First record of male freshwater eels (Anguilla dieffenbachii) caught at sea
Citation
Jellyman D J, Stewart A (2024). First record of male freshwater eels (Anguilla dieffenbachii) caught at sea. Version 1.2. The National Institute of Water and Atmospheric Research (NIWA). Samplingevent dataset. https://nzobisipt.niwa.co.nz/resource?r=nz_male_anguilla_at_sea&v=1.2 https://doi.org/10.15468/pvnc7n accessed via GBIF.org on 2024-12-05.Description
Two silver (migratory) male freshwater eels, Anguilla dieffenbachii, were caught in a commercial trawl net in the South Taranaki Bight in April 2014. The capture date and the relatively small eye size indicated that both eels had probably only recently entered the sea. This is the first record of male A. dieffenbachii caught at sea, en route to the presumed spawning area in the South Fiji BasinSampling Description
Study Extent
South Taranaki BightSampling
On 22 April 2014, two A. dieffenbachii were caught in the D'Urville Sea Valley, South Taranaki Bight, by a commercial trawler; the centroid of the trawl shot, 40 22’S, 174 03E, was 36 km NNE of Stephens Island (Marlborough Sounds), and 98 km West of Foxton Beach. The trawl (116 m opening, 60 m height, 108 mm codend mesh) was deployed at 2140 h on 21 April and retrieved at 0600 h the following day. The average bottom depth was 122 m, but as the trawl fished mid-water, the actual depth of capture is uncertain. The eels were noticed by Ministry for Primary Industries onboard observers who froze them prior to forwarding to the Museum of New Zealand, Te Papa Tongarewa, for confirmation of identification.Method steps
- When thawed, one eel measured 608 mm TL and 474 g, and the second 648 mm (but was not weighed). Both eels were identified as A. dieffenbachii from external features (body shape, colour, insertion and length of the dorsal fin and pattern of vomerine teeth), while examination of the gonads confirmed they were males. As they were catalogued as museum specimens, it was not permitted to make incisions and remove both testes, so no gonadosomatic index could be calculated. The eye indices (vertical x horizontal diameter; Todd Citation1981b) were 9.36 and 9.88 mm2 respectively; the average index for silver longfin male eels of similar lengths at the start of their seaward migration would be 9.2 and 10.26 mm2 respectively (calculated from the eye index/total length relationship given by Todd (Citation1981b)).
Additional info
marine, harvested by iOBISTaxonomic Coverages
New Zealand Longfin Eel
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Anguilla dieffenbachiicommon name: New Zealand longfin eel, ōrea rank: species
Geographic Coverages
South Taranaki Bight, New Zealand
Bibliographic Citations
- Don J. Jellyman & Andrew I. Stewart (2019) First record of male freshwater eels (Anguilla dieffenbachii) caught at sea, New Zealand Journal of Marine and Freshwater Research, 53:2, 288-291 - DOI: 10.1080/00288330.2018.1550792
Contacts
Don J. Jellymanoriginator
position: Researcher
National Institute of Water & Atmospheric Research
Christchurch
NZ
Andrew Stewart
originator
position: Researcher
Museum of New Zealand, Te Papa Tongarewa
Wellington
NZ
Don J. Jellyman
metadata author
position: Researcher
National Institute of Water & Atmospheric Research
Christchurch
NZ
Don J. Jellyman
administrative point of contact
position: Researcher
National Institute of Water & Atmospheric Research
Christchurch
NZ
userId: https://orcid.org/0000-0002-6941-2703