318 
Fishery Bulletin 111(4) 
880 
770 - 
E" 660 ■ 
E 
£ 550 - 
a> 
0) 440 - 
£ 330 - 
220 - 
110 - 
B 
3 60 
3.15 
270 
2.25 
1.80 
1.35 
0.90 
0.45 
I 1 1 1 1 1 1 1 1 1 1 
3 6 9 12 15 18 21 24 27 30 
Age (years) 
6 8 10 12 14 16 18 20 
Age (years) 
Fork length (mm) 
Figure 5 
Comparisons of parameters by region, and fits 
of Arafura Sea data points, for John’s Snap- 
per (Lutjanus johnii) sampled during the pe- 
riod of February 1989-April 2002 in 4 regions 
of Australia — north Queensland, Kimberley, 
Cape York, and Arafura Sea: (A) fork length 
(mm) at age (years) with von Bertalanffy 
growth function (sexes pooled; see Table 2); 
(B) otolith weight at age with first-order poly- 
nomials (see Table 3); and (C) gonad weight 
at fork length with exponential relationships 
(see Table 5). 
creased with distance from the equator, but they in- 
voked major regional differences in exploitation rate 
as an explanation. At a smaller latitudinal scale, Saari 
(2011) concluded that Red Snapper (L. campeclianus ) 
from northern Texas and Alabama reach significantly 
larger L„ than do Red Snapper from southern Texas 
and northwestern Florida. Saari (2011) discussed se- 
vere overfishing as the primary cause of the difference, 
as well as differences in environmental factors, fish- 
ing behavior between sectors, habitat-preference, and 
management regimes. In eastern Indonesia, the Crim- 
son Snapper ( L . erythropterus) and Malabar Snapper 
grow faster than their conspecifics in northern Austra- 
lia, but Fry and Milton (2009) interpreted this pattern 
in relation to the genetic evidence for separate stocks. 
Mangrove Jack at the southern end of their Austra- 
lian range have faster juvenile growth and are larger 
at a given age, but Russell et al. 2 were concerned that 
sample sizes were too small for any inferences to be 
made from such observations. 
There is no doubt that heavy fishing can affect body 
sizes of fishes across latitudes. Throughout the 1970s, 
there was a ten-fold increase in mean body size of 326 
fish species from low to high latitudes in the North 
Atlantic. However, this trend began to weaken under 
heavy fishing pressure in the early 1980s, and, by 1991, 
mean body sizes had declined steeply to the extent 
that a gradient was no longer detectable (Fisher et al., 
2010). This homogenization of community size struc- 
tures was a breakdown of Bergmann’s rule that Fisher 
et al. (2010) predicted will lead to declining stability in 
populations, communities, and ecosystems. 
The earliest explanations for James’s rule concerned 
a quandary posed by the temperature-size rule (Atkin- 
son, 1994); for most ectotherms, decreased nutrition 
and decreased temperature both reduce growth rates, 
but each affects maturity differently. Decreased nutri- 
tion results in delayed maturity at a smaller size, yet 
decreased temperature usually results in delayed ma- 
turity at a larger size. This puzzle led Berrigan and 
Charnov (1994) to propose that the effects of tempera- 
ture on maturity are associated with the existence of a 
negative correlation between and the growth coef- 
ficient, K, in the VBGF. 
In contrast, the latitudinal studies of tropical fish 
growth at the largest scales, over 56° of latitude for 
Ocean Surgeon ( Acanthurus bahianus) and 14° of lati- 
tude for Stoplight Parrotfish ( Sparisoma viride), have 
shown that growth rate is faster in cooler waters (22.6- 
28.1°C), not slower. Maximum age, adult survivorship, 
terminal size, and absolute growth rate are inversely 
related to temperature in populations of Ocean Sur- 
2 Russell, D. J., A. J. McDougall, A. S. Reicher, J. R. Ovenden, 
and R. Street. 2003. Biology, management and genetic 
stock structure of mangrove jack (Lutjanus argentimacula- 
tus) in Australia, 198 p. Queensland Department of Prima- 
ry Industries, Brisbane, Australia. [Available from http;// 
era.deedi.qld.gov.au/3119/l/BiologyManGeneticStock_report_ 
final%5Bl%5D-sec.pdf.] 
