true

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

Dauahk Bridge ISRA

143/179

Dauahk Bridge ISRA

Dauahk Bridge

Summary

Dauahk Bridge is located on the western side of Pohnpei Island in the Federated States of Micronesia. The area provides a passage from the barrier reef surrounding Pohnpei to the lagoon. The passage has a unique reef bridge across the mouth, joining one side of the channel to the other. Within this area there are: threatened species and reproductive areas (Grey Reef Shark Carcharhinus amblyrhynchos).

Dauahk Bridge

Dauahk Bridge

DESCRIPTION OF HABITAT

Dauahk Bridge is located on the western side of Pohnpei island in the Federated States of Micronesia. Pohnpei is surrounded by a lagoon, enclosed by a discontinuous barrier reef (Rowley et al. 2019), and Dauahk Bridge provides a passage from the reef to the lagoon. The passage has a unique reef bridge across the mouth, joining one side of the channel to the other. Pohnpei is a volcanic island with high elevation and dense vegetation, resulting in high annual precipitation levels (Rowley et al. 2019), with runoff influencing the surrounding reefs and lagoon.

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 100 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

One Qualifying Species considered threatened with extinction according to the IUCN Red List of Threatened Species regularly occurs in the area. This is the Endangered Grey Reef Shark (Simpfendorfer et al. 2020).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Dauahk Bridge is an important reproductive area for one shark species.

Young-of-the-year (YOY) Grey Reef Sharks are regularly and predictably observed aggregating in the area on the incoming tide when currents are strong (J Hartup pers. obs. 2024). Between 2014–2023, in each of the ~18 recreational dive surveys conducted in the area, aggregations of Grey Reef Sharks have been encountered. Aggregations consist of 10–25 YOY individuals (<75 cm total length [TL]), 8–10 juveniles (~100 cm TL), and 3–5 adults (~180 cm TL). All sizes were estimated visually, and the size-at-birth for this species is 45–64 cm TL (Ebert et al. 2021), indicating that the majority of individuals in the area would be classified as neonates or YOY (62.5% out of a maximum 40 sharks observed per encounter; J Hartup pers. obs. 2024). This is the only area around the island of Pohnpei where higher numbers of YOY Grey Reef Sharks have been recorded. Sharks are observed hanging in the current and at times hunting reef fish, however more information is required to determine if the area serves as an important feeding area. The large proportion of YOY individuals observed in aggregations highlight the importance of this area for reproductive purposes for Grey Reef Sharks.

Dauahk Bridge

SUBMIT A REQUEST

ISRA SPATIAL LAYER REQUEST

To make a request to download the ISRA Layer in either a GIS compatible Shapefile (.shp) or Google Earth compatible Keyhole Markup Language Zipped file (.kmz) please complete the following form. We will review your request and send the download details to you. We will endeavor to send you the requested files as soon as we can. However, please note that this is not an automated process, and before requests are responded to, they undergo internal review and authorization. As such, requests normally take 5–10 working days to process.

Should you have questions about the data or process, please do not hesitate to contact us.

    * indicates required

    Industry or sector (*)

    Under the terms and conditions of our User License Agreement , full and appropriate acknowledgement is required in any materials and publications derived from the data (and copies should be sent to the IUCN SSC Shark Specialist Group through the contact form). For any publications making substantial use of the data, the ISRA welcomes the opportunity for co-authorship, collaboration, and to comment prior to publication.


    Furthermore, we need to know whether you are a commercial or non-commercial user. Non-commercial includes scientific research, education or conservation. Commercial is defined as follows: any use by, on behalf of, or to inform or assist the activities of a commercial entity (that operates ‘for profit’) or use by a non-profit for the purposes of revenue generation

    Type of use(*):

    Please specify which layer (ex. all layers, layers within a specific Region, layers within a Jurisdiction or a single ISRA): Purpose (*):

    Please provide a description of how you intend to use the ISRA GIS Dataset. The more details you provide, the faster we can respond to your request. We may require further clarification prior to providing access. (min. 100 characters – max 1,000 characters)



    File format request (*)

    By providing your personal data, you consent to its processing as described below. The IUCN SSC Shark Specialist Group will use the information you provide on this form to send the documents you requested. You can change your mind at any time by writing to the ISRA Data Coordinator www.sharkrayareas.org/contact. All personal details provided will be treated with respect. For any information you can visit our Privacy Policy.
    Please read the User License Agreement and ISRA Layer Metadata Description

    This form uses Google reCaptcha to reduce spam. Privacy - Terms