Minister CHEN, Wu-hsiung
Council of Agriculture,
37 Nanhai Rd.
Republic of China
November 2, 2011
Dear Minister Chen,
It is with considerable concern that we receive unconfirmed reports on a proposal to conduct live-captures of the Critically Endangered Indo-Pacific humpback dolphins (Sousa chinensis) in the Eastern Taiwan Strait (ETS) for the purpose of scientific research.
As you know, this population numbers fewer than 100 individuals, and faces a number of conservation threats including pollution, fisheries bycatch, reduced freshwater flow into estuarine habitat, noise, and loss of habitat due to land reclamation. The Eastern Taiwan Strait Sousa Technical Advisory Working Group (ETSSTAWG) consists of 17 international marine mammal experts. This group was established in 2008 to provide expert advice and feedback on matters pertaining to this population of Sousa.
Despite the weather-related difficulties in conducting field studies of Sousa in the ETS, recent work has demonstrated that Sousa are present year-round in the nearshore waters of Taiwan (Wang et al. 2011, Marine Mammal Science 27: 652-658). This was based on direct observations and photographic identification of known individuals from a small vessel.
Additional research might provide more insight into the presence, distribution, demographics and habitat use of Sousa in the ETS. However, this new insight for a Critically Endangered species must fundamentally be based on the ultimate goal of conservation and recovery of the population. Scientific research must not become a new conservation threat to members of this population.
The ETSSTAWG has solicited external expert advice on the risks and benefits related to possible satellite-tagging of ETS Sousa. We summarize the feedback that we received in this letter.
Live-captures and tagging of cetaceans elsewhere reveals some important gain in scientific understanding of marine mammal ecology, but also the following:
• captures cause stress in both the targeted individual and other members of the population during netting and capture operations. This can affect the health and well-being of the population.
• captures can kill individuals through drowning in nets, boat strikes, and/or stress.
• capture operations over a sustained period of time can displace members of the population from preferred feeding or resting habitat.
• the attachment of satellite tags to Sousa will cause injury, and can lead to subsequent infection, illness and even death after release.
• the process of capture, handling, tagging and release of the individual may very well change the subsequent behaviour, distribution, and habitat use of the individual. This means that even the best data collected from successfully attached tags may lead to erroneous results and conclusions.
• Even if one or more individuals move beyond their distribution as presently understood, this does not reduce the importance of protecting what has clearly been established to be ‘Priority Habitat’.
In short, tagging Sousa entails a high degree of risk to individuals, something that could lead to impacts at the population level. The ETSSTAWG strongly opposes any form of live-capture or biopsy sampling of individuals of this Critically Endangered population for scientific or other purposes.
However, the ETSSTAWG does recognize the merit in conducting non-invasive research that provides more insight into the habitat needs of this small cetacean. In this context, we urge members of the scientific and management establishment in Taiwan to consider the following non-harmful research options to supplement what has already been published in the scientific literature:
• land-based surveys using photo-identification methods.
• Ship-based surveys using trained professionals on small vessels and by using best practices to minimize noise and stress to ETS Sousa.
• Acoustic monitoring using Passive Acoustic Monitoring (PAM) or Marine Autonomous Recording Units (MARUs) and/or other devices that record Sousa vocalizations throughout the year.
• A combination of acoustic and sighting efforts to provide complementary information.
• Increased efforts to monitor bycatch of small cetaceans and to recover any dead carcasses of ETS Sousa.
We note that in other regions where other populations of Sousa are being studied (e.g. Hong Kong), a combination of non-invasive approaches have been very successful in generating high quality scientific results in support of management.
In reviewing any research proposal that involves ETS Sousa, the ESTSSTAWG recommends that:
• The need for the study must be clearly explained, including a description of the potential way in which results will lead to different management scenarios.
• Why other methods fail to deliver answers to the questions posed.
• A comprehensive summary of the risks to members of the population associated with the study proposal must be included.
• The potential for physical or physiological trauma leading to compromised health or reduced reproductive potential be fully described.
• The minimum sample size required to generate information of value be discussed and explained in detail including statistical analyses.
• If there exist any risks to individual members of the population, the consideration of alternative study designs or approaches to research must be included and described.
In summary, the ETSSTAWG does not support any proposal to live-capture members of the ETS Sousa population or any study which relies on invasive methods such as biopsies. The risk of disturbance, injury and/or death outweighs any possible benefit associated with the resulting scientific information. On the contrary, the ETSSTAWG strongly considers non-invasive alternatives using a combination of acoustic technologies and direct observation to be likely to generate more defensible and meaningful scientific information without further harming this population.
Finally, while additional evidence of year-round habitat use along the nearshore waters of western Taiwan would incrementally improve our understanding of ETS Sousa ecology, it should not detract from the importance of protecting this area from impacts. Simply put, the shallow nearshore waters of the eastern Taiwan Strait represent Priority Habitat for ETS Sousa, and efforts must be made to reduce the threats of bycatch, pollution, freshwater discharge, noise and land reclamation in this area (Ross,P.S. et al, 2010. Averting the baiji syndrome: Characterising habitat for critically endangered dolphins in eastern Taiwan Strait. Aquatic Conservation: Marine and Freshwater Ecosystems 20: 685-694).
As always, the ETSSTAWG remains openly available for those seeking advice on matters related to ETS Sousa.
Peter S. Ross, PhD
Eastern Taiwan Strait Sousa Technical Advisory Working Group
- Minister LEE, Lou-chuang, National Science Council firstname.lastname@example.org
- Premier WU Den-yih, Chair, National Council for Sustainable Development c/o NCSD Secretariat Environmental Protection Administration email@example.com
- Office of Legislator TIEN, Chiu-Chin firstname.lastname@example.org
- Wild at Heart Legal Defense Organisation
- Matsu’s Fish Conservation Union
- Randall Reeves, Chairman, Cetacean Specialist Group, IUCN
- Members of the Eastern Taiwan Strait Sousa Technical Advisory Working Group
See: COA responds to ETSSTAWG letter