碩士 / 國立臺灣大學 / 海洋研究所 / 105 / Spatial structure of a population provides bet-hedging capacity to maintain population stability, which has become an important management concern of exploited marine species. Population spatial structure has been suggested to be affected by both biological processes and environmental changes. For biological processes, two most discussed issues are the abundance and size structure of populations. First, population abundance can critically determine their occupied areas, as explained by the density-dependent habitat selection theory. Second, size structure influences population spatial structure because individuals of different sizes inhabit different areas due to size-specific requirements and mobile capabilities. In addition, environmental changes can force populations shift their distribution and thus alter spatial structure.
Here, we examined how the spatial structure (measured by coefficient of variation) of nine exploited fish species in the North Sea responded to changes in abundance, size structure, and environment, using data from the International Bottom Trawl Survey from 1991-2015. Applying empirical dynamic modeling approaches, we found that population spatial variation responded more to changes in abundance and size structure than to changes in the environment. More specifically, population spatial variation increased in response to decreasing abundance and mean age. However, environment exhibited no consistent effect on population spatial variation. Our results suggest that size-selective fishing may enhance spatial population variation through reducing abundance and/or truncating size structure, and thus exert more pressure on exploited populations than previously thought.
| Identifer | oai:union.ndltd.org:TW/105NTU05279002 |
| Date | January 2017 |
| Creators | Jheng-Yu Wang, 王政喻 |
| Contributors | 謝志豪 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 46 |
Page generated in 0.0196 seconds