Fish Survey in Wangsukcheon Stream Confirms Species Ranging from Mandarin Fish and Draco to Endangered Sira

A fish survey was conducted in Wangsukcheon Stream, which traverses Guri and Namyangju in Gyeonggi Province and connects to the Han River, to identify various freshwater fish species. According to a video from the YouTube channel 'TV Saengmul Dogam', this survey was a river monitoring project performed for educational purposes with support from Gyeonggi Province, involving local research institutes, the Korean Native Fish Conservation Association, and students from the Department of Life Science at Daejin University. The video captures the process of verifying the ecological value of Wangsukcheon using cast nets and dip nets, even in rainy conditions.

High Species Diversity on a Rainy Day, Major Fish Species Found in Wangsukcheon

Although it was raining on the day of the survey, the video explains that rainy weather makes it more advantageous to confirm species diversity as the mobility of fish increases. As a result of the investigation using cast nets and dip nets, various species such as Pale Chub, Stone Gudgeon, Stone Bitterling, Korean Bitterling, and Dark Chub were captured. In particular, a very large individual of Dark Chub drew attention at the survey site. It was also confirmed that the population is abundant, with nearly a hundred fish being caught in a single cast net.

In the patient tactical investigation using dip nets, species such as Korean Bitterling, Korean Bitterling, Rosy Bitterling, and Korean Bitterling appeared in succession. The Korean Bitterling was in a state of displaying deep nuptial coloration ahead of spawning, and the Rosy Bitterling maintained its unique beauty even in a faded color state. Additionally, the Korean Bitterling, a major species of Wangsukcheon, was observed. The Korean Bitterling is characterized by having very colorful patterns. Other species confirmed include Mudfish, Loach, Mandarin Fish, and Draco.

The Reappearance of Sira and the Difficulty of Species Identification

One of the notable discoveries in this exploration is the appearance of Sira. While there were stories in the past that Sira had almost become extinct in Wangsukcheon, this survey discovered robustly sized Sira, demonstrating the excellent species-forming capability of the river. The video mentions that species such as Mandarin Fish, Draco, and even Gukjunggae, which has been found in Gwangneung Arboretum, inhabit Wangsukcheon. In particular, species like Saekom-iguri, which live hiding under stones, were also confirmed during this survey.

As various fingerlings were discovered, the process of distinguishing species was also carried out. The video explains that distinguishing fingerlings is difficult enough that one must refer to early life cycle papers, raise and observe them directly, or extract and analyze DNA after alcohol fixation. On-site, Tteoknapjulgaeng-i was discovered, which is characterized by a long line extending to the center of its body. Also, among the loach species, Saekom-iguri, which has reddish fins and snout, was observed.

Furthermore, methods for distinguishing Stone Bitterling and Wemeci were presented. Since the body shapes of these two species are similar, it is very difficult for laypeople to distinguish them, but the Wemeci in the Han River system has patterns on its fins and a higher body height compared to the Stone Bitterling. While the Stone Bitterling is mainly found in areas with flowing stones and gravel, the Wemeci was observed in places where sand and gravel are mixed.

Morphological Characteristics and Identification Methods for Major Fish Species

The specific characteristics of the surveyed species are summarized as follows. First, the body shapes of Mudfish and Korean Bitterling are 99% similar, but while the Korean Bitterling has patterns on its fins, the Mudfish does not. Among the bitterling lineage, the Korean Bitterling is a special species that displays nuptial coloration to spawn in autumn, unlike other Korean bitterlings that spawn in spring. They spawn near small organisms.

Rosy Bitterling and Tteoknapjulgaeng-i have similar habits and are easy to confuse, but they can be distinguished by the length of the line on the center of their bodies. While the line of the Rosy Bitterling only extends to about the middle of the body, the line of the Tteoknapjulgaeng-i occupies more than two-thirds of the body. In addition, it was confirmed that benthic fish like Miro, carnivorous species like Eollukdongsal, and carp and Pale Chub constitute the ecosystem of Wangsukcheon. In the case of Pale Chub, males are characterized by having brilliant colors in summer and well-developed long anal fins.