Trophic levels of teleost and elasmobranch species in the Persian Gulf and Oman Sea

Abstract

Summary Knowing the trophic level of marine organisms is essential to understanding their ecological role in the ecosystem and for quantifying the ecosystem effects of fishing to establish effective management of fishing resources. In comparison to other systems, information about the trophic level of marine organisms in the Persian Gulf and Oman Sea is very scarce. Here, the main aim was to estimate trophic level in these areas using all available diet information from different marine species using TrophLab software. The trophic level of 32 fish species was estimated with the available diet data. The trophic level ranged from 2.28 to 4.50. High trophic levels were found for Chorocentrus nudus (TL = 4.7), Saurida tumbil (TL = 4.6), Rhizoprionodon acutus (TL = 4.5), Torpedo sinuspersici (TL=4.5), Gymnura poecilura (TL = 4.5), Sphyraena putnamae (TL = 4.5) and Euthynnus affinis (TL = 4.5). In contrast, lower trophic levels were estimated for Tenualosa ilisha (TL = 2.28) and Sardinella sindensis (TL = 2.92). As expected, a positive correlation was found between the trophic level and body size, indicating changes in the diet due to variations in predatory capacities. The results of this study may be useful in the formulation of trophic indicators and modelling of the ecosystems.

Buried in the sand: Uncovering the ecological roles and importance of rays

“…3.2 SCA Szczepanski and Bengtson (2014) 3.5 SCA Woodland, Secor, and Wedge (2011) Southern eagle ray (Myliobatis goodei, Myliobatidae) 3.2 SCA Molina and Cazorla (2015) Cowtail ray (Pastinachus sephen, Dasyatidae) 3.2 SCA Rastgoo et al (2018) 3.3 SCA Rastgoo and Navarro (2016) Shark ray (Rhina ancylostoma, Rhinidae) 3.2 SIA Borrell et al (2011) Giant manta ray (Mobula birostris, Mobulidae) 3.4 SIA Burgess et al (2016) Giant devil ray (Mobula mobular, Mobulidae) 3. (Navia et al, 2016).…”

“…(4.5;Rastgoo & Navarro, 2016;Rastgoo et al, 2018), while larger species such as the shark ray (Rhina ancylostoma, Rhinidae; mean weight 77.4 kg [D'Alberto, White, Chin, & Simpfendorfer, 2019]) and the spotted eagle ray (Aetobatus ocellatus, Aetobatidae; mean weight 41.4 kg [D'Alberto et al, 2019]) had relatively low TLs (3.2; Borrell,…”

Comparative diets of sympatric batoid elasmobranchs in the Gulf of Oman

“…Valinassab et al 2006, Jabado et al 2017, Rastgoo & Navarro 2017. Indeed, 82 species of sharks and more than 20 species of batoids have been described for the Gulf of Oman and nearby areas (Almojil et al 2015), though several species appear to be declining, evidently from degradation and disappearance of habitats or the direct impacts of fishing (Valinassab et al 2006, Jabado et al 2017).…”

Preliminary assessment of the trophic structure of demersal fish community in the Sea of Oman

“…This means a lot still needs to be done by biologists in order to fully comprehend the complexity of fish trophic strategies, essential information for management policy guidance considering the basal feeding requirements of targeted fish species within their ecosystem of interest. Information on fish diet is particularly scarce in the Arabian Gulf and Sea of Oman, despite the peculiarity of this region in terms of diversity of marine habitats, oceanographic conditions and marine biodiversity (Rastgoo and Navarro, 2017).…”

“…It is relatively deep, with 3/4 th of its waters being more than 1,000 m depth (Rastgoo and Navarro, 2017). Oceanographic conditions characterizing the Sea of Oman are described in detail in Banse and Piontkovski (2006), Al-Hashmi et al (2010), Piontkovski et al (2011) and Piontkovski and Chiffings (2014).…”