Biodiversity Journal - For wildlife research and environmental studies

Ingrid N. Visser

Biodiversity Journal, 15 (3): 547-584

Ingrid N. Visser, Tracy E. Cooper, David Cothran, Gerald McCormack, Heiko Grimm, Pirjo H. Mäkeläinen & Mathieu Cusson
Images confirm records of Fijian orca (Orcinus orca Linnaeus, 1758), including a group with indistinct saddle patches
https://doi.org/10.31396/Biodiv.Jour.2024.15.3.547.584

ABSTRACT
We collated (n=36) records of orca (Orcinus orca Linnaeus, 1758, also known as the killer whale (Cetacea Delphinidae) in the waters of the Republic of Fiji, South Pacific Ocean. Using standardised criteria, we classified these records into Confirmed, Presumed and Unconfirmed. We then conflated replicated records to create (n=12) unique meta-records between 1994-2024. We confirm, for the first time with photographs/video, the species as present in Fijian waters with evidence (photos/video) for (n=6) records between 2006–2024 which illustrate species-specific characteristics. From within that dataset, we report on a group of five orca which had either extremely faint ‘belt’ shaped saddle patches, or no saddle patches. Based on this pigmentation anomaly we consider that they may be an aberrant group or belong to a previously undescribed tropical ecotype.
Biodiversity Journal, 14 (1): 0061-0164

Ingrid N. Visser, Marianne Nyegaard & London A. Fletcher
Orca, Orcinus orca (Linnaeus, 1758) (Mammalia Cetacea), interactions with ocean sunfishes (Family Molidae, genus Mola Kölreuter, 1766 and Masturus Gill, 1884): A global review.
https://doi.org/10.31396/Biodiv.Jour.2023.14.1.61.164

ABSTRACT
To better understand the interactions between orca, Orcinus orca (Linnaeus, 1758), killer whale (Mammalia Cetacea Delphinidae) and the large species of ocean sunfish (molids), Mola spp. and Masturus lanceolatus (Tetraodontiformes Molidae Actinopterygii), we searched for published and unpublished records of contact between these taxa. We reviewed a total of 73 interactions between 1961 and 2022, with social media in recent decades clearly facilitating dissemination of records. The interactions were primarily clustered in hotspots in Oceania (n=17), the eastern Pacific Ocean off Central and North America (n=33), and the South Atlantic off South Africa (n=10). We assessed predation risk for the molids by distinguishing between non-predation (n=29) and predation (n=42) interactions (the status of two interactions could not be established). We document what we believe to be the first confirmed predation by orca on M. alexandrini (n=3) and we reaffirm that predation occurs on M. mola and Ma. lanceolatus. Both non-predation and predation interactions involved orca who had previously been documented feeding on fish (elasmobranch and teleost) (n=9) and mammals (pinnipeds and cetaceans) (n=19). The most common orca group size was a single orca (n=27) and where molid numbers could be established (n=65), all but one interaction involved a single molid. During interactions the orca exhibited cooperative hunting and food sharing and learning/teaching may have been occurring. The relatively low number of interactions found for these two sympatric and charismatic species is surprising. Explanations may include prey-selection specificity by some orca and/or reflect the opportunistic nature of human documentation. However, our findings suggest that molids are potentially a localized food source for some orca in Oceania and the eastern Pacific, as predation was documented for 65% and 58% of interactions within those regions respectively.
Biodiversity Journal, 14 (1): 0019-0060

Ingrid N. Visser & London A. Fletcher
First records of orca, Orcinus orca (Linnaeus, 1758) (Mammalia Cetacea), predation on sharptail ocean sunfish, Masturus lanceolatus (É. Liénard, 1840) (Pisces Molidae), with novel components of foraging behaviour discovered through social media.
https://doi.org/10.31396/Biodiv.Jour.2023.14.1.19.60

ABSTRACT
Foraging techniques for orca - Orcinus orca (Linnaeus, 1758), killer whale, Mammalia, Cetacea), have been documented since at least the 16^th century and in the last few decades a wide range of behaviours such as ‘carousel feeding’, ‘intentional stranding’ and ‘karate-chop-ping’ have been added to the species repertoire. During a recent global review, where records were sourced primarily through social media postings, orca interactions with the large species of ocean sunfish - Mola spp. and Masturus lanceolatus (É. Liénard, 1840) (Actinopterygii, Tetraodontiformes, Family Molidae) - were collated. We discovered orca utilizing novel components of foraging strategies on these fishes. Specifically, after targeting the molids pectoral fins, the orca; (i) created a wound in the side of the molid and removed the intestines (and potentially other organs) from the still-alive molid and consumed them and (ii) then disarticulated the molid and inserted their rostrum (maxillae & mandibles) into the body cavity to extract tissue. These behaviours were documented in the South Atlantic, Oceania and the eastern Pacific Ocean, with those in the latter including what we believe to be the first confirmed predation by orca of Ma. lanceolatus. That, coupled with the novel behaviours described, may suggest an orca ecotype which has yet to be formally described, highlighting how social media can be used to document biodiversity.
Biodiversity Journal, 14 (1): 0003-0017

Marianne Nyegaard, Ingrid N. Visser & London A. Fletcher
Ocean sunfish, genus Mola Kölreuter, 1766 (Pisces Molidae), exhibit surprising levels of agility during interactions with orca, Orcinus orca (Linnaeus, 1758) (Mammalia Delphinidae)
https://doi.org/10.31396/Biodiv.Jour.2023.14.1.3.17

ABSTRACT
Ocean sunfish (Mola spp.) are well known for their large adult size and peculiar morphology, which in combination give them the resemblance of a giant, swimming fish head. At first glance, this unusual body form hints at locomotive ineptitude, and traditionally molids have indeed been considered poor swimmers. Although this archaic view has been thoroughly rebutted in recent years, with studies revealing molids are strong swimmers (for example their ability to rapidly accelerate, with recorded burst speeds for Mola mola of 6.6 m/s), their fine scale maneuverability is unclear. Furthermore, many natural molid behaviours are not well understood, including antipredator behaviours, as opportunities to observe this taxa in the wild are limited. Unexpectedly, during a recent global review of molid interactions with orca (a molid predator), a number of video recordings revealed surprisingly rapid and agile molid movements. These included the molids turning up-side down, rolling backwards, pivoting and spinning. These behaviours appeared to be deliberate attempts on behalf of the molids to keep the clavus (‘tail’) towards the orca, keep the ventral area away, evade the orca, and/or discourage the orca from making physical contact. Here, we describe eight ‘Evade’ behaviours based on video analysis, present detailed descriptions and provide examples.
Biodiversity Journal, 13 (4): 0917-0948

Krista van der Linde, Ingrid N. Visser, Sarah E. Richard, Tracy E. Cooper, Terry M. Hardie & Rick Bout
Troubled waters: A case study of cohabitation conflicts for a leopard seal, Hydrurga leptonyx de Blainville, 1820 (Mammalia Phocidae) in northern New Zealand
https://doi.org/10.31396/Biodiv.Jour.2022.13.4.917.948

ABSTRACT
The >9.5-year residency of an adult female leopard seal, Hydrurga leptonyx de Blainville, 1820 (Mammalia Phocidae) in New Zealand (NZ) provided an opportunity to investigate this species in the framework of human-wildlife conflicts and management. We examined >2,000 sighting records and collated observations of this leopard seal. We qualitatively describe conflicts originating from both the humans and leopard seal’s perspectives. Humans created conflicts for the leopard seal by providing misinformation about the species (and therefore negatively influencing public perception), making proposals or threats to disturb/harm, and causing inconvenience, tension, disputes, disturbance and harm to her. Conversely, the leopard seal created conflicts for humans including, causing inconveniences, tension, damage to property and disturbance. Short-term mitigation tools along with longer-term preventive strategies to reduce, mitigate and/or eliminate these conflicts are provided and we recommend that the NZ Government Authorities, who are legally mandated to protect the species, take the lead in implementing these in collaboration with stakeholders. Implementation of these tools and strategies, in a proactive rather than reactive manner, will assist with protection and management of leopard seals in all areas where they cohabitate with humans (both within NZ and internationally).
Biodiversity Journal, 13 (3): 0685-0693

Ingrid N. Visser, Krista van der Linde, Sarah E. Richard, Tracy E. Cooper, Terry M. Hardie & Rick Bout
Can a leopard seal, Hydrurga leptonyx de Blainville, 1820 (Mammalia Phocidae), change its spots? (Spoiler alert: at least one adult female can)
https://doi.org/10.31396/Biodiv.Jour.2022.13.3.685.693

ABSTRACT
Leopard seals, Hydrurga leptonyx de Blainville, 1820 (Mammalia Phocidae) have variable spots on their pelage, allowing for identification of individuals. We monitored a subset of spots (n=40) on the face and neck of an adult female leopard seal residing in New Zealand. We compared images that were 1,701 days (~4 years and 8 months) apart. The use of scars, acquired from wounds, allowed for cross-matching and confirmation that this was the same individual. We investigated if the spots were more visible when the animal was wet or dry. We found that all 40 spots were visible during this time period and when the animal was both wet and dry. However, they were better defined, and therefore more visible, when the pelage was wet. Additionally, we identified a number of new and emerging spots, none of which masked or obscured the 40 aforementioned spots. These changes illustrate that diligence must be applied when matching individuals over long periods, to ensure that mis-matches and missed matches do not occur. Our findings do not invalidate photo-ID studies for leopard seals, rather they show that this is a robust system of identification, as spots were not lost over time and spot patterns were an effective tool for both individual identification and observing pigmentation change.
Biodiversity Journal, 12 (1): 0001-0002

Ingrid N. Viesser
Orcinus orca (Linnaeus, 1758) (Mammalia Cetacea)
https://doi.org/10.31396/Biodiv.Jour.2021.12.1.I.II
Biodiversity Journal, 11 (4): 1067-1086

Ingrid N. Visser, Tracy E. Cooper & Heiko Grimm
Duration of pseudo-stalked barnacles (Xenobalanus globicipitis) on a New Zealand Pelagic ecotype orca (Orcinus orca), with comments on cookie cutter shark bite marks (Isistius sp.); can they be used as biological tags?
https://doi.org/10.31396/Biodiv.Jour.2020.11.4.1067.1086

ABSTRACT
This is the first published report of a New Zealand Pelagic ecotype orca (Orcinus orca Linnaeus, 1758, killer whale, Mammalia Cetacea) as a host for the pseudo-stalked barnacle (Xenobalanus globicipitis Steenstrup, 1852, Crustacea Coronulidae). The barnacles were documented on an adult female and she hosted >79, >3.5 times higher than any other orca worldwide. They were distributed on her dorsal fin (n=3), pectoral fins (n=>36) and tail flukes (n=>40), with a higher density on her right appendages (n=>48) compared to her left (n=>28). We also document, for the first time, the longevity of X. globicipitis hosted on an orca, with a minimum duration of 36 days. We provide a global overview of the distribution of X. globicipitis on orca, based on historic and recent publications. In previous reviews (spanning 111 years of records) X. globicipitis were documented in ten regions, while we add ten more regions, in just 13 years. This leads us to speculate as to the causes of this rapid increase, which may be linked to observer bias, improved research tools, a change in the distribution of either O. orca or X. globicipitis, with distribution of the latter perhaps influenced by oceanic conditions such as marine heatwaves and acidification triggered by climate change. As such, we discuss if either pseudo-stalked barnacles (or bite marks from cookie cutter sharks, Isistius sp., Chondrichthyes Squaliformes) can be used as biological tags or markers for orca ecotypes. We recommend separate management plans for orca ecotypes.

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Ingrid N. Visser