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Vol. 46 No. 1, 2007
The Spatial and Temporal Distribution Patterns of the Argentine ShortFinned Squid, Illex argentinus, Abundances in the Southwest Atlantic and the Effects of Environmental Influences
Chih-Shin Chen1,*, Tai-Sheng Chiu2, and Wen-Bin Haung3
1Institute of Fishery Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan
2Institute of Zoology, College of Life Science, National Taiwan University, Taipei 106, Taiwan
3Institute of Biological Resources and Technology, National Hualien University of Education, Hualien 970, Taiwan
Chih-Shin Chen, Tai-Sheng Chiu, and Wen-Bin Haung (2007)
The spatial and temporal distribution patterns of the Argentine
short-finned squid, Illex argentinus, abundances and relationships
between the squid abundance and environmental variables in the
Southwest Atlantic were analyzed using a geographical information
system and statistical methods. The abundances of squid were estimated
by standardizing commercial catch per unit effort (CPUE) data from the
Taiwanese squid fishery during 1986-2003. Illex argentinus
has a clear general annual migration pattern, which consistently
occurred in different years. The monthly distribution patterns of sea
surface temperature (SST) corresponded to the current systems in the
Southwest Atlantic. Local squid abundances showed a negative
correlation with SSTs during Mar.-Aug., although it was difficult to
determine if this reflected any causal link. The Southern Oscillation
Index (SOI) and SSTs on the southern and northern portions of the
Patagonian Shelf were analyzed to investigate the teleconnection
between them and a lag-effect on squid abundances. SSTs on both the
southern and northern portions of the Patagonian shelf showed a link
with the SOI, at respective lag times of 2 and 3 yr. No significant
correlation was found between the SOI and squid abundances, or between
SSTs of the southern portion of the Patagonian Shelf and squid
abundances within the calculated range of the time lag (10 yr), while
SSTs of the northern portion of the shelf were negatively correlated
with squid abundances with a lag of 1 yr. Cold events on the northern
portion of the Patagonian Shelf in the previous year could be a key
factor for the high squid abundance in the current year. Whether or not
there are high or low abundances, the distribution patterns of squid on
the Patagonian Shelf are locally influenced by the presence of thermal
fronts, which are themselves dependent upon the distribution and
strength of the cold currents.
Key words: Illex argentinus, Squid abundance, Environmental influence, SST, Southern Oscillation Index (SOI).
*Correspondence: Tel: 886-2-33664549. Fax: 886-2-23639847. E-mail:ccshin@ntu.edu.tw
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