National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
@ established in 1881 =< 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Abstract—An unusually strong year 
class of goosefish (Lophius ameri- 
canus) was first observed in the spring 
of 2015, and the length mode for this 
particular cohort remained evident for 
several years. We collected monthly 
samples from within this length mode 
over a period of 3 years and considered 
them fish with known ages for validat- 
ing ages estimated by using illicia and 
vertebrae. Recent research had found 
vertebral ages for goosefish to be inac- 
curate, and a method in which illicia 
are used for Lophius species in Europe 
seemed promising. However, ring 
counts from illicia matched the known 
age only 50% of the time and were not 
replicable (9% agreement). Ring counts 
from vertebrae never matched the 
known age but were replicable in 68% 
of samples. Marginal increment anal- 
ysis of illicia from fish that matched 
the known age provided evidence that 
one annulus is formed on the illicium 
in spring or summer of each year for 
fish aged from 1 to 2 years. Because of 
the low accuracy of age estimates made 
with both illicia and vertebrae, as well 
as the high bias of aging with verte- 
brae, we concluded that the methods 
based on these structures did not pro- 
vide useful age estimates of goosefish. 
The observed growth rate, based on the 
progression of the length mode during 
our study, was much faster than the 
growth rates based on vertebral ages. 
Manuscript submitted 27 May 2021. 
Manuscript accepted 23 November 2021. 
Fish. Bull. 120:138—25 (2021). 
Online publication date: 29 December 2021. 
doi: 10.7755/FB.120.1.2 
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. 
Validation of methods for aging goosefish 
(Lophius americanus) based on length-mode 
progression of a strong cohort 
Sandra J. Sutherland (contact author) 
R. Anne Richards 
Email address for contact author: sandy.sutherland@noaa.gov 
Northeast Fisheries Science Center 
National Marine Fisheries Service, NOAA 
166 Water Street 
Woods Hole, Massachusetts 02543 
The goosefish (Lophius americanus) is 
one of the most economically important 
fish species of the continental shelf off 
the northeastern United States. This 
species has been managed conserva- 
tively because of major uncertainties 
in stock assessment (NDPSWG, 2007; 
Haring and Maguire, 2008). One of the 
most significant uncertainties is the 
growth curve, which has been viewed 
with caution (NDPSWG, 2007) because 
it appears linear rather than asymp- 
totic (Richards et al., 2008). 
The growth curve for goosefish is 
based on ages derived from vertebrae, 
with an aging method that was used at 
the NOAA Northeast Fisheries Science 
Center (NEFSC) during 1998-2007. 
Age estimation efforts at the NEFSC 
were suspended in 2007, because of 
concerns raised at a stock assessment 
review (NDPSWG, 2007). The struc- 
tures normally used to estimate ages 
for other fish species (e.g., scales and 
sagittal otoliths) cannot be used for 
goosefish because they lack scales and 
because sagittal otoliths are not reli- 
able structures for aging this species 
(Armstrong et al., 1992; Hartley, 1995). 
The vertebral method was described 
by Armstrong et al. (1992), who exam- 
ined marginal increment widths on ver- 
tebrae and concluded that rings were 
formed in May of each year. Results 
from Armstrong et al. (1992) indicate 
that vertebrae met the minimal crite- 
ria for use as an aging structure (Van 
Oosten, 1928). However, direct valida- 
tion of the vertebral aging method had 
not been undertaken, perhaps because 
goosefish have very poor survival in cap- 
tivity (Richards et al., 2011). Recently, 
Bank et al. (2020) successfully com- 
pleted a direct age validation study that 
involved chemical marking of wild and 
laboratory-maintained goosefish. They 
demonstrated that the vertebral aging 
method was accurate less than 50% of 
the time for fish up to 2.4 years after 
tagging. However, results of their pre- 
liminary examination indicate that use 
of illicia (first spines on the dorsal fin) 
might provide more reliable age esti- 
mates. Illicia are the primary structures 
used to age white anglerfish (L. piscato- 
rius) and black anglerfish (LZ. budegassa) 
in Europe (Duarte et al.'; Farifia et al., 
2008; Landa et al., 2013). 
An opportunity for further age vali- 
dation work was presented by an 
exceptionally strong recruitment event 
Duarte, R., J. Landa, I. Quincoces, 
H. Dupouy, E. Bilbao, J. Dimeet, A. Marcal, 
H. McCormick, and G. Ni Chonchuir. 2002. 
Anglerfish ageing guide, 40 p. Working 
document of the 4th international ageing 
workshop on European anglerfish; Lisbon, 
14-18 January. [Available from website.] 
