Fishermen operating out of Chenggong port in Taitung County found a female tiger shark weighing 500 kg trapped in the stationary net. It had a round belly which indicated that it was expecting pups.
The fishermen immediately opened up the female tiger shark and saved 38 pups averaging about 80 cm in length, which the fishermen sent to the Eastern Marine Biology Research Center of the Fisheries Research Institute for observation.
The next day, another female tiger shark was caught by the net in Taitung County’s Changbin Township and the fishermen took out 37 pups averaging 60 cm in length, but despite the center’s efforts, seven died by the evening due to their premature birth and lack of oxygen.
The center placed the pups in an artificial pond. Since the first batch of tiger shark pups has reached the full-term gestation, they were active in the pool and able to eat the squid and shrimps fed by caretakers; whereas, the second batch which has not reached full term were not as active.
Ho Yuan-shing, head of the Eastern Marine Biology Research Center, said the fact that two female tiger sharks got caught in the stationary nets in two days might mean the period coincides with the birthing season of tiger sharks.
Female tiger sharks expecting pups tend to swim closer to the coast because there is more food, Ho added.
Female tiger sharks can give birth to anywhere from 10 to 80 pups at a time, according to the Sharks-World website. The eggs hatch internally, and embryos may remain in gestation for as long as 15 months. At birth, the pups are almost 3 ft in length. They will be on their own from the second they are born.
Tiger sharks have been recorded with the most attacks on humans only behind the great white sharks. In addition, they are classed as “near threatened” by the International Union for Conservation of Nature and Natural Resources.
The rescued shark pups were taken care of until they were deemed fit to be released into the sea bearing microsatellite markers to record their movement patterns. According to Ho, the microsatellite markers will fall off after 240 days, drifting on the ocean before sending information back to the center via satellite for analysis.