5 research outputs found
Biological Aspects and Feeding Habits of Spinetail Devil Ray (Mobula mobular) landed in the Palabuhanratu Nusantara Fishing Port
Get PDFOptimal management of aquatic resources requires a good understanding of the biological aspects and other information related to these resources. This study was conducted to determine the biological aspects and feeding habits of Mobula mobular landed in the Palabuhanratu Nusantara Fishing Port. The research was conducted from September 2021 to May 2022. Data collected through a direct survey that included aspects of biology, stomach contents and information on fishing grounds. It was recorded that 21 individuals of M. mobular landed in the area during the study period. According to the Chi-Square test, the sex ratio between females and males is balanced with the growth pattern of M. mobular was negatively allometric. The male of M. mobular was generally found as immature individuals. The prey items identified in the stomachs belong to five groups: decapods, copepods, gastropods, Polychaeta, and others. Decapods were the most important prey (Index of Relative Importance 99,54%), while the other prey groups were only as complementary food. M. mobular is categorized as a plankton feeder. The fullness index value was 23.8%, while the vacuity index was 76.2% and categorized as relatively low fed. M. mobular is classified as an omnivorous animal that tends to be carnivorous with an animal preference with a trophic value of level 3
Conditions for Sediment Coating Microplastic in Mangrove Ecosystems in Kupang and Rote, East Nusa Tenggara, Indonesia
No full textThe observation and direct sampling, as well as laboratory tests of this research was conducted from June until October 2018. This study aims to determine the existence of microplastics in the sediment of water bodies in Kupang and Rote Districts based on the number, type, size and abundance of microplastics. The data used in this study include the type of sediment, microplastic abundance and the characteristics of the data collection area. Microplastics are plastic particles sized less than 5 mm, and in our research, were divided into 4 types: manifold fiber, fragment, film and pellets. Herein, 849 particles of microplastic were found: 635 fibers, 160 particle fragments, and 54 particle films. The primary influencing factor for microplastic deposition is the sedimentary texture itself. Sediments of a coarse type do not capture as much microplastic as do sediments of a finer texture. Data collection area characteristics also affect accumulation
Structure of Seagrass Community in the Karapyak Beach, Pangandaran Regency, West Java
No full textKarapyak Beach is one of the beaches that has a variety of abundant marine ecosystems. One of the marine ecosystems is seagrass. This study aims to identify the structure of seagrass communities in Karapyak waters based on seagrass species, species density, species frequency, diversity, and uniformity. This research was conducted in February – April 2021. The method used is a survey method with direct observation at each predetermined station using a square transect measuring 1 x 1 m2. While the determination of stations and observation points is done by purposive sampling method. The research location is divided into three stations, each station is divided into five substations (plots), and a 50 m transect line is made perpendicular to the shoreline. Furthermore, the results showed four types of seagrass found in the waters of Karapyak Beach, namely Cymodocea rotundata, Thalassia hemprichii, Halodule pinifolia, Halodule uninervis. The density of seagrass at station I was in the medium category, namely 125 individuals/m2, with a cover percentage of 86%. Then the lowest seagrass density was found at the second station, which was 104 individuals/m2 including the unhealthy category with a cover percentage of 58%. While the highest density score was shown at the third station, namely 144 individuals/m2 with a closing percentage of 94%
Age, growth, and intrinsic sensitivity of Endangered Spinetail Devil Ray (Mobula mobular) and Bentfin Devil Ray (M. thurstoni) in the Indian Ocean
No full textDevil rays (Mobula spp.) are caught in fisheries across the Indian Ocean, with reports of significant recent declines in catch and sightings. Globally, the few populations studied have extremely low population growth rates due to low fecundity and long reproductive cycles, making them highly vulnerable to overfishing. To allow for assessment of the current sustainability of devil ray catch in the Indian Ocean, we provide estimates of age using the caudal vertebrae; somatic growth using a Bayesian, multi-model approach; maximum intrinsic rate of population increase (rmax); and fishing mortality for Endangered Spinetail Devil Ray (Mobula mobular) and Bentfin Devil Ray (M. thurstoni) sampled from small-scale fisheries catch in Indonesia, Kenya, and Pakistan. The oldest individuals of Spinetail Devil Ray (n = 79) and Bentfin Devil Ray (n = 59) were 17.5 and six years, respectively. Both species had relatively low growth coefficients (k = 0.05 and g = 0.19 year−1, respectively), with the von Bertalanffy and logistic models providing the best fitting growth models, and low rmax (0.109 and 0.107 year−1, respectively) indicating that they are highly sensitive to overexploitation. Fishing mortality F estimates (0.16 and 0.18 year−1, respectively) were higher than rmax and exploitation ratio E (0.77 and 0.80, respectively) were higher than an optimum value of 0.5 for biological sustainability for both species, suggesting that the fisheries catches of the species are unsustainable. We demonstrate an approach to assess data-poor species and apply this to two Indian Ocean devil ray species. The results highlight the urgent need for better management actions to reduce the catch of all devil rays to prevent species extinction and aid in population recovery.Sample and data provision in Indonesia were possible due to support from the National Research and Innovation Agency and the Ministry of Marine Affairs and Fisheries, Republic of Indonesia as well as research collaboration with the Universitas Padjadjaran. Sample and data provision in Pakistan were made possible by in-kind contribution and collaboration with WWF Pakistan, with thanks to Dr Tahir Rasheed, Regional Head of Sindh and Balochistan Umair Shahid, WWF Mozambique, as well as Ms. Summaiya Abid and Ms. Julaila Haroon. Additional acknowledgement of the Directorate General of Marine Fisheries Department's provision of the requisite biological laboratory facility and expertise of Ms. Kashifa Zohra and Mr. Hamid Badar Osmany. Further gratitude is extended to Farhan Khan, Deputy Commissioner of Fisheries Development Commissioner and IOTC focal point, and Mr Samar Khan Baloch, CITES focal point, Pakistan. Data provision in Kenya were supported by Joey Ngunu. We would also like to acknowledge the support of all the fishers, traders, and local government officials at landing sites across the three sampling countries for supporting data and sample collection. We also thank the reviewers for their constructive feedback, which has improved this work.This work was supported by a Save Our Seas Foundation Small Grant (456) and Banyan Tree Global Foundation Greater Good Grant (2021–011). EB was funded by a Natural Environment Research Council (NERC) PhD studentship through the IAPETUS2 Doctoral Training Partnership (award ref. 2284959). AT is supported by the King Abdullah University of Science and Technology (KAUST) Global Fellowship Program (Award No. ORA-2022–5001)
Condition Correlation of Coral Reef and Abundance of Indicators Reef Fish in Mandrajaya Water Ciletuh Geopark West Java
Get PDFThe coral reef ecosystem has role as feeding and nursery ground for indicator reef fishes. Coral reef ecosystems in recent years has decline in function, globally the area of coral reefs has decline about 11%. This study aims to analyze the correlation between the condition of life coral reef with the abundance of indicators reef fish. This research was conducted in the waters of Mandrajaya (Ciletuh Geopark) with 5 stations. The method used in this research is Line Intercept Transect (LIT) and Underwater Visual Census (UVC). Data observed were the percentage of live coral and dead coral, as well as the number of indicator reef fish found. Results show that the percentage value of life coral is 51.17% dominated by the CF (Coral Foliose) category, this value shows that the condition of living coral cover is included in the good category. The obtained Mortality Index is worth 0.43 (low), this value is obtained from the ratio of life coral and dead coral. A total number of indicators reef fish is 31 individuals / 1750m² from four species, dominated by Chaetodon octofasciatus (12 individuals). Correlation between life coral cover and abundance of indicators reef fish was positive and had a sufficient relationship on both variables (r = 0.58) with a determinant coefficient of 48%
