42 
National Marine 
Fisheries Service 
NOAA 
FishBry Bulletin 
.%» established in 1881 -d=. 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Preliminary assessment of a direct age- 
determination method for 3 commercially 
important crustaceans from Jllaska 
Email address for contact author: rwkilada@gmail.com 
Abstract — Management of commer- 
cially important crab and shrimp 
species in Alaska has been hindered 
by the inability to directly determine 
the age of individual animals. We in- 
vestigated the applicability of a re- 
cently developed method of age de- 
termination to red king crab (Para- 
lithodes camtschaticus), southern 
Tanner crab (Chionoecetes bairdi), 
and spot shrimp (Pandalus platycer- 
os) from Alaska. The cuticle struc- 
tures of the mesocardiac ossicles 
of crabs and the eyestalks of spot 
shrimp were visualized with histo- 
logical staining to identify the en- 
docuticle, where growth bands have 
been observed in other crustaceans. 
For all species, paired light and dark 
bands were observed in longitudinal, 
thin sections of these structures in 
the majority of specimens exam- 
ined. The proximal portion of the 
mesocardiac ossicle, where growth 
bands were observed, was absent in 
the foregut exuviae of red king and 
southern Tanner crabs that molted 
in captivity. If validated, counts of 
growth bands hold promise as a reli- 
able measure for determining age of 
these species. 
Manuscript submitted 10 August 2015. 
Manuscript accepted 25 October 2016. 
Fish. Bull. 115:42-49 (2017). 
Online publication date: 15 November 2016. 
doi: 10.7755/FB.115.1.4 
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. 
Raouf Kilada (contact author)''^ 
Joel B. Webb^ 
Kevin W. McNeel^ 
Laura M. Slater^ 
Quinn Smith^ 
Jayde Ferguson^ 
' Department of Biology 
University of New Brunswick (Saint John) 
100 Tucker Park Road 
Saint John, New Brunswick E2L 4L5, Canada 
^ Department of Marine Science 
Suez Canal University 
Ismailia 41522, Egypt 
^ Division of Commercial Fisheries 
Alaska Department of Fish and Game 
P.O. Box 115526 
Juneau, Alaska 99811-5526 
^ Age Development Unit, Mark, Tag, and 
Age Laboratory 
Alaska Department of Fish and Game 
P.O. Box 115526 
Juneau, Alaska 99811-5526 
For many fish and invertebrate 
species, age can be determined di- 
rectly from growth bands recorded 
in calcified hard structures. These 
structures include bones, scales, and 
otoliths in fish species (Campana, 
2001) and statoliths and shell sec- 
tions in a variety of invertebrates 
(Jensen, 1969; Kilada et ah, 2007; 
Abele et ah, 2009). Similar meth- 
ods have not been applied to de- 
capod crustaceans because of the 
presumed loss and replacement of 
calcified structures during ecdysis 
(Vogt, 2012). Instead, indirect meth- 
ods, including captive observations, 
tag-recapture experiments, accumu- 
lation of lipofuscin in neural tissue, 
and analysis of size-frequency dis- 
5 Division of Commercial Fisheries 
Alaska Department of Fish and Game 
351 Research Court 
Kodiak, Alaska 99615 
* Division of Commercial Fisheries 
Alaska Department of Fish and Game 
P.O. Box 1 10024 
Juneau, Alaska 99811-0024 
^ Pathology Laboratory 
Alaska Department of Fish and Game 
333 Raspberry Road 
Anchorage, Alaska 99518-1599 
tributions, have been applied to in- 
fer age (Hartnoll, 2001; Vogt, 2012; 
Pinchuk et ah, 2016). 
A lack of reliable age information 
impedes assessment and manage- 
ment of crustacean fisheries (Caddy, 
1986). In Alaska, some major crab 
stocks are assessed and managed by 
using length-based population mod- 
els (e.g., Zheng et ah, 1995), in which 
data on abundance, harvest, growth, 
and mortality are integrated. Howev- 
er, the accuracy of these models may 
be compromised if the growth or mor- 
tality rates are not truly representa- 
tive of processes in situ. In contrast, 
age-structured models implicitly ac- 
count for variability in growth and 
mortality by incorporating compre- 
