Checklist of the tidal pool fishes of Jeju Island, Korea.

Seventy-six species of fishes, representing 60 genera and 34 families, were recorded from tidal pools on Jeju Island, southern Korea. The major families in terms of species were the Gobiidae (11 species), Pomacentridae (8 species), Blenniidae (6 species), and Labridae (5 species). Thirty-nine species were classified as tropical, 26 as temperate and 11 as subtropical.

Introduction

Jeju Island is located southwest of the Korean Peninsula (Kim and Go 2003, Kim et al. 2009, Kwun et al. 2017) and has a volcanic rocky shoreline. The island lies in the southernmost temperate region of Korea, and many subtropical and temperate species of fishes inhabit the coastal and adjacent waters of the island (Kim 2009). Many marine fish species use tidal pools for part of their life cycle (Andrade et al. 2007, González-Murcia et al. 2012, Choi and Lee 2013), so studies of the occurrence PageBreakof fish species in tidal pools provide important information on local fish biodiversity and for the conservation of coastal ecosystems (Machado et al. 2015, Torres-Hernández et al. 2016).

The first checklist of the fishes of Jeju Island (Uchida and Yabe 1939) included 162 species from coastal and adjacent waters. Subsequent inventories (Kim and Lee 1994, Yoo et al. 1995, Kim et al. 2009) recorded up to 655 species from the island environs, including freshwater fishes, and additional species have more recently been reported from the island’s coastal waters (Kwun et al. 2012, Kwun et al. 2013, Song et al. 2013, Kim et al. 2014, Myoung et al. 2014, Kim 2015, Lee and Kim 2015, Kwun et al. 2016b, Yeo and Kim 2016).

Until now, Kwun et al. (2017) provided the only report specifically addressing fishes from tidal pools of the island. Their preliminary sampling of tidal pools in four regions of the island yielded 50 species for which voucher specimens were retained. However, the sampling only encompassed four months (July–October) and therefore did not account for seasonal occurrences of tidal pool fishes.

Here the first comprehensive list of tidal pool fishes on Jeju Island is provided, based on a detailed survey over all four seasons.

Materials and methods

The study area involved four coastal regions of Jeju Island, including areas where Kwun et al. (2017) collected fishes: Oedo (north), Sindo (west), Yerae (south), and Seongsan (east) (Fig. 1). Fishes were caught using hand net and dredge, and all specimens were fixed whole in 99% ethanol. Our fish list was based on the data of Kwun et al. (2017), but many fishes caught during the survey, which occurred between February 2016 and January 2017 (all four seasons), were new records for the four regions. The specimens were classified to family level according to An (2011), and species were identified according to Kim et al. (2005), Allen and Erdmann (2012), Nakabo (2013), Allen et al. (2015), Ikeda and Nakabo (2015), and Kwun and Kim (2015). Fishes were categorized by climate zone on group (temperate, subtropical, and tropical) according to Froese and Pauly (2017). Photographs of the newly collected fishes are provided in Figures 2–12, and the voucher specimen list is provided as an Appendix. Voucher specimens were deposited at the National Marine Biodiversity Institute of Korea, Marine Fish Diversity (MFD; formerly Biodiversity Dynamics Team: BDT).

Figure 1.

Map showing the location of Jeju Island and sampling sites.

Figure 2.

A , MFD-746, 77.3 mm standard length (SL) B , MFD-902, 47.5 mm SL.

Figure 12.

A , MFD-807, 36.2 mm SL B , MFD-808, 53.1 mm SL.

A , MFD-669, 42.9 mm SL B , MFD-627, 29.3 mm SL.

A , MFD-671, 47.8 mm SL B , MFD-927, 19.3 mm SL.

A , MFD-860, 82.8 mm SL B , MFD-866, 101.1 mm SL.

A , MFD-663, 55.6 mm SL B , MFD-845, 33.7 mm SL.

A , MFD-850, 92.9 mm SL B , MFD-482, 25.7 mm SL.

A , MFD-318, 47.5 mm SL B , MFD-144, 50.2 mm SL.

A , MFD-682, 29.8 mm SL B , MFD-495, 20.7 mm SL.

Results and discussion

Seventy-six fish species, representing 60 genera and 34 families, were recorded (Table 1). The sample from Seongsan included the largest number of species (54), followed by Yerae (44 species), Sindo (38 species), and Oedo (31 species) (Table 2). The most important families in terms of species were the (11 species), followed by (8), (6) and (5). Among the 76 species, 20 occurred in PageBreakPageBreakPageBreakPageBreakall four regions. The tidal pools of Jeju Island have the highest fish species diversity in such habitats yet reported worldwide, exceeding the 72 species reported from Yakushima Island, Japan, and 62–63 species reported from Taiwan (Murase 2015). Although tidal pool fishes have been fewer reported compared to more than 600 species in the adjacent waters, we think tidal pools of Jeju Island are very important for fish habitat, zoogeography, and worth of conservation.

Table 1.

Tidal pool fishes in Jeju Island, Korea. New records in this paper indicated with a tick after the species name.

Scientific name	Distribution	Regions of occurrence	Record of Jeju Island (Kim et al. 2009)
Clupeiformes
Engraulidae
Engraulis japonicus	Temperate	Sindo, Yerae	√
Clupeidae
Spratelloides gracilis	Tropical	Yerae	√
Siluriformes
Plotosidae
Plotosus lineatus	Tropical	Sindo, Seongsan	√
Mugiliformes
Mugilidae
Chelon macrolepis	Tropical	Yerae, Seongsan	–
Mugil cephalus	Subtropical	Sindo, Yerae	√
Moolgarda seheli	Tropical	Seongsan	–
Oedalechilus labiosus	Tropical	Yerae, Seongsan	–
Atheriniformes
Notocheiridae
Iso flosmaris√	Temperate	Sindo	√
Atherinidae
Atherion elymus	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Beloniformes
Hemiramphidae
Hyporhamphus sajori√	Temperate	Oedo	√
Scorpaeniformes
Scorpaenidae
Sebastes inermis√	Subtropical	Seongsan	√
Hypodytes rubripinnis√	Tropical	Seongsan	√
Hexagrammidae
Hexagrammos otakii	Temperate	Sindo, Yerae, Seongsan	√
Cottidae
Furcina osimae√	Temperate	Sindo, Seongsan	√
Pseudoblennius cottoides	Temperate	Seongsan	√
Pseudoblennius percoides√	Temperate	Seongsan	√
Pseudoblennius marmoratus√	Temperate	Seongsan	√
Vellitor centropomus√	Temperate	Seongsan	√
Cyclopteridae
Eumicrotremus uenoi√	Temperate	Seongsan	–
Perciformes
Plesiopidae
Plesiops coeruleolineatus√	Tropical	Oedo	√
Apogonidae
Apogon doederleini	Subtropical	Oedo, Yerae	√
Lutjanidae
Lutjanus fulviflamma√	Tropical	Yerae	√
Gerreidae
Gerres oyena√	Tropical	Yerae	√
Pempheridae
Pempheris japonica√	Tropical	Sindo	√
Pempheris schwenkii	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Kyphosidae
Girella leonina	Subtropical	Yerae, Seongsan	–
Girella punctata	Temperate	Oedo, Sindo, Yerae, Seongsan	√
Microcanthus strigatus	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Chaetodontidae
Chaetodon auriga√	Tropical	Seongsan	√
Teraponidae
Terapon jarbua	Tropical	Yerae, Seongsan	√
Kuhliidae
Kuhlia mugil	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Oplegnathidae
Oplegnathus fasciatus	Temperate	Oedo	√
Cheilodactylidae
Goniistius zonatus√	Tropical	Seongsan	√
Pomacentridae
Abudefduf bengalensis	Tropical	Oedo, Sindo, Yerae	–
Abudefduf notatus	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Abudefduf septemfasciatus	Tropical	Oedo, Sindo, Yerae, Seongsan	–
Abudefduf sexfasciatus√	Tropical	Seongsan	√
Abudefduf sordidus	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Abudefduf vaigiensis	Tropical	Sindo, Yerae, Seongsan	√
Chromis notata	Subtropical	Oedo, Sindo, Yerae, Seongsan	√
Pomacentrus coelestis	Tropical	Sindo, Yerae, Seongsan	√
Labridae
Halichoeres poecilopterus	Subtropical	Yerae	√
Halichoeres tenuispinis	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Pteragogus flagellifer	Tropical	Sindo	√
Stethojulis interrupta terina√	Tropical	Seongsan	√
Stethojulis trilineata√	Tropical	Seongsan	–
Stichaeidae
Dictyosoma burgeri	Temperate	Sindo, Seongsan	√
Dictyosoma rubrimaculatum	Subtropical	Seongsan	√
Zoarchias major	Temperate	Oedo, Sindo, Seongsan	√
Enneapterygius etheostomus	Temperate	Oedo, Sindo, Yerae, Seongsan	√
Blenniidae
Entomacrodus stellifer stellifer	Tropical	Oedo, Yerae	√
Istiblennius dussumieri	Tropical	Sindo	√
Istiblennius enosimae	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Omobranchus elegans	Subtropical	Oedo, Sindo, Yerae, Seongsan	√
Parablennius yatabei	Temperate	Sindo, Yerae, Seongsan	√
Petroscirtes breviceps	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Chaenopsidae
Neoclinus bryope	Temperate	Seongsan	√
Gobiesocidae
Aspasma minima	Subtropical	Oedo, Sindo, Seongsan	–
Lepadichthys frenatus√	Temperate	Yerae	√
Gobiidae
Bathygobius fuscus	Tropical	Oedo, Sindo, Yerae, Seongsan	√
Chaenogobius annularis	Temperate	Oedo, Sindo, Yerae, Seongsan	√
Chaenogobius gulosus	Temperate	Oedo, Sindo, Yerae, Seongsan	√
Eviota abax	Temperate	Oedo, Sindo, Yerae, Seongsan	√
Eviota prasina	Tropical	Yerae	√
Istigobius campbelli	Tropical	Oedo, Yerae, Seongsan	√
Luciogobius guttatus√	Subtropical	Oedo, Sindo, Yerae, Seongsan	√
Clariger cosmurus√	Temperate	Yerae	–
Mugilogobius fontinalis	Tropical	Sindo	√
Tridentiger obscurus	Temperate	Yerae	√
Trimma grammistes√	Temperate	Sindo	√
Ptereleotridae
Parioglossus dotui	Subtropical	Oedo, Sindo, Yerae, Seongsan	√
Siganidae
Siganus fuscescens√	Tropical	Oedo, Seongsan	√
Tetraodontiformes
Monacanthidae
Stephanolepis cirrhifer√	Temperate	Oedo, Seongsan	√
Tetraodontidae
Arothron hispidus√	Tropical	Yerae, Seongsan	√
Arothron stellatus√	Tropical	Seongsan	√
Takifugu niphobles	Temperate	Yerae, Seongsan	√

Table 2.

Number of fish species and major fish families in tidal pools in four regions of Jeju Island, Korea.

Region	No. of species	Major speciose family
Oedo (north)	31	Gobiidae (7 species) Pomacentridae (5 species) Blenniidae (4 species)
Seongsan (east)	54	Pomacentridae (7 species) Gobiidae (7 species) Cottidae (5 species)
Sindo (west)	38	Gobiidae (8 species) Pomacentridae (7 species) Blenniidae (5 species)
Yerae (south)	44	Gobiidae (10 species) Pomacentridae (7 species) Blenniidae (5 species)

In terms of distribution, most species were in the tropical group (39 species), followed by the temperate group (26) and subtropical group (11) (Table 1). Diverse and complicated water masses exist around Jeju Island (Kim et al. 2009); especially adjacent waters are known to be influenced directly by the high temperature and salinity Tsushima Warm Current, and so subtropical fishes are frequently found (Kim 2009). The present result showed the tropical and subtropical species to comprise 65.8% (50 species) of the total fish fauna, but most tropical and subtropical species have been recorded by Kim et al. (2009). Therefore, the present species diversity is not related to climate change, and continuous monitoring studies are needed to understand species dynamics.

Twenty-six species represent new records for the island, compared to the study by Kwun et al. (2017). Ten species were not listed for Korea before (cf. Kim et al. 2009). Eight species (, , , , , , , and ) represent new reports of occurrence in winter and spring. Although sampling did not occur in all months, three species (, , ) were present in all seasons, suggesting that they are year-round residents of the tidal pools.

Species notes

Kai, Ikeguchi & Nakabo, 2017 (Fig. 5B) was recorded in Korea as (Kim 2015), but is a junior synonym of and this species is reported for the new record through recent taxonomic reviewes (Lee et al. 2017, Oku et al. 2017).

Figure 5.

A , MFD-933, 75.6 mm SL B , MFD-932, 17.8 mm SL.

The species of (Fig. 7A) differed from in melanophore pattern (Okiyama 2014), but a molecular comparison showed it to correspond to . It may represent a difference in larvae growth.

Figure 7.

A , MFD-894, 10.8 mm SL B , MFD-778, 25.7 mm SL.

(Richardson, 1846) was recorded in Korea as (An 2011, Kwun et al. 2017), but is a junior synonym of (Yagishita and Nakabo 2000, Nakabo 2013).

A partial albino specimen of Yatsu, Yasuda & Taki, 1978 was collected, representing the first report of albinism in this species (Kwun et al. 2016a).