Feeding ecology of Ellochelon vaigiensis (Quoy & Gaimard, 1825) living in the Mekong Delta, Vietnam

Abstract

Ellochelon vaigiensis (squaretail mullet) adapts to a wide salt spectrum, grows quickly and is easy to raise with other species, so it is the object of attention in aquaculture. Information on the biology and ecology of the species, diet, in particular, is still scattered. Here, we explore the feeding habit, feeding intensity, and food composition of the squaretail mullet. A total of 942 fish (526 males and 416 females) were collected from November 2020 to October 2021 at four coastal sites in the Mekong Delta, Vietnam. The squaretail mullet is an algi‐omnivorous fish, as their relative gut length (1.81) falls into the range 1–3, and the diet is mostly based on algae. The feeding intensity is high due to the high value of the fullness index (4.39 ± 0.08%). The fullness index did not vary by sampling site and month, while RGL and FI changed depending on sex. Bacillariophyta (49.13%), detritus derived from organic matter (30.37%), and Cyanophyta (18.39%) are the dominant food items in the diet composition of E. vaigiensis, in which detritus is the most important food with the highest IRI index. Besides, Euglenophyta (1.00%), Chlorophyta (0.95%), Paramecium (0.06%), Copepoda (0.04%), Rotatoria (0.03%), Polychaeta (0.02%), and Cladocera (0.01%) are also recorded and ranked based on their biovolume. Some differences in diet composition are observed between immature and mature at different seasons and their interactions. Our results increase the knowledge about the feeding ecology of squaretail mullet and can help the sustainable management of this commercially important fish species.

Food habits of two mullets inhabiting Iraqi marine waters, Northwest Arabian Gulf

“…Ashiq Ur Rahman et al [22] found that P. subviridis in the Parangipettai waters, India consumed detritus, diatoms, dinoflagellates, algae, zooplankton, polychaetes, foraminiferans, larval forms and miscellaneous items. Similar results were obtained for the other species of the mullet, Ellochelon vaigiensis in the Mekong Delta, Vietnam, where detritus was the essential food in the diet composition of the species and did not vary with sex, body size, season, and sampling site [48]. Several authors considered the diatoms were the most important food items for this species.…”

The reproductive biology of Ellochelon vaigiensis from the Vietnamese Mekong Delta

“…The growth pattern of E. vaigiensis is negative allometry because the b value is <3 (2.13–2.68), and this fish is well adapted to the environment as the CF value approaches the well‐being threshold of 1 (0.97–1.13) (Dinh, Truong, Nguyen, Tran, et al., 2022 ). This squaretail mullet is an algi‐omnivorous with the food composition of mainly Bacillariophyta, followed by detritus (30.3%) and Cyanophyta (18.3%) (Dinh, Truong, Nguyen, Lam, et al., 2022 ). Nguyen et al.…”

Variations in length-weight relationship, growth and body condition of the commercial mullet Ellochelon vaigiensis in the Vietnamese Mekong Delta

“…This fish can reach the maximum length of 63 cm in Indo-Pacific and Caribbean regions [ 5 ], but common fish caught at 35 cm in the Western Central Pacific [ 6 ]. Ellochelon vaigiensis is available throughout the year and is considered to be an essential food source in the VMD [ 7 , 8 , 9 ], where it is facing the loss of habitats and population degradation due to anthropogenic and natural threats, e.g., overexploitation, environmental pollution, and climate change [ 10 ].…”