In 2020 and 2021, Taijiang National Park Administration entrusted the team of Dr. Hung-Chang Liu of the Taiwan Academy of Ecology with the task to implement an ecological survey plan for terrestrial/land crabs in Taijiang National Park. After an investigation and a collection of records in recent years, it was found that there were 6 families and 32 species of land crabs in the supratidal zone of Taijiang National Park, including the 4 newly recorded species Ocypode Cordimana, Geograpsus Crinipes, Epigrapsus Politus and Sesarmops Imperator. Among them, the most northern distribution of Ocypode Cordimana is currently recorded in Taijiang National Park, which is assumed to be the result of the northward migration of tropical species after global warming.
The most representative land crab in Taijiang National Park - Cardisoma carnifex (Brown land crab)
Taijiang National Park is a wetland national park with an abundance of Cardisoma Carnifex and a wide variety of Parasesarma Pictum and Neosarmatium in the coastal wetlands. In 2021, Dr. Liu's team recorded more than 4,000 females Cardisoma Carnifexes with eggs in the Ching-Tsao-Lun area of Taijiang National Park, which is not only the largest group of Cardisoma Carnifex in Taiwan, but also rare in the world. These female crabs can grow up to 11 cm wide, and comparing to the Cardisoma Carnifexes’ group in the Houwan area of Kenting National Park, which head and breastplate width has grew by an average of 1 cm in 5 years as recorded, Cardisoma Carnifexes in Ching-Tsao-Lun area of Taijiang National Park is very rare to see such huge shells, making it deserving special attention and conservation.
Unveiling the mystery of the eggs release cycle of land crabs
We encourage the public to work together and assist wildlife conservation
Every month in Taijiang National Park, land crabs release their eggs to the sea. The breeding season of the Cardisoma Carnifex is from June to November, the eggs release cycle lasts about 7 days during the new moon and full moon, and the breeding peaks in July and August. Regarding Concave Land Hermit crabs, their breeding season is from May to September, and for Coenobita Rugosus, the breeding season is from May to October, the eggs release cycle of these 2 kinds of crabs is a half-month cycle and thus the same as that of the Cardisoma Carnifex. The Epigrapsusnotatus has egg-holding female crabs to release their eggs from September to November, and they release their eggs after the full moon. The breeding season for Ocypode Sinensis is from April to September, and their egg-holding female crabs release eggs almost every day.
The investigation and establishment of Taijiang National Park’s abundant ecological data of land crabs in the past 2 years allows the public to learn more about the life of land crabs, and understand their value as a natural resource. Taijiang Office will continue to protect the land crab resources, and also encourage people to help with conservation by not catching, not feeding and not eating them, and also not driving into coastal beaches and other habitats. When land carbs release their eggs, it is better to avoid driving near around the coastal areas to make Taijiang National Park keep being a land crab paradise.