**6. Current ecosystem changes revealed through whale demography**

Commercial whaling of humpback, Antarctic blue and fin whales in the Antarctic was suspended in 1963, 1964 and 1976, respectively. As an effect of these conservation measures, the abundance of these species have increased in recent decades, i.e. there have been recoveries from past commercial harvesting. The speed of recovery varies among species and populations. The increases in abundance of the recovering species will have effects on the ecosystem as a whole. In this section the current information on abundance and abundance trends of baleen whale species is examined, as well as some aspects of current nutritional conditions, feeding ecology and biological parameters of the Antarctic minke whale, a species which benefited from the krill surplus during the last century.

## **6.1 Abundance trend of baleen whales**

Estimates of abundance of large whales in the Antarctic are based on systematic sighting surveys in open sea carried out under sampling methods advocated in DISTANCE [20], and the guidelines for surveys and analyses agreed by the IWC Scientific Committee (SC) [21]. Dedicated sighting surveys were carried out in the Indo-Pacific sector of the Antarctic under the JARPA/JARPAII programs using the IWC SC-agreed methodology and guidelines. Overall, the IWC SC carried out three circumpolar sighting surveys under the IDCR/SOWER programs (CPI, CPII and CPIII).

*Glaciers and the Polar Environment*

**5.3 Interpretation of results**

**Figure 4.**

in the Indo-Pacific sector.

was due primarily to an increase in recruitment (**Figure 5**), arising in turn from an increase in carrying capacity [18], presumably due to an increase in the abundance of krill. A similar pattern was found for the Western South Pacific population.

*Time trajectory of total (1+) population size for the Eastern Indian Ocean population of Antarctic minke whale (reference-case), by cohort. The dotted lines indicate 95% asymptotic confidence intervals (modified from [18]).*

1970's coincided roughly with the period over which the ASM decreased.

The results of this section can be summarized as following:

It is interesting to note that the increase in total population size from 1930 to the

• The average ASM of Antarctic minke whales declined from roughly 11 years for the cohorts of the 1950's to roughly 7 years for the cohorts of the 1970's; this trend was similar for females and males, and for the two populations occurring

• The population of Antarctic minke whale increased from 1930 until the early 1970's, but declined subsequently and then re-stabilised. A similar pattern is

• The increase in abundance was due primarily to higher recruitments resulting from an increase in carrying capacity with more food being available for these

evident for the two populations occurring in the Indo-Pacific sector.

Antarctic minke whales during the middle decades of the last century.

These historical changes in the demography of Antarctic minke whale are consistent with expectations under the krill surplus hypothesis. The harvesting of large whales in the Antarctic Ocean started in 1904, and several species of large whales such as the Antarctic blue and humpback whales were heavily depleted by

*Time trajectory of recruitment for the Antarctic minke whale of the Eastern Indian Ocean population (from* 

*1930 and from 1975) for the reference case analysis, by cohort (modified from [18]).*

**92**

**Figure 5.**

#### *6.1.1 Humpback whales*

Abundance and abundance trend estimates based on JARPA and JARPAII focused mainly in Areas IV (Population D) and V (Population E) (**Figure 1**). In Area IV the abundance was estimated in 29,067 whales (CV = 0.255) based on sighting data collected in 2007/08; in Area V the abundance was estimated in 13,894 whales (CV = 0.338) based on sighting data collected in 2008/09 [22].

**Figure 6** shows the abundance trend of Populations D and E based on JARPA and JARPAII sighting data. For comparison purposes, the figure includes data from the IDCR/SOWER programs [23]. The figure shows a clear increasing trend, which is consistent for the JARPA/JARPAII and IDCR/SOWER survey data. Annual rate of increase was estimated at 13.6% (95% CI = 8.4–18.7%) and 14.5% (95% CI = 7.6–21.5%) for Areas IV and V, respectively, which were statistically greater than zero [22].

#### *6.1.2 Antarctic minke whale*

Abundance estimates and abundance trends of Antarctic minke whale for the Eastern Indian Ocean population (Area IV) and Western South Pacific population (Area V) have been conducted based on sighting surveys under JARPA [24]. Abundance estimates for the Eastern Indian Ocean population ranged from 16,562 (CV = 0.542) in 1997/98 to 44,945 (CV = 0.338) in 1999/00. Estimates for the Western South Pacific Ocean population ranged from 74,144 (CV = 0.329) in 2004/05 to 151,828 (CV = 0.322) in 2002/03.

Estimates of the annual rates of increase in abundance were 1.8% (95% CI: −2.5%, 6.0%) for the Eastern Indian Ocean population and 1.9% (95% CI: −3.0%, 6.9%) for the Western South Pacific population, which were not statistically greater than zero (**Figure 7**) [24].

The estimates based on IDCR/SOWER data were 55,237 (CV: 0.17) in Circumpolar II (CPII) and 59,677 (CV: 0.34) in circumpolar III (CPIII) for the Eastern Indian Ocean population (Area IV). For the Western South Pacific population (Area V) were 300,214 (CV: 0.13) in CPII and 183,915 (CV: 0.11) in CPIII.

#### *6.1.3 Fin whales*

For the purpose of the abundance estimates based on JARPA and JARPAII surveys, south of 60°S, the whole area was divided into a western area (Areas IIIE+IV) and eastern area (Areas V + VIW). For the western area the abundance was

#### **Figure 6.**

*Annual abundance trend for humpback whales in Areas IV (Population D) (left) and V (Population E) (right), south of 60°S. Estimates were based on sighting data collected by JARPA and JARPAII surveys primarily during January to February. Estimates from the IDCR-SOWER surveys [23] are shown for comparative purposes (filled circles). Vertical lines show 95% confidence intervals (modified from [22]).*

**95**

in summer.

**Figure 7.**

*6.1.4 Antarctic blue whales*

*Whales as Indicators of Historical and Current Changes in the Marine Ecosystem…*

estimated as 3,087 (CV = 0.191) in 1995/96, and 2,610 (CV = 0.285) in 2007/08. For the eastern area the abundance was estimated as 1,879 (CV = 0.226) in 1996/97, and 14,981 (CV = 0.298) in 2008/09. For the western area the increasing trend between 1995/96 and 2007/08 seasons was estimated at 8.9% (95%CI: -0.145%, 32.4%), while the trend in the eastern area between 1996/97 and 2008/09 was estimated at 12.0% (95%CI: 2.6%, 21.5%). The estimate for the eastern area was statistically greater than zero [25]. It should be noted that the JARPA/JARPAII surveys do not cover the latitudinal sector 50°-60°S, where fin whales distribute in large numbers

*Annual abundance trend for Antarctic minke whales of the Eastern Indian Ocean population (Area IV) (left) and Western South Pacific population (Area V) (right), together with their 95% CIs, based on sighting data from JARPA. The IDCR/SOWER estimates are shown for comparison (open triangles). The dashed curves indicate the 95% CIs for the exponential model applied to the JARPA estimates (modified from [24]).*

There is limited information on stock structure of Antarctic blue whales. Abundance of this species for the Indo-Pacific sector of the Antarctic (35°E-145°W), south of 60°S was 664 (CV = 0.328) in 2005/06 and 2006/07 seasons. The abundance was estimated at 1,223 whales (CV = 0.345) in the 2007/08 and 2008/09 seasons. The abundance trend was estimated at 8.2% (95% CI: 3.9%, 12.5%) between

For most of the populations of these whale species were over-exploited in the past, but there is now scientific evidence of their recovery, although the speed of recovery is different among species and populations. The populations of Antarctic

Substantial increases in the abundance of some species could have an implication on their pattern of distribution. Antarctic humpback whales from population D (Area IV) have increased substantially over recent decades, while the abundance of the Eastern Indian Ocean Population of Antarctic minke whale (Area IV) has been rather stable since the 1990s. We might expect some changes in the pattern of distribution of these two species. The spatial distribution of Antarctic minke and humpback whales was examined in the Indian sector (Area IV) based on JARPA/JARPAII sighting data for three periods: early (1989/1990, 1991/1992 and 1993/1994), middle (1995/1996, 1997/1998 and 1999/2000) and late (2001/2002, 2003/2004 and 2005/2006) [26]. Spatial distribution was estimated using generalized additive models (GAM).

Presence or absence of whales was used as the response variable while seafloor depth,

Mean probabilities of occurrence of Antarctic minke whales in the survey area in early, middle and late periods were 0.41, 0.46 and 0.41, while those of humpback whales were 0.14, 0.35 and 0.46. Occupied area indices (probabilities of occurrence

distance from shelf break and longitude were used as explanatory variables.

1995/96 and 2008/09, which was not statistically greater than zero [25].

minke whale appear to be stable in recent years.

**6.2 Changes in the distribution pattern of baleen whales**

*DOI: http://dx.doi.org/10.5772/intechopen.94323*

*Whales as Indicators of Historical and Current Changes in the Marine Ecosystem… DOI: http://dx.doi.org/10.5772/intechopen.94323*

**Figure 7.**

*Glaciers and the Polar Environment*

Abundance and abundance trend estimates based on JARPA and JARPAII focused mainly in Areas IV (Population D) and V (Population E) (**Figure 1**). In Area IV the abundance was estimated in 29,067 whales (CV = 0.255) based on sighting data collected in 2007/08; in Area V the abundance was estimated in 13,894

**Figure 6** shows the abundance trend of Populations D and E based on JARPA and JARPAII sighting data. For comparison purposes, the figure includes data from the IDCR/SOWER programs [23]. The figure shows a clear increasing trend, which is consistent for the JARPA/JARPAII and IDCR/SOWER survey data. Annual rate of increase was estimated at 13.6% (95% CI = 8.4–18.7%) and 14.5% (95% CI = 7.6–21.5%) for Areas IV and V, respectively, which were statistically greater

Abundance estimates and abundance trends of Antarctic minke whale for the Eastern Indian Ocean population (Area IV) and Western South Pacific population (Area V) have been conducted based on sighting surveys under JARPA [24]. Abundance estimates for the Eastern Indian Ocean population ranged from 16,562 (CV = 0.542) in 1997/98 to 44,945 (CV = 0.338) in 1999/00. Estimates for the Western South Pacific Ocean population ranged from 74,144 (CV = 0.329) in

Estimates of the annual rates of increase in abundance were 1.8% (95% CI: −2.5%, 6.0%) for the Eastern Indian Ocean population and 1.9% (95% CI: −3.0%, 6.9%) for the Western South Pacific population, which were not statistically greater than zero

For the purpose of the abundance estimates based on JARPA and JARPAII surveys, south of 60°S, the whole area was divided into a western area (Areas IIIE+IV)

The estimates based on IDCR/SOWER data were 55,237 (CV: 0.17) in Circumpolar II (CPII) and 59,677 (CV: 0.34) in circumpolar III (CPIII) for the Eastern Indian Ocean population (Area IV). For the Western South Pacific population (Area V) were 300,214 (CV: 0.13) in CPII and 183,915 (CV: 0.11) in CPIII.

and eastern area (Areas V + VIW). For the western area the abundance was

*Annual abundance trend for humpback whales in Areas IV (Population D) (left) and V (Population E) (right), south of 60°S. Estimates were based on sighting data collected by JARPA and JARPAII surveys primarily during January to February. Estimates from the IDCR-SOWER surveys [23] are shown for comparative purposes (filled circles). Vertical lines show 95% confidence intervals (modified from [22]).*

whales (CV = 0.338) based on sighting data collected in 2008/09 [22].

*6.1.1 Humpback whales*

than zero [22].

(**Figure 7**) [24].

*6.1.3 Fin whales*

*6.1.2 Antarctic minke whale*

2004/05 to 151,828 (CV = 0.322) in 2002/03.

**94**

**Figure 6.**

*Annual abundance trend for Antarctic minke whales of the Eastern Indian Ocean population (Area IV) (left) and Western South Pacific population (Area V) (right), together with their 95% CIs, based on sighting data from JARPA. The IDCR/SOWER estimates are shown for comparison (open triangles). The dashed curves indicate the 95% CIs for the exponential model applied to the JARPA estimates (modified from [24]).*

estimated as 3,087 (CV = 0.191) in 1995/96, and 2,610 (CV = 0.285) in 2007/08. For the eastern area the abundance was estimated as 1,879 (CV = 0.226) in 1996/97, and 14,981 (CV = 0.298) in 2008/09. For the western area the increasing trend between 1995/96 and 2007/08 seasons was estimated at 8.9% (95%CI: -0.145%, 32.4%), while the trend in the eastern area between 1996/97 and 2008/09 was estimated at 12.0% (95%CI: 2.6%, 21.5%). The estimate for the eastern area was statistically greater than zero [25]. It should be noted that the JARPA/JARPAII surveys do not cover the latitudinal sector 50°-60°S, where fin whales distribute in large numbers in summer.

#### *6.1.4 Antarctic blue whales*

There is limited information on stock structure of Antarctic blue whales. Abundance of this species for the Indo-Pacific sector of the Antarctic (35°E-145°W), south of 60°S was 664 (CV = 0.328) in 2005/06 and 2006/07 seasons. The abundance was estimated at 1,223 whales (CV = 0.345) in the 2007/08 and 2008/09 seasons. The abundance trend was estimated at 8.2% (95% CI: 3.9%, 12.5%) between 1995/96 and 2008/09, which was not statistically greater than zero [25].

For most of the populations of these whale species were over-exploited in the past, but there is now scientific evidence of their recovery, although the speed of recovery is different among species and populations. The populations of Antarctic minke whale appear to be stable in recent years.

#### **6.2 Changes in the distribution pattern of baleen whales**

Substantial increases in the abundance of some species could have an implication on their pattern of distribution. Antarctic humpback whales from population D (Area IV) have increased substantially over recent decades, while the abundance of the Eastern Indian Ocean Population of Antarctic minke whale (Area IV) has been rather stable since the 1990s. We might expect some changes in the pattern of distribution of these two species. The spatial distribution of Antarctic minke and humpback whales was examined in the Indian sector (Area IV) based on JARPA/JARPAII sighting data for three periods: early (1989/1990, 1991/1992 and 1993/1994), middle (1995/1996, 1997/1998 and 1999/2000) and late (2001/2002, 2003/2004 and 2005/2006) [26]. Spatial distribution was estimated using generalized additive models (GAM). Presence or absence of whales was used as the response variable while seafloor depth, distance from shelf break and longitude were used as explanatory variables.

Mean probabilities of occurrence of Antarctic minke whales in the survey area in early, middle and late periods were 0.41, 0.46 and 0.41, while those of humpback whales were 0.14, 0.35 and 0.46. Occupied area indices (probabilities of occurrence

of Antarctic minke whales less probabilities of occurrence of humpback whales) were also calculated. If the index is 1, only Antarctic minke whales were present in a grid cell, while only humpback whales were present if the index is −1. If the index is 0, probabilities of the presence of Antarctic minke whales and humpback whales in a grid cell were identical. Mean occupied area indices in early, middle and late periods were 0.28, 0.11 and − 0.07, respectively. The authors [26] concluded that the spatial distribution of humpback whales expanded to the south during the period investigated, while that of Antarctic minke whales remained stable. A summary of their results is presented in **Figure 8**.

The analyses were conducted based on sighting data obtained in the open sea. It should be mentioned that in the most recent period, Antarctic minke whales have also been observed frequently in polynias within the pack-ice [27], reflecting perhaps a response of this species to the geographical expansion of humpback whales to the south.

## **6.3 Changes in energy storage and stomach content weight**

Nutritional condition in Antarctic minke whales has been investigated through different indices: blubber thickness under the assumption that the amount of lipids increase with the thickness of the blubber, girth and total fat. These data have been collected for more than 25 years during the JARPA and JARPAII surveys in the Indo-Pacific sector of the Antarctic (Areas IV and V). Regression analyses has shown that blubber thickness, girth and fat weight of sexually mature whales have been decreasing for nearly two decades [28]. The decrease per year was estimated at approximately 0.02 cm for mid-lateral blubber thickness and 17 kg for fat weight, corresponding to 9% for both measurements over the 18-year period (**Figure 9**).

#### **Figure 8.**

*Probability of occurrence of humpback (left) and Antarctic minke (right) whales in the Indian sector (Area IV) during three time periods [26]. Red indicates high probability of occurrence.*

**97**

*Whales as Indicators of Historical and Current Changes in the Marine Ecosystem…*

Another study has reported the results of an analysis of temporal trend in stomach content weight in the Antarctic minke whale based on JARPA/JARPAII surveys [29]. A linear mixed-effects analysis showed a 31% (95% CI: 12.6–45.3%) decrease in the weight of stomach contents over the 20 years since 1990/91. A similar pattern of decrease was found for both males and females, except in the case of females sampled at higher latitudes in the Ross Sea (**Figure 1**). These results are consistent with the decline in energy storage reported above. Humpback whales are not found in the Ross Sea, where both Antarctic krill and ice krill (*E. crystallorophias*) are available, and where the authors [29] found no change in prey abundance for

*Yearly trends in blubber thickness (a) and fat weight (b) for Antarctic minke whale in the Indo-Pacific sector* 

The studies summarized above suggested a decrease in the abundance of krill for

As indicated above, the ASM has remained stable at 7–8 years until the 1998 cohort (at least). The proportion of pregnant animals among mature females (PPF) for the Antarctic minke whale has been examined based on JARPA/JARPA surveys conducted between 1987/88 and 2010/11 [30]. The PPF for the Eastern Indian Ocean and Western South Pacific populations was high: 0.932 and 0.904, respectively, using data from all years combined. Linear regression analyses of the PPF

• The abundance of the once over-exploited large whale species such as the Antarctic blue, fin and humpback whales, has been increasing since the 1980's (at least). In particular, the increasing trends of Populations D and E of humpback whale and that of a population of fin whales in the eastern part of

the research area were statistically significantly greater than zero.

• Since about 1990, the abundance of two populations of Antarctic minke

whale has been rather stable as revealed by the SCCA analyses and abundance

*DOI: http://dx.doi.org/10.5772/intechopen.94323*

Antarctic minke whales.

*of the Antarctic (modified from [28]).*

**Figure 9.**

**6.4 Biological parameters**

**6.5 Interpretation of results**

estimated by sighting surveys.

Antarctic minke whales, except in the Ross Sea.

over the years showed no significant temporal trend.

The results of this section can be summarized as following:

*Whales as Indicators of Historical and Current Changes in the Marine Ecosystem… DOI: http://dx.doi.org/10.5772/intechopen.94323*

#### **Figure 9.**

*Glaciers and the Polar Environment*

their results is presented in **Figure 8**.

whales to the south.

of Antarctic minke whales less probabilities of occurrence of humpback whales) were also calculated. If the index is 1, only Antarctic minke whales were present in a grid cell, while only humpback whales were present if the index is −1. If the index is 0, probabilities of the presence of Antarctic minke whales and humpback whales in a grid cell were identical. Mean occupied area indices in early, middle and late periods were 0.28, 0.11 and − 0.07, respectively. The authors [26] concluded that the spatial distribution of humpback whales expanded to the south during the period investigated, while that of Antarctic minke whales remained stable. A summary of

The analyses were conducted based on sighting data obtained in the open sea. It should be mentioned that in the most recent period, Antarctic minke whales have also been observed frequently in polynias within the pack-ice [27], reflecting perhaps a response of this species to the geographical expansion of humpback

Nutritional condition in Antarctic minke whales has been investigated through different indices: blubber thickness under the assumption that the amount of lipids increase with the thickness of the blubber, girth and total fat. These data have been collected for more than 25 years during the JARPA and JARPAII surveys in the Indo-Pacific sector of the Antarctic (Areas IV and V). Regression analyses has shown that blubber thickness, girth and fat weight of sexually mature whales have been decreasing for nearly two decades [28]. The decrease per year was estimated at approximately 0.02 cm for mid-lateral blubber thickness and 17 kg for fat weight, corresponding to 9% for both measurements over the 18-year period (**Figure 9**).

*Probability of occurrence of humpback (left) and Antarctic minke (right) whales in the Indian sector (Area* 

*IV) during three time periods [26]. Red indicates high probability of occurrence.*

**6.3 Changes in energy storage and stomach content weight**

**96**

**Figure 8.**

*Yearly trends in blubber thickness (a) and fat weight (b) for Antarctic minke whale in the Indo-Pacific sector of the Antarctic (modified from [28]).*

Another study has reported the results of an analysis of temporal trend in stomach content weight in the Antarctic minke whale based on JARPA/JARPAII surveys [29]. A linear mixed-effects analysis showed a 31% (95% CI: 12.6–45.3%) decrease in the weight of stomach contents over the 20 years since 1990/91. A similar pattern of decrease was found for both males and females, except in the case of females sampled at higher latitudes in the Ross Sea (**Figure 1**). These results are consistent with the decline in energy storage reported above. Humpback whales are not found in the Ross Sea, where both Antarctic krill and ice krill (*E. crystallorophias*) are available, and where the authors [29] found no change in prey abundance for Antarctic minke whales.

The studies summarized above suggested a decrease in the abundance of krill for Antarctic minke whales, except in the Ross Sea.

#### **6.4 Biological parameters**

As indicated above, the ASM has remained stable at 7–8 years until the 1998 cohort (at least). The proportion of pregnant animals among mature females (PPF) for the Antarctic minke whale has been examined based on JARPA/JARPA surveys conducted between 1987/88 and 2010/11 [30]. The PPF for the Eastern Indian Ocean and Western South Pacific populations was high: 0.932 and 0.904, respectively, using data from all years combined. Linear regression analyses of the PPF over the years showed no significant temporal trend.

#### **6.5 Interpretation of results**

The results of this section can be summarized as following:


Deteriorating nutritional conditions of the Antarctic minke whales suggest less food available for this species in recent years. Less availability/abundance of Antarctic krill could be a response to environmental changes (e.g. global warming) and/or competition for food with the increasing large whale species such as Antarctic blue, fin and humpback whales. No evidence of global warming exists for the Indo-Pacific sector of the Antarctic [31], so competition for food could be a more plausible interpretation for the results of nutritional deterioration in the Antarctic minke whale. This reflects the end of the period of a krill surplus hypothesised during the past century. Nutritional deterioration as a consequence of competition is not entirely consistent with the low ASM and high APR of the Antarctic minke whale over more recent years. Under the competition hypothesis, this could be the result of a temporal phenomenon in that the response of ASM and APR to environmental changes producing a nutritional deterioration may be subject to time lags.

Direct competition occurs when two predators are present in the same area as a prey species, and may interfere with each other's access to the prey. Indirect competition may occur when two predators occur in different parts of the area of prey, but because the prey's production is limited, consumption by the one predator limits the production available for the other, and *vice versa* [32]. To investigate the plausibility of the competition hypothesis, estimates of krill biomass trends in the research area are required. There is some partial information on krill abundance based on dedicated krill surveys in the past, but the information is scattered and needs to be combined with that from new surveys in a comprehensive and consistent way so that time series data can be obtained. The period of these demographic changes in the Antarctic minke whales coincides with the post whaling era (1970's-) which has been characterized as 'unfavorable climate conditions and increasing competition for krill' [3].

Antarctic minke whales could also be using alternative feeding areas (e.g. polynias within the pack-ice) in response to the increase in abundance and geographical expansion of these other large whale species. This could provide an alternative explanation from sighting surveys and population models of a decrease and then re-stabilization of Antarctic minke whales abundance in open areas since the 1970's.

The increase of the Adelie penguins (*Pygoscelis adeliae*) in East Antarctic in recent decades [33] seems immediately not to be consistent with the competition hypothesis. The authors of the Adelie penguin study provided two explanations for the increase of this species: (i) harvesting of baleen whales, krill and fish across East Antarctic waters through the 20th century could have reduced competition between Adelie penguins and other predators for food, improving prey availability, and (ii) a proposed reduction in sea-ice extent in the mid-20 century may also have benefited Adelie penguins by enabling better access to the ocean for foraging. Since recovery of krill-eating large baleen whales has been reported since the 1980's, it is suggested that their explanation of environmental factors for the demographic changes of Adelie penguins since the

**99**

*Whales as Indicators of Historical and Current Changes in the Marine Ecosystem…*

1980's is more plausible. Perhaps environmental changes have stronger effects on landbased predators such as the penguins than on sea-based predators such as whales.

This review of the scientific evidence for ecosystem changes in the Indo-Pacific sector of the Antarctic has highlighted the importance of long-time monitoring research programs focused on the collection of biological data for krill predators (both land-based and sea-based predators) as well as data on sea ice cover and environmental variables. The hypothesis proposed for the recent demographic changes found in whales is competition. To investigate this hypothesis further, estimates of krill abundance as well additional data collection of the predators and improved modelling analyses are required (see [34]). Also, oceanographic data obtained for more than 30 years in the Indo-Pacific sector of the Antarctic by JARPA/JARPAII surveys should be analysed to explore further the possible effect of global warming

In this context, Japan has started a new non-lethal research program to continue studying whales and the environment in the Indo-Pacific sector of the Antarctic. The program called JASS-A (Japanese Abundance and Stock structure Survey in the Antarctic) started in the austral summer of 2019/20, and will continue for at least eight years. It will conduct systematic sighting surveys for abundance estimates, biopsy sampling for genetic analysis of population structure, oceanographic and marine debris surveys, satellite tracking and photo-identification for studies on stock structure, distribution and movement of large whales, and Unmanned Aerial Vehicle (UAV) to observe whales outside of the main survey area. The analyses of the data to be collected will assist to examine the plausibility of the hypothesis proposed in this study further, in particular the observation that Antarctic minke whales have been moving into polynias within the pack-ice in recent years.

The authors thank the Fisheries Agency, Government of Japan for permits and funding for the whale surveys conducted in the Antarctic under the JARPA and JARPAII. They also thank the crew and researchers that participated in the surveys under the JARPA, JARPAII and IDCR/SOWER for collecting data and samples used

*DOI: http://dx.doi.org/10.5772/intechopen.94323*

on the pattern of demographic changes found in whales.

in the analyses and studies summarized in this chapter.

The authors declare that there is no conflict of interest.

**7. Conclusions**

**Acknowledgements**

**Conflict of interest**

1980's is more plausible. Perhaps environmental changes have stronger effects on landbased predators such as the penguins than on sea-based predators such as whales.
