Aspects of reproductive biology of the red gobyTrypauchen vagina(Gobiidae) from the Mekong Delta

Abstract

This study provides knowledge on reproductive traits of Trypauchen vagina, a target fish for catching, based on data analysis of 701 individuals collected in the Mekong Delta from January to December 2015. The species is a multiple spawner depositing eggs in early wet season (June-August) since gonadosomatic index reaches a high point during this period, supported by the appearance of ripe and spent gonads at that time. Male and female fish matures firstly at 16.59 and 16.81 cm in total length respectively. The species displays high batch fecundity (4,000-12,750 eggs/female). Knowledge of length at first maturity and spawning season is essential for local authorities to set the suitable fish length and time for fishing. The results provide fundamental information on the reproductive biology and contributed to knowledge for fish population sustainable management.

Reproductive biology of the unique mudskipper Periophthalmodon septemradiatus living from estuary to upstream of the Hau River

“…The length at first mature ( L m ) of the mudskipper P. septemradiatus could be related to the changes of biotic and abiotic conditions since L m of this fish increased gradually from LD to BD. Male and female P. septemradiatus matured firstly at different TL which is also found in the small‐scale goby P. elongatus (Tran, ), the large‐scale goby P. serperaster (Dinh et al, ), the duckbill sleeper B. butis (Dinh & Le, ) and the red goby T. vagina (Dinh, ). However, size at first maturity of these four gobiid species was greater that of P. septemradiatus .…”

“…Many gobiid species are serial spawners depositing eggs more than one time during the spawning period (Longhurst & Pauly, 1987). Indeed, P. septemradiatus was an iteroparous species which is also found in some gobiid species of the family Gobiidae such as the small-scale goby P. elongatus (Tran, 2008), the boddart's goggle-eyed goby B. boddarti (Dinh et al, 2015), the large-scale goby P. serperaster (Dinh et al, 2016), the red goby T. vagina (Dinh, 2018) and the goby S. pleurostigma (Dinh & Tran, 2018 The mudskipper P. septemradiatus spawned throughout a year-round as the mature ovaries and testes were monthly found in study regions. It was likely that the reproducing season of this species was not related to the variation of environmental factors.…”

“…Additionally, male P. septemradiatus released sperms several times as mature testis comprised different types of spermatocytes (SC1, SC2, ST and SZ). Likely, the small‐scale goby P. elongatus (Tran, ), the boddart's goggle‐eyed goby B. boddarti (Dinh et al, ), the large‐scale goby P. serperaster (Dinh et al, ), the red goby T. vagina (Dinh, ) and the goby S. pleurostigma (Dinh & Tran, ) in the estuary of Hau River are also multiple spawners. Many gobiid species are serial spawners depositing eggs more than one time during the spawning period (Longhurst & Pauly, ).…”

“…Meanwhile, some burrowing fish such as the atlantic mudskipper Periophthalmus barbarus in Imo estuary, Nigeria reproduces mainly in May due to high nutrients transported by rainfall to the study region at that time (Etim, King, & Udo, ; Udo, ); the giant mudskipper P. schlosseri in the coastal mudflat in Malaysia spawns during the south‐west monsoon season from April to October because of abundant food resources in this area at that time (Mazlan & Rohaya, ). Similarly, some species of the family Gobiidae, living in situ inside burrows in the Mekong Delta, spawn mainly in the wet season in which the high rainfall aids in transport of nutrients to the estuarine region, for example, the small‐scale goby P. elongatus (Tran, ), the boddart's goggle‐eyed goby B. boddarti (Dinh et al, ), the large‐scale goby P. serperaster (Dinh et al, ), the red goby T. vagina (Dinh, ) and the goby S. pleurostigma (Dinh & Tran, ) deposit eggs in the wet season (Table ). A period from May to October is also the spawning season for some other gobies living in different habitats such as the round goby N. melanostomus (Macinnis & Corkum, ), the crystal goby Crystallogobius linearis (Caputo, Mesa, Candi, & Cerioni, ) and the whitebarred goby Amblygobius phalaena (Takegaki, ; Table ).…”

“…Similarly, some species of the family Gobiidae, living in situ inside burrows in the Mekong Delta, spawn mainly in the wet season in which the high rainfall aids in transport of nutrients to the estuarine region, for example, the small-scale goby P. elongatus (Tran, 2008), the boddart's goggle-eyed goby F I G U R E 7 Relationships between fecundity and fish weight and total length of Periophthalmodon septemradiatus. LD, ALT, PT, TH, and DB represent for Long Duc-Soc Trang, An Lac Tay-Soc Trang, Phu Thu-Can Tho, Tan Hung-Can Tho, and Binh Duc-An Giang, respectively B. boddarti (Dinh et al, 2015), the large-scale goby P. serperaster (Dinh et al, 2016), the red goby T. vagina (Dinh, 2018) and the goby S. pleurostigma (Dinh & Tran, 2018) deposit eggs in the wet season (Table 3). A period from May to October is also the spawning season for some other gobies living in different habitats such as the round goby N. melanostomus (Macinnis & Corkum, 2000), the crystal goby Crystallogobius linearis (Caputo, Mesa, Candi, & Cerioni, 2003) and the whitebarred goby Amblygobius phalaena (Takegaki, 2000; Table 3).…”