首页   按字顺浏览 期刊浏览 卷期浏览 Spatial and Temporal Heterogeneity of Larval Shad in a Large Impoundment
Spatial and Temporal Heterogeneity of Larval Shad in a Large Impoundment

 

作者: MichealS. Allen,   DennisR. Devries,  

 

期刊: Transactions of the American Fisheries Society  (Taylor Available online 1993)
卷期: Volume 122, issue 6  

页码: 1070-1079

 

ISSN:0002-8487

 

年代: 1993

 

DOI:10.1577/1548-8659(1993)122<1070:SATHOL>2.3.CO;2

 

出版商: Taylor & Francis Group

 

数据来源: Taylor

 

摘要:

Factors that affect recruitment of threadfin shadDorosoma petenenseand gizzard shadD. cepedianum, two important prey species in southern reservoirs, are not well understood. Larval shad typically have not been identified to species, though interactions between shad larvae likely affect their recruitment and that of their predators. Using myomere counts to identify larval shad to species, we quantified spatial and temporal variation in species distributions in West Point Reservoir, Alabama–Georgia. We sampled larvae every 3–4 d at three distances from shore (inshore and 25 and 50 m offshore) at each of three sites. Larval threadfin shad migrated offshore in all three sites, whereas larval gizzard shad were evenly distributed across distances from shore. Because of these movement differences, larval gizzard shad and larval threadfin shad may encounter different habitat-specific predation rates, climatic effects, and food availability. In addition, larval gizzard shad were present before larval threadfin shad and grew beyond the size vulnerable to our capture techniques before threadfin shad abundance peaked. If zooplankton densities are reduced by young-of-year shad, as documented in other systems, later-hatched threadfin shad would encounter fewer zooplankton than were available to the earlier larval gizzard shad. Threadfin shad would have reduced growth and greater vulnerability to predation and starvation.

 

点击下载:  PDF (700KB)



返 回