Jakes-Cota et al.: Age and growth of Scorpaena mystes 
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—® Males: L, = 34.76(1 — e-0-202(-(-1.28))) 
—@— Females: L; = 48.22(1 —e~? 195-08) 
Results of the edge type analysis indi- 
cate that the periodicity of annulus for- 
mation in stone scorpionfish has an 
annual pattern. The highest percentages 
of opaque edges among all otoliths ana- 
lyzed coincided with the highest condi- 
tion factor values reported by Jakes-Cota 
et al. (2017) for stone scorpionfish for 
the months of August and September. 
This finding indicates that conditions for 
growth (e.g., high temperatures and high 
food availability) are favorable in our 
study area (Le Cren, 1951). In contrast, 
the highest percentages of translucent 
edges among all otoliths analyzed coin- 
cided with the lowest condition factor val- 
ues reported by Jakes-Cota et al. (2017) 
for the months of February—June. This 
finding indicates conditions (e.g., low 
temperatures and scarce food) are unfa- 
vorable in our study area and may limit 
growth (Le Cren, 1951). The annual peri- 
T 
10 
Age (years) 
Figure 2 
Growth curves from the von Bertalanffy growth function fitted to length- 
at-age data for male (black dots) and female (gray dots) stone scorpionfish 
(Scorpaena mystes) caught in the Gulf of California in Mexico during May 
2015—April 2016. L,=total length at age t. 
than 30 cm TL were scarce in our sampling, possibly a 
consequence of cumulative mortality in which larger and 
older individuals are removed by fishing or die naturally 
(Csirke, 1980). 
The characteristics of the length—weight relationship 
indicate an isometric growth pattern for both males and 
females. Similar results were reported for this species 
even when males and females were not analyzed sepa- 
rately (Jakes-Cota et al., 2017). In contrast to these find- 
ings, it has been reported that other species of the genus 
Scorpaena, such as the black scorpionfish (S. porcus) (Bilgin 
and Celik, 2009; Demirhan and Can, 2009), Madeira rock- 
fish (S. maderensis) (La Mesa et al., 2005), and small red 
scorpionfish (S. notata) (Neves et al., 2015), commonly 
have positive allometric growth. However, as in our study 
of the stone scorpionfish and in studies of other scorpion- 
fish species, such as the blackbelly rosefish (Helicolenus 
dactylopterus) (Massuti et al., 2000), results also indicate 
isometric growth. 
The relationship between OR and TL of stone scorpion- 
fish in our study was linear and statistically significant, 
indicating that these measurements have a relation of 
proportionality and that the OR may be a predictor of fish 
length. This relationship has been reported for other species 
of Scorpaena, such as the Madeira rockfish (La Mesa et al., 
2005) and small red scorpionfish (Scarcella et al., 2011). 
odicity of annulus formation in otoliths 
has been reported for other scorpionfish 
species, such as the black scorpionfish 
(Bilgin and Celik, 2009; Demirhan and 
Can, 2009; La Mesa et al., 2010), small 
red scorpionfish (Scarcella et al., 2011; 
Neves et al., 2015), Madeira rockfish 
(La Mesa et al., 2005), and blackbelly 
rosefish (Massuti et al., 2000). 
Annuli were apparent in the otoliths 
of stone scorpionfish used in this study. 
In general, translucent bands are slightly wider than the 
opaque bands, and as the number of annuli increased, 
the widths of both bands decreased. Both bands were 
clearly observed and distinguished, and it was relatively 
simple to count them, as evidenced by the low values of 
CV and APE; these low values indicate a high concor- 
dance between counts performed independently by read- 
ers and reflect consistency between observations. In this 
study, we found a significant relationship between the 
OR and length of fish, an annual pattern of annulus for- 
mation in otoliths, and a high precision in the counting of 
annuli between technicians. These results indicate that 
the otolith is a structure that can be used reliably in age 
estimation of stone scorpionfish. 
This study is the first to report age and individual 
growth characteristics for stone scorpionfish. We found 
males up to 10 years old and females up to 15 years old, 
and we determined that individuals 4—7 years old com- 
posed the most abundant age class in our sample. 
Individual growth characteristics were significantly 
different between males and females. In addition, our 
results indicate that females are larger, heavier, and 
older than males. This pattern of distinctive growth 
between males and females has been reported previ- 
ously for the black scorpionfish (Bilgin and Celik, 2009). 
However, it is also common that males reach lengths, 
