, I 



; F: 



L i 



Figure 18-1. Diagram of Video Recording Equipment. 



NOTE: A) TV camera, B) Photo tube, C) Wild M-5 microscope, D) wide-angle 

 attachment, E) metal light shield vyith deep red glass bottom, F) container with 

 test organisms, G) 800 nm interference filter, H) metal diaphram, I) clear glass, 

 J) dark field stage with halogen light. Components E-H are shown separated 

 from each other for graphic clarity. 



18-1). Video images were obtained using a Cohu 4400 television camera 

 attached to the M-5 microscope body. The field of view recorded was 10 x 10 

 mm. Optimum image contrast was obtained using a halogen light source with 

 dark field optics at 8.5 volts (Figure 18-1). 



Spectroradiometer (ISCO-SR) readings indicate light transmitted through 

 the stage filters was as low as 680 nm. Peak transmission occurred between 

 810-840 nm. With the exception of light experiments, nauplii were moved 

 directly from constant light temperature boxes to the microscope stage. Room 

 lights were extinguished and, following a two-minute acchmation period, larvae 

 were taped for 3-5 minute intervals using filtered substage illumination. 

 Swimming parameters reported were determined by analysis of 30-60 second 

 portions of these tapes; results are pooled from replicate samples. 



275 



