. Visser,1 Matt P. Drennan,2 Richard W. White,3 Stephen F. MacLean,4 Lisa C. Lagerstrom,5 and John M. Francis6 ... Erect-crested E. atratus Spellerberg, 1975 Fiordland E. pachyrhynchus Spellerberg, 1975 Little Blue E. minor Dix, 1993 Notman, 1985 du Toit et al., 2004 ...

Molecular ecology, Jan 19, 2015

Global climate change during the Late Pleistocene periodically encroached and then released habit... more Global climate change during the Late Pleistocene periodically encroached and then released habitat during the glacial cycles, causing range expansions and contractions in some species. These dynamics have played a major role in geographic radiations, diversification and speciation. We investigate these dynamics in the most widely distributed of marine mammals, the killer whale (Orcinus orca), using a global dataset of over 450 samples. This marine top predator inhabits coastal and pelagic ecosystems ranging from the ice edge to the tropics, often exhibiting ecological, behavioral and morphological variation suggestive of local adaptation accompanied by reproductive isolation. Results suggest a rapid global radiation occurred over the last 350,000 years. Based on habitat models, we estimated there was only a 15% global contraction of core suitable habitat during the Last Glacial Maximum, and the resources appeared to sustain a constant global effective female population size through...

New Zealand Journal of Marine and Freshwater Research, 1999

Two orca (Orcinus orca, Linnaeus, 1758), photo-identified as part of an ongoing study in New Zeal... more Two orca (Orcinus orca, Linnaeus, 1758), photo-identified as part of an ongoing study in New Zealand waters, have a series of deep scars in their dorsal lumbar-caudal regions which suggests they were caused by propellers. One of the animals, first noted to have the scars in 1982, is considerably smaller than an adult of similar age. The known home range of these orca are presented. A third orca hit by a boat is presumed dead.

New Zealand Journal of Marine and Freshwater Research, 1999

... A migration pattern for Antarctic orca has been suggested before, by Mikhalev (1981) who com-... more ... A migration pattern for Antarctic orca has been suggested before, by Mikhalev (1981) who com-mented orca leave the Antarctic before winter, and Kasamatsu (1995) proposed orca migrate into Ant-arctic waters in early January and leave in late Feb-ruary. ...

Marine Mammal Science, 2000

Endangered Species Research, 2014

Conservation initiatives are typically constrained by economic circumstances, a factor certainly ... more Conservation initiatives are typically constrained by economic circumstances, a factor certainly true for marine mammal conservation in New Zealand. Most research in this field has been conducted following concerns over anthropogenic impacts on populations and has therefore been funded and/or driven by stakeholder interest. Bottlenose dolphins Tursiops truncatus are classified as 'Nationally Endangered' in New Zealand waters. Here, we present the first study on occurrence, site fidelity and abundance of this species off Great Barrier Island (GBI), a previously overlooked region within the home range of the North Island population. Dedicated boat-based photo-identification surveys were conducted monthly from 2011−2013, resulting in 1412 sighting records of 154 individuals. Dolphins were recorded during all months of the year, with a higher probability of encounter in deeper waters during summer and shallower waters during winter and spring. Group sizes (median = 35, mean = 36) were higher than previously reported for this population in other regions. Individual re-sighting patterns were variable; however, overall site fidelity was high (mean monthly sighting rate = 0.33). A Robust Design approach resulted in seasonal fluctuations in abundance and temporary emigration. Based on a super-population estimate, 171 dolphins (CI = 162−180) visited the area during 2011−2013. Our data suggest that GBI is a potential hotspot for bottlenose dolphins of the North Island population rather than a corridor to reach other destinations. We highlight the need for researchers, managers and funding agencies to consider the entire range of a population when conducting or funding research.

Aquatic Mammals, 2008

The common dolphin (Delphinus sp.) is the most frequently observed cetacean species in the Haurak... more The common dolphin (Delphinus sp.) is the most frequently observed cetacean species in the Hauraki Gulf, a large shallow body of water on the northeastern coastline of North Island, New Zealand. Herein, we present the first data relating to the occurrence and distribution of common dolphins in this region and assess the possible effects of abiotic parameters on the demographics of this population. The presence of associated marine species is quantified, and differences in the occurrence and demographics of single and multi-species groups are examined. Sightings data were collected between February 2002 and January 2005 during boat-based surveys. We recorded 719 independent encounters with common dolphins, involving 1 to > 300 animals. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups made up of < 50 animals. Larger aggregations were most frequent during the austral winter when nutrient upwelling typically leads to increased prey availability within the region. Over 70% of groups encountered contained immature animals and 25% of groups included neonates. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Month, season, depth, and SST significantly affected group composition. Common dolphins were observed in association with four cetacean and eight avian species, most frequently with the Australasian gannet (Morus serrator) and the Bryde's whale (Balaenoptera brydei). The distribution of dolphin-only groups differed significantly from that of dolphin-whale groups, with mono-specific groups found on average in waters that were 3.6 m shallower and 3.1ºC warmer. The year-round occurrence and social organisation of common dolphins in Hauraki Gulf waters suggest this region is important both as a calving and nursery ground.

Aquatic Mammals, Jun 1, 2011

Forty-nine species of cetaceans have been recorded in the literature with cookie cutter shark (Is... more Forty-nine species of cetaceans have been recorded in the literature with cookie cutter shark (Isistius sp.) bites. The first record of a cookie cutter shark bite mark on orca (Orcinus orca) was from New Zealand waters in 1955. We present 37 unpublished records of cookie cutter shark bite marks on orca in tropical to cold waters; a further six published records were collated, and additionally 35 individuals with bite marks were noted in photo-identification catalogues. A total of 120 individuals and 198 bite marks were recorded, with the northernmost at 70° 44' N and the southernmost at 77° 14' S. We provide the first healing rate of a cookie cutter shark bite mark on an orca in New Zealand waters, with a maximum of 150 d between open wound and healed scar. Longevity of scars is considered, with one particular bite mark still visible as a dark grey oval/elliptic mark 1,158 d post photographing the open wound. Open cookie cutter shark bite marks were not observed on orca photographed in Antarctic waters, despite the majority of bite marks being recorded on Antarctic orca. This suggests a high level of movement outside the Antarctic cold water regions as the known distribution of cookie cutter sharks is in warm temperate to tropical waters. Supporting evidence for these movements is given by records of Antarctic orca in New Zealand waters with open cookie cutter shark bite marks.

Killer whales of ecotype C (Orcinus orca, TCKW) were studied in McMurdo Sound, Antarctica, during... more Killer whales of ecotype C (Orcinus orca, TCKW) were studied in McMurdo Sound, Antarctica, during Dec 2014-Jan 2015 by dart biopsy sampling and photo-identification (photo-ID). We collected 33 dart biopsy samples including 27 samples from killer whales (26 type C, 1 type B) and 6 samples from Antarctic minke whales (Balaenoptera bonaerensis). With the exception of 7 type-B killer whales (TBKW; 5 adults, 2 calves), all killer whales sighted in the McMurdo Sound region were TCKW. By combining images from our 2013/14 and 2014/15 with an existing catalogue compiled by the Orca Research Trust ('AKWIC') and photos submitted by 'citizen scientists', we have created an expanded photo-identification catalogue for Antarctic killer whales that is scheduled to go online in 2015. Preliminary analysis of the database provides evidence for long-distance migrations of TCKW between the Ross Sea and New Zealand waters: (a) One adult female TCKW has been re-sighted in both New Zealand ...

Anomalous pigmentations have been recorded in many cetacean species. However, typically only one ... more Anomalous pigmentations have been recorded in many cetacean species. However, typically only one variation is reported from a population at a time (e.g., an albino). Here we record a spec- trum of pigmentation from common dolphins (Delphinus sp.) off northern New Zealand. All- black, dark-morph, pale-morph, and all-white individuals, as well as variations between these have been recorded. Pale-coloured pectoral

Marine Mammal Science, 2008

observed a group of seven killer whales (Orcinus orca) conduct a coordinated attack on a crabeate... more observed a group of seven killer whales (Orcinus orca) conduct a coordinated attack on a crabeater seal (Lobodon carcinophaga) by creating a wave to wash the hauled-out seal off floating ice. Since then a number of similar events have been witnessed along the Antarctic Peninsula. The increased tourist ship traffic in this area has provided an opportunity for many observers equipped with cameras and video recorders to document a number of these. Given that it is often difficult to gain an accurate description of events involving a number of killer whales moving quickly and typically under water, in an ice-filled environment, the availability of good quality video recordings is often the best way of documenting such a fast-moving incident. The vantage point is of importance and those observations from the bow of a large ship, which can maneuver to within a short distance of the animals, are of significantly better quality than those at water level. Still photography, in addition to video, is of particular importance in any attempt to identify individual whales or groups.

Killer whales (Orcinus orca) interact with longline fisheries around the world, however they have... more Killer whales (Orcinus orca) interact with longline fisheries around the world, however they have not previously been reported taking fish off longlines in New Zealand waters. Two new killer whale prey species (school shark, Galeorhinus galeus and blue-nose, Hyperoglyphe antarchia) have been recorded. A great deal of effort has been applied, world wide, to reduce killer whale-fishery interactions, but few methods are successful. Fishers in New Zealand have used 'tuna bombs' and shooting.

Marine Mammal Science, 1999

New Zealand Journal of Marine and Freshwater Research, 2004

Reports of anomalously pigmented cetaceans, including melanistic (all-black) individuals are infr... more Reports of anomalously pigmented cetaceans, including melanistic (all-black) individuals are infrequent. We observed four melanistic southern right-whale dolphins (Lissodelphis peronii) including a calf, off Kaikoura (42°34¢S, 173°50¢E), New Zealand. We also compiled records of melanistic individuals from five other species of cetaceans. The ecological context of melanistic pigmentation of cetaceans is not well understood; however, it may increase heat absorption, affect ability to capture prey, impair visual/social communication, and/or increase conspicuousness to predators.

Aquatic Mammals, 2008

... Ingrid N. Visser,1 Matt P. Drennan,2 Richard W. White,3 Stephen F. MacLean,4 Lisa C. Lagerstr... more ... Ingrid N. Visser,1 Matt P. Drennan,2 Richard W. White,3 Stephen F. MacLean,4 Lisa C. Lagerstrom,5 and John M. Francis6 ... Erect-crested E. atratus Spellerberg, 1975 Fiordland E. pachyrhynchus Spellerberg, 1975 Little Blue E. minor Dix, 1993 Notman, 1985 du Toit et al., 2004 ...

Molecular ecology, Jan 19, 2015

Global climate change during the Late Pleistocene periodically encroached and then released habit... more Global climate change during the Late Pleistocene periodically encroached and then released habitat during the glacial cycles, causing range expansions and contractions in some species. These dynamics have played a major role in geographic radiations, diversification and speciation. We investigate these dynamics in the most widely distributed of marine mammals, the killer whale (Orcinus orca), using a global dataset of over 450 samples. This marine top predator inhabits coastal and pelagic ecosystems ranging from the ice edge to the tropics, often exhibiting ecological, behavioral and morphological variation suggestive of local adaptation accompanied by reproductive isolation. Results suggest a rapid global radiation occurred over the last 350,000 years. Based on habitat models, we estimated there was only a 15% global contraction of core suitable habitat during the Last Glacial Maximum, and the resources appeared to sustain a constant global effective female population size through...

New Zealand Journal of Marine and Freshwater Research, 1999

Two orca (Orcinus orca, Linnaeus, 1758), photo-identified as part of an ongoing study in New Zeal... more Two orca (Orcinus orca, Linnaeus, 1758), photo-identified as part of an ongoing study in New Zealand waters, have a series of deep scars in their dorsal lumbar-caudal regions which suggests they were caused by propellers. One of the animals, first noted to have the scars in 1982, is considerably smaller than an adult of similar age. The known home range of these orca are presented. A third orca hit by a boat is presumed dead.

New Zealand Journal of Marine and Freshwater Research, 1999

... A migration pattern for Antarctic orca has been suggested before, by Mikhalev (1981) who com-... more ... A migration pattern for Antarctic orca has been suggested before, by Mikhalev (1981) who com-mented orca leave the Antarctic before winter, and Kasamatsu (1995) proposed orca migrate into Ant-arctic waters in early January and leave in late Feb-ruary. ...

Marine Mammal Science, 2000