Bomb Radiocarbon
Speckled hind (
)
Epinephelus drummondhayi
Long-lived deep-water grouper of the Gulf of Mexico
Species of Concern Program - Office of Protected Resources - SEFSC/PIFSC
Published in Canadian Journal of Fisheries and Aquatic Sciences
Great longevity of speckled hind (Epinephelus drummondhayi), a deep-water grouper, with novel use of post-bomb radiocarbon dating in the Gulf of Mexico
Growth characteristics are poorly understood for speckled hind (Epinephelus drummondhayi), a tropical deep–water grouper of economic importance that is considered overfished. Age has been validated for early growth, but the validity of adult age estimates is unknown. A few studies of growth zones in otoliths have revealed maximum age estimates of 15 to 34 years, which have been uncritically assumed as longevity. To answer questions about adult age, bomb radiocarbon dating was used to provide validated age estimates. A novel aspect of this study was use of the post-bomb radiocarbon decline (~1980 - 2004) to age younger fish, an approach that was validated with known-age otoliths. Bomb radiocarbon dating provided valid length–at–age estimates ranging from ~5 years to more than 45 years. Age was unexpectedly greater than previous estimates for more than half the fish used in this study, and longevity may approach 60 to 80 years. This study extends the utility of bomb radiocarbon dating by more than 20 years and adds to the growing perspective that tropical fishes can be long lived.
Allen H. Andrews1, Beverly Barnett2, Robert Allman2, Ryan P. Moyer3, Hannah Trowbridge2
1. NOAA Fisheries – Pacific Islands Fisheries Science Center
2. NOAA Fisheries – Southeast Fisheries Science Center
3. Florida Fish & Wildlife Conservation Commission
This species was listed as aSpecies of Concern Program with NOAA Fisheries - Office of Protected Resources,but has since been delisted based on an evaluation of the petition (Federal Register: SPH-DelistingSOC-fr77-25687.pdf). However, this species is still regulated by the South Atlantic Fishery Management Council (SAFMC) and the Gulf of Mexico Fishery Management Council (GMFMC).
Publication: Great longevity of speckled hind
This is a supplemental figure that I think we should have used in lieu of the one we used in the publication. This one shows the extrapolated (some people just cannot handle this approach...) ages from otolith mass. While the ages have a high degree of uncertainty (maybe a +/- a decade), plotting them in this manner is more appropriate than stacking up all these pre-bomb fish at the rise (~1958). The speckled hind can certainly reach 60 years of age and may reach upwards to 80 years in some cases. Each 14C measurement was the result of extractions made with a New Wave Research micromilling machine (Elemental Scientific Lasers, Bozeman, MT, USA; http://www.nwrlasers.com/milling/micromill/).