Zamora-Garcia et al.: Catch rate, length, and sex ratio of Mer/uccius productus in the Gulf of California 373 
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Standard length (cm 
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J A 
Maturity stage 
Figure 6 
Box plots of standard lengths of Pacific hake (Merluccius productus) caught in the 
northern Gulf of California in Mexico, by sex and maturity stage (juvenile [J] and 
adult [A]), during (A) 2015, (B) 2016, (C) 2017, (D) 2018, and (E) 2019. Dark and 
light gray boxes represent lengths of females and males, respectively. The thick line 
within each box indicates the median, the upper and lower parts of each box rep- 
resent the first and third quartiles (the 25th and 75th percentiles), and the whis- 
kers extending above and below each box correspond to 1.5 times the interquartile 
range. Outliers are presented as gray dots with one-tenth transparency to improve 
visualization. 
general case—with all years pooled—(F=129.16, P<0.05) 
Table 3 and consistently in every single year evaluated (Table 4; 
Fig. 7, A-E). Similarly, the model fits for 2015 and 2018 
Ratio of the number of males to the number of females, were close to each other (Fig. 7F); even so, statistical differ- 
by maturity stage Guvenile [J] or adult [A]) and by year, ences were detected (F=80.67, P<0.05). Females always had 
for Pacific hake (Merluccius productus) caught in the 
northern Gulf of California in 2015-2019. Sex ratios 
also are provided for all years and both maturity stages 
higher values of b than males. However, no significant dif- 
ferences were found in the LWR between juveniles and 
combined. The critical value for each chi-square (y”) test adults (F=0.72, P=0.97). 
was 3.81. Asterisks (*) indicate significant departures Both analyses of covariance revealed no significant effect 
from the null hypothesis of an equal sex ratio (a male-to- of sex in the TL-SL (P=0.22) and FL-SL (P=0.49) relation- 
female ratio of 1.00). M=male; F=female; and N=none. ships and a high level of correlation for both (r>0.99). The 
va ea SF Sas le ae al resulting estimates of the regression parameters for the 
Maturity Sex Observed , TL-SL relationship were 0.89 for a and 1.21 for b, and 
stage estimates of the parameters for the FL-SL relationship 
were 0.51 for a and 1.10 for bd. 
B 
ley 
Discussion 
Reports from previous studies have highlighted that the 
NGC is the winter spawning ground for the Pacific hake 
because its larvae are dominant in larval fish assemblages 
(Aceves-Medina et al., 2004; Sanchez-Velasco et al., 2009; 
Peiro-Alcantar et al., 2013). Also, the high proportion of 
adults in the catch in this zone (70%) and the sudden 
increase of catch rates in a relatively limited area found 
in this study indicate that the fishery for Pacific hake 
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