Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Distribution and abundance of finless porpoise in the Inland Sea of Japan

Distribution and abundance of finless porpoise in the Inland Sea of Japan Aerial sighting surveys were conducted in 2000 to evaluate the distribution and abundance of finless porpoise Neophocaena phocaenoides in the Inland Sea of Japan. We flew 60 north–south transects (2,218 km in total) at intervals of 6.43 km over the study area between 131°3′ and 134°59′ E. In total, 148 groups were detected by two observers. The average group size was 1.56 individuals. The effective strip half-width of each observer was estimated to be 107 m (coefficient of variation [CV] = 8.26%). Porpoise abundance was estimated at 7,572 individuals and the density was as low as 0.506 individuals/km2 (CV = 17.3%). The sea is among the Japanese waters with the lowest density in spite of its favorable topographical conditions. In the western stratum of the study area, where the estimated density was 1.31 individuals/km2, we observed a relatively regular distribution. In the central-eastern stratum, which had an estimated density of 0.208 individuals/km2, we confirmed a clumped distribution that was restricted to inshore waters or near islands. No individuals were observed in waters between 132°51′ and 133°11′E, and between 133°43′ and 133°59′E, where sand dredging and other human activities have been active, suggesting that habitat fragmentation has occurred. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Marine Biology Springer Journals

Distribution and abundance of finless porpoise in the Inland Sea of Japan

Download PDF
8 pages

Loading next page...
 
/lp/springer-journals/distribution-and-abundance-of-finless-porpoise-in-the-inland-sea-of-FpLB0V4DGq

References (29)

Publisher
Springer Journals
Copyright
Copyright © 2006 by Springer-Verlag
Subject
Life Sciences; Zoology ; Microbiology ; Oceanography ; Biomedicine general; Ecology
ISSN
0025-3162
eISSN
1432-1793
DOI
10.1007/s00227-006-0363-8
Publisher site
See Article on Publisher Site

Abstract

Aerial sighting surveys were conducted in 2000 to evaluate the distribution and abundance of finless porpoise Neophocaena phocaenoides in the Inland Sea of Japan. We flew 60 north–south transects (2,218 km in total) at intervals of 6.43 km over the study area between 131°3′ and 134°59′ E. In total, 148 groups were detected by two observers. The average group size was 1.56 individuals. The effective strip half-width of each observer was estimated to be 107 m (coefficient of variation [CV] = 8.26%). Porpoise abundance was estimated at 7,572 individuals and the density was as low as 0.506 individuals/km2 (CV = 17.3%). The sea is among the Japanese waters with the lowest density in spite of its favorable topographical conditions. In the western stratum of the study area, where the estimated density was 1.31 individuals/km2, we observed a relatively regular distribution. In the central-eastern stratum, which had an estimated density of 0.208 individuals/km2, we confirmed a clumped distribution that was restricted to inshore waters or near islands. No individuals were observed in waters between 132°51′ and 133°11′E, and between 133°43′ and 133°59′E, where sand dredging and other human activities have been active, suggesting that habitat fragmentation has occurred.

Journal

Marine Biology – Springer Journals

Published: Jul 8, 2006

There are no references for this article.