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Quantifying Behaviours of Minke Whales (Balaenoptera acutorostrata) According to their Breathing Ecology in the St. Lawrence River Estuary

Curnier, M., Tscherter, U. (2006)

Poster presentation at the 20th Annual Conference of the European Cetacean Society in Gdynia, 2007

Abstract
In order to maximise the time submerged underwater, whales’ breaths are often clumped together in short series, rather than being regularly spaced. The pattern in which whales come to the surface, respire, and dive again varies with behaviour and activity level. Minke whale blow rates were investigated in the St Lawrence Estuary. Samples of at least 25 minutes were collected throughout the summer feeding seasons (June to October) of 1995-1998 from presumably undisturbed minke whales performing four different behaviours; 1) Near-surface feeding (NS), at depths of 10-50m; 2) Deep feeding (DF), at depths >50m; 3) travelling (TRV) and 4) Surface feeding (SF). NS and DF samples were ascertained with SONAR. From these samples, various dive parameters were calculated and statistically assessed using Kruskal-Wallis Test across the four behaviours.

Significant differences were found in all the dive features over all behaviour types: 1) overall mean surfacing intervals, (H3 = 32.43, p = 0.000); 2) mean dive duration, (H2 = 46.86, p = 0.000); 3) mean time between blows in a surfacing, (H2 = 17.63, p = 0.000); 4) mean surfacing duration, (H2 = 36.84, p = 0.000); and 5) mean number of blows in a cycle, (H2 = 47.35, p = 0.000). (SF does not show clearly measurable intervals and thus only parameter 1) was assessed). Further, when each behaviour was compared individually against each other for all the dive parameters, only 5 out of 18 showed no significance.

This study has shown demarcated differences in the breathing regimes of minke whales according to their behaviour. Detailed knowledge of their blow patterns may provide a framework for defining activities by assisting in accurate determination and numerical categorisation of their specific behaviour types for future ethological studies.
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Lateralisation of Minke Whales (Balaenoptera acutorostrata) whilst Surface Feeding in the St. Lawrence Estuary, Canada

Koster, S., Tscherter, U. (2006)

Poster presentation at the 20th Annual Conference of the European Cetacean Society in Gdynia, 2007

Abstract
Lateralisation behaviour has been studied in different non-human species, also in marine mammals, but not in minke whales. This study examined if minke whales have a predominant use of one side of their bodies during surface feeding. This includes manoeuvres in lateral plane (1), where the whale is lying on its right or left side, manoeuvres in ventral plane (2), involving rolling back to dorsal-ventral plane, and in regular surfacings (3), rolling to the right or left side. In addition, the incidence of these manoeuvres was examined over different feeding habitats and tide phases. In lateral plane manoeuvres (N=1828) the 45 identified whales occurred more frequently on the right side (97.6%) than the left side (2.4%). In the ventral plane manoeuvres (N=582) the 42 identified whales rolled back over the right side more often (96.9%) then over the left side (3.1%). In the normal plane manoeuvres (N=144) 10 identified whales exhibit a significant difference between the roll to the right side (95.8%) and rolling to the left side (4.2%).

There is no significant correlation for all behaviours when comparing the side of lateralisation in respect of tide phases ((1) p=0.211; (2) p=0.307; (3) p=0.862). Comparison between different feeding habitats and the side of lateralisation showed no significance in lateral manoeuvres ((1) p=0.302), but significant correlation in ventral and dorsal-ventral manoeuvres ((2) p=0.05, (3) p=0.016). This study indicates that minke whales (N=45) exhibit a lateralisation side with a strong preference to the right side on a population level. This can be correlated with the area but not with the tide phases.

These results suggest behavioural lateralisation possibly related to an asymmetry of function in the brain. However, not much is known about the brain of minke whales to confirm this.
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Site Fidelity of Individual Minke Whales (Balaenoptera acutorostrata) in the St. Lawrence Estuary

Morris, C., Tscherter, U. (2006)

Poster presentation at the 20th Annual Conference of the European Cetacean Society in Gdynia, 2007

Abstract
Boat-based photo-identification surveys conducted from 1999 through 2004 were used to assess habitat use of minke whales, Balaenoptera acutorostrata, in the summer feeding grounds of the St. Lawrence Estuary in Eastern Canada. 4’289 day-sightings of 209 individual minke whales were identified on 547 days. 35 regular visitors (i.e. seen on at least 40 different days in 4 to 6 different years) were included in this study. The sightings of these animals were analysed to identify individual preferences for one of the two main feeding sites found in the study area, which are (A) the slopes along the Laurentian Channel Head and (B) the confluence area of the Saguenay River as well as the Saguenay Fjord. On average these 35 whales were seen on 72.2 different days (SD = 25.1; range: 41-141) in 5.7 different years (SD = 0.6). 25 animals showed strong small-scale site fidelity with over 75% of sightings in their primary feeding area.

These results indicate a strong specialisation of certain individuals to the unique environmental conditions of this area. This is further supported by the acquisition of individually distinguished feeding behaviour, observed over the last six years.
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Occurrence and apparent feeding of lampreys on individually identified minke whales in the St. Lawrence Estuary, Canada

Nichols, O.C., Tscherter, U. (2006)

Poster presentation at the 30th Annual Larval Fish Conference of the American Fisheries Society in Lake Placid, 2007

Abstract
During a photo-identification study of minke whales (Balaenoptera acutorostrata), lampreys were observed on 109 occasions on 47 individually identified whales during the years 1999-2004. The number of lampreys observed attached to a single whale ranged from one to four. In 18 cases, the same whale was observed multiple times over a period of days to weeks, likely with the same lamprey(s) attached. In two instances, whales were observed immediately (maximum of 20 and 180 minutes) following lamprey detachment, and bloody lesions on the whale’s body could be precisely identified as the area of previous lamprey attachment based on orientation relative to body markings, indicating that the lampreys were likely feeding on the whale’s blood.
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A Comparison of Minke Whale (Balaenoptera acutorostrata) DorsalFin Edge Marks (DEMs) Between Two Geographically Distinct Study Populations

Tetley, M., Tscherter, U., and Fairbairns, B. (2006)

Poster presentation at the 20th Annual Conference of the European Cetacean Society in Gdynia, 2007

Abstract
Photo-identification is widely used as a tool for investigating the life history and behavioural ecology of cetaceans. However, there still remain a large number of assumptions, errors and bias which need to be overcome in its application to a wide range of differing species. Minke whales (Balaenoptera acutorostrata) have proven to be successful candidates for the use of photo-identification methods, although much work remains to refine and develop these techniques for effective use with this species.

A comparative study was conducted on dorsal fin edge marks (DEMs) between two geographically distinct populations of B.acutorostrata, in the St. Lawrence Estuary, Canada, and the Inner Hebridean Islands, Scotland. A new not really new though, as it has been used by ORES dorsal fin layout system was used to test for significant differences occurring in the position (Anterior, Posterior, Upper, Lower and Tip) and morphology (Rounded, Squared, Triangular, indented, amputated) of DEM’s observed between the two populations. Results showed that there was a slight variation in the positioning of marks along the dorsal fin edge between the two distinct areas. However, no significant difference was found between the frequencies of DEM morphologies between the two regions. Therefore it was concluded that the unique processes by which these different shaped marks occur may be the same between the two different areas.

Investigating the processes by which whales acquire markings can help to increase understanding of their life history and subsequent impacts that may affect them. It is hoped that conducting comparative photo-identification studies of minke whales, between isolated studies, will help not only to increase our level of understanding but also develop and standardise the techniques used to investigate B.acutorostrata.
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Temporal stability of dorsal fin marks facilitates long-term photo-identification of Minke Whales (Balaenoptera acutorostrata)

Morris, C., Tscherter, U. (2005)

In: P. G. H. Evans and V. Ridoux.(Eds.). European Research on Cetaceans Vol. 159, Proceedings of the 15th Annual Conference of the European Cetacean Society, La Rochelle, 2005

Abstract
The feasibility of photo-identification studies depends on the ability to correctly identify a high percentage of individual animals. New natural markings may result in false negatives when matching two photographs. Here we present the analysis of the stability of dorsal edge marks (DEMs) such as nicks and dents which are the main characteristics used to identify minke whales (Balaenoptera acutorostrata) in the St. Lawrence Estuary in Eastern Canada.

For this study we used sighting data from 1999 to 2004 when approximately 80% of all minke whales identified in any given season returned the following year. Of the 117 individuals identified by DEMs in at least two different years during this period, only 7 individuals (5.98%) acquired a new dorsal edge mark. The identities of these 7 minke whales were confirmed by the original DEMs as well as secondary features such as scars and body pigmentation. Additionally, dorsal edge marks of most animals known for more than ten years also remained stable.

We conclude that minke whales of the St. Lawrence have a relatively low rate of change in this primary feature. Thus we are confident that mis-identifications of individuals caused by acquisitions of new markings are highly unlikely.
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Identifying a majority of Minke Whales (Balaenoptera acuto rostrata) in the St. Lawrence based on the presence of dorsal fin edge marks

Tscherter, U., Morris, C. (2005)

In: P. G. H. Evans and V. Ridoux.(Eds.). European Research on Cetaceans Vol. 159, Proceedings of the 15th Annual Conference of the European Cetacean Society, La Rochelle, 2005

Abstract
Natural features such as dorsal fin shapes and marks as well as lateral scars and body pigmentation patterns are used to identify minke whales (Balaenoptera acutorostrata) in the summer feeding grounds of the St. Lawrence Estuary in Eastern Canada. For this study we focused on analysing photographs of whales that either have dorsal edge marks (DEMs) such as nicks, dents and cut offs at the tip and those who do not. DEMs are features whose presence can be photographically documented irrespective of most environmental and lighting conditions that usually limit the photo-documentation of lateral features. During the seasons 1999 to 2004, of over 5000 day-sightings of minke whales photographed, a mean of 70% showed dorsal edge marks. In any given year, between 65 and 73% of individual minke whales could be identified on the basis of DEMs.

These results suggest a high identification success rate for the study area based upon a single feature that can be well documented under a wide range of weather conditions, distances, relative angles, and behaviours even if only one side of the whale is photographed.
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Individual surface feeding strategies of Minke Whales, Balaenoptera acutorostrata, in a confined environment.

Thomson, J.A., Kuker, K.J., and Tscherter, U. (2003)

Poster presentation at the 15th Biennial Conference of the Society for Marine Mammalogy, Greensboro, 2003

Abstract
Studies of baleen whale foraging behaviour in the North Atlantic have anecdotally suggested that individuals using the same strategy may show consistent preference for a particular, smaller-scale feeding technique. However, quantitative evidence to support this suggestion is lacking because of the challenges inherent in conducting fine-scale, long-term behavioural studies of known individuals in the wild. The minke whales (Balaenoptera acutorostrata) of the Saguenay River, Québec, Canada, provide an ideal opportunity to conduct such a study. The Saguenay is a calm, relatively confined feeding ground to which several well-known individuals return annually. The aim of this three-year study was: 1) to describe the general surface feeding strategy of minke whales in the Saguenay and 2) to analyze and discuss differences in feeding techniques of five well-known individuals using this strategy.
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Minke whales' respond to food stress in a main feeding ground

Tscherter, U., and M. Weilenmann, M. (2003)

Poster presentation at the 17th Annual Conference of the European Cetacean Society, Las Palmas.

Abstract
The St. Lawrence minke whale population exhibited a high degree of multiple-site tenacity and multiple-area fidelity through 1999 in the Laurentian Channel Head (LCH) of the St. Lawrence estuary. This site tenacity/area fidelity was challenged by a decrease in food productivity beginning in 2000. The challenge led to a change in both the whales distribution and feeding behaviour but not all whales abandoned the area. Critical to these long-term observations was the development of a minke whale photo-identification method by Tscherter and others. During years of abundant food relatively consistant populations of both finback whales and minke whales were in the area, which in turn lead to an extensive whale-watching industry. So long as food was not in short supply whales spatial and temporal distribution in the LHC was related to the relative abundance of fish, which, in turn was predicted by the euphausiid distribution. Thus, a change in whales' distribution indicates a change in food availability. There was a species specific difference in the response to this challenge. Finback whales left the area, moved downriver and switched to krill.

Minke whales reacted differently. Firstly, the temporal distribution shifted from a peak in September 1999 (48% of summer sightings) to a peak in July 2000 (34% of summer sightings), explained by reduced time in the area on the part of some individuals and fewer transient individuals present. Those remaining left the main feeding ground in the LCH. In 1999, 99% of all minkes were sighted along the steep contour lines of the channel head compared to 29% in 2002. Some animals moved into new secondary areas such as the Saguenay-Fjord, where they adapted their feeding techniques and strategies to the different oceanographic conditions. These adaptations included frog lunging, underwater blows, and bubbling strategies and unusual grouping behaviour.
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Is Temporal-spatial distribution predicted by lunar phase ?

Tscherter, U., E. M. N. Lynas, and S. Gal (2001)

In: P. G. H. Evans, et al. (Eds.). European Research on Cetaceans Vol. 15, Proceedings of the 15th Annual Conference of the European Cetacean Society, Rome, 6 -10 May 2001, pp 108-110.

Introduction
North Atlantic minkes whales are known to forage independently for the most part. Nevertheless, individuals form mobile local aggregations across the season in prime feeding areas, some with annual sighting histories >10 years. Information on these aggregations: composition, association patterns, distribution and temporal specificity is a necessary part of any integrated coastal zone management plan (MPAs), including non-lethal population estimators. Non-random associations lead to underestimates of abundance; temporary emigration and short residence patterns lead to overestimated abundance.


Testing association and abundance patterns of minke whales

Lynas, E. M. N., U. Tscherter, and N. Kelly (2001)

In: P. G. H. Evans, et al. (Eds.). European Research on Cetaceans Vol. 15, Proceedings of the 15th Annual Conference of the European Cetacean Society , Rome, 6 -10 May 2001, pp 77.

Introduction
Among cetacea, numbers of individuals within particular habitat areas naturally vary. Such variability can have a pronounced affect on habitat use and exploitation, on commercial human activities such as fishing, whale watching, and eco-tourism, and even on the outcome of population parameter estimates such as sighting and capture-recapture surveys. During two consecutive seasons of minke whale census in the Laurentian Channel Headwaters (LCH) region of the St.Lawrence estuary, we identified from 1 to 54 individuals daily (DEM photo-identification method) in a well-defined foraging area 200 km2. The question arises whether or not such variability in local numbers is predictable and what mechanism(s) might be involved.


Long-term use, differiential residence time and site exploitation by minke whales

Tscherter, U. and Lynas, E.M.N. (2000)

Fourteenth Annual Conference of the European Cetacean Society, Cork Lynas, E.M.N. 1989 The breathing ecology of minke whales Eighth Biennial Conference on the Biology of Marine Mammals. MontereyCA. Dec. 5-9, 1989