Ecological Characteristics of Korean Gudgeon, Squalidus multimacultus in Cheokgwa Stream, Korea
점몰개(Squalidus multimacultus)의 생태적 특징을 연구하기 위해 2020년 1월부터 12월까지 태화강 지류 척과천에서 조사를 실시하였다. 본 종의 서식지 하상구조는 모래(sand)가 매우 풍부하였으며, 수심은 25~164㎝이었고 평균 68㎝로 다소 깊었으며, 유속이 0.21±0.26(0.16~0.43)m/sec로 느렸다. 암수 성비는 1 : 0.99이었다. 전장빈도분포도에 따른 연령은 여름(6-7월)기준으로 50mm 미만(29.4~49mm)은 만1년생, 50~69mm은 만 2년생, 70~89mm은 만 3년생, 90mm 이상은 만 4년생으로 추정되었다. 생식가능 전장의 크기는 암컷과 수컷 모두 40mm 이상 되면 성적 성숙이 이루어졌다. 산란시기는 7월에서 8월(산란성기 8월)이었며 수온은 23.8~25.4℃이었다. 포란수는 평균 1,395(648~2,201)개 이었고 성숙란은 노란색 구형으로 직경이 0.67±0.24(0.62~0.83)mm이었다. 먹이생물은 부착조류(Attached algae), 동물플랑크톤(Zooplankton), 수서곤충(Aquatic insects), 연체동물(Mullusca) 등이었다. 식성은 잡식성이었으나 섭취한 먹이의 양이 95% 이상은 부착조류로 식물성 먹이를 섭취하고 있었다. 점몰개의 크기가 클수록 동물성 먹이인 수서곤충을 섭식하는 양과 섭식 빈도가 증가하였으며 수서곤충을 섭식한 개체는 식물성 먹이를 거의 섭취하지 않았다.
This study surveyed the ecological characteristics of Squalidus multimacultus at Taehwa River tributary Cheokgwa Stream from January to December 2020. The species inhabited the riverbed that was mostly covered with sand. The water depth was 25-164 ㎝, and the average was rather deep at 68 ㎝. The stream velocity was slow at 0.21±0.26 (0.16-0.43) m/sec. The gender ratio of females to males was 1:0.99. The age according to the total length-frequency distribution indicated that the group with less than 50 mm (29.4 - 49 mm) in total length was one year old, the group with 50 - 69 mm was two years old, the group with 70 - 89 mm was three years old, and the group over 90 mm was four years old. The total length of sexually mature fishes was 40 mm for both males and females. The spawning season was from July to August, and the water temperatures was 23.8 - 25.4℃ during the period. The prosperous spawning season was August. The average number of eggs in the ovaries was 1,395 (648 - 2,201) per matured female, and the matured eggs were yellowish and spherical with a mean diameter of 0.67±0.24 (0.62 - 0.83) mm. The live foods were of S. multimacultus attached algae, zooplankton, aquatic insects, and Mollusca. The feeding habits of S. multimacultus were omnivorous, but more than 95% of the stomach content was plant-attached algae. The larger the size of this species, the greater the amount and frequency of eating aquatic insects, which were animal feeds. The population that ate aquatic insects did not eat vegetable food.