Technical Reports of the Ins�tute of Cetacean Research (2020)

pp. 59–60

CommentaryThe views expressed here are those of the author and do not necessarily reﬂect the views of the Institute of Cetacean
Research

Comments on the use of lethal and non-lethal techniques inthe studies of large whales
Genta Yasunaga
Institute of Cetacean Research, 4–5 Toyomi-cho, Chuo-ku, Tokyo 104–0055, Japan
Japan designed and implemented whale research programs under special scien�ﬁc permit in both the Antarc�c and western North Paciﬁc. These research programs
ceased on 30 June 2019 when Japan withdrew from theInterna�onal Conven�on for the Regula�on of Whaling(ICRW). The research programs involved both lethal andnon-lethal techniques. One of the issues frequently discussed among scien�sts was of the need to take whales
for scien�ﬁc purposes. I thought it would be appropriate
to express my comments on this topic now that the research programs have ceased.
In my view, the following aspects are relevant when
making a decision on lethal take of whales for scien�ﬁc purposes: i) whether the samples and data to becollected are required for conserva�on and managementof the whale stock (s); ii) the availability of non-lethal
techniques for ge�ng the same kind of samples anddata; iii) the eﬀect of the lethal take on the whale stock(s) involved.
Regarding i) above, it is recognized that considerable
biological informa�on is required for the appropriate
conserva�on and management of whale resources. For
example, samples and data are required to inves�gate
relevant parameters such as growth, reproduc�on, recruitment, natural mortality, abundance, distribu�on,
feeding ecology, environmental factors, interac�ons withother species, and the inter-annual variability of thesefactors (Ohsumi et al., 2007). Some of this informa�on
can be obtained only through the lethal sampling ofwhales, for example earplugs for age es�ma�on andsexual organs for inves�ga�on of maturity and pregnancy.
These basic biological data are important for es�mating several parameters such as age and length at sexual
maturity, natural mortality, recruitment and so forth,which are important parameters in popula�on dynamics
models. Lethal sampling is also required to inves�gate
stomach contents (qualita�ve and quan�ta�ve) which,in turn, allows us to inves�gate the feeding impact of thespecies (stock) in the ecosystem.

Regarding ii) above, scien�sts should make eﬀorts
to develop new non-lethal techniques to obtain the required informa�on for conserva�on and management. In
this sense, scien�sts of the Ins�tute of Cetacean Research(ICR) have commenced several research projects to inves�gate the sexual maturity status of females throughprogesterone levels in blubber (Inoue et al., 2019). They
have also started researching the feasibility of the DNA
methyla�on proﬁling in skin to obtain age informa�onof whales (Tanabe et al., 2020; Goto et al., 2020). Skinand blubber can be obtained through biopsy sampling.
The Interna�onal Whaling Commission Scien�ﬁc Commi�ee (IWC SC) recommended that a ﬁeld and analy�cal
protocol should be developed to assist the evalua�on ofthe u�lity of novel non-lethal techniques (IWC, 2016).
In response to this recommenda�on, scien�sts from theICR developed a protocol consis�ng of several ques�onsthat should be responded to in order to evaluate novel
non-lethal techniques (Mogoe, 2018). The protocol consists of four ques�ons: Ques�on 1 is whether �ssues orother kinds of samples can be obtained by a non-lethaltechnique. Ques�on 2 is whether a suﬃcient number ofsamples for sta�s�cal analyses can be obtained by thenon-lethal technique. Ques�on 3 is whether the samples
obtained by the non-lethal technique can produce scien�ﬁc informa�on comparable to that produced by alethal sampling technique. Ques�on 4 is whether thecost of obtaining the samples is reasonable for producing
relevant scien�ﬁc informa�on. Ques�on 1 and Ques�on
2 are technical in nature. Ques�on 3 is analy�cal while
Ques�on 4 is of a logis�cal nature. If the answers to
all these ques�ons are aﬃrma�ve, then the non-lethal
technique can be considered appropriate and feasible(Mogoe, 2018).
Regarding iii) above, only abundant species and stocks
can be considered for lethal sampling. Furthermore, popula�on dynamics models should be applied to evaluate
the eﬀect on the stocks of the number of whales taken
lethally. For example, in the case of the former Japanese59

Technical Reports of the Ins�tute of Cetacean Research (2020)

whale research under special scien�ﬁc permit in the Antarc�c, the eﬀect of the take of 333 whales on the stocksof Antarc�c minke whales was examined based on Hi�erFi�er model, and results suggested no nega�ve eﬀect on
the stocks (GOJ, 2018).
In summary, the issue of lethal versus non-lethal techniques to study whales is not a ʻblack and-whiteʼ ma�er.
In making a decision on the need for lethal sampling, theu�lity of the target data and samples for conserva�onand management, the availability/feasibility of non-lethal
techniques to obtain the same samples, as well as thestatus of the stock (s) should be considered.

REFERENCES
Goto, M., Kitakado, T. and Pastene, L.A. 2020. A preliminary
study of epigene�c es�ma�on of age of the Antarc�c minke
whale Balaenoptera bonaerensis. Cetacean Population
Studies 2: 5–14.
Government of Japan. 2018. Research Plan for New
Scien�ﬁc Whale Research Program in the Antarc�c Ocean(NEWREP-A). Available at: h�ps://www.jfa.maﬀ.go.jp/j/whale/pdf/151127newrep-a.pdf.

60Inoue, S., Yasunaga, G. and Pastene, L.A. 2019. Comparison ofprogesterone concentra�ons in blubber and plasma amongfemale Antarc�c minke whales of known reproduc�ve status.
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