A total of 3 815 individuals were collected from the three habitats, comprising 154 species belonging to 57 families (Table A1). In the mangrove area, 2 623 individuals of 117 species belonging to 48 families were collected. In contrast, fewer fish were recorded in the seagrass beds (754 individuals belonging to 46 species of 28 families) and coral reefs (438 individuals belonging to 61 species of 35 families). More number of species and individuals were recorded in the mangroves than that in the seagrass beds and coral reef habitats (Table 1). The mean number of individuals in the samples collected for five consecutive days in mangrove area was significantly higher than that in seagrass beds and coral reefs in wet season (p<0.05) (Fig. 2a). The mean number of species in the samples collected for five consecutive days in mangrove was significantly higher than that in coral reefs in wet season and in seagrass in dry season (p<0.05) (Fig. 2b). In addition, there was no significant difference in the mean number of individuals and species between seagrass beds and coral reefs.
Species Common name Family Number of individuals Mangrove Seagrass bed Coral reef Cynoglossus macrolepidotus Tonguesole Cynoglossidae 0 0 1 Cynoglossus joyneri Red tonguesole Cynoglossidae 2 0 0 Brachirus orientalis Oriental sole Soleidae 9 1 0 Pardachirus pavoninus Peacock sole Soleidae 1 0 0 Sardinella zunasi Japanese sardinella Clupeidae 5 9 1 Konosirus punctatus Dotted gizzard shad Clupeidae 0 4 0 Thrissa setirostris Longjaw thryssa Engraulidae 0 1 0 Dasyatis akajei Whip stingray Dasyatidae 1 0 1 Siganus fuscescens Mottled spinefoot Siganidae 260 48 104 Siganus guttatus Orange-spotted spinefoot Siganidae 14 0 1 Leiognathus brevirostris Shortnose ponyfish Leiognathidae 5 1 4 Leiognathus equulus Common ponyfish Leiognathidae 202 11 1 Leiognathus berbis Berber ponyfish Leiognathidae 1 0 0 Nuchequula nuchalis Spotnape ponyfish Leiognathidae 14 1 3 Gazza minuta Toothpony Leiognathidae 15 0 0 Gerres oblongus Slender silver-biddy Gerreidae 200 53 1 Gerres filamentosus Whipfin silver-biddy Gerreidae 48 34 0 Gerres erythrourus Deep-bodied mojarra Gerreidae 0 5 0 Gerres limbatus Saddleback silver-biddy Gerreidae 0 1 0 Gerres macracanthus Longspine silverbiddy Gerreidae 15 0 0 Upeneus tragula Freckled goatfish Mullidae 74 2 3 Upeneus sulphureus Sulphur goatfish Mullidae 1 0 0 Parupeneus ciliatus Whitesaddle goatfish Mullidae 2 0 1 Parupeneus indicus Indian goatfish Mullidae 0 1 2 Parupeneus multifasciatus Manybar goatfish Mullidae 0 0 1 Terapon jarbua Jarbua terapon Terapontidae 15 66 39 Therapon oxyrhynchus Sharpbeak terapon Terapontidae 2 0 0 Terapon theraps Largescaled terapon Terapontidae 2 0 0 Pelates quadrilineatus Fourlined terapon Terapontidae 218 35 0 Scarus frenatus Bridled parrotfish Scaridae 0 0 4 Scarus ghobban Blue-barred parrotfish Scaridae 6 0 5 Leptoscarus vaigiensis Marbled parrotfish Scaridae 1 0 0 Sillago maculata Trumpeter whiting Sillaginidae 98 12 30 Sillago japonica Japanese sillago Sillaginidae 38 1 0 Lutjanus malabaricus Malabar blood snapper Lutjanidae 0 0 1 Lutjanus russellii Russell's snapper Lutjanidae 12 3 6 Lutjanus fulviflamma Dory snapper Lutjanidae 2 1 17 Lutjanus argentimaculatus Mangrove red snapper Lutjanidae 1 0 1 Lethrinus haematopterus Chinese emperor Lethrinidae 0 1 8 Lethrinus ornatus Ornate emperor Lethrinidae 3 0 1 Lethrinus nebulosus Spangled emperor Lethrinidae 10 1 1 Lethrinus harak Thumbprint emperor Lethrinidae 0 0 1 Scolopsis monogramma Monogrammed monocle bream Nemipteridae 17 0 10 Scolopsis vosmeri Whitecheek monocle bream Nemipteridae 2 0 4 Scolopsis lineata Striped monocle bream Nemipteridae 0 0 3 Scolopsis taenioptera Lattice monocle bream Nemipteridae 3 0 0 Pentapodus setosus Butterfly whiptail Sparidae 1 0 0 Acanthopagrus schlegelii Blackhead seabream Sparidae 0 0 7 Acanthopagrus chinshira Okinawan yellow-fin seabream Sparidae 1 0 0 Rhabdosargus sarba Goldlined seabream Sparidae 0 1 0 Labracinus cyclophthalmus Fire-tail devil Pseudochromidae 0 0 1 to be continued
Table A1. The number of individuals of fish in mangrove, seagrass bed and coral reef in Wenchang, China
Habitat/habitat group All species/% (n) Individuals/% Mangrove Mangrove species 57.3 (67) 31.3 Mangrove–seagrass species 13.7 (16) 17.9 Mangrove–reef species 14.5 (17) 2.9 Mangrove–seagrass–reef species 14.5 (17) 48.0 Seagrass bed Seagrass species 21.7 (10) 2.8 Mangrove–seagrass species 34.8 (16) 19.9 Seagrass–reef species 6.5 (3) 0.4 Mangrove–seagrass–reef species 37.0 (17) 76.9 Coral reef Reef species 39.3 (24) 16.1 Seagrass–reef species 4.9 (3) 3.0 Mangrove–reef species 27.9 (17) 10.1 Mangrove–seagrass–reef species 27.9 (17) 70.8 Note: Number of fish species is shown in parentheses.
Table 1. Percentage contribution by species and individuals for each habitat group
Figure 2. Mean number of fish species (a) and individuals (b) during sampling months in each habitat. The error bars are standard deviations. MG, SG, and CR represent mangroves, seagrass, and coral reefs, respectively.
The most dominant families in the mangrove were Gobiidae (20 species, 17.1%, represented by Oxyurichthys ophthalmonema), followed by Labridae (5 species, 4.3%, represented by Halichoeres nigrescens), and Leiognathidae (5 species, 4.3%, represented by Leiognathus equulus) (Fig. 3a). In the seagrass beds, Gerreidae (4 species, 8.7%), Leiognathidae (3 species, 6.5%), and Lutjanidae (2 species, 4.3%) were the dominant families, and the representative species included Gerres oblongus, Leiognathus equulus, and Lutjanus russellii. In the coral reef, the most dominant families were Labridae (8 species, 13.1%), Lethrinidae (4 species, 6.6%), and Lutjanidae (4 species, 6.6%), with Lethrinus haematopterus being the representative species.
Figure 3. Relative family composition of fish species (a) and the number of individuals (b) in the three habitats.
In terms of individual numbers, Gobiidae was the dominant family in the mangrove area, accounting for 21.3% of all species, followed by Mugilidae and Siganidae, which together accounted for 22.4% of the species (Fig. 3b). Mugilidae was the most dominant species in the seagrass beds, representing approximately 47.7%, followed by Terapontidae (101 individuals, 13.4%) and Gerreidae (94 individuals, 12.5%). Siganidae (105 individuals, 24.0%), Mugilidae (89 individuals, 20.3%), and Terapontidae (39 individuals, 8.9%) were the three dominant species in the coral reef.
The similarity indices suggested that fish assemblages can be divided into three groups (coral, seagrass, and mangrove habitat type) (Figs 4a, b). The results of similarity tests using NPMANOVA revealed a highly significant difference among habitats (F2, 27=4.01, p=0.003).
Of the 154 species recorded, 101 species (accounting for approximately 65.6% of all species) occurred in a single habitat, whereas the individuals accounted for 23.7% of all species. However, only 36 species were recorded in two habitats and 17 species were recorded in three habitats; thus, 34.4% of all species were recorded in multiple habitats (Table 1). Specifically, 16 species were recorded in the mangrove–seagrass areas, 17 species were recorded in the mangrove–coral reef areas, 3 species were recorded in the seagrass–coral reef areas, and 17 species were recorded in the mangrove–seagrass–coral reef areas. In the mangrove and coral reef areas, the local species represented more than 35% of the total species. In comparison, in the seagrass area, species that used multiple habitats accounted for 78.3% of all species. In terms of individuals, more than 60% of all individuals used two or three habitats, especially seagrass and coral reef areas. The mangrove–seagrass–coral reef species contributed to approximately 70% of all individuals in seagrass and coral reef areas, although seagrass–coral reef species only represented 0.4% of individuals in the seagrass beds. Minimal differences were found in both fish species and individuals using the mangrove–seagrass–coral reef continuum (Table 1).
The length of eight species (Mugil cephalus, G. oblongus, Siganus fuscescens, Terapon jarbua, Sillago maculata, Upeneus tragula, L. russellii, and Monacanthus chinensis) was higher in coral reef than that in seagrass and mangrove areas, showing possible ontogenetic habitat shifts from mangrove or seagrass beds to coral reef (Fig. 5). This shift might explain the trend towards changing habitats by individuals and species. On the whole, in their early stages of development, these fish mainly inhabited the mangrove and seagrass beds, which is consistent with the fact that mangrove and seagrass habitats serve as nurseries for fish (Beck et al., 2001).
Connectivity of fish assemblages along the mangrove-seagrass-coral reef continuum in Wenchang, China
- Received Date: 2019-07-09
- Accepted Date: 2019-09-30
- Available Online: 2020-12-28
- Publish Date: 2020-08-25
- connectivity /
- fish /
- mangrove /
- seagrass /
- coral reef /
- Wenchang /
- northern South China Sea
Abstract: Understanding the connectivity of fish among different typical habitats is important for conducting ecosystem-based management, particularly when designing marine protected areas (MPA) or setting MPA networks. To clarify of connectivity among mangrove, seagrass beds, and coral reef habitats in Wenchang, Hainan Province, China, the fish community structure was studied in wet and dry seasons of 2018. Gill nets were placed across the three habitat types, and the number of species, individuals, and body size of individual fish were recorded. In total, 3 815 individuals belonging to 154 species of 57 families were collected. The highest number of individuals and species was documented in mangroves (117 species, 2 623 individuals), followed by coral reefs (61 species, 438 individuals) and seagrass beds (46 species, 754 individuals). The similarity tests revealed highly significant differences among the three habitats. Approximately 23.4% species used two habitats and 11.0% species used three habitats. A significant difference (p<0.05) in habitat use among eight species (Mugil cephalus, Gerres oblongus, Siganus fuscescens, Terapon jarbua, Sillago maculata, Upeneus tragula, Lutjanus russellii, and Monacanthus chinensis) was detected, with a clear ontogenetic shift in habitat use from mangrove or seagrass beds to coral reefs. The similarity indices suggested that fish assemblages can be divided into three large groups namely coral, seagrass, and mangrove habitat types. This study demonstrated that connectivity exists between mangrove–seagrass–coral reef continuum in Wenchang area; therefore, we recommend that fish connectivity should be considered when designing MPAs or MPA network where possible.
|Citation:||Jianguo Du, Meiling Xie, Yuyu Wang, Zehao Chen, Wenhua Liu, Jianji Liao, Bin Chen. Connectivity of fish assemblages along the mangrove-seagrass-coral reef continuum in Wenchang, China[J]. Acta Oceanologica Sinica, 2020, 39(8): 43-52. doi: 10.1007/s13131-019-1490-7|