1 
A modeling approach to identify optimal 
habitat and suitable fishing grounds 
for neon flying squid ( Ommastrephes bartramii) 
in the Northwest Pacific Ocean 
Email address for contact author: xjchen@shou.edu.cn 
1 College of Marine Sciences 
Shanghai Ocean University 
999 Hucheng Ring Road 
Shanghai 201306, China 
2 The Key Laboratory of Shanghai Education Commission 
for Oceanic Fisheries Resources Exploitation 
999 Hucheng Ring Road 
Shanghai 201306, China 
3 The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources 
(Shanghai Ocean University) 
Ministry of Education 
999 Hucheng Ring Road 
Shanghai 201306, China; 
Abstract — We developed a habitat 
suitability index (HSI) model to 
understand and identify the optimal 
habitat and potential fishing grounds 
for neon flying squid ( Ommastrephes 
bartramii) in the Northwest Pacific 
Ocean. Remote sensing data, includ- 
ing sea surface temperature, sea 
surface salinity, sea surface height, 
and chlorophyll-a concentrations, as 
well as fishery data from Chinese 
mainland squid fleets in the main 
fishing ground (150-165°E longitude) 
from August to October, from 1999 to 
2004, were used. The HSI model was 
validated by using fishery data from 
2005. The arithmetic mean model- 
ing with three of the environmental 
variables — sea surface temperature, 
sea surface height anomaly, and 
chlorophyll-a concentrations — was 
defined as the most parsimonious HSI 
model. In 2005, monthly HSI values 
>0.6 coincided with productive fish- 
ing grounds and high fishing effort 
from August to October. This result 
implies that the model can reliably 
predict potential fishing grounds 
for O. bartramii. Because spatially 
explicit fisheries and environmental 
data are becoming readily available, it 
is feasible to develop a dynamic, near 
real-time habitat model for improving 
the process of identifying potential 
fishing areas for and optimal habitats 
of neon flying squid. 
Manuscript submitted 1 December 2008. 
Manuscript accepted 28 August 2009. 
Fish. Bull. 108:1-14 (2010). 
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. 
Xinjun Chen (contact author ) 1 - 2 3 
Siquan Tiam 1 - 2 - 3 
Yong Chen 3 - 4 
Bilin Liu 1 - 2 - 3 
4 School of Marine Sciences 
University of Maine 
Orono, Maine 04469 
Two predominant currents, the warm 
Kuroshio Current and the cold Oyas- 
hio Current, meet in the Northwest 
Pacific Ocean. The interaction of 
these two currents between the sub- 
tropical and subarctic fronts forms a 
transition region (Roden, 1991). The 
dynamic of the physical oceanographic 
structures in this region, includ- 
ing meandering eddies and frontal 
zones, results in a highly productive 
habitat, which serves as a favorable 
feeding ground for various commer- 
cially important species, such as neon 
flying squid ( Ommastrephes bartra- 
mii), Pacific saury ( Cololabis saira), 
anchovy ( Engraulis japonicus), and 
albacore ( Thunnus alalunga ) (Pearcy, 
1991; Zainuddin et al., 2006). 
The neon flying squid (O. bartramii) 
is an important oceanic squid, which 
has been commercially harvested by 
the Japanese since 1974, and later 
by South Koreans and the Chinese 
(including Taiwanese) (Wang and 
Chen, 2005). There are four stocks of 
O. bartratnii (Bower and Ichii, 2005). 
Of the four stocks, the western win- 
ter-spring cohort of neon flying squid 
is a traditional fishing target for the 
Chinese mainland squid jigging fleet 
in the area of 39-46°N latitude and 
150-165°E longitude from August to 
November (Chen and Tian, 2005), 
with Chinese mainland jigging repre- 
senting from 75% to 84% of the total 
catch (Chen et al., 2008a). 
The biology and distribution of O. 
bartramii have been the subject of 
several studies in recent decades (Yat- 
su and Watanabe, 1996; Yatsu and 
Mori, 2000; Watanabe et al., 2004; 
Wang and Chen, 2005). The western 
winter-spring cohort of neon flying 
squid can be found from subtropi- 
cal waters to the subarctic boundary 
during the first half of the summer 
and then migrates northward into 
the subarctic domain from August 
to November. Ommastrephes bar- 
tramii gradually mature in fall and 
are thought to begin their spawning 
