|
|
|
|
|
|
|
|
|
|
|
RSS |
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
Population parameters and exploitation status of banana jellyfish (Catostylus perezi, Ranson, 1945) in the northern waters of the Oman Sea
|
Seyed Ahmadreza Hashemi1   , Mastooreh Doustdar1 , Ashkan Azhdari1 , Ghasem Rahimi1 , Rahimeh Rahmati1 |
| 1- Iranian fishery science reserch institute |
|
|
Abstract: (36 Views) |
Introduction
More than 1,400 jellyfish species have been identified worldwide (Brotz et al., 2017). However, only 23 edible jellyfish species have been studied for their nutritional properties, with a growing commercial market primarily observed in Asia (Edelist et al., 2021). Various studies and field reports indicate that large-scale and frequent jellyfish blooms have occurred globally since the 1950s. Jellyfish have long been consumed as food in many Southeast Asian countries, particularly China, largely due to their high collagen content (Subhan et al., 2021). Jellyfish blooms have been shown to significantly impact human activities worldwide, including tourism, aquaculture, fishing operations, power plant cooling systems, and seawater desalination plants. Despite these challenges, jellyfish also contribute positively to marine ecosystems by providing habitat for various fish species and playing a role in carbon sequestration (Edelist et al., 2021). Jellyfish are polypless members of the phylum Cnidaria. These gelatinous marine animals possess a bell-shaped body and trailing tentacles. They use the pulsation of their umbrella-like bell for locomotion, while their tentacles are primarily used for capturing prey (Sealifebase, 2023). Jellyfish inhabit all of the world’s oceans, occurring from the surface to great depths. Fossil evidence suggests that jellyfish have existed in marine environments for over 500 million years—possibly up to 700 million years—and they represent some of the oldest known multicellular organisms with differentiated tissues (Gueroun et al., 2021). In the southern waters of Iran, at least six jellyfish species belonging to three families have been documented. Among these, Cassiopea andromeda is endemic to the Persian Gulf and Nayband Bay, whereas the remaining five species exhibit broader distributions across the region (Owfi, 2020). In the Tis (Chabahar) and Pozm areas, the dominant jellyfish species is the banana jellyfish (Catostylus perezi), which is also the predominant species in the northern Indian Ocean and is currently subject to commercial harvesting (Gueroun et al., 2021). C. perezi, commonly known as the banana jellyfish, is distributed across the western Indian Ocean from Kuwait to India. It belongs to the subphylum Metazoa, phylum Cnidaria, class Scyphozoa, order Rhizostomeae, family Catostylidae (Riyas et al., 2019).
Methodology
The study area is situated in the northern part of the Oman Sea, within Sistan and Baluchistan Province, Iran, covering an east longitude range of 28°60′ to 20°61′ and a north latitude range of 14°25′ to 60°25′. Two landing sites—Pozm Port (28°60′ E, 14°25′ N) and Tis Port (62°60′ E, 35°25′ N)—were selected as sampling stations for the banana jellyfish. At each station, several specimens were collected, counted, and rinsed before being transported to the laboratory for subsequent biochemical analysis. The primary method of jellyfish capture in this region involves the use of a scoop net/cast net.
Result
Sampling of banana jellyfish was conducted in the Tis and Pozm regions from June to December 2024 (corresponding to the Persian year 1403). The highest frequency of occurrence was recorded in August (48%), while the lowest was observed in June (1%). A total of 503 individuals were subjected to biometric measurements during the study period. The mean total length of the sampled jellyfish was 20±6 cm, with a range of 8–40 cm (Fig. 1). The mean wet weight was 326 ± 899 g, with individual weights ranging from 180 g to 1,700 g. The highest length frequency was observed in 17–20 cm size class (approximately 20%), whereas the lowest frequency was recorded in the 38–41 cm size class (1%).
Figure 1: Location of jellyfish data collection areas in the northern waters of the Sea of Oman (Sistan and Baluchestan Province)
Discussion and conclusion
The estimated values of maximum sustainable yield (MSY), maximum constant yield (MCY), and total allowable catch (TAC) were all higher than the actual catch recorded for banana jellyfish in 2024. This suggests that the current level of harvesting in the northern Oman Sea (Sistan and Baluchistan Province) remains below the optimal exploitation level. The exploitation coefficient (E) was less than 0.5, and fishing mortality (F) was lower than natural mortality (M), further indicating the absence of significant fishing pressure on this species. According to Sparre and Venema (1998) and King (2007), the exploitation rate should not exceed 0.5, and fishing mortality should remain below natural mortality; otherwise, it signals overfishing. Two primary factors influence stock pressure:1) The intensity of fishing and harvesting from the population, and 2) Environmental variables affecting the survival and accessibility of the stock (Mateus and Estupiñán, 2002).
The length-based spawning potential ratio (LBSPR) index for the study period exceeded 0.8, indicating no signs of overfishing and a healthy stock status (Cousido-Rocha et al., 2022; Deng et al., 2024). The LBSPR serves as an estimator of the spawning potential ratio (SPR), where values below approximately 0.2 (B/B₀ ≈ 0.2) suggest severe depletion, while values above 0.6 (B/B₀ ≈ 0.6) reflect a favorable stock condition (Zhai et al., 2020; Froese et al., 2018). The ratio of available fishing mortality to maximum sustainable yield fishing mortality was less than one (F/FMSY<1) and the ratio of available biomass to sustainable biomass was greater than one (B/BMSY>1), indicating no overfishing. Froese and Pauly (2020) consider the fishing mortality at maximum sustainable yield (FMSY) and natural mortality (M) to be equivalent (FMSY ≈ M). F/FMSY values above one mean overfishing and less than one means underfishing, and B/BMSY values above one mean underfishing and less than one mean overfishing (Ji et al., 2019). Overall, the results indicate that the banana jellyfish population in the northern Oman Sea is currently underexploited and shows no signs of overfishing. Continued monitoring and adaptive management strategies are recommended to ensure the long-term sustainability of this resource.
Conflict of Interest
There are no known conflicts of interest associated with this study.
Acknowledgements
This article is a part of the final report of a research project approved by the Iranian Fisheries Science Research Institute (IFSRI). |
|
| Keywords: Banana jellyfish, Spawning potential ratio, Vonbertalanffy equation, Exploitation. |
|
|
Full-Text [PDF 941 kb]
(6 Downloads)
|
Type of Study: Research |
Subject:
ارزيابي ذخاير و پويايي جمعيت
Received: 2024/12/22 | Accepted: 2025/05/12
|
|
|
|
|
|
|
| Send email to the article author |
|
|
|
| Add your comments about this article |
|
|
|
|
|
|
|
|
|
|
|
