171 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
ft* established in 1881 
Spencer F. Baird 
First U S Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Adaptive and plastic variation in growth and 
maturation of the cutlassfish Trichiurus japonicus 
in the subtropical Pacific Ocean 
Email address for contact author: huiyuwasung@ntu.edu.tw 
Abstract— We investigated varia¬ 
tion in growth and maturation in 
response to 1) spatial variation in 
climate and 2) exploitation of the 
subtropical cutlassfish Trichiurus 
japonicus, an important fishery spe¬ 
cies whose population ecology is 
virtually unknown. Individuals of 
this cutlassfish species were sam¬ 
pled monthly at 2 primary landing 
sites: Kengfang, in northeast (NE) 
Taiwan, and Tsukuan, in southwest 
(SW) Taiwan, during 2013-2015. 
Habitat temperatures were about 
1-4°C lower at the NE site than at 
the SW site, and the length at age 
of adult fish had an inverse pattern 
with temperature (NE lengths >SW 
lengths at age). The probabilistic 
maturation reaction norms did not 
differ significantly between the 2 ar¬ 
eas, but ages and lengths at matura¬ 
tion were higher for males from NE 
than for males from SW. Differences 
in asymptotic lengths (NE>SW) and 
growth coefficients (NE<SW), togeth¬ 
er with narrower length distribution 
at the SW site than at the NE site, 
indicate potentially different mor¬ 
tality between the areas (NE<SW). 
These results indicate plastic varia¬ 
tion in maturation and potentially 
adaptive variation in growth for this 
species that are related to the differ¬ 
ences in temperature and mortality 
between the areas, although reliable 
proxies for mortality are lacking. 
The observed life-history variation 
was consistent with the tempera¬ 
ture-size rule that organisms tend 
to grow faster, mature earlier, and 
reach smaller asymptotic sizes at 
warmer temperatures and may indi¬ 
cate an adaptive divergence of cut¬ 
lassfish populations. 
Manuscript submitted 21 July 2017. 
Manuscript accepted 1 February 2018. 
Fish. Bull. 116:171-182 (2018). 
Online publication date: 22 February 2018. 
doi: 10.7755/FB. 116.2.6 
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. 
Hui-Yu Wang (contact author) 1 
Mikko Heino 1 ' 2 ' 3 4 
1 Institute of Oceanography 
National Taiwan University 
No. 1, Sec. 4, Roosevelt Road 
Taipei 10617, Taiwan 
2 Department of Biological Sciences 
University of Bergen 
RO. Box 7803 
5020 Bergen, Norway 
Life-history traits (i.e., growth rate, 
and age and length at maturation) 
are key determinants of population 
demography and the rates of popu¬ 
lation growth (Roff, 1992; Stearns, 
1992) and provide insight into the 
sustainability of exploited species 
experiencing environmental changes 
and fisheries exploitation (Clark, 
1991; Zhou et ah, 2012; Wang et 
al., 2014). Studies on the variation 
in life histories have, however, paid 
more attention to temperate fish spe¬ 
cies (i.e., primarily the species in the 
Northern Atlantic) than to subtropi¬ 
cal or tropical species, the abundance 
of which is predicted to decrease sig¬ 
nificantly under the effects of climate 
change (Cheung et al., 2010). Con¬ 
sequently, it is imperative that we 
enhance our understanding of life- 
history variation for subtropical and 
tropical species. 
Intraspecific variation in growth 
and maturation reflects the effects 
of both the physical and biological 
environments through a combina¬ 
tion of phenotypic plasticity and ge¬ 
netic variability (Stearns, 1992; Law, 
2000). For example, food availability 
and temperature can influence con- 
3 Institute of Marine Research 
RO. Box 1870 
Nordnes, 581 7 Bergen, Norway 
4 International Institute for Applied 5ystems 
Analysis 
Schlossplatz 1 
A-2361 Laxenburg, Austria 
sumption and assimilation, in turn 
influencing an animal’s energetic 
condition, growth rates, and matu¬ 
ration schedules (Saborido-Rey and 
Kjesbu 1 ). Simultaneously, because of 
the heritability of life-history traits 
and their association with fitness at¬ 
tributes (i.e., fecundity and survival), 
physical or biological factors can po¬ 
tentially influence growth and matu¬ 
ration through adaptive processes 
(known as the “habitat template the¬ 
ory”) (Southwood, 1977; Reznick et 
al., 1990; Arendt and Wilson, 1999). 
Furthermore, fishing-induced mor¬ 
tality also can cause plastic changes 
(e.g., through relaxing density-depen¬ 
dent processes) and adaptive genetic 
changes (through altering the ge¬ 
netic makeup of life-history traits) in 
growth and maturation (Law, 2000; 
Reznick and Ghalambor, 2005). To¬ 
gether, these factors can affect varia¬ 
tion in growth and maturation for 
an exploited species (Carlson et ah, 
2007; Sharpe and Hendry, 2009; En- 
berg et al., 2012). 
1 Saborido-Rey, F., and O. S. Kjesbu. 
2005. Growth and maturation dynam¬ 
ics, 26 p. [Available from website.] 
