Life History and Ecology of Bluenose Warehou (Hyperoglyphe antarctica, Centrolophidae) in the Southern Atlantic

James B Bell,Freja Azzopardi,James Glass,Rodney Green,Simon A Morley,Warren Glass,Amelia E Bridges,Ramon Benedet,Georgia R Robson,Clive N Trueman,David K A Barnes,Simon Robertson,Oliver Yates,Vladimir Laptikhovsky,Martin A Collins,Harry Stanton

doi:10.3389/fmars.2021.610172

Abstract

Bluenose warehou (Hyperoglyphe antarctica) is a popular commercial fish in Australia and New Zealand, but its biology and ecology are very poorly known in other regions where it is found. We present here the first life history data for this species from the south Atlantic, focusing upon the exclusive economic zone (EEZ) of the United Kingdom Overseas Territory (UKOT) of Tristan da Cunha (TdC). Here, bluenose is known from several seamounts and island margins, typically occurring in waters between 200 and 1,000 m depth and is the target species of trawl and longline fishery operating since 1997. We use a suite of methods to describe important life history parameters, including length-weight and age-length relationships and size at recruitment, as well as examining commercial longline survey data to uncover habitat preferences of bluenose. This work has formed an important part of the United Kingdom government’s Blue Belt Program in TdC. It has underpinned the development of the first stock assessment for this species in the Atlantic, as well as a range of improved conservation measures for some of the more vulnerable species that occur in these areas, including seabirds and cold-water corals.

Highlights

Bluenose warehou (Hyperoglyphe antarctica, Carmichael, 1819), hereafter bluenose, is a large demersal finfish (Osteichthyes: Centrolophidae) that occurs in deep-water throughout the temperate Southern Hemisphere except the SW Atlantic (Kailola et al, 1993; Piotrovsky, 1994; Froese and Pauly, 2019)
There were no significant differences in bluenose catch per unit effort (CPUE) between any of the areas surveyed during research fishing longline sets
Typically non-linear relationships with CPUE which were likely to some degree indicative of the influence of the conditions upon vessel efficiency

Summary

Introduction

Bluenose warehou (Hyperoglyphe antarctica, Carmichael, 1819), hereafter bluenose, is a large demersal finfish (Osteichthyes: Centrolophidae) that occurs in deep-water throughout the temperate Southern Hemisphere except the SW Atlantic (Kailola et al, 1993; Piotrovsky, 1994; Froese and Pauly, 2019). Juveniles are thought to associate with drifting debris in the top 100 m of the water column (Last et al, 1993; Duffy et al, 2000) until they reach a total length of approximately 30–40 cm (rarely up to 50 cm). At full size, they recruit to the demersal habitat of adults and sub-adults (Horn, 1988; Duffy et al, 2000). The main prey species for bluenose are pelagic cephalopods, demersal and pelagic fishes, and crustaceans (Horn and Massey, 1989; Piotrovsky, 1994; Laptikhovsky et al, 2019)

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Conclusion