FISHERY BULLETIN: VOL. 76. NO, 2 

 Table 2. — Summary of field data collected during observations of preju venile and juveniles Mugil cephalus in Hawaii during 1972-73. 



'Daylight observations of mullet. 

 ^ Night observations of mullet. 



one of the cement culverts in Kuapa Pond (Hawaii 

 Kai), Maunalua Bay. The tide was low and just 

 starting to turn and flood. Prior to this day heavy 

 rains washed down large amounts of silt, rocks, 

 and debris to a depth of about 0.2-0.5 m. A narrow 

 channel was cut through the mud by the trickling 

 stream, and isolated "tide pools" or pockets of 

 water were common. An estimated several thou- 

 sand prejuvenile and juvenile mullet 18-80 mm SL 

 were found dead along the bottom of the culvert. 

 Although it appeared that the fish had a free exit 

 at higher tide levels, via the shallow ( 1 cm deep at 

 low tide) channel to the cooler tidal region (26°- 

 30°C), the fish were presumably trapped physi- 



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cally by the debris and/or by a very rapid increase 

 in water temperature. Dead mullet were found in 

 the pockets with water temperatures of 39.5°- 

 42.5°C. The only survivors observed were mullet 

 20-35 mm SL slowly swimming in small pockets at 

 temperatures as high as 39.0°-41.1°C. Salinity 

 measurements were not made, but would be ex- 

 pected to be low. 



Juvenile mullet 3=50 mm SL were not observed 

 or collected in tide pools at low tide. At low tide 

 these larger fish occurred beyond the tide line in 

 tide pools with open connections to deeper water or 

 along sills and sand/mud flats which sloped into 

 deeper water. These areas were characterized by 



