摘要:

Short-term impacts of commercial barge traffic on fish eggs, larvae, young-of-the-year (age-0) fishes, and small adults in the main channel of the upper Mississippi River were examined. Barge passages caused significant changes in the distribution of eggs and larvae in the study area. The mean catch of ichthyoplankton was reduced in both surface and bottom waters for 90 min after passage of vessels (generally loaded barges) downstream. The effects of upstream traffic (unloaded barges) on catch ranged from nil in surface or bottom samples to short-term increases in surface samples immediately after passage. No consistent effect on the catch of age-0 or small adult fishes in surface or bottom trawls was evident. Physical damage to eggs, but not to larvae or small fish, was significant.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<162:EOBTOD>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Reciprocal diet switches were conducted with first-feeding white sturgeons Acipenser transmontanus to investigate possible mechanisms of food acceptance and food preferences. Survival and relative growth rates were significantly reduced following a switch from a more natural diet (chopped Tubifex sp. worms) to a prepared diet (Biodiet), whereas growth was improved, and survival was improved or unaffected, following the reciprocal diet switch. Feeding observations, followed by assessment of stomach fullness, indicate that strong or exclusive preferences for Tubifex can develop quickly. These data suggest that the animals are more “prepared” physiologically and anatomically to accept and assimilate the more natural diet than the prepared diet during the early life stages. Associative learning of pre- and postingestional stimuli may be important in the development of food preferences.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1986)115<166:EODSBN>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1984.10492807

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1984.10492810

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor