Following a workshop in Taiwan in May, where experts proposed a recovery target of 100 for the critically endangered population of Taiwanese white dolphins, new research has painted a clearer picture of the alternative: their path towards extinction.
In a paper published recently in the journal Endangered Species Research, Claryana Araújo and colleagues describe what is likely to happen to the dolphins, currently numbering no more than 74, in a range of scenarios that could occur over the next 100 years.
Using a simulation programme, they first show what is likely to happen to the population if there is no change to the current serious threat of injury and entanglement in fishing gear – the subject of the May workshop. According to the results, in this baseline scenario the population declined and, in 66% of the simulations, became extinct in 100 years or less.
Unsurprisingly, when the researchers then looked at other future scenarios in which the impact from fishing gear increased and the size and quality of the dolphins’ coastal habitat declined, the likelihood of the their extinction within 100 years also increased, with up to 92% of the simulations giving this result.
Araújo said, “The results of this study confirm the very delicate situation of the Taiwanese white dolphins, and that the population is declining.”
Indeed, the fact that the dolphins are critically endangered is already no longer a matter of debate. However, the results of the study confirm that simply stopping the situation from becoming worse will not be enough to save them: the existing threats need to be reduced and, where possible, removed.
This message will be important as the government sets about responding to the situation. Thanks to campaigning by Taiwanese NGOs, the dolphins are already considered in Environmental Impact Assessments for major new projects. Now, with the proposed designation of part of their habitat as ‘Major Wildlife Habitat’ under the Wildlife Conservation Act in May, there could soon be an even stronger mandate both at the national and local government levels to address their plight.
A rapid, coordinated effort will be needed to address the existing threats, which, in addition to fishing gear, also include water and air pollution, underwater noise, land reclamation, and the loss of freshwater flowing into the dolphins’ habitat, due to the damming and diversion of rivers along western Taiwan.
Compared to the threat from fishing gear, less information is available on these other factors, which, the researchers point out, means that they probably underestimated their impact in the study. This suggests that the danger to the dolphins may be even greater than the results show, and their extinction more imminent if action is not taken.
“Based on the data available,” said Araújo, “the mortality due to fisheries interactions is the most serious, immediate threat for this population. And even with uncertainties regarding the level of the other threats and the exact mortality rate, the population shows a decline. This tells us that urgent conservation actions are needed.”
Reducing the number of dolphin deaths from fisheries interactions will not be as straightforward as simply monitoring fishing boat activities and enforcing penalties for catching dolphins.
According to the researchers, thousands of fishers, many of them small scale artisanal fishers, operate along Taiwan’s west coast, making it impossible to effectively observe all their activities and prevent dolphin deaths.
The only feasible solution would be to implement a total ban on gill nets and trawlers within the dolphins’ habitat, they say, echoing the findings of the May workshop.
The workshop also explored ways to work with fishers and fishing authorities to achieve adequate protection for the dolphins while also addressing the issue of overexploitation of fish, and working towards more sustainable long-term fisheries.
In a paper published recently in the journal Endangered Species Research, Claryana Araújo and colleagues describe what is likely to happen to the dolphins, currently numbering no more than 74, in a range of scenarios that could occur over the next 100 years.
Using a simulation programme, they first show what is likely to happen to the population if there is no change to the current serious threat of injury and entanglement in fishing gear – the subject of the May workshop. According to the results, in this baseline scenario the population declined and, in 66% of the simulations, became extinct in 100 years or less.
Unsurprisingly, when the researchers then looked at other future scenarios in which the impact from fishing gear increased and the size and quality of the dolphins’ coastal habitat declined, the likelihood of the their extinction within 100 years also increased, with up to 92% of the simulations giving this result.
Araújo said, “The results of this study confirm the very delicate situation of the Taiwanese white dolphins, and that the population is declining.”
Indeed, the fact that the dolphins are critically endangered is already no longer a matter of debate. However, the results of the study confirm that simply stopping the situation from becoming worse will not be enough to save them: the existing threats need to be reduced and, where possible, removed.
This message will be important as the government sets about responding to the situation. Thanks to campaigning by Taiwanese NGOs, the dolphins are already considered in Environmental Impact Assessments for major new projects. Now, with the proposed designation of part of their habitat as ‘Major Wildlife Habitat’ under the Wildlife Conservation Act in May, there could soon be an even stronger mandate both at the national and local government levels to address their plight.
A rapid, coordinated effort will be needed to address the existing threats, which, in addition to fishing gear, also include water and air pollution, underwater noise, land reclamation, and the loss of freshwater flowing into the dolphins’ habitat, due to the damming and diversion of rivers along western Taiwan.
Compared to the threat from fishing gear, less information is available on these other factors, which, the researchers point out, means that they probably underestimated their impact in the study. This suggests that the danger to the dolphins may be even greater than the results show, and their extinction more imminent if action is not taken.
“Based on the data available,” said Araújo, “the mortality due to fisheries interactions is the most serious, immediate threat for this population. And even with uncertainties regarding the level of the other threats and the exact mortality rate, the population shows a decline. This tells us that urgent conservation actions are needed.”
Reducing the number of dolphin deaths from fisheries interactions will not be as straightforward as simply monitoring fishing boat activities and enforcing penalties for catching dolphins.
According to the researchers, thousands of fishers, many of them small scale artisanal fishers, operate along Taiwan’s west coast, making it impossible to effectively observe all their activities and prevent dolphin deaths.
The only feasible solution would be to implement a total ban on gill nets and trawlers within the dolphins’ habitat, they say, echoing the findings of the May workshop.
The workshop also explored ways to work with fishers and fishing authorities to achieve adequate protection for the dolphins while also addressing the issue of overexploitation of fish, and working towards more sustainable long-term fisheries.
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