true

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

ISRA FACTSHEETS

NEW ZEALAND & PACIFIC ISLANDS REGION

Central Chatham Rise ISRA

126/179

Central Chatham Rise ISRA

Central Chatham Rise

Summary

Central Chatham Rise is located in the central part of a ridge on the eastern side of New Zealand. This area is characterised by muddy and sandy substrates with high microbenthic and low meiofaunal biomass. The area is dominated by the Subtropical Front where subtropical waters and subantarctic waters mix. The area overlaps with two Key Biodiversity Areas. Within this area there are: threatened species (Spiny Dogfish Squalus acanthias); range-restricted species (Northern Spiny Dogfish Squalus griffini); and reproductive areas (Pale Ghostshark Hydrolagus bemisi).

Central Chatham Rise

Central Chatham Rise

DESCRIPTION OF HABITAT

Central Chatham Rise is located in the central part of a ridge on the eastern side of New Zealand. It rises from deep areas to 50 m in the western side and to sea level near the Chatham Islands (McGregor et al. 2019). The area is characterised by abyssal hills and plains with muddy and sandy substrates along high microbenthic and low meiofaunal (Nodder et al. 2003). Phosphorite nodules are spread around the crest of the rise along with exposed basement rock substrates (Bowden et al. 2017; Leduc et al. 2024). These habitats sustain large densities of deep-water corals (Leduc et al. 2024). The area has a stable and permanent oceanography dominated by the Subtropical Front where there is a mix of subtropical waters and subantarctic waters (Sutton 2001; Chiswell et al. 2015). North subtropical waters are warmer, more saline and nutrient poor compared to the cold and nutrient rich subantarctic waters from the south (McGregor et al. 2019). This front is divided by a frontal zone in the north and south (Sutton 2001). Sea surface temperatures are warmer during austral autumn with a shallow mixed layer in subtropical waters while in spring, temperatures are cooler and there is a deeper mixed layer (Sutton 2001). Due to the oceanographic and habitat features in the rise, this area has the highest species richness for demersal fishes (Leathwick et al. 2006)

The area overlaps with the Chatham (offshore) and East Coast South Island (offshore) Key Biodiversity Areas (KBA 2024a; 2024b).

This Important Shark and Ray Area is benthic and pelagic and is delineated from surface waters (0 m) to 670 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 Vulnerable Spiny Dogfish (Finucci et al. 2020).

CRITERION B

RANGE RESTRICTED

This area holds the regular presence of the Northern Spiny Dogfish, Smooth Skate, Australasia Narrow-nosed Spookfish, Pale Ghostshark, and Dark Ghostshark. These species were regularly encountered in independent research surveys using demersal trawls (200–1,300 m) conducted in January–February annually from 2009–20124 and bi-annually since 2014 (O’Driscoll et al. 2011; Stevens et al. 2012, 2013, 2014, 2015, 2017, 2018, 2021, 2023; B Finucci unpubl. data 2024). Due to the fishing gear selectivity, the abundance recorded for some of the species is underestimated and does not represent their true abundances in the area.

For Northern Spiny Dogfish, 140 individuals were recorded in the area between 2009–2024 (except 2015, 2019, and 2023) with Central Chatham Rise having the second largest number of individuals recorded during research surveys for this species in all New Zealand. This species is endemic to the New Zealand Shelf LME.

For Smooth Skate, 102 individuals were recorded in the area between 2009–2024 with Central Chatham Rise having the third largest number of individuals recorded during research surveys for this species in all New Zealand. This species is endemic to the New Zealand Shelf LME.

For Australasia Narrow-nosed Spookfish, 1,186 individuals were recorded in the area between 2009–2024 with Central Chatham Rise having the second largest number of individuals recorded during research surveys for this species in all New Zealand. This species is endemic to the New Zealand Shelf LME.

For Pale Ghostshark, 1,074 individuals were recorded in the area between 2009–2024 with Central Chatham Rise having the second largest number of individuals recorded during research surveys for this species in all New Zealand. This species is endemic to the New Zealand Shelf LME.

For Dark Ghostshark, 4,997 individuals were recorded in the area between 2009–2024 with Central Chatham Rise having the largest number of individuals recorded during research surveys for this species in all New Zealand. This species is endemic to the New Zealand Shelf LME.

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Central Chatham Rise is an important reproductive area for one shark and two chimaera species.

Based on records from research demersal trawl surveys conducted in yearly between January–February from 2009–2014 and bi-annually since 2014 (O’Driscoll et al. 2011; Stevens et al. 2012, 2013, 2014, 2015, 2017, 2018, 2021, 2023) young-of-the-year (YOY) individuals and late-stage pregnant females (with egg cases ready to be deposited or with near-term embryos) of Spiny Dogfish, Pale Ghostshark and Dark Ghostshark are regularly found in the area (B Finucci unpubl. data 2024). Species maturity was assessed at sea using the National Institute of Water and Atmospheric Research’s standard shark macroscopic maturity staging key. YOY were determined either through physical assessment at sea or estimated from published growth curves based on their size (Hanchett 1988; Berio et al. 2024). Due to the fishing gear selectivity, the abundance of YOY recorded does not represent the true abundances of these life-stages in the area.

For Spiny Dogfish, 10,934 individuals were caught. Of these, 26 YOY and 2,586 late-stage pregnant females (23.6% of catches) were caught at depths of 220–587 m. YOY were defined as individuals measuring <30 cm TL (Hanchett 1988).

For Pale Ghostshark, 7,916 individuals were caught. Of these, 16 YOY and 117 late-stage pregnant females (1.47% of catches) were caught at depths of 369–670 m. YOY were defined as individuals measuring <20 cm TL (Berio et al. 2024). Central Chatham Rise was the area with the largest number of pregnant females with egg cases sampled in all New Zealand.

For Dark Ghostshark, 11,856 individuals were caught. Of these, two YOY and 103 late-stage pregnant females (0.86% of catches) were caught at depths of 243–486 m. YOY were defined as individuals measuring <20 cm TL (Berio et al. 2024). Central Chatham Rise was the area with the second largest number of pregnant females with egg cases sampled in all New Zealand.

Central Chatham Rise

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