摘要:

A hydrophone is described for determining the swimming depth of fish fitted with location-only ultrasonic transmitters. The linear array of 13 transducer elements gives omnidirectional sensitivity horizontally and a two-degree angle of acceptance vertically. The hydrophone is lowered through the water and depth of maximum horizontal signal from a transmitter is determined. Fifty-four trials in a stratified lake, with signal source at distances from 10 to 100 m and at depths from 0.5 to 20.5 m, gave a mean error of −0.46 m (standard deviation = 1.47 m).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<635:ALHFDS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Standing crops of juvenile rainbow trout in seven bank crib and six pool digger areas were compared with those in natural overhanging banks and pools. There was no difference in biomass, average weight, or number of trout between altered and natural areas. Trout comprised a significantly greater percentage of the total fish biomass in bank crib sections than pool digger sections. A low ratio (1.1:1) of number of age 0+ to older juvenile trout reflected selectivity of the older trout for the sample sections, since Cayuga Inlet in general had a much higher ratio (4.2:1).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<637:EOSIOJ>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Abnormal specimens of Nocomis leptocephalus with four barbels on the left side of the mouth, Campostoma anomalum with a vertebral deformity, and Notropis cerasinus with a pug head were collected during recent sampling of the ichthyofauna of the New and Roanoke River drainages in southwestern Virginia. A review of the literature revealed that no anomalies have previously been reported for these species.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<642:NAITCG>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1974)103<643:STMIAA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1974.10492884

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1974.10492898

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor