Sample checklist of Gastropoda and Bivalvia in Cham Islands, Vietnam

Abstract Background Cham Islands (Cu Lao Cham) is a group of 8 small islands in the Quang Nam province, Central Vietnam. There is only one study that mentioned the diversity of marine molluscs in this area. However, the data on species composition have not been digitised and not stored or shared for other purposes. Our paper aims to share the checklist of marine mollusc species (Bivalvia and Gastropoda) species that we collected from the littoral zone of Cham Islands in May 2017. This is the first digitised and online data of marine molluscs in Vietnam. It is very important for researchers in various fields such as the structure and function of ecology and biodiversity monitoring. New information This study provides a checklist of the marine bivalves and snails in the Cham Islands of Vietnam. Moreover, this first widely shared data of biodiversity in Vietnam can trigger biodiversity data papers in this data-poor country. The data of this study will be important inputs for better understanding biodiversity on the Cham Islands and Vietnam as well as for forming the basis for monitoring, exploitation and conservation of biodiversity in this area. In total, 145 taxa were recorded, 46 bivalve taxa and 99 snail taxa, from which 128 were identified to the species level and 17 were identified to the genus level. There are 116 new species records for the Cham Islands. The specimens are currently deposited in the Institute of Ecology and Biological Resources (IEBR), Vietnam Academy of Science and Technology (VAST).


Introduction
Cham Islands forms a part of Cu Lao Cham Marine Protected Area and has been recognised by UNESCO as a World Biosphere Reserve (Cu Lao Cham Marine Park) in 2009. There is only one study on macrobenthic fauna on the coral reefs that also mentioned marine molluscs in the Cu Lao Cham Sea (Tuyen 2013). However, its data on the species checklist was not digitised or stored in any database. Therefore, it was not widely used by other scientists. Our aim here is to show the list of snails (Gastropod) and bivalves (Bivalvia) that we found during our survey in May 2017 from Cham Islands. This checklist is the first formal biodiversity data of this group of islands of Vietnam.

General description
Purpose: This study aims: 1. to provide the list of snail and bivalve species distributed in Cham Islands; 2. to store and register the specimens for future studies.
The survey was conducted in May 2017 in the littoral zones of Cham Islands to the depths between 5 and 10 metres.
Additional information: This is a database of the scientific names and the coordinates of collected specimens.

Project description Title: Sample checklist of Gastropoda and Bivalvia in Cham Islands, Vietnam
Personnel: The researchers involved in this project were Dr. Do Van Tu (sample collection, taxonomic identification, data management), Dr. Le Hung Anh (sample collection) and Dr. Tran Anh Tuan (map drawing) from the Institute of Ecology and Biological Resources and Dr. Luu The Anh (sample collection) from theInstitute of Geography. Both institutes are under the Vietnam Academy of Science and Technology. Moreover, Dr. Takenori Sasaki from the University Museum, The University of Tokyo, helped to verify the identification of all species.
Study area description: Cham Archipelago consists of one large island surrounded by seven small islands covering a sea area of 15 square kilometres and it is located in Central Vietnam, 16 kilometres from the coast and 19 kilometres to the east of the ancient Hoi An town, Quang Nam province (source: https://en.wikipedia.org). The names of islands are the Hon Lao (Pearl), Hon Dai (Long), Hon Mo (Tomb), Hon Kho me (Big Dry), Hon Kho con (Small Dry), Hon La (Leaf), Hon Tai (Ear) and Hon Ong (East Wind). The coral reefs and seagrass beds are widely distributed in the shallow waters of Cu Lao Cham. The researchers have recorded 261 species of Scleractinian coral, 15 species of soft coral, 3 species of fire coral (Milleporidae), 1 species of blue coral (Helioporidae) and 2 species of horny coral (Antipatharia) in this area (Ngoc 2018).
We only surveyed around the large island (Hon Lao) and three other small islands (Hon Tai, Hon La, Hon Dai) (Fig. 1). The sampling sites were sandy beaches, rocky shores and coral reefs. The collection of specimens was approved by Management Board of Cu Lao Cham Marine Protected Area.

Quality control:
The scientific names in this paper are based on the identification by experienced experts in the field of the taxonomy of marine molluscs, namely, Dr. Takenori Sasaki from the University Museum, the University of Tokyo and Dr. Do Van Tu from Institute of Ecology and Biological Resources. All taxon names were checked against the Taxon Match tool in the World Register of Marine Species (WoRMS) in order to standardise and correct them, if necessary (http://www.marinespecies.org/aphia.php?p=match).
Step description: NA

Geographic coverage
Description: The survey conducted in the Cham Islands including the large island (Hon La) and three other small islands (Hon Tai, Hon Dai, Hon La). Cham Islands belongs to Hoi An city, Quang Nam province. This island is located in Central Vietnam.

Temporal coverage
Notes: The field survey was conducted from 10-05-2017 through to 12-05-2017. The data were created from June 2017 until now. Some specimens could not be identified to the species level for the moment and the data will be updated in the future.

Collection data
Collection name: IEBR_Molluscs

Data resources
Data package title: Checklist of marine mollusc in Cham Islands, Hoi An city, Quang Nam province, Vietnam

Alternative identifiers: Do Van Tu
Number of data sets: 1

Data format: Darwin Core
Description: The checklist is based on identifying the collected specimens to the species level where possible.

SCIENTIFIC_NAME Complete scientific name including author and year
Specimen_number The code of the sample is used for identifying the sample from which the record is derived.
We also considered the specimen number as the voucher number.

Locality_Name
Name of locality where the sample was collected

Longtitude
The geographic longitude (in decimal degrees)

Latitude
The geographic latitude (in decimal degrees) Collected_Date DDMMYY

Family
The full scientific name of the family in which the taxon is classified New_Record New record for the Cham Islands