365 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
@ established in 1881 =< 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Abstract—The fishery for Pacific hake 
(Merluccius productus) was established 
in the northern Gulf of California 
(NGC) in Mexico in 2000. To describe 
relevant features of the fishery and bio- 
logy of Pacific hake, we analyzed 5 years 
of data from an on board observers pro- 
gram. Using generalized additive mod- 
els, we standardized catch per unit of 
effort (CPUE), mean standard length 
(SL), and sex ratio. Also, we investigated 
by year the joint effect of maturity stage 
and sex on size distribution, biometric 
relationships, and the effect of maturity 
stage (juvenile or adult) on sex ratio. 
For all characteristics, significant inter- 
annual variability was observed. An 
average decrease was observed both in 
CPUE (52%) and mean SL (7%) during 
January—March. Adult males were 
more abundant in catch, with a male-to- 
female ratio of 1.12:1.00 (P<0.05), and 
adult females were larger than males 
(F=807.09, P<0.05). Our results support 
the previously suggested hypothesis 
that the NGC is the winter spawning 
ground for Pacific hake in the region. 
Further research is needed to deter- 
mine the status of the stock in the NGC 
and to outline specific potential man- 
agement strategies. 
Manuscript submitted 31 January 2020. 
Manuscript accepted 17 November 2020. 
Fish. Bull. 118:365-379 (2020). 
Online publication date: 17 December 2020. 
doi: 10.7755/FB.118.4.6 
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. 
Catch rate, length, and sex ratio of 
Pacific hake (Merluccius productus) in 
the northern Gulf of California 
Oscar G. Zamora-Garcia' 
J. Fernando Marquez-Farias 
(contact author)? 
Aristételes Stavrinaky-Suarez? 
Carlos Diaz-Avalos* 
Noemi I. Zamora-Garcia” 
Raul E. Lara-Mendoza® 
Email address for contact author: fmarquez@uas.edu.mx 
" Posgrado en Ciencias del Mar y Limnologia 
Universidad Nacional Autonoma de Mexico 
Avenida Ciudad Universitaria 3000 
04510 Coyoacan, Mexico City, Mexico 
* Facultad de Ciencias del Mar 
Universidad Autonoma de Sinaloa 
Paseo Claussen s/n 
Colonia Los Pinos 
82000 Mazatlan, Sinaloa, Mexico 
3 Environmental Defense Fund de Mexico 
Surfrider Way 5701 
Goleta, California 93117 
“ Departamento de Probabilidad y Estadistica 
Instituto de Investigaciones en Matematicas 
Aplicadas y en Sistemas 
Universidad Nacional Autonoma de Mexico 
Circuito Escolar s/n, Ciudad Universitaria 
04510 Coyoacan, Mexico City, Mexico 
The Pacific hake (Merluccius produc- 
tus) is the most productive and eco- 
nomically important fish species on the 
west coasts of the United States and 
Canada (Hamel et al., 2015), with land- 
ings exceeding 400,000 metric tons (t) 
in recent years (Grandin et al., 2020). 
This species is distributed from the Gulf 
of Alaska to Costa Rica, including the 
Gulf of California (Lloris et al., 2003). 
In Mexico, early estimates of biomass 
of Pacific hake in the northern Gulf of 
California (NGC) ranged from 30,000 to 
65,000 t (Mathews et al., 1974; Padilla- 
Garcia, 1981), and the maximum sus- 
tainable yield was 2288-11,453 t. 
Despite the known abundance of Pacific 
hake, trawlers licensed to catch shrimp 
° Comisién Nacional de Acuacultura y Pesca 
Secretaria de Agricultura y Desarrollo Rural 
Avenida Camaron Sabalo 1210 
82100 Mazatlan, Sinaloa, Mexico 
® Direccién General Adjunta de Investigacion 
Pesquera en el Atlantico 
Instituto Nacional de Pesca y Acuacultura 
Secretaria de Agricultura y Desarrollo Rural, 
Avenida Mexico 190 
Colonia del Carmen 
04100 Coyoacan, Mexico City, Mexico. 
and finfish species were not interested 
in commercial use of Pacific hake until 
the late 1990s (Ramirez-Rodriguez, 
2017). Total landings of Pacific hake 
have ranged from 197 t (in 2000) to a 
peak of 6628 t (in 2014), with a mean of 
approximately 2225 t for 2000-2019 in 
the NGC (Fig. 1). 
The Pacific hake, one of the most 
abundant fish species in the California 
Current Large Marine Ecosystem, plays 
a significant ecological role as a link 
between species of low (euphausiids) 
and high (sharks and seals) trophic lev- 
els (Ressler et al., 2007). Because of the 
commercial importance of this demersal 
species, its biological, ecological, migra- 
tory, and fishery traits have been widely 
