Taiwan’s Fisheries Research Institute (FRI), in collaboration with local and Japanese universities, presented its findings on the behavioral characteristics and thermoregulation mechanisms of the shortfin mako shark on Monday.
The species of shark, classified as “endangered” by the International Union for Conservation of Nature, is one of the most common bycatches of Taiwanese commercial longline and gillnet fisheries, the FRI told a news conference.
The joint research was carried out by FRI in conjunction with Japan’s Graduate University for Advanced Studies (SOKENDAI) and National Kaohsiung University of Science and Technology.
Photo: CNA
According to SOKENDAI professor Yuki Watanabe, Taiwanese and Japanese fishers have helped to capture shortfin mako sharks and tag them with custom-made data loggers, which transmitted the data via satellite.
The loggers, which capture video recordings, monitored the sharks’ body temperatures and tracked their movements, SOKENDAI researcher Soma Tokunaga said.
Analysis of the data revealed the unique thermoregulation abilities of the shortfin mako that are not found in other shark species, one of which is the ability to regulate body temperature so that it stays warmer than the surrounding water, Tokunaga said.
When hunting prey even at depths of 1km where water temperatures are as low as 4°C to 5°C, the shark can use this ability to its advantage.
FRI Deputy Director-General Yeh Hsin-ming (葉信明) said the research also shows that the shortfin mako experiences only a slight decrease in body temperature averaging about 2°C to 4°C after each deep dive of several hundred meters.
This is vastly different to other types of shark, which typically keep themselves warm through a “countercurrent heat exchange,” where blood vessels transfer surrounding heat into the body, Yeh said.
The study found that during the day, the shortfin mako shark could be found in areas from the surface to depths of 300m and frequently crosses the thermocline, likely related to feeding behavior, FRI associate researcher Chiang Wei-chuan (江偉全) said.
At night, it prefers to inhabit depths of between 100m and 200m, Chiang added.
SOKENDAI is working on a report to publish the findings in international journals, Yeh said, adding that the research would also be presented at a scientific conference next month.
The research would serve as a useful resource for regional fisheries management organizations and others for research into the sustainability of the species, he said.
With climate change leading to variations in sea surface temperatures, the shortfin mako shark’s activity would also change, and as such, the findings could provide valuable insights for fisheries management, Tokunaga said.
Civil society groups yesterday protested outside the Legislative Yuan, decrying Chinese Nationalist Party (KMT) efforts to pass three major bills that they said would seriously harm Taiwan’s democracy, and called to oust KMT caucus whip Fu Kun-chi (傅?萁). It was the second night of the three-day “Bluebird wintertime action” protests in Taipei, with organizers announcing that 8,000 people attended. Organized by Taiwan Citizen Front, the Economic Democracy Union (EDU) and a coalition of civil groups, about 6,000 people began a demonstration in front of KMT party headquarters in Taipei on Wednesday, organizers said. For the third day, the organizers asked people to assemble
POOR IMPLEMENTATION: Teachers welcomed the suspension, saying that the scheme disrupted school schedules, quality of learning and the milk market A policy to offer free milk to all school-age children nationwide is to be suspended next year due to multiple problems arising from implementation of the policy, the Executive Yuan announced yesterday. The policy was designed to increase the calcium intake of school-age children in Taiwan by drinking milk, as more than 80 percent drink less than 240ml per day. The recommended amount is 480ml. It was also implemented to help Taiwanese dairy farmers counter competition from fresh milk produced in New Zealand, which is to be imported to Taiwan tariff-free next year when the Agreement Between New Zealand and
A woman who allegedly spiked the food and drinks of an Australian man with rat poison, leaving him in intensive care, has been charged with attempted murder, the Taipei District Prosecutors’ Office said yesterday. The woman, identified by her surname Yang (楊), is accused of repeatedly poisoning Alex Shorey over the course of several months last year to prevent the Australian man from leaving Taiwan, prosecutors said in a statement. Shorey was evacuated back to Australia on May 3 last year after being admitted to intensive care in Taiwan. According to prosecutors, Yang put bromadiolone, a rodenticide that prevents blood from
China is likely to focus on its economy over the next four years and not set a timetable for attempting to annex Taiwan, a researcher at Beijing’s Tsinghua University wrote in an article published in Foreign Affairs magazine on Friday. In the article titled “Why China isn’t scared of Trump: US-Chinese tensions may rise, but his isolationism will help Beijing,” Chinese international studies researcher Yan Xuetong (閻學通) wrote that the US and China are unlikely to go to war over Taiwan in the next four years under US president-elect Donald Trump. While economic and military tensions between the US and China would
RSS