東沙環礁潟湖魚卵及仔稚魚種類組成及分布調查計畫 Investigation Project on the Composition and Distribution of Fish Eggs and Larval Fish in the Dongsha Atoll Lagoon

Data Records

The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 53 records.

2 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.

Versions

The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Shao K, Meng P, Jeng M, Severinghaus L (2025). 東沙環礁潟湖魚卵及仔稚魚種類組成及分布調查計畫 Investigation Project on the Composition and Distribution of Fish Eggs and Larval Fish in the Dongsha Atoll Lagoon. Version 1.4. Marine National Park Headquarters. Samplingevent dataset. https://ipt.taibif.tw/resource?r=tsatel_2005_2011&v=1.4

Rights

Researchers should respect the following rights statement:

The publisher and rights holder of this work is Marine National Park Headquarters. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.

GBIF Registration

This resource has been registered with GBIF, and assigned the following GBIF UUID: 9fa565db-42bc-4da7-8a1f-8170da097bb8.  Marine National Park Headquarters publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Taiwan Biodiversity Information Facility.

Keywords

Samplingevent; Observation

Contacts

Geographic Coverage

This dataset comprises survey data from 25 sampling stations within the waters surrounding Dongsha Atoll located in Kaohsiung City, Taiwan. Dongsha Atoll is a circular atoll with a diameter of approximately 25 kilometers and a total area of about 500 square kilometers. At the center of the atoll lies a lagoon with a maximum depth of 16 meters, characterized by numerous coral knolls, shallow banks, sandy substrates, and seagrass bed habitats. 本資料集包含臺灣高雄市東沙環礁周遭海域共25個樣站之調查資料。東沙環礁為一直徑約 25 公里，面積約 500 平方公里的圓形環礁，環礁中間為一水深 16 公尺以淺的潟湖，潟湖中具有許多珊瑚丘與淺灘，及沙地和海草床棲地。

Taxonomic Coverage

Fishes of Actinopteri and Elasmobranchii

Temporal Coverage

Project Data

(1) Theme: The Dongsha Atoll is located between 20°47’ to 22°35’ N and 116°42’ to 116°55’ E. It is the only fully developed atoll in Taiwan. Monitoring the ecological restoration status of coral reefs within the atoll lagoon and predicting their potential are crucial bases for future management policies by the Dongsha Marine National Park Administration. Over the past 4–5 years, the administration has collected comprehensive monitoring data on corals, reef fish, hydrology (currents), and water quality, but lacks information on the early life history of fish. Therefore, this project aims to conduct two to four surveys within one year to investigate the composition and distribution of species of the fish larvae. By utilizing morphological characteristics and DNA barcoding methods, we will understand the distribution of fish eggs and larvae inside and outside both the Dongsha Island Lagoon and the Dongsha Atoll Lagoon. This will enable us to select representative species in conjunction with adult fish composition data for further exploration of the interrelationships between Dongsha fish and fish populations in adjacent waters of the South China Sea, specifically studying metapopulations to understand the mechanisms behind the formation, supplementation, and maintenance of Dongsha fish assemblages as a reference for future resource conservation and management strategies. (2) Background: The Dongsha Islands consist mainly of Dongsha Atoll, Beiwei Tan, and Nanwei Tan. Historically known as "Crescent Island," Dongsha Atoll is located 240 nautical miles southwest of Kaohsiung. It is a circular atoll with a diameter of approximately 25 kilometers and an area of about 500 square kilometers. The center of the atoll features a lagoon with a depth of less than 16 meters, containing numerous coral mounds and shallow areas, sandy substrates, and seagrass beds. Dongsha Island is situated on the western side of the atoll, shaped like a horseshoe, elongated east-west and narrow north-south, strategically positioned at the southern end of the Taiwan Strait. Dongsha Island lies northwest of Indo-Malayan area (Woodland, 1983) or East Indian region (Randall, 1998), commonly referred to as the Coral Triangle, which is recognized as a global marine biodiversity hotspot that should be prioritized for conservation. Early studies suggested that this region serves as a single center of origin in the Indo-Pacific area, dispersing outward with a decrease in species richness with distance (Briggs, 1974, 1984, 1992). Additionally, Dongsha Island is at the northern end of the South China Sea, near rich fishing grounds that not only host migratory fish resources but also economically valuable reef-associated and deep-sea fish from different marine ecosystems. Consequently, fishing vessels from mainland China, Hong Kong, and Taiwan regularly catch fish using bottom longlining, purse seine, or torch light net in these waters. However, past research on fish assemblages in the Dongsha Islands has been quite limited. The earliest known biological survey report from Dongsha Island dates back to 1917 in Taiwan Fisheries Magazine No. 23, which recorded 13 species of fish (including seven unidentified species). The National Taiwan University’s Institute of Oceanography conducted surveys using research vessel Chiu-Lien to Dongsha Island (Yang et al., 1975), along with sporadic economic fish species investigations by the Fisheries Research Institute. Between 1990 and 2010, supported by various governmental bodies including the Council of Agriculture and Kaohsiung City Government, several comprehensive surveys were conducted (Fang et al., 1990; Chen et al., 1994; Chen et al., 2005; Zheng et al., 2005; Zheng et al., 2006; Zheng et al., 2008), increasing coral reef fish records to 73 families comprising 643 species (Chen, 2010). In terms of fish larvae data, Huang and Qiu (1994) recorded three families and three species from Dongsha Island; Lu (2005) collected 224 fish larvae belonging to 23 families and 25 species over five sampling trips in August 2004. However, there has been no investigation into fish eggs; they have only been categorized as part of plankton. Marine fishes typically exhibit a bipartite life history type where eggs and larvae drift through different coastal and offshore regions during various life stages such as hatching, metamorphosis, and settlement (Sale,1980; Booth and Brosnan, 1995). As a result, there can be significant differences in composition among eggs, larvae, and adult fishes within the same area. To fully understand local fish assemblage structures and their functions while formulating appropriate conservation strategies, merely relying on adult assemblage data is insufficient. Investigating local egg and larval populations is essential to grasp their ecological roles within ecosystems—estimating which species utilize the Dongsha Atoll Lagoon for spawning and rearing their young while assessing resource replenishment status and recovery potential. Furthermore, one critical objective of establishing protected areas is ensuring habitat integrity for biodiversity conservation within these zones. Thus, exploring whether self-recruitment can sustain local populations or if external metapopulations are necessary for population maintenance is vital for evaluating protected area effectiveness (Almany et al., 2009). In coral reef ecosystems characterized by spatial discontinuity among reefs combined with territorial fidelity among adult reef fishes leading to limited migration distances; it is generally accepted that factors such as larval duration during early life stages and current direction are primary determinants influencing population connectivity across independent reefs (Shulman and Bermingham, 1995; Riginos and Victor, 2001; Cowen and Sponaugle, 2009; Sivasundar and Palumbi, 2010). Existing studies exploring marine population connectivity primarily utilize genetic structures across different coral reef locations as indirect evidence for connectivity among populations (Hellberg, 2007; Jones et al., 2009a). While this approach addresses historical connectivity over larger temporal (100-10,000 years) or spatial scales (>100 km), it struggles to answer ecological connectivity questions among populations within or outside protected areas over several biological generations (1-10 years) (Jones et al., 2009b). To study population connectivity among fish species within the Dongsha Atoll Lagoon more precisely over time-space scales requires investigating spatiotemporal distributions of early life history assemblages while estimating contributions from self-recruitment within these populations (Riginos and Victor, 2001; Botsford et al., 2009). Additionally, comparing differences between egg-larval compositions versus adult assemblages may reveal suitable species with distinct early life history traits. Future studies could employ higher resolution genetic markers for subsequent parentage analysis to provide direct evidence regarding ecological connectivity among populations (Jones et al., 2005; Hellberg, 2007; Saenz-Agudelo et al., 2009). Ultimately, findings from this research will be crucial for developing management strategies for protected areas as well as evaluating conservation effectiveness (Almany et al., 2009; Edwards et al., 2010; Weeks et al., 2010). Therefore, we propose conducting a one-year survey plan focusing on the assemblage structures and habitat distributions of fish eggs and larvae around Dongsha Islands as groundwork for long-term monitoring efforts aimed at understanding interrelationships between fish populations of Dongsha Island and surrounding South China Sea regions. (3) Objectives: 1.To understand the composition of eggs and larvae of the fishes of the Dongsha Islands while discovering more new records or potential new species. 2.To understand the early life history of local fishes, including reproductive seasons, spawning quantities, settlement periods of larvae, and replenishment rates, based on the distribution of various types of fish eggs and larvae. 3.To understand how different habitat types within the Dongsha Atoll Lagoon contribute to fish community dynamics. 4.To establish a specimen collection and database for eggs and larvae of the fishes of the Dongsha Islands along with relevant explanatory materials while integrating data collected during Basic Ecological Resource Survey conducted by Taiwanese Coral Reef Society​ and National Park Association in Taiwan from November 2004 to July 2005—providing educational resources for ecological conservation efforts while preparing for future publications like guides on larvae of the fishes of the Dongsha Islands.

Sampling Methods

The sampling stations were selected around the inner and outer reef of Dongsha Atoll.

Method step description:

1. 2005 investigation: The study was conducted through underwater observations and specimen collection, with dive survey stations planned around Dongsha Island and the larger atoll. Surveys were carried out from April 1–3 at four subtidal stations in the waters around Dongsha Island (three inside the atoll and one south of Dongsha Island) and from July 2–5 at five subtidal stations (Figure 3-1). Fish surveys employed the visual strip-transect method (McCormick and Choat, 1987), with 2–3 divers at each station laying out transects measuring 50 m × 20 m. Observations recorded the species, body length, and abundance of all fish within the transect for community analysis. Complementary collection methods were used to survey cryptic species, providing a more comprehensive dataset. Table 3-1 presents the fish species list for Dongsha Island. Species abundance at individual stations was recorded as follows: "+" indicates 1–4 individuals, "++" indicates 5–16 individuals, "+++" indicates 17–32 individuals, and "++++" indicates 32 or more individuals observed. For the 2005 data, abundance was categorized based on the total number of "+" at each station: 1–6 "+" was classified as "R" (rare), 7–12 "+" as "O" (occasional), 13–24 "+" as "C" (common), and 25 or more "+" as "A" (abundant). In the 2004 survey (Chen et al., 2005) and Chen et al. (1995), an asterisk (*) indicates the presence or absence of a species, rather than its abundance value.
2. 2011 investigation: Fish eggs and larvae were collected using two methods: plankton nets and light traps. A plankton net (90 cm diameter, mesh size 330 μm) was used to perform a single horizontal tow at each sampling station within and outside the Dongsha Atoll. Each tow lasted 10–15 minutes, and a flowmeter (HydroBios) was mounted at the net opening to estimate the actual volume of water filtered. Modified light traps (46 cm height × 30 cm length × 30 cm width; 8 kg weight, mesh size 0.5 mm) were deployed at night at six or seven stations and within the Dongsha Island Lagoon for light-attracted sampling. In addition to collecting pelagic eggs from the water surface, subtidal coral reefs were surveyed through diving to investigate demersal-spawning or mouthbrooding fish species and their larvae. Larvae newly settled onto coral reefs, seagrass beds, and sandy-muddy substrates were also observed and collected to understand their species composition and distribution. This information was compared with the species composition of fish eggs and larvae collected from the water column. Adult fish specimens were also collected for DNA sequences barcoding to aid in species identification. All samples collected were preserved in 95% ethanol and transported to the laboratory for morphological and DNA sequences barcoding analysis to identify species and calculate abundance. Additionally, pound nets were deployed twice at the mouth of the Dongsha Island Lagoon for supplementary sampling.

Additional Metadata