Behavior and swimming performance of local fish in the ecosystem waters of rivers, oxbow and peat swamps

The four fish species, Trichogaster pectoralis, Barbodes schwanenfeldii, Osphronemus gouramy, and Wallago leeri have the same body size, representing different habitats. Therefore, this study aimed to determine the four species swimming abilities and speeds, including sustained, maximum sustained, prolonged swimming speed, and burst speed. The four species were brought using oxygenated plastic bags to the Aquatic Resources Utilization Laboratory at Riau University. Then it was acclimated in an aquarium measuring 100×50×50 cm with an aeration and filtering system to maintain water quality. The four groups of species were forced to swim in the swimming channel of the flume tank, with different current speeds for each individual tested. The swimming activity of the fish was recorded using a high-speed video camera (Casio HS Exlim, EX-ZR400, Casio Computer Co. LTD, Japan). The results showed that the swimming speed of B. schwanenfeldii was higher than O. gouramy, T. pectoralis, and W. leeri. The maximum sustained swimming speed of B. schwanenfeldii is about 5.1 BL/s, and 14.2 BL/s for the burst speed. Meanwhile, the sustained swimming speed of O. gouramy (1.6 BL/s) and the burst speed is 7.2 BL/s. The maximum sustained swimming speed of T. pectoralis was 1.6 BL/s, and the burst speed was 5.7 BL/s. In addition, the maximum sustained swimming speed of W. leeri is only 0.5 BL/s and 2.4 BL/s for the burst speed. The ability of these four fish to swim was influenced by the morphology of the tail fin, body shape, and the habitat where they live.

Reproduction cycle of Longtail shad (Tenualosa macrura) in Bengkalis Waters, Riau, Indonesia

Tenualosa macrura is an endangered fish in Riau Province, which is classified as a protected fish. Therefore, the first step is to study the reproductive cycle, aiming o prevent these species from extinction. The observation was carried out for 13 months from January 2019 to February 2020 (except February 2019) in Indonesia's Bengkalis waters. This study's purpose was to determine the spawning season, fecundity, and behavior of this species. The results showed that the relationship between length and weight positively correlates with the length-weight of male T. macrura (R² = 0.84) and female (R² = 0.67), while the length-weight of all males and females were reported to be (R² = 0.95). Meanwhile, the relationship between fecundity and length-weight has no relationship. Furthermore, the spawning season lasted throughout the year, and it occurred at every low tide (dark moon) and high tide (full moon). Despite being discovered occasionally in a limited amount, the greatest amount of T. macrura was reported between July and September each year.(AU)

Reproduction cycle of Longtail shad (Tenualosa macrura) in Bengkalis Waters, Riau, Indonesia

Tenualosa macrura is an endangered fish in Riau Province, which is classified as a protected fish. Therefore, the first step is to study the reproductive cycle, aiming o prevent these species from extinction. The observation was carried out for 13 months from January 2019 to February 2020 (except February 2019) in Indonesia's Bengkalis waters. This study's purpose was to determine the spawning season, fecundity, and behavior of this species. The results showed that the relationship between length and weight positively correlates with the length-weight of male T. macrura (R² = 0.84) and female (R² = 0.67), while the length-weight of all males and females were reported to be (R² = 0.95). Meanwhile, the relationship between fecundity and length-weight has no relationship. Furthermore, the spawning season lasted throughout the year, and it occurred at every low tide (dark moon) and high tide (full moon). Despite being discovered occasionally in a limited amount, the greatest amount of T. macrura was reported between July and September each year.

Application of active acoustic technology to assess the target strength of seahorses based on the presence of a reproductive organ

This study aims to provide reliable information on comparing the target strength (TS) values of seahorses based on the reproductive state. This study was carried out using hydro-acoustic technology in a water tank environment. Data were obtained using the single-beam scientific echo-sounder SIMRAD EK-15 at a frequency of 200 kHz and analyzed via the Sonar-4 software. The measurement result of the TS (mean±S.E.M.) of Hippocampus kuda female, male and pregnant male seahorses were -56.24±0.047, -57.25±0.032, and -58.26±0.06, respectively. There was a significant difference in the mean TS value of H. kuda based on the reproductive state (P < 0.05). Furthermore, the response to the mean TS value of pregnant H. kuda male (the presence of a brood pouch) was lowly significant compared to the female (absence of a brood pouch) (P< 0.05). The results showed a possibility of finding a pregnant H. kuda male in a water column through active acoustic methods in the future.(AU)

Application of active acoustic technology to assess the target strength of seahorses based on the presence of a reproductive organ

This study aims to provide reliable information on comparing the target strength (TS) values of seahorses based on the reproductive state. This study was carried out using hydro-acoustic technology in a water tank environment. Data were obtained using the single-beam scientific echo-sounder SIMRAD EK-15 at a frequency of 200 kHz and analyzed via the Sonar-4 software. The measurement result of the TS (mean±S.E.M.) of Hippocampus kuda female, male and pregnant male seahorses were -56.24±0.047, -57.25±0.032, and -58.26±0.06, respectively. There was a significant difference in the mean TS value of H. kuda based on the reproductive state (P < 0.05). Furthermore, the response to the mean TS value of pregnant H. kuda male (the presence of a brood pouch) was lowly significant compared to the female (absence of a brood pouch) (P< 0.05). The results showed a possibility of finding a pregnant H. kuda male in a water column through active acoustic methods in the future.(AU)

Application of active acoustic technology to assess the target strength of seahorses based on the presence of a reproductive organ

This study aims to provide reliable information on comparing the target strength (TS) values of seahorses based on the reproductive state. This study was carried out using hydro-acoustic technology in a water tank environment. Data were obtained using the single-beam scientific echo-sounder SIMRAD EK-15 at a frequency of 200 kHz and analyzed via the Sonar-4 software. The measurement result of the TS (mean±S.E.M.) of Hippocampus kuda female, male and pregnant male seahorses were -56.24±0.047, -57.25±0.032, and -58.26±0.06, respectively. There was a significant difference in the mean TS value of H. kuda based on the reproductive state (P < 0.05). Furthermore, the response to the mean TS value of pregnant H. kuda male (the presence of a brood pouch) was lowly significant compared to the female (absence of a brood pouch) (P< 0.05). The results showed a possibility of finding a pregnant H. kuda male in a water column through active acoustic methods in the future.

Temperature effect on the maximum swimming speed of jack mackerelTrachurus japonicus through muscle contraction monitoring

The purpose of this study is to know the effect of temperature on fish muscle contraction of jack mackerel (Trachurus japonicus), which muscle contraction will determine the tail beat frequency and maximum swimming speed. The maximum swimming speed of was evaluated according to the measurement of the muscle contraction time with electric stimuli of 2-7 V, 50 ms. Fish were separated into four groups for temperature acclimation at 10, 15, 18 and 22ºC to reflect typical changes in seasonal water temperature in Japan. Results showed that the swimming speed of the fish was positively related to the tail-beat frequency at all temperatures. The muscle contraction time was also affected by the acclimated temperature, which longer at the lower temperature than higher ones. Mean contraction time (Tm) was 45.1 ms at 10 ºC, 32.7 ms at 15 ºC, 32.9 ms at 18 ºC, and 31.9 ms at 22 ºC, respectively. The mean of maximum tail-beat frequency (Fmax) obtained from Fmax = ½ Tm was 11.4 Hz at 10 ºC, 15.8 Hz at 15 ºC, 16,4 Hz at 18 ºC, and 16.6 Hz at 22 ºC. These were used to estimate the maximum swimming speed (Umax) at each temperature, resulting in 9.45 FL s-¹ at 10 ºC, 13.5 FL s-¹ at 15 ºC, 14.0 FL s-¹ 18 ºC, and 14.2 FL s-¹ at 22 ºC. The seasonal temperature effects on the swimming performance of T. japonicus, which lower water temperature in the winter made low swimming performance.(AU)

Temperature effect on the maximum swimming speed of jack mackerelTrachurus japonicus through muscle contraction monitoring

The purpose of this study is to know the effect of temperature on fish muscle contraction of jack mackerel (Trachurus japonicus), which muscle contraction will determine the tail beat frequency and maximum swimming speed. The maximum swimming speed of was evaluated according to the measurement of the muscle contraction time with electric stimuli of 2-7 V, 50 ms. Fish were separated into four groups for temperature acclimation at 10, 15, 18 and 22ºC to reflect typical changes in seasonal water temperature in Japan. Results showed that the swimming speed of the fish was positively related to the tail-beat frequency at all temperatures. The muscle contraction time was also affected by the acclimated temperature, which longer at the lower temperature than higher ones. Mean contraction time (Tm) was 45.1 ms at 10 ºC, 32.7 ms at 15 ºC, 32.9 ms at 18 ºC, and 31.9 ms at 22 ºC, respectively. The mean of maximum tail-beat frequency (Fmax) obtained from Fmax = ½ Tm was 11.4 Hz at 10 ºC, 15.8 Hz at 15 ºC, 16,4 Hz at 18 ºC, and 16.6 Hz at 22 ºC. These were used to estimate the maximum swimming speed (Umax) at each temperature, resulting in 9.45 FL s-¹ at 10 ºC, 13.5 FL s-¹ at 15 ºC, 14.0 FL s-¹ 18 ºC, and 14.2 FL s-¹ at 22 ºC. The seasonal temperature effects on the swimming performance of T. japonicus, which lower water temperature in the winter made low swimming performance.

Analysis of reproduction and spawning season of glass catfish Ompokhypophthalmus (Bleeker): case in lakes in Buluh Cina Village, Riau,Indonesia

The purpose of this research was to determine the reproductive system and fish spawning season (Ompok hypophthalmus) in Pinang Luar and Pinang Dalam Lakes in Buluh Cina Village of Kampar. This research was conducted at Oxbow Lake of Buluh Cina Village and the Ecology Laboratory of the Faculty of Fisheries and Marine Sciences, University of Riau. Sampling collection of O. hypophthalmuswas carried out at Oxbow Lake (Pinang Dalam and Pinang Luar Lakes) of Buluh Cina from September to November 2016. Meanwhile, measurement of in situ water quality anddata retrieval was carried out only on September 14, 2016. O. hypophthalmus is estimated to experience spawning only oncea year. Spawning time or spawning of fish in November in 2016 was estimated to be exactly the time after the full moon in November before December. Glass catfish studied was not related to the rainy season which usually occurs in the same fish in the Kampar river, because that year coincided with the summer in those months. In recent years, there has been a lot of talk about global climate change which causes uncertain environmental and seasonal conditions. Erratic seasonalconditions have caused the rainy and dry seasons to be erratic. Every living creature, including fish, is strongly influenced byits environmental parameters, whether in the form of the season or the environmental conditions of its own environmental parameters. Although this research was onlycarried out in a short period of time, it was necessary to look at the influence of the environment on fish that was focusedon glass catfish (O. hypophthalmus) at Oxbow Lake of Buluh Cina Kampar Protected Forest.(AU)

Analysis of reproduction and spawning season of glass catfish Ompokhypophthalmus (Bleeker): case in lakes in Buluh Cina Village, Riau,Indonesia

The purpose of this research was to determine the reproductive system and fish spawning season (Ompok hypophthalmus) in Pinang Luar and Pinang Dalam Lakes in Buluh Cina Village of Kampar. This research was conducted at Oxbow Lake of Buluh Cina Village and the Ecology Laboratory of the Faculty of Fisheries and Marine Sciences, University of Riau. Sampling collection of O. hypophthalmuswas carried out at Oxbow Lake (Pinang Dalam and Pinang Luar Lakes) of Buluh Cina from September to November 2016. Meanwhile, measurement of in situ water quality anddata retrieval was carried out only on September 14, 2016. O. hypophthalmus is estimated to experience spawning only oncea year. Spawning time or spawning of fish in November in 2016 was estimated to be exactly the time after the full moon in November before December. Glass catfish studied was not related to the rainy season which usually occurs in the same fish in the Kampar river, because that year coincided with the summer in those months. In recent years, there has been a lot of talk about global climate change which causes uncertain environmental and seasonal conditions. Erratic seasonalconditions have caused the rainy and dry seasons to be erratic. Every living creature, including fish, is strongly influenced byits environmental parameters, whether in the form of the season or the environmental conditions of its own environmental parameters. Although this research was onlycarried out in a short period of time, it was necessary to look at the influence of the environment on fish that was focusedon glass catfish (O. hypophthalmus) at Oxbow Lake of Buluh Cina Kampar Protected Forest.