Introduction
Biodiversity is unusually high in the archipelagos of south-east Asia and scientists have recognized a biogeographic area, referred to as the Coral Triangle, with the highest marine biodiversity in the world (Hoeksema, Reference Hoeksema and Renema2007). Indonesia, Papua New Guinea and the Philippines cover more than 90% of the Coral Triangle's surface area, and within the Coral Triangle, the Philippines are the centre for species diversity of marine fishes (Carpenter & Springer, Reference Carpenter and Springer2005). The authors calculated that the central Philippines has the highest fish diversity in the region with, at that time, as many as 1736 marine fish species. New records of fishes, however, have continuously increased that number (Bucol & Alcala, Reference Bucol and Alcala2014; Motomura et al., Reference Motomura, Alama, Muto, Babaran and Ishikawa2017; Saceda-Cardoza & Bos, Reference Saceda-Cardoza and Bos2017) especially in the southern Philippines, where little marine research has been conducted. Recent studies have reported new fish records (Bos & Gumanao, Reference Bos and Gumanao2013; Bos & Smits, Reference Bos and Smits2013) and new species descriptions (Motomura et al., Reference Motomura, Okamoto and Iwatsuki2001; Bos, Reference Bos2014; Carpenter et al., Reference Carpenter, Williams and Santos2017) have further enriched our knowledge of marine fish biodiversity in the southern Philippines. Moreover, overfishing in shallow coral reefs (Nañola et al., Reference Nañola, Aliño and Carpenter2011) may have locally shifted fishing pressure to deeper mesophotic coral ecosystems, partly explaining the increasing number of new records of mesophotic fishes (Rocha et al., Reference Rocha, Pinheiro, Shepherd, Papastamatiou, Luiz, Pyle and Bongaerts2018; Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019).
The present study contributes to the growing knowledge of marine fish biodiversity in the Philippines by reporting eight species for the first time and providing information about their biogeographic distributions and range extensions.
Materials and methods
Local fish markets in Davao City, Panabo City and Tagum City along the coast of the Davao Gulf, Philippines (see map in Bos et al., Reference Bos, Gumanao, Alipoyo and Cardona2008) have regularly been visited between May 2017 and June 2020. Fish were purchased and measured fresh at the laboratory of the Davao del Norte State College in Panabo City. Standard (SL), Fork (FL) and Total Length (TL) were determined at 1 mm accuracy using a measuring board and individuals were weighed on an electronic scale with an accuracy of 1 g. Subsequently, specimens were preserved and added to the collection of the research museum of the Davao del Norte State College.
For identification purposes, meristic traits were counted and, if necessary, additional body measures were taken to determine species-specific morphometrics (e.g. Randall & Kulbicki, Reference Randall and Kulbicki2006). FishBase (Froese & Pauly, Reference Froese and Pauly2021) was used for initial identifications and fish family and/or genus specific literature (provided below) was used for final confirmation of identifications.
Results
Thirty-one individuals of nine fish species, previously unknown from Philippine seas, were found at fish markets along the coast of the Davao Gulf between May 2017 and June 2020. These include seven species belonging to the Labridae, Nemipteridae, Priacanthidae and Serranidae (Perciformes; Figure 1), and a filefish belonging to the Monacanthidae (Tetraodontiformes; Figure 2). Individual length and weight measurements are provided in Table 1.
Fig. 1. New records of Perciform fishes from the Philippines (a) Bodianus leucosticticus (SL 134 mm), (b) Bodianus masudai (SL 125 mm), (c) Bodianus rubrisos (SL 124 mm; reported once from the Philippines), (d) Parascolopsis melanophrys (SL 130 mm), (e) Pristigenys meyeri (SL 231 mm) (f) Liopropoma latifasciatum (SL 156 mm) (g) Odontanthias chrysostictus (SL 126 mm) (h) Odontanthias randalli (SL 104 mm).
Fig. 2. New record of a Tetraodontiform fish from the Philippines; Thamnoconus multilineatus (SL 133 mm).
Table 1. Standard, Fork, Total Length (mm) and wet weight (g) of eight newly recorded fishes from the Philippines found at local fish markets in Davao City and Davao del Norte province between May 2017 and July 2020
Data are presented per fish family of the Perciformes (4 families) and the Tetraodontiformes (1 family).
a Recently reported from a more northern location in the Philippines (Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019).
b Newly reported maximum Standard Length.
Two individuals of the wrasse Bodianus leucosticticus (Bennett, 1832) (Labridae) were encountered at the Panabo market on 17 August 2018 and 20 August 2018 respectively (Figure 1a). Additionally, seven individuals were found at the Panabo market on 19–23 June 2020. The colour of this fish is dorsally red and ventrally white. The head has a purplish brown appearance. The body is covered with accentuated red dots and interrupted stripes. The base, as well as the tissue between the spines of the dorsal fin, show rows of black dots and some faint yellow blotches (Gomon, Reference Gomon2006). Standard length ranged from 101–135 mm (Table 1). Selected meristic counts: Dorsal fin XII,10 and Anal fin III,12–13.
Three individuals of the wrasse Bodianus masudai Araga and Yoshino, 1975 (Labridae) were encountered at the Panabo market on 5 July 2020 (Figure 1b). This species can be recognized by three red stripes radiating from the snout, through the eye, over the entire body. The lower stripe marks the centre of the body, while the upper stripe follows the dorsal edge of the body. The two areas in between the stripes are yellowish. The ventral side of the body is white. This species has a conspicuous black botch at the posterior edge of the operculum. The dorsal is mostly red with a white margin, while the anal fin has a white base, a red stripe and a white margin. The caudal fin is entirely red with posteriorly a narrow white margin. The pelvic fin has a dark, almost black, tip and the pectoral fin is transparent (Gomon, Reference Gomon2006). The standard length ranged from 112–125 mm (Table 1). Selected meristic counts: Dorsal fin XII,10 and Anal fin III,12.
Although encountered once at a more northern location in the Philippines (Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019), we report one individual of the rare wrasse Bodianus rubrisos Gomon, Reference Gomon2006 (Labridae) that was encountered at the Panabo fish market on 15 August 2018 (Figure 1c); not considered a new record for the current paper. This species can be recognized by the relatively pointed snout. The dorsal part of the body is bright red, while the ventral part is white. The red colour consists of multiple lines running from the eye to the tail with three main lines appearing as disconnected elongated blotches. The caudal and dorsal fins are entirely red, while the dorsal fin base and the proximal band of the dorsal fin have scattered black dots. The base of the pectoral fin has a conspicuous red mark. Selected meristic counts: Dorsal fin XII,10 and Anal fin III,12.
Two individuals of Parascolopsis melanophrys Russell & Chin, Reference Russell and Chin1996 (Nemipteridae) constitute a first record for the Philippines. One individual was found at the Sasa market, Davao City, on 31 May 2017 (Figure 1d) and a second individual was found at the Panabo market on 5 July 2020. The dorsal side of this species is rosy pink and becomes lighter toward the ventral side. It has a mid-lateral yellow stripe from above the pectoral fin towards the caudal peduncle merging into the yellowish caudal tail. Two conspicuous black blotches mark the forehead just dorsal-posterior to the eyes and are disconnected at the sagittal plane. The bases of the anal and the pelvic fins appear sulphur yellow. Standard length ranged from 116–130 mm (Table 1). Selected meristic counts: Dorsal fin X,9, Anal fin III,7 and 35 lateral line scales.
Two individuals of Pristigenys meyeri (Günther, 1872) (Priacanthidae) were encountered at the markets in Panabo City and Tagum City on 23 January 2018 and 27 May 2018, respectively (Figure 1e). This bigeye species has up to 11 narrow red bars on the head and body, with irregular red spots and markings between the bars. Furthermore, the head is covered with irregular red spots and lines. The margins on the soft dorsal, caudal, anal and pelvic fins are black. Standard length ranged from 231–238 mm (Table 1). Selected meristic counts: Dorsal fin X,13, Anal fin III,12 and 33–34 lateral line scales.
Three individuals of Liopropoma latifasciatum (Tanaka, 1922) (Serranidae: Liopropomatinae) were found at the Panabo market on 16 August 2018 (1 individual) and 20 June 2020 (2 individuals). This basslet is mostly pink in colour with the anterior sections of the anal and second dorsal fins yellow (Figure 1f). Also, the upper and lower edges of the caudal tail are yellow. A brown stripe runs laterally through the eye along the body midline to the caudal peduncle. Standard length ranged from 115–144 mm (Table 1). Selected meristic counts: Dorsal fin XIII,13, Anal fin III,9 and 52 lateral line scales.
Six individuals of Odontanthias chrysostictus (Günther, 1872) (Serranidae: Anthiinae) were encountered at the Tagum market on 30 June 2017 (Figure 1g). This species is recognized by a compressed body with entirely pink background colour. It has bright yellow spots on most dorsal body scales. The nape is mostly yellow and has a yellow stripe from the snout, below eye to the base of pectoral fin and faintly visible on the pectoral fin. The dorsal spines are pink with yellow interconnecting membranes, while the soft dorsal fin is yellow with scattered pink spots along its base. The third dorsal ray is highly extended. Anal spines are pink with some yellow blotch on the tissue around the first couple of anal rays. The caudal fin is bright yellow with pink edges formed by the upper and lower rays. Standard length ranged from 89–126 mm (Table 1), with 126 mm being the largest standard length ever recorded. Selected meristic counts: Dorsal fin X,15–16 and Anal fin III,7.
Five individuals of Odontanthias randalli White, Reference White2011 (Serranidae: Anthiinae) were found at the Panabo market between 22 June and 5 July 2020 (Figure 1h). This species is recognized by conspicuous colouration in sulphurous yellow and pink. Two yellow lines run from the snout through the eye and along the upper jaw both ending at the edge of the operculum. The third spine of the dorsal fin is elongated, whereas the third ray has a long yellow filament. The dorsal fin is yellow anteriorly with a pink margin. The posterior part of most body scales is yellow causing a spotted appearance. The anal and pelvic fins have an anterior yellow line. The base of the caudal tail is yellow connecting to yellow upper and lower rays. Standard length ranged from 93–115 mm (Table 1). Selected meristic counts: Dorsal fin X,16 and Anal fin III,7.
One individual of the filefish Thamnaconus multilineatus (Tanaka, 1918) (Tetraodontiformes: Monacanthidae) was found at the Panabo market on 13 June 2020 (Figure 2). This fish has a blue-grey colour with mostly parallel brown-yellow lines marking the ventral part of the body and radiating from the snout and the eye to the caudal peduncle. The dorsal, caudal and anal fins are transparent with a touch of yellow. Selected meristic counts: Dorsal fin rays 31 and Anal fin rays 31.
Discussion
The eight new records for the Philippines presented in this paper were all found in fish markets along the coast of the Davao Gulf in the southern Philippines, an area that has not received as much scientific attention as other regions in the archipelago. The nine reported species are inhabitants of mesophotic coral ecosystems and, despite some having large biogeographic distribution areas, may have gone largely unnoticed and are considered uncommon in the Indo-Pacific region (Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019). Due to lack of population data, the Red List of Threatened Species categorizes them into ‘Least Concern’ or does not provide a conservation status at all (IUCN, 2020), which may not correctly represent the actual status of their populations. Mesophotic fishes are usually not found at depths shallower than 30 m and may neither be encountered by divers using regular scuba equipment nor be found on fish markets. However, due to overfishing in shallow coral reefs (Nañola et al., Reference Nañola, Aliño and Carpenter2011), fishermen may target deeper fish communities, causing mesophotic species to appear more frequently on markets (Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019).
Bodianus leucosticticus occurs in two seemingly isolated populations with one in the Western Indian Ocean (Somalia, Mozambique, Mauritius, Réunion) and the other population in Taiwan and south of Japan (Gomon, Reference Gomon2006; Froese & Pauly, Reference Froese and Pauly2021). Gomon (Reference Gomon2006) already predicted that this species will likely turn up at intermediate locations. The present observation constitutes the first record of B. leucosticticus in the Philippines and extends the biogeographic range of the Indo-Pacific population. Similarly, as for B. leucosticticus, B. masudai seemingly occurs in two Indo-Pacific populations; a northern population in Japan, Taiwan, and a southern population near New Caledonia (Gomon, Reference Gomon2006). The currently observed individuals most probably belong to the northern population. Bodianus rubrisos has been reported from Japan, Taiwan and Bali, Indonesia (Gomon, Reference Gomon2006) and recently from the Philippines (Pinheiro et al., Reference Pinheiro, Shepherd, Castillo, Abesamis, Copus, Pyle, Greene, Coleman, Whitton, Thillainath and Bucol2019). The current record confirms a relatively large biogeographic distribution area.
Parascolopsis melanophrys is an extremely rare, yet conspicuous, fish that was reported once from West-Timor in Indonesia and once from Sabah in Malaysia (Russell & Chin, Reference Russell and Chin1996). The present observations constitute the third and fourth individuals ever reported as well as the first record from the Philippines. The present record from the Davao Gulf extends the biogeographic range of P. melanophrys by 1940 km to the north and 920 km to the east. The individuals reported here were slightly smaller than the two type specimens (Russell & Chin, Reference Russell and Chin1996).
Pristigenys meyeri occurs in isolated populations in the Western Pacific: thus far recorded from Japan, South China Sea, Sulawesi, New Guinea and Samoa (Froese & Pauly, Reference Froese and Pauly2021). It is considered a reef-associated species, but commonly appears at a depth range of 100–200 m (Fricke et al., Reference Fricke, Kulbicki and Wantiez2011). The present observation constitutes the first record of Pristigenys meyeri in the Philippines, but does not extend the known biogeographic distribution of this species.
Liopropoma latifasciatum has a biogeographic range in the western Indo-Pacific from Japan to Korea and Taiwan (Shen, Reference Shen1993). The present observation constitutes the first official record of Liopropoma latifasciatum from the Philippines and supports the report of the presence of this species in Palau (Myers, Reference Myers1999).
So far, Odontanthias chrysostictus has only been reported from Manado, Sulawesi in Indonesia (Randall & Heemstra, Reference Randall and Heemstra2006). The present observation constitutes the first record from the Philippines extending its biogeographic range by 630 km northward. Two of the six individuals were larger (Table 1) than the earlier reported maximum SL of 118 mm (Randall & Heemstra, Reference Randall and Heemstra2006). Odontanthias randalli has only been reported from Lombok, Indonesia (Froese & Pauly, Reference Froese and Pauly2021) and the current observation extends the biogeographic range of this species by 2000 km northward.
Thamnaconus multilineatus is only known from Japan and Taiwan (Masuda et al., Reference Masuda, Amaoka, Araga, Uyeno and Yoshino1984). The current observation therefore extends the biogeographic range of this fish by 1800 km to the south. The observed individual was relatively small (Table 1) compared with the reported standard length of up to 260 mm (Masuda et al., Reference Masuda, Amaoka, Araga, Uyeno and Yoshino1984).
Reporting of new species records is of utmost importance to understand marine biodiversity and changing distribution patterns possibly occurring over time. Furthermore, this information is needed to improve fisheries and population management, and to support conservation efforts, especially in the fragile mesophotic ecosystems where the reported fishes dwell (Rocha et al., Reference Rocha, Pinheiro, Shepherd, Papastamatiou, Luiz, Pyle and Bongaerts2018). The current observations of eight new records of fishes extend our knowledge of fish biodiversity in the Philippines and further underline the exceptionally high marine biodiversity in the Coral Triangle.
Acknowledgements
We are grateful to the highly collaborative fish vendors at the Panabo market and to the anonymous reviewers who helped improve the manuscript.
Author contributions
GSG – fieldwork, lab work, analysis, writing; KJSG – fieldwork, lab work; ARB – fieldwork, lab work, analysis, writing. The authors read and approved the final manuscript.
Ethical standards
All fish were purchased at local fish markets in the Philippines.
Availability of data and materials
The collected fishes are available as preserved specimens in the museum of the Davao del Norte State College, Panabo City, the Philippines.
