Zamora-Garcia et al.: Catch rate, length, and sex ratio of Merluccius productus in the Gulf of California 375 
Total weight (g 
Total weight (g 
as 
[o) 
[o) 
(o>) 
Standard length (cm) 
Standard length (cm) 
40 
Standard length (cm) 
Figure 7 
Standard lengths and total weights of Pacific hake (Merluccius productus) caught in the northern Gulf of California 
in Mexico during (A) 2015, (B) 2016, (C) 2017, (D) 2018, and (E) 2019. Open circles and solid lines indicate observed 
and predicted lengths and weights for females, respectively. Open triangles and dashed lines indicate observed and 
predicted lengths and weights for males, respectively. (F) Lines indicate the length—weight relationship for Pacific 
hake caught in each year evaluated. 
observed to migrate nearer to the bottom (Godinez-Pérez, 
2016). Diel vertical migration has been reported for Pacific 
hake in other regions (Hamel et al., 2015). 
Winter spawning of Pacific hake has been reported for 
other populations in the eastern Pacific Ocean (Saun- 
ders and McFarlane, 1997). However, slight differences 
exist between the spawning time and sites of Pacific 
hake from the NGC and those for Pacific hake from the 
coastal stock and from Baja California Sur. The Pacific 
hake in the coastal stock spawn during January—March 
several kilometers offshore (Agostini et al., 2006), and 
Pacific hake from Baja California Sur spawn during 
February—May, peaking in May (Balart-Paez, 2005). 
Pacific hake in NGC spawn only during December— 
May, peaking in December—February (Denton-Castillo, 
2018). The difference in spawning times and sites 
between these stocks could serve as a gene flow barrier 
that fosters the genetic isolation indicated by results 
of other studies (Iwamoto et al., 2015; Garcia-De Leon 
et al., 2018). 
