Growth analysis and age validation of a deepwater Arctic fish, the Greenland halibut (Reinhardtius hippoglossoides)

Abstract

The accuracy of age interpretations on a deep-sea, Arctic fish species, the Greenland halibut ( Reinhardtius hippoglossoides ) was tested using several age validation methods. Consistent annual growth increments were either not formed or not visible in either whole or sectioned otoliths from three fish marked with oxytetracyline and recaptured after 2–4 years at liberty. Bomb radiocarbon assays based on a local reference chronology indicated that both whole and sectioned otoliths underestimated age by 1–15 years, with an average of 6 years. Growth rates estimated using the tag recapture model GROTAG were consistent with growth rates based on the radiocarbon assays and were less than half that of previously reported growth rates. The failure of otolith sections to provide an accurate age is unusual, but may be symptomatic of very slow-growing species with unusually shaped otoliths. Greenland halibut living in the deep-sea, Arctic environment are slower growing and longer lived than previously suspected, suggesting that the age-structured basis for current fisheries management warrants careful examination. Our results highlight the importance of using rigorous tests of ageing accuracy for exploited species and confirm that such age validation methods can be applied successfully in challenging environments such as the deep sea or the Arctic.

Age determination, bomb-radiocarbon validation and growth of Atlantic halibut (Hippoglossus hippoglossus) from the Northwest Atlantic

“…Nevertheless, halibut live in the same environment as that used to develop the reference chronology for the northwest Atlantic , and thus are well-matched signals. Bomb radiocarbon has also proven effective in validating the accuracy of ageing methods for other flatfish species, including Pacific halibut (Piner and Wischniowski 2004), yellowtail flounder (Limanda ferruginea; Dwyer et al 2003), and Greenland halibut (Treble et al 2008).…”

“…The IPHC has greater confidence in age readings of Pacific halibut prepared with break and burn compared to those aged whole (Forsberg 2001); only the former has been validated as producing accurate ages (Piner and Wischniowski 2004). In general, thinsectioning and break-and-burn ageing techniques would be expected to provide more accurate age estimates than surface readings because of the asymmetric growth of old otoliths (Chilton and Beamish 1982;Treble et al 2008).…”

Oocyte development and vitellogenin production in Northwest Atlantic Greenland halibut Reinhardtius hippoglossoides

“…For example, tag and recapture data have recently suggested that the growth rate of Greenland halibut may be less than half of what was previously reported (Treble et al, 2008), with current estimates for adult fish ranging from less than 1 cm per year (Albert et al, 2009) to 3 cm per year (Treble et al, 2008). Here we monitored fish over a complete year and therefore were able to provide the first data on growth in captivity.…”

Monitoring beaked redfish (Sebastes mentella) in the North Atlantic, current challenges and future prospects

“…13) is oxytetracycline (OTC) marking of juveniles in order to follow growth increments in the otoliths from the time of marker injection (e.g. Greenland halibut: Treble et al 2008). …”