true

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

Molokini Crater ISRA

68/179

Molokini Crater ISRA

Molokini Crater

Summary

Molokini Crater is located west of Maui, in the Hawaiian Islands of the United States of America. The area encompasses Molokini Islet – the rim of a volcanic crater. It is characterised by sandy patches, coral, and basaltic boulders. The outer crest is influenced by strong currents from the Alalakeiki Channel, and the inner cove is protected from major ocean swells. This area overlaps with the Molokini Shoal Marine Life Conservation District. Within this area there are: threatened species (e.g., Whitetip Reef Shark Triaenodon obesus); reproductive areas (e.g., Grey Reef Shark Carcharhinus amblyrhynchos); resting areas (Whitetip Reef Shark); and undefined aggregations (Grey Reef Shark).

Molokini Crater

Molokini Crater

DESCRIPTION OF HABITAT

Molokini Crater is located in the Alalakeiki Channel, ~4.82 km west of Makena, Maui, in Hawaii – an island state of the United States of America. The area includes the range around Molokini Islet – a rim of a volcanic crater – and includes Kahuluele Bay on the inner cove (Szuster & Needham 2010). It also encompasses the pelagic-facing range off the southern rim which is characterised by a slope (Friedlander et al. 2016). The inside of the crater reaches depths of 30 m and is protected from ocean swells (Friedlander et al. 2016). The area is also characterised by sand patches, coral, and basaltic boulders (SHADR 2024a). The outside of Molokini Crater is influenced by strong currents from the Alalakeiki Channel.

This Important Shark and Ray Area overlaps with the Molokini Shoal Marine Life Conservation District (SHADR 2024b).

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 90 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

Two Qualifying Species considered threatened with extinction according to the IUCN Red List of Threatened Species regularly occur in the area. These are the Endangered Grey Reef Shark (Simpfendorfer et al. 2020a) and the Vulnerable Whitetip Reef Shark (Simpfendorfer et al. 2020b).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Molokini Crater is an important reproductive area for two shark species.

Recreational divers regularly observe neonate/young-of-the-year (YOY) Grey Reef Sharks in this area between June–September (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). Between 2012–2016, recreational dives were undertaken year-round (~300 dives per year). Between 2017–2024, ~10 dives were undertaken each year, in different seasons (J Glazner, M Rudenko, B Anderson pers. obs. 2024). Grey Reef Sharks at this life stage were observed on 50% of dives, mostly between June–September. Grey Reef Sharks were observed in aggregations of up to 35 individuals (mean = 3 individuals) and were visually estimated to measure between 60–150 cm total length (TL). Most (80%) of the individuals were estimated to be 60–90 cm TL, classifying them as neonates or YOY considering their reported size-at-birth of 45–60 cm TL (Ebert et al. 2021). Grey Reef Sharks at these life stages use this area seasonally, with most being observed between June–September. Outside of this period, there are only sightings of adults recorded, either solitary or up to three individuals (J Glazner pers. obs. 2024).

Recreational divers regularly observe neonate/YOY Whitetip Reef Sharks in this area (J Glazner, M Rudenko, & B Anderson, pers. obs. 2024). Between 2012–2016, recreational dives were undertaken year-round (~300 dives per year). Between 2017–2024, ~10 dives were undertaken each year, in different seasons (J Glazner, M Rudenko, & B Anderson, pers. obs. 2024). Whitetip Reef Sharks at this life stage were observed on 85% of dives, mostly between May–July (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). Whitetip Reef Sharks were observed in aggregations of up to 10 individuals (mean n = 2). Size of the individuals in this area was visually estimated between 60–150 cm TL. Approximately half of the Whitetip Reef Sharks observed in this area are considered neonates/YOY as are visually estimated to measure 60–90 cm TL (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). The size-at-birth of this species is 52–60 cm TL (Ebert et al. 2021). Aggregations of ~35 Whitetip Reef Shark pups have also been photographed, with the dive centre reporting that pregnant females give birth to 6-8 pups in this area in August (Island Style Diving 2024). Additionally, the regular and predictable observation of early life stage Whitetip Reef Sharks is reported in recreational activities within the no-take zone which has been delineated within this area (Szuster & Needham 2010).

CRITERION C

SUB-CRITERION C3 – RESTING AREAS

Molokini Crater is an important resting area for one shark species.

Whitetip Reef Sharks are regularly observed resting under ledges at both edges of the crater and on the sand inside caves in this area (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). Between 2012–2016, recreational dives were undertaken year-round (~300 dives per year). Between 2017–2024, ~10 dives were undertaken each year, in different seasons (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). Sightings occurred year-round and groups of up to five individuals resting together were recorded. Resting was the most frequently observed behaviour for this species and was observed during the day (07:00­–11:00) (J Glazner, M Rudenko, & B Anderson pers. obs. 2024), which is typical of this primarily nocturnal hunter (Randall 1977).  Recreational divers estimate that resting behaviour is observed in 80% of all sightings of the species within this area (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). Additional observations of resting Whitetip Reef Sharks have been shared online by recreational divers, where individuals rest on top of the reef as well as under caves which characterise this area. Whitetip Reef Sharks rest on the inside of the crater, which is protected from major ocean swells (Friedlander et al. 2016). Although Whitetip Reef Sharks are known to rest elsewhere, this area has more frequently recorded observations of resting groups compared to adjacent areas that were surveyed by recreational divers.

CRITERION C

SUB-CRITERION C5 – UNDEFINED AGGREGATIONS

Molokini Crater is an important area for undefined aggregations of one shark species.

Grey Reef Sharks are regularly and predictably observed using a cleaning station in this area, at a site within the area known locally as ‘backwall’. Grey Reef Sharks are cleaned by the Hawaiian Cleaner Wrasse Labroides phthirophagus outside of the crater on the wall at ~23 m in the area. Between 2012–2016, recreational dives were undertaken year-round (~300 dives per year). Between 2017–2024, ~10 dives were undertaken each year, in different seasons (J Glazner, M Rudenko, & B Anderson pers. obs. 2024). This behaviour was reported on an estimated 15% of dives when the species was observed (J Glazner, M Rudenko, & B Anderson pers. obs. 2024).

Molokini Crater

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