THE INFLUENCE OF TEMPERATURE ON LARVAL AND 

 JUVENILE GROWTH IN THREE SPECIES OF SOUTHERN 



CALIFORNIA ABALONES^ 



David L. Leighton^ 



ABSTRACT 



Larvae of the abalones //a/ioijs rufescens, H. corrugata, and H. fulgens displayed most rapid growth 

 and best survival at 15°-18°, 18°-21°, and 20°-23°C, respectively. Survival of larvae and postlarvae was 

 poor above these optimal ranges. However, juveniles 3 mo to 1 yr old were tolerant of a broader 

 temp)erature range. The warm- water species, H. fulgens, increased in shell length at an average rate of 

 88 fi per day at 26°C. Mean shell elongation rates were 77 and 64 /z per day in H. rufescens and in H. 

 corrugata at their respective optima. 



An expanding body of literature exists concerning 

 aspects of the biology and culture of the abalone 

 Haliotis (e.g., Sakai, 1962; Oba, 1964; Tamura, 

 1966; Imai, 1967; Tanaka, 1969; Shibui, 1971a; 

 and McBeth, 1972, which succeeded the pioneer- 

 ing studies of Murayama, 1935, and Ino, 1952). In 

 these studies little attention was directed to prob- 

 lems of larval development, and essentially no 

 information has been obtained on the limitations 

 imposed by temperature on growth and survival of 

 larvae and postlarvae with the single exception of 

 the observations on H. sorenseni, reported by 

 Leighton (1972). In 1962, Kan-no and Kikuchi 

 related results of a 3-wk experiment in which 

 juvenile H. discus hannai were reared at five dif- 

 ferent temperatures, but most investigators have 

 merely reported the range of temperature prevail- 

 ing during observations (e.g., Oba, 1964; Shibui, 

 1971b). 



This paper describes results of experiments in 

 which groups of larvae, postlarvae, and juveniles 

 were reared at a series of temperatures encompas- 

 sing the natural range to examine the influence of 

 these factors on development and survival. Larvae 

 were obtained from three American west coast 

 species spawned in the laboratory: The red 

 abalone, H. rufescens, the pink abalone, H. cor- 

 rugata, and the green abalone, H. fulgens. 



'This work is a result of research sponsored by NOAA Office of 

 Sea Grant U.S. Department of Commerce, under Grant #UCSD 

 2-35208 with the Institute of Marine Resources in cooperation 

 with California Marine Associates, Cayxicos, Calif The study 

 was carried out in the aquarium laboratory of the Southwest 

 Fisheries Center, National Marine Fisheries Service, NOAA, La 

 Jolla, Calif 



^Scripps Institution of Oceanography, University of California 

 at San Diego, La Jolla, CA 92037; present address: California 

 Marine Associates, P.O. Box 136, Cayucos, CA 93430. 



MATERIAL AND METHODS 



Ripe abalone were collected off southern 

 California by diving. In transportation to the 

 laboratory, care was taken to avoid subjecting the 

 animals to desiccation or other physical shock 

 which might have induced premature release of 

 gametes. Adult abalone were allowed a laboratory 

 "conditioning period" of about 2 wk before at- 

 tempts were made to induce spawning. Water 

 temperature in tanks containing abalone of both 

 sexes was raised approximately 5°-8°C above am- 

 bient, following the thermal shock method of Ino 

 ( 1952) and Oba (1964); a procedure which was only 

 occasionally successful. Most productive spawn- 

 ings in terms of quantity and viability were those 

 which occurred spontaneously in the laboratory. 

 Natural cues and events associated with "mass 

 spawnings" are not well understood (Owen and 

 Meyer, in press) and were not investigated in this 

 study. 



Fertilized eggs were collected as soon as possible 

 after their release. The eggs, which settle rather 

 rapidly, were siphoned or pipetted into freshly 

 filtered seawater (Cuno filter unit,^ ca. 5 yu ) at 

 the same temperature as that of the spawning 

 environment. Repetition of the process several 

 times, each time using freshly filtered seawater, 

 was usually sufficient to wash eggs free of excess 

 sperm and debris. Incubation was carried out at 

 ambient temperatures and larvae treated as de- 

 scribed elsewhere (Leighton, 1972). 



While some experiments were performed with 

 eggs at early cleavage stages, most observations 



Manuscript accepted December 1973. 

 FISHERY BULLETIN: VOL. 72. NO. 4, 1974. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



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