Reef Fishes of Yap, Federated States of Micronesia
Allen, G. (2007). Reef Fishes of Yap, Federated States of Micronesia.
Abstract: 1. A list of fishes was compiled for 46 sites including 19 at Yap, 12 at Ngulu, and 15 at Ulithi. The survey involved approximately 60 hours of scuba diving to a maximum depth of 55 m. 2. A total of 625 species was recorded including 349 new range records. An additional 91 new records for Yap State, primarily observed by Brian Greene in 2007 are also reported. The total known fish fauna of Yap State now stands at 787 species in 275 genera and 76 families. 3. A formula for predicting the total reef fish fauna based on the number of species in six key indicator families indicates that at least 928 species can be expected to occur at Yap and outlying atolls. 4. Gobies (Gobiidae), wrasses (Labridae), damselfishes (Pomacentridae), groupers (Serranidae), butterflyfishes (Chaetodontidae), and surgeonfishes (Acanthuridae) are the most speciose families in the Yap region with 103, 92, 68, 47, 34 and 34 species respectively. 5. Species numbers at visually sampled sites during the 2007 survey ranged from 35 to 169, with an average of 131. 6. Ulithi Atoll had the highest average number of species (143.6) per site, followed by Ngulu Atoll (134.3), and Yap (130.5). 7. Outer reefs had the highest fish diversity with an average of 148.6 species per site. Passages were generally less speciose with an average of 135.7 species per site. Lagoon sites and coastal bays at Yap Island were the least diverse habitats with 115.2 and 50.6 species per site respectively. The latter habitat, although poor in number of species, is populated by a unique gobiid community. 8. Three new species were collected during the survey including a goby belonging to an apparently undescribed genus, a damselfish in the genus Pomacentrus, and a dottyback belonging to Lubbockichthys. The goby was common on soft silty bottoms at Yap Island at depths of 10-20 m. The new Pomacentrus is apparently widespread in Micronesia and was previously collected at Pohnpei. It was common in a variety of habitats, but was most abundant on the upper edge of outer reef slopes between about 4 and 12 metres. The dottyback was collected on the outer reef at Ulithi in 55 m depth. 9. The highly threatened Napoleon Wrasse (Cheilinus undulatus) was relatively abundant, being observed at 50 percent of the survey sites. The estimated average total length of observed individuals was 48 cm. Site Y-17 (lagoon hole on east side of Yap) appears to be an important nursery area for both Napoleon Wrasse and Bumphead Parrotfish (Bolbometopon muricatum). 10. Sharks were seen at 50 percent of the survey sites, but generally in small numbers. They were most abundant at Ulithi Atoll, where 20 or more grey reef sharks (Carcharhinus amblyrhynchos) were seen as several sites. Although environmental conditions appear ideal for reef sharks, relatively few were seen at Ngulu Atoll, which is indicative of foreign shark-fin poaching.
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MAG: 2330838030 CorpusID: 131179105 OpenAlex: W2330838030
