Update of analyses on efficiency of biopsy sampling for sei,
Bryde’s and common minke whales, based on data andsamples obtained during the 2014-2016 JARPNII surveys
GENTA YASUNAGA1, SATOKO INOUE1, HIDEYOSHI YOSHIDA2 AND TOSHI KITAKADO3
1

Institute of Cetacean Research, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 2368648, Japan
3
Tokyo University of Marine Science and Technology, 5-7 Konan 4, Minato-ku, Tokyo 108-8477, Japan

2

ABSTRACTTo refine the preliminary analyses regarding success proportions of biopsy and lethal sampling for sei,
Bryde’s and common minke whales based on the JARPNII data for 2014-2016 submitted to the Expert
Panel review workshop for NEWREP-NP, the differences between the two approaches were assessedusing a generalized linear model (GLM) for the response variable adjusting for potential covariates(sampling method, research year, Beaufort scale and visibility at experiment and sampling vessels)
based on these data. The analyses show that the success proportions for biopsy sampling weresignificantly lower than for lethal sampling for all whale species. Explanatory variables in the bestfitting model for sei and Bryde’s whales included only ‘method’, and that for common minke whale
included ‘method’ and ‘vessel’, indicating that environmental covariates had no significant effect. In
common minke whales, only two biopsy specimens could be sampled in 14 trials, suggesting biopsy
sampling is not feasible for these whales in the coastal components of the program. On the other hand, it
has been noted that experience and training can play an important role in the efficiency of biopsy
sampling following introduction of the Larsen system for the 2015 JARPNII. For this system theshooters would benefit from more experience and training time. These results and conclusions support
the preliminary analyses submitted to the Expert Panel workshop.
KEYWORDS: SCIENTIFIC PERMITS; COMMON MINKE WHALE; BRYDE’S WHALE; SEI
WHALE; SURVEY VESSEL; BIOPSY SAMPLINGINTRODUCTION
The International Whaling Commission’s Scientific Committee (IWC SC) convened an Expert Panel workshop
to review the Proposed Research Plan for the New Scientific Whale Research Program in the western North
Pacific (NEWREP-NP) in Tokyo from 30 January to 3 February 2017.
At this workshop, the proponents summarized results of the feasibility study on non-lethal techniques to evaluate
whether the objectives of the research could be achieved by non-lethal methods based on data and samples
collected from the JARPN II surveys for 2014-2016 (Yasunaga et al., 2017). Biopsy sampling was possible forsei and Bryde’s whales by sighting and sampling vessel in the offshore component of the program and forcommon minke whales by small-type catcher boat in the coastal components. However, given the main objectiveof JARPNII and available research resources, biopsy sampling is not feasible for common minke whale in the
coastal components, whereas it is feasible for sei and Bryde’s whales in the offshore component. In addition, theproponents submitted additional analyses to the Expert Panel in response to their request during the meeting;these suggested that success proportions for biopsy sampling for all three species were significantly lower thanthose for catches (IWC, 2017). In the report of the Expert Panel on NEWREP-NP, the Panel agreed with theproponents’ conclusions that it is feasible to collect biopsy samples from all three species, and that it is moredifficult to conduct biopsy sampling for common minke whales in the coastal waters than for sei and Bryde’s
whales in offshore waters. However, the Panel noted that the success of biopsy sampling for common minke
whales might be dependent on other covariates. Given this, the Panel recommended that various factors such as1

sea state, swell, visibility, experience of sampler, vessel and equipment be considered in assessing the efficiencyof biopsy sampling of common minke whales.
The aim of this report is to refine the preliminary analyses submitted in the Expert Panel workshop. The successproportions for biopsy and lethal sampling are estimated by generalized linear models in the context of otherpotential covariates (research year, Beaufort scales and visibility at experiment, and vessel).
MATERIALS AND METHODS
Research area and platform
For the main objective of JARPNII (feeding ecology and ecosystem studies), the field survey involved two
components: offshore and coastal (two localities: Sanriku and Kushiro). The offshore research area involved subareas 7, 8 and 9, as established by the IWC but excluding the EEZs of foreign countries, and the coastal researchareas were located in the sub-area 7CN (Kushiro) and 7CS (Sanriku) established by the IWC (Figure 1). The
coastal surveys were mainly conducted within a 30 nautical miles radius from the port in the respective area (theKushiro port or the Ayukawa port), and limited within the maximum of 50 n. miles radius from the port. The
biopsy and lethal sampling in offshore and coastal areas were conducted by the three sighting and sampling
vessels (SSV1-3) and the four small-type catcher boats (SCB1-4). The surveys were conducted from April to
October in the years 2014-2016 (Table 1).
Target sample size and effort
The target sample sizes for the biopsy and lethal sampling were 10 and 90 for sei whales and 25 and 25 for
Bryde’s whales in each year’s research. Allocation of effort between lethal (90%) and non-lethal (10%) activities
was set without the target sample sizes for the biopsy sampling for common minke whales (sample size for lethal
sampling in each year and component: 51 animals).
Sampling devices of biopsy and lethal sampling
The improved Larsen system described by Larsen (1998) was used. The chamber was modified to 9mm,
allowing the use of 9mm, 0.380 and 0.357 blank ammunition. It was fitted with a valve for adjusting the gaspressure entering the barrel from the chamber. The barrel consisted of a 48.5cm long aluminium cylinder thatallowed the use of darts with 27mm diameter floats. The open sight was replaced by an electronic aiming device(red-dot-sight), which allowed faster aiming and thus faster shooting. The biopsy darts consisted of a carbon
fibre shaft to which a polyethylene float was high-pressure moulded. The float also functioned as a stop to limit
penetration into the tissue. In the float end of the dart, a threaded insert was used for attaching the screw-on
biopsy tip. The biopsy tip was a stainless cylinder with a 9mm outer diameter, an internal diameter of 7mm andthree internal barbs for sample retention. The length of the biopsy tip was normally between 20 and 50mm
depending of which species was targeted, with 40mm the most commonly used for balaenopterids. The weightof the dart without a sampling tip was 32g (Larsen, 1998).
A whaling harpoon (SSV: 75mm in diameter; SCB: 50mm in diameter) with four flexible barbs is fired from awhaling cannon mounted on the forecastle of the SSVs and SCBs, and the top case of the harpoon in loaded witha penthrite cartridge and fuse (Ishikawa and Shigemune, 2005).
Data collection and definition
Experimental and environmental data such as time spent, sea state (the Beaufort scale), visibility and sea surface
temperature were recorded by researchers during the experiments.
To compare the efficiency between biopsy and lethal sampling, ‘success proportion’ is defined as the following
equation.
Success proportion = Number of sampled whales or biopsy samples / Number of targeted whales
where ‘Number of sampled whales or biopsy samples’ is the number of individual whales obtained or biopsy
samples obtained, and ‘Number of targeted whales’ is the total number of individuals identified as the target
species and chased for sampling by SSVs and SCBs.

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Statistical analysis
The differences of success proportion for biopsy and lethal sampling for sei, Bryde’s and common minke whales
were assessed by a generalized linear model (GLM) as the response variable adjusting for covariates (sampling
method, research year, Beaufort scale and visibility at experiment and sampling vessels) based on data from the
JARPNII for 2014-2016. In this analysis, the binomial distribution was assumed for the response variable,
outcome of sampling (failure = 0; success = 1). For explanatory variables, sampling method (lethal sampling = 0;biopsy sampling = 1), research year (sei and Bryde’s whales: 2015 = 0; 2016 = 1, common minke whale: 2014 =0; 2015 = 1; and 2016 = 2) and vessels (sei and Bryde’s whales: SSV1 = 0; SSV2 = 1 and SSV3 = 2, common
minke whale: SCB1 = 0; SCB2 =1; SCB3 = 2 and SCB4 = 3) were analysed as categorical variables, and sea
condition (Beaufort scale classes from 0 to 7) and visibility (n.mile) at the time of the experiment as a numericalvariables. Covariates within a given process were grouped together in a base set of linear models to describe
individual processes (Table 1). The Bayesian information criterion (BIC) was used to select the best-fitting
model (Schwarz 1978). A p value of less than 0.05 was considered to indicate statistical significance in all tests.
In GLM analyses with the sampling methodologies as the explanatory variables, point estimates were estimatedby prediction using the fitted model, and their standard errors were estimated approximately by the delta method.
RESULTS
Table 2 shows a summary of experiments of biopsy and lethal sampling during JARPNII for 2014-2016. Table 3
shows BICs for the each candidate model for sei, Bryde’s and common minke whales. The best model withlowest BIC (Schwarz 1978) was Model 1 for sei and Bryde’s whales and Model 5 for common minke whales.
Table 4 shows estimated coefficients of each explanatory variable in the selected models. The coefficientestimates and p values for the explanatory variable indicated that the success proportions of biopsy sampling
were lower than those of lethal sampling for all three species. Table 5 and Figure 2 shows the estimates and thestandard errors of the success proportion of biopsy and lethal sampling for sei and Bryde’s, and those for each
vessel for common minke whales. Only two biopsy samples for common minke whales were collected in 14
trials in the coastal components for 2014-2016, so that the estimates of success proportions of biopsy sampling
were much lower than those of lethal sampling.
DISCUSSION
In the GLM analyses, the selected explanatory variables in the best-fitting model for sei and Bryde’s whales
included only ‘method’. The present analyses support the preliminary analyses presented at the Expert Panelworkshop, because the estimates of success proportions (sei: Biopsy 0.571 ± 0.066, Lethal 0.905 ± 0.021;
Bryde’s: Biopsy 0.782 ± 0.047, Lethal 0.926 ± 0.036) for biopsy and lethal sampling in the present analyses were
the approximately same as levels of those (sei: Biopsy 0.490 ± 0.050, Lethal 0.894 ± 0.018; Bryde’s: Biopsy
0.694 ± 0.038, Lethal 0.926 ± 0.029) in the preliminary analyses (IWC, 2017). Furthermore, it is suggested that
the Larsen system is one of the most efficient method for biopsy sampling, and relatively robust in any sea
conditions (Nishiwaki et al., 1990). It is used regularly during the IWC POWER surveys in the North Pacific so
the shooters of the Larsen system were experienced crew members for the offshore component. Therefore, thesuccess proportions would be affected only by methods for sei and Bryde’s whales in the offshore area.
In the analysis for common minke whale, the best-fitting model included ‘method’ and ‘vessel’ as explanatory
variables, because the estimate of success proportions for lethal sampling for the SCB2, 3 and 4 were higher thanfor the SCB1. Success proportions for biopsy sampling were significantly lower than lethal sampling; moreover
only two biopsy specimens could be sampled in 14 trials, suggested biopsy sampling is not feasible for common
mink whales in the coastal components. On the other hand, it has been noted that experience and training canplay an important role in the efficiency of biopsy sampling in the coastal components, because the Larsen system
was introduced in the 2014 Kushiro survey for the costal components. Here the shooters would benefit from
more experience and training time.
REFERENCES
International Whaling Committee. 2017. “Issues derived from discussion on Document SC/J17/JR03” in Annex
D of Report of the Expert Panel of the final review on the western North Pacific Japanese Special Permit
programme (JARPNII). J. Cetacean Res. Manage. 18 (Suppl.): in press.
Ishikawa, H. and Shigemune, H. 2005. Improvements in more human killing methods of Antarctic minke whales,
Balaenoptera bonaerensis, in the Japanese Whaling Research Program under Special Permit in the
Antarctic Sea (JARPA). Jpn. J. Zoo. Wildl. Med. 10(1):27-34.

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Larsen, F. 1998. Development of a biopsy system primarily for use on large cetaceans. Paper SC/50/O15
presented to the IWC Scientific Committee, May 1998 (unpublished) 8pp.
Nishiwaki, S., Joyce, G., Ensor, J., Sanpera, M.C. and Kasamatsu, F. 1990. Report on the biopsy dart samplingfeasibility study during the 12th IWC/IDCR Southern hemisphere minke whale assessment cruise, 1989/90.
International Whaling Commission Scientific Committee paper SC/42/SHMi21. 12pp.
Schwarz, G. 1978. Estimating the dimension of a model. Ann. Stat. 6:461–464.
Yasunaga, G., Mogoe, T., Tamura, T., Yoshida, H., Bando, T. and Kato, H. 2017. Results of the feasibility study
on non-lethal techniques to address the key research objective of JARPNII, based on data and samples
obtained in the period 2014-2016. Paper SC/J17/JR03 presented to the presented to the Expert Panel of thereview on the western North Pacific Japanese Special Permit programme (NEWREP-NP), January, 2017
(unpublished). 38pp.

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Table 1. Candidate model set for estimation of sampling success proportions in sei, Bryde’s and common mike
whalesModel
Candidate model components
Model 0β0 (intercept only)
Model 1β1Method
Model 2β0 + β1Method + β2Year
Model 3β0 + β1Method + β2Sea condition
Model 4β0 + β1Method + β2Visibility
Model 5β0 + β1Method + β2Vessel
Model 6
β0 + β1Method + β2Year +β3Sea condition
Model 7β0 + β1Method + β2Year +β3Visibility
Model 8β0 + β1Method + β2Year +β3Vessel
Model 9β0 + β1Method + β2Sea condition +β3Visibility
Model 10β0 + β1Method + β2Sea condition +β3Vessel
Model 11
β0 +β1Method + β2Visibility + β3Vessel
Model 12
β0 +β1Method + β2Year +β3Sea condition + β4Visibility
Model 13
β0 +β1Method + β2Year +β3 Sea condition + β4 Vessel
Model 14
β0 +β1Method + β2Year +β3 Visibility + β4Vessel
Model 15
β0 +β1Method + β3Sea condition + β4Visibility + β5Vessel
Model 16
β0 +β1Method + β2Year +β3Sea condition + β4Visibility + β5Vessel

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Table 2. Success proportions, sampled whale numbers, target whale (experiment) numbers and averagetime of experiment in sei, Bryde’s and common minke whales for a) biopsy and b) lethal sampling in
the JARPNII surveys over 2014-2016a) Biopsy sampling using Larsen system
SpeciesComponent

Research
year
2015

0.615

16

26

14.3

Sei whale

Offshore

2016

0.533

16

30

15.8

2015-2016

0.571

32

56

15.0

2015

0.786

33

42

16.0

2016

0.778

28

36

18.9

2015-2016

0.782

61

78

17.3

Bryde's whale

Offshore

SanrikuCommon minke
whale
KushiroSuccess
proportion

Number ofsampled whales

Number oftargeted whales

Average of time ofexperiment (min.)

2015

0.000

0

1

-

2016

0.333

1

3

52.0

2015-2016

0.250

1

4

52.0

2014

0.500

1

2

33.0

2015

0.000

0

7

-

2016

0.000

0

1

-

2014-2016

0.100

1

10

33.0

Researchyear

Success
proportion

Number ofsampled whales

Number oftargeted whales

Average of time ofexperiment (min.)

2015

0.891

90

101

14.1

b) Lethal samplingSpecies

Sei whale

Bryde's whale

Component

Offshore

Offshore

SanrikuCommon minke
whale
Kushiro

2016

0.918

90

98

16.2

2015-2016

0.904

180

199

15.2

2015

0.862

25

29

11.4

2016

1.000

25

25

16.0

2015-2016

0.926

50

54

13.7

2014

0.638

30

47

27.7

2015

0.576

19

33

20.2

2016

0.640

16

25

38.9

2014-2016

0.619

65

105

28.3

2014

0.646

51

79

20.3

2015

0.689

51

74

17.0

2016

0.553

21

38

13.9

2014-2016

0.644

123

191

17.8

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Table 3. BICs for candidate models for sampling success proportions for sei, Bryde’s and common minke whales
Modelsei whale
Bryde’s whale
common minke whale
Model 0
236.9
120.6
419.5
Model 1
411.4
213.0
120.1
Model 2
218.5
124.3
422.3
Model 3
242.4
130.2
423.0
Model 4
218.0
123.6
413.9
Model 5
218.5
122.0
407.7
Model 6
247.9
134.8
433.8
Model 7
223.5
127.2
424.2
Model 8
224.0
126.0
418.9
Model 9
247.5
134.0
424.6
Model 10
247.9
134.3
421.2
Model 11
223.5
125.3
410.3
Model 12
253.1
138.3
433.7
Model 13
253.4
138.9
431.8
Model 14
229.1
128.9
421.2
Model 15
253.0
138.1
423.1
Model 16
258.6
142.3
432.6

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Table 4. Results of generalized linear model analyses with estimates of success proportions for sampling by
biopsy and lethal sampling for sei, Bryde’s and common minke whales in relation to explanatory variablesa) Sei whale (Model 1)
Estimate
Std. Errorz value
Pr (>|z|)(Intercept)
2.24850.24129.323
p < 0.05
Method1-1.9608
0.3621-5.416p < 0.05
Null deviance: 231.39 for 254 degrees of freedom; Residual deviance: 201.87 for 253 degrees of freedomb) Bryde’s whale (Model 1)
Estimate
Std. Errorz value
Pr (>|z|)(Intercept)
2.52570.51964.861
p < 0.05
Method1-1.24810.5876-2.124p < 0.05
Null deviance: 115.67 for 131 degrees of freedom; Residual deviance: 110.31 for 130 degrees of freedomc)Common minke whale (Model 5)
Estimate
Std. Errorz value
Pr (>|z|)Method0-0.38420.2449-1.5690.117
Method1-2.9965
0.8172-3.667p < 0.05
SCB2
1.23200.3551
3.470
p < 0.05
SCB3
1.40980.33924.156
p < 0.05
SCB4
1.07920.35693.024
p < 0.05
Null deviance: 429.75 for 310 degrees of freedom; Residual deviance: 378.98 for 305 degrees of freedom
Table 5. Estimates and standard errors of success proportions for biopsy and lethal sampling for sei, Bryde’s andcommon minke whales
Species
VesselLethalBiopsySei whale
0.905 ± 0.021
0.571 ± 0.066
Bryde’s whale
0.926 ± 0.036
0.782 ± 0.047
SCB1
0.405 ± 0.059*
SCB2
0.700 ± 0.054*
Common minke whale
SCB3
0.736 ± 0.046
0.170 ± 0.110
SCB4
0.667 ± 0.058
0.128 ± 0.089*: Biopsy samples were not obtained.

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Sampling success proportion

Figure 1. Research areas for the whale sampling surveys in the offshore (upper) and coastal (lower)
component of JARPN II
1.00
Lethal Sampling
0.75

Biopsy Sampling

0.50
0.25
0.00

SCB1

Sei whale Bryde's whale

SCB2

SCB3

SCB4

Common minke whale

Figure 2. Comparison of estimates and standard errors for success proportions for lethal and biopsy sampling forsei, Bryde’s and common minke whales

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