Bomb Radiocarbon

Giant Sea Bass can live more than 50 years 

Published in Bulletin of Southern California Academy of Sciences - 2012

Bomb radiocarbon dating and estimated longevity of Giant Sea Bass (Stereolepis gigas)

In January 2010, a massive giant sea bass (500 lbs, 227 kg; near maximum reported size of 557 lbs, 253 kg) was captured off Santa Cruz Island by commercial gill-netters. This specimen presented a unique opportunity for a first-time estimation and validation of longevity for the largest nearshore teleost of the northeastern Pacific. A transverse section of the sagittal otolith produced consistent counts of 62 opaque annuli along two different axes of the ventral sulcus region, translating into an estimated birth year of 1948. This age estimate was supported by measurements of radiocarbon (14C) in the other sagittal otolith core (within the first year of growth), relative to ∆14C reference records used for bomb radiocarbon dating. Two otolith core samples produced ∆14C values that were classified as pre-bomb (prior to ~1958-59), indicating a minimum lifespan of 51 years. It is possible that giant sea bass can normally live more than 60 or 70 years, but a previous estimate of up to 100 years remains unfounded. The mircostructure of this otolith was sampled with a series of extractions made with a New Wave Research micromilling machine (Elemental Scientific Lasers, Bozeman, MT, USA; http://www.nwrlasers.com/milling/micromill/).

Authors: Larry Allen and Allen Andrews

Publication in Bulletin Southern California Academy of Sciences:

http://www.bioone.org/toc/soca/111/1 

Giant sea bass are now protected because of its rarity. Fish of this size are exceedingly rare and it had been decades since one close to 500 lbs. had been landed. The one captured most recently was accidental/incidental and was not targeted by the fishermen. Unfortunately, the fish did not survive capture and could not be returned to the sea. This capture provided a very unique opportunity to determine the longevity of this species in a manner that would not have been possible otherwise.

Despite their protection, ignorance is one of the biggest threats to this species. A recent landing of a small giant sea bass was recorded and the fishermen prosecuted. The fish is gone and the men got 120 hours of community service. Please share your awareness and help fishermen understand that rebuilding of this fishery will take decades.