INTRODUCTION
The Kuwaiti territorial marine waters, affected by a subtropical climate, are located in the north-western corner of the Arabian Gulf, a shallow marginal northern extension of the Indian Ocean (Pous et al., Reference Pous, Carton and Lazure2012). The Kuwaiti marine coastal area receives enormous amounts of fluvial input via the Shatt Al-Arab, the confluent delta of the Tigris and Euphrates rivers. In general, the salinity also increases during the winter season due to low precipitation and recently due to the desalination process (Al-Dousari, Reference Al-Dousari2009). In this area, high plankton productivity, as a result of high nutrient levels, is usually present (Kuwait Institute for Scientific Research, 2005; Al-Kandari et al., Reference Al-Kandari, Al-Yamani and Al-Rifaie2009; Al-Yamani & Saburova, Reference Al-Yamani and Saburova2010, Reference Al-Yamani and Saburova2011).
Kuronuma & Abe (Reference Kuronuma and Abe1972, Reference Kuronuma and Abe1986) presented some of the earliest information on the ichthyofauna of Kuwait. In recent decades, there have been several works that have provided additional information on the marine fish fauna of Kuwait (Relyea, Reference Relyea1981; Bishop & Abdul-Ghaffar, Reference Bishop and Abdul-Ghaffar1993; Carpenter et al., Reference Carpenter, Krupp, Jones and Zajonz1997a, Reference Carpenter, Harrison, Hodgson, Al Saffar and Al Hazeemb; Krupp et al., Reference Krupp, Almarri, Zajonz, Carpenter, Almatar and Zetzsche2000; Bishop, Reference Bishop2003; Kuwait Institute for Scientific Research, 2005).
In the present paper, we report on the presence of the pixie triplefin (Enneapterygius pusillus) and the cheekspot blenny (Parablennius opercularis) in the Kuwaiti territorial waters of the Arabian Gulf.
The pixie triplefin and the cheekspot blenny were observed and photographed in situ by the second and third authors during a scuba diving survey at the Qit at Binaya patch reef (off Al Khiran) and Sabah Al Ahmad Sea City, Kuwait, Arabian Gulf (Figure 1). The Qit at Binaya patch reef lies south of Al Khiran, extending to an area of approximately 1 km2. Fishes were photographed on the evening of 21 July 2014, using a compact digital camera, Panasonic Model TZ 25, with an inbuilt Leica DC Lens, 16× optical zoom and underwater housing. Both specimens were encountered at depths of 3–6 m in a coral reef area with a sandy bottom. E. pusillus was found among Cyphastrea spp. and Porites spp. hard corals, whereas P. Opercularis was observed living in association with bryozoan Schizoporella errata encrusting dead barnacle shells. The fishes were difficult to collect due to their swift motion and cryptic behaviour.
Locality of pixie triplefin and cheekspot blenny, Kuwait, Arabian Gulf.
RESULTS
Family TRIPTERYGIIDAE
Enneapterygius pusillus Rüppell, 1835
MATERIALS OBSERVED
Qit at Binaya patch reef, south of Al Khiran, Kuwait, north-west corner of the Arabian Gulf, 28°38′15.16″N 48°25′13.26″E, at a depth of 6 m, 21 July 2014 (Figure 2).
A male Enneapterygius pusillus recorded from Qit at Binaya patch reef, Kuwait (photo by Dinesh Kumar Raja).
DESCRIPTION
Although the photographed fish would not allow for specific measurements, the total length was estimated at about 30 mm, which is the maximum size given for the male and female of this species when photographed in southern Oman by Randall (Reference Randall1995).
The field photographs of our specimen allowed us to observe the following key characteristics: fin ray counts of D–III, XII, 10 and P–14, very high first dorsal fin, black pelvic-fin base and proximal portion of the fins, five dark-greenish bars, more or less x-shaped or ‘hourglass-shaped’, the first one (behind pectoral fin base) being more indistinct and the last one (on the caudal peduncle) being triangular with a straight, well-defined rear edge.
REMARKS
The observed characters of the present specimen agree with the description given by Randall (Reference Randall1995a) and Holleman (Reference Holleman2005). It is possible to identify fish species in the wild using appropriate visual criteria (see Louisy, Reference Louisy2005) and new records of small cryptobenthic fish species have been reported using live photographs (Ballesta & Miller, Reference Ballesta and Miller1998; Francour et al., Reference Francour, Bilecenoglu and Kaya2007). The photograph of the pixie triplefin reveals obvious characters that are enough to establish that our own specimen is a male Enneapterygius pusillus. According to Holleman (Reference Holleman2005), male Enneapterygius Pusillus have a very high first dorsal fin and the pelvic-fin base and proximal portion of these fins are black. Our specimen clearly shows these two features. The body bars are very similar to those illustrated in a photo of a male E. pusillus taken by Randall (Reference Randall1995a) and also shown in Holleman (Reference Holleman2005, plate 2E).
Enneapterygius tutuilae Jordan & Seale, 1906, considered as a senior synonym of Enneapterygius altipinnis Clark, 1980 from the Red Sea by Fricke (Reference Fricke1994) and Holleman (Reference Holleman2005), is also shown to have a high first dorsal fin. Enneapterygius pallidus is another species of this genus with a high first dorsal fin. A current belief is that both Enneapterygius pusillus and Enneapterygius pallidus are either the same species or complex of the species (Holleman, Reference Holleman2005).
Enneapterygius tutuilae is distributed from the Red Sea, south to East Africa (Fricke, Reference Fricke1999) and east to the Philippines and Taiwan (Fricke, Reference Fricke1997), while Enneapterygius pallidus has a distribution confined to the Eritrean waters of the Red Sea (Froese & Pauly, Reference Froese and Pauly2014). On the other hand, Enneapterygius tutuilae, in males at least, has quite uniformly-coloured, wide, dark, oblique bars, together with two prominent whitish saddles – or bars – extending onto the rear part of the second and third dorsal fins (according to the diagnosis and photographs in Holleman, Reference Holleman2005). However, these characters are not present in our specimen. The anterior part of the body of Enneapterygius pallidus is greenish and the remaining body is transparent with 8–9 narrow bars, faint orange bars and a pigmented membrane between the first two spines (Holleman, Reference Holleman2005; Holleman & Bogorodsky, Reference Holleman and Bogorodsky2012).
The pixie triplefin (Enneapterygius pusillus) was previously recorded on the coasts of Oman, the Arabian Sea (Randall, Reference Randall1995a; Manilo & Bogorodsky, Reference Manilo and Bogorodsky2003), from the sea of Oman (Jawad et al., Reference Jawad, Louisy and Al-Mamary2010) and from Musandam, Oman, the southernmost part of the Arabian Gulf (Randall, Reference Randall1995a). It is also reported from Jubail, Saudi Arabia and the Arabian Gulf (Krupp et al., Reference Krupp, Abuzinada and Nader1996). The presence of this species was not unexpected in Kuwaiti waters, northern Arabian Gulf, as it has been previously reported from this area, but not specifically from Kuwaiti waters (Holleman, Reference Holleman2005). The general environment of the Kuwaiti waters is characterized as having contrasting seasonal changes and a peculiar hydrographic status, as it is affected by the freshwater flux from the Shatt Al-Arab River on one side (Al-Kandari et al., Reference Al-Kandari, Al-Yamani and Al-Rifaie2009; Al-Yamani & Saburova, Reference Al-Yamani and Saburova2010, Reference Al-Yamani and Saburova2011) and the increasing levels of salinity from the desalination process on the other (Al-Dousari, Reference Al-Dousari2009), which may result in some discrepancies in the local ichthyofauna. Thus, the present record can be considered important for the understanding of the zoogeographical patterns of the area.
Information on the ecology of small cryptobenthic fish species in general, and triplefins in particular, from the northern Arabian Gulf, and particularly from Kuwaiti waters, is lacking. The reason for why Enneapterygius pusillus has not been recorded before in this part of the gulf might be that it is rare in the area and/or that there has so far been a lack in adequate sampling. The use of various fish sampling methods in the area, including scuba diving and underwater photography, has already repudiated the presumed rarity of several species (Jawad et al., Reference Jawad, Louisy and Al-Mamary2010) and the present record of Enneapterygius pusillus proves this trend.
Family BLENNIIDAE
Parablennius opercularis (Murray, 1887)
MATERIALS OBSERVED
Qit at Binaya patch reef, south of Al Khiran, Kuwait, north-western corner of the Arabian Gulf, Kuwait, 28°38′15.16″N 48°25′13.26″E and Sabah Al Ahamd Sea City, Al Khiran, south of Kuwait, 28°39′33.24″N 48°20′56.44″E, at depths of 3–6 m, 21 July 2014 (Figures 3 & 4).
Cheekspot blenny (Parablennius opercularis) living in association with encrusting bryozoan Schizoporella errata at Qit at Binaya patch reef, Kuwait (photo by Nithyanandan Manickam).
Cheekspot blenny (Parablennius opercularis) showing its characteristic body features (photo by Dinesh Kumar Raja).
DESCRIPTION
Although we were unable to measure the specific size of the photographed fish, the total length was estimated at about 50 mm, which is within the size range given for this species.
The photographs taken in the field for our specimen allowed us to note the following characteristics of this species: fin ray counts D–XII, 16–17, large supraorbital tentacles with five branches, no cirri on nape, small cirus on the posterior end of the anterior nostril, body mainly olive to brown, but changed to whitish according to the background (Figure 4), brown olive spot as large as the eye on each cheek behind the eye and a greenish spot present on the membrane between the first and second dorsal spines (Figure 4).
REMARKS
The description of the present specimen agrees with the description of Parablennius opercularis in Randall (Reference Randall1995a). In some cases, when the position of the fish is suitable for identification, scientists are able to recognize this cryptic species using underwater photography (Ballesta & Miller, Reference Ballesta and Miller1998; Louisy, Reference Louisy2005; Francour et al., Reference Francour, Bilecenoglu and Kaya2007).
Parablennius pilicornis and Parablennius thysanius are the only other blenniid species found in the area adjacent to the Arabian Gulf. The former species differs from the cheekspot blenny observed in the present study by having completely different body colouration, which is easy to recognize.
Carpenter et al. (Reference Carpenter, Harrison, Hodgson, Al Saffar and Al Hazeem1997b) has recorded this species from Kuwait and has suggested that it is a rare species. The photograph they used for this species is taken from Randall's book, ‘Coastal fishes of Oman’ (Randall, Reference Randall1995a). Therefore, it is not confirmed that Carpenter et al. (Reference Carpenter, Harrison, Hodgson, Al Saffar and Al Hazeem1997b) have collected specimens of this species from Kuwaiti waters. In addition, their record has not been internationally verified, i.e. it is not reported by Froese & Pauly (Reference Froese and Pauly2014). Accordingly, the record by Carpenter et al. (Reference Carpenter, Harrison, Hodgson, Al Saffar and Al Hazeem1997b) is considered ambiguous, whereas the present record confirms the presence of cheekspot blenny in Kuwaiti waters.
This species is recorded from the Saudi Arabian waters of the Arabian Gulf and its northernmost occurrence was recorded from the Qatari waters of the Arabian Gulf (Froese & Pauly, Reference Froese and Pauly2014). The lack of previous records of this species from the northern part of the Arabian Gulf may be due to the lack of ichthyological surveys or that it has only recently arrived in the area. The current record may represent a natural range extension. More ichthyological investigations are necessary to explore the area of the northern Arabian Gulf to understand whether this species has established a sustainable population in this region.
ACKNOWLEDGEMENTS
We would like to thank the owner of La Ala Al Kuwait Real Estate Co., Mr Fawaz Al Marzouq, for giving us permission to publish this data and Ian Williams, Project Director, Sabah Al Ahmad Sea City for his encouragement and support. We thank Sergey Bogorodsky of the Station of Naturalists, Omsk, Russia, Ronald Fricke of Staatliches Museum für Naturkunde, Rosenstein, Germany and Helen Larson, Museum and Art Gallery, Northern Territory, Australia for the confirmation of the identification of the two species observed in the present study. Our thanks are also due to James Bishop, Mariculture and Fisheries Department, Kuwait Institute of Scientific Research, Kuwait, William Ludt, Louisiana State University, USA for their suggestions. We are also grateful to Mr Bernard Gonzalez for his assistance in preparing the location map and Hasan Ali Hasan and Jag Jeevan Singh, La' Ala Al Kuwait Real Estate Co. K.S.C., Kuwait for their logistical support.
