77 
NOAA 
National Marine 
Fisheries Service 
Abstract— The wreckfish ( Polyprion 
americanus), a commercially impor- 
tant, long-lived, demersal fish, is 
found in the eastern Atlantic from 
Norway to South Africa and in the 
western Atlantic from the Grand 
Banks, Newfoundland, to Argentina. 
Using bomb radiocarbon analysis, 
we validated the annual increment 
formation observed in otoliths and 
determined that increment counts 
are a good proxy for age. The maxi- 
mum observed age was 80 years, 
more than double the previously 
reported maximum age of 39 years 
in the North Atlantic population. 
The updated fit of the length-at-age 
information to the von Bertalanffy 
growth model resulted in L k, and 
to estimates of 1026 mm in fork 
length, 0.124/year, and -4.96 years, 
respectively. We used these updated 
values for maximum age and growth 
parameters to estimate rates of in- 
stantaneous and age-varying natural 
mortality, and found that instanta- 
neous natural mortality ranged from 
0.088 to 0.091 and age-varying natu- 
ral mortality reached an asymptote 
of 0.07-0.12 by 15 years of age. This 
study highlights the need for age 
validation in long-lived fish species 
to prevent inaccurate estimates of 
age that ultimately can lead to mis- 
management of a species 
Manuscript submitted 11 February 2015. 
Manuscript accepted 16 November 2015. 
Fish. Bull. 114:77-88 (2016). 
Online publication date: 3 December 2015. 
doi: 10.7755FB.114.1.7 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Fishery Bulletin 
<%■» established 1881 •<?> 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Age validation of the North Atlantic stock of 
wreckfish ( Polyprion americanus ), based on 
bomb radiocarbon 0 4 C), and new estimates of 
life history parameters 
Adam R. Lytton (contact author) 
Joseph C. Ballenger 
Marcel J. M. Reichert 
Tracey I. Smart 
Email address for contact author: lyttona@dnr.sc.gov 
South Carolina Department of Natural Resources 
217 Fort Johnson Road 
Charleston, South Carolina 29412-9110 
Deepwater fishes (depths >400 m) 
are becoming increasingly important 
to commercial fisheries (Clarke et al., 
2003). Unfortunately, the general lon- 
gevity — some species such as orange 
roughy ( Hoplostethus atlanticus) live 
up to 150 years — and slow matura- 
tion rates of many deepwater fishes 
make them highly susceptible to 
overfishing and slow to recover from 
an overfished state (Clark, 2001; Rob- 
erts, 2002; Clarke et al., 2003). An 
additional issue is that deepwater 
fish species are difficult to age (Fen- 
ton et al., 1991, Friess and Sedberry, 
2011;). Accurate aging is critical for 
the estimation of several life history 
parameters, such as growth, mortal- 
ity, and stock productivity, and is es- 
sential for any age-structured model 
of population dynamics. 
One deepwater species whose age 
estimates are subject to aging error 
is the wreckfish ( Polyprion ameri- 
canus). This grouper-like, commer- 
cially important, long-lived, demersal 
fish is found in the eastern Atlantic 
from Norway to South Africa and in 
the western Atlantic from the Grand 
Banks, Newfoundland, to Argentina, 
although it is noticeably absent from 
tropical latitudes— an absence that 
indicates an antitropical distribu- 
tion for this species (Sedberry et al., 
1999). Using microsatellite genetic 
markers, Ball et al. (2000) deter- 
mined that North Atlantic and South 
Atlantic populations are genetically 
distinct. Our study focused on the 
North Atlantic, and unless otherwise 
specified, wreckfish hereafter refers 
to the stock in the North Atlantic. 
Adult wreckfish are found concen- 
trated around steep, rocky bottoms 
and deep coral reefs, occurring in 
lower concentrations along flat hard 
bottom, from depths of 40 to 800 m; 
however, most wreckfish occur in 
waters deeper than 300 m, and at a 
maximum reported depth of 1000 m 
(Sedberry et al., 1999). They grow to 
a size of 2 m and can approach 50 kg 
in weight (Sedberry et al., 1999). 
Until the mid-1980s, when crews 
aboard pelagic longliners acciden- 
tally “discovered” the resource along 
the Charleston Bump, an area off the 
coast of South Carolina (Sedberry et 
al., 1999), wreckfish were unexploited 
commercially in the western North 
Atlantic. The fishery for this species 
developed rapidly, and the majority 
of effort was focused on or around 
the Charleston Bump, where land- 
ings peaked at 4.2 million lb whole 
weight (ww) in 1989 (Vaughan et al., 
