SERFLING and FORD: ECOLOGICAL STUDIES OF PANULIRUS INTERRUPTUS 



Aquaculture of P. interruptus or other palinurid 

 lobsters, starting with the egg, has been attempt- 

 ed by several investigators as a means of bypass- 

 ing what appears to be an inefficient recruitment 

 process in nature. Yet all attempts to culture the 

 phyllosoma larval stages from the egg through to 

 the puerulus stage have been unsuccessful (for 

 example, see Dexter 1972). This approach does not 

 appear to be feasible at the present time, par- 

 ticularly on a mass culture basis, due to the long 

 duration (5-10 mo in nature) and the poorly un- 

 derstood requirements of the delicate phyllosoma 

 larval stages. In contrast, the succeeding puerulus 

 and juvenile stages of spiny lobsters respond well 

 to laboratory culture (Kensler 1967; Witham et al. 

 1968; Serfling and Ford in press a, b). Thus, if the 

 puerulus stage of P. Interruptus proves to be 

 abundant and relatively easy to collect in large 

 numbers, particularly in certain offshore waters 

 where these individuals might otherwise be swept 

 away from coastal nursery grounds, it may be ad- 

 vantageous to supplement natural stocks by 

 collecting pueruli and holding them in mass cul- 

 ture under controlled, optimal conditions through 

 at least the early juvenile stages. These pueruli 

 could either be reared directly to a marketable size 

 under artificial conditions, or returned to the 

 ocean, after passing the potentially critical early 

 juvenile stages, for final growth and maturation. 

 This approach to spiny lobster culture has also 

 been proposed for P. argus by Ingle and Witham 

 (1969). 



The lack of ecological information on the 

 puerulus stage of any spiny lobster species is due 

 largely to the fact that investigators usually have 

 been unable to collect more than a few individuals, 

 despite extensive sampling in areas where they 

 might be expected to occur. Consequently, the 

 central question precluding further research has 

 concerned the mode of life of the puerulus stage, 

 i.e., whether it is primarily a benthic or pelagic 

 form. 



Evidence presented in the literature thus far 

 supports about equally each side of the issue. 

 Investigators who have failed to collect more than 

 a few isolated pueruli, even after years of exten- 

 sive sampling by conventional methods (Lewis et 

 al. 1952; Johnson 1956, 1960, 1971; Harada 1957; 

 Saisho 1966; Sims and Ingle 1966; Lazarus 1967), 

 have concluded that the puerulus stage of their 

 respective species is either primarily benthic, or 

 concentrated in unknown pelagic areas. On the 

 other hand, Gurney (1942), Sheard (1949), George 



and Cawthorn (1962), Chittleborough and Thomas 

 (1969), and Chittleborough (1970) were able to 

 collect small numbers of individuals in net hauls 

 far out to sea, and thus suggested that the 

 puerulus is a free-swimming stage. 



Harada (1957) and Johnson (1960) reported 

 collecting a few pueruli which were attracted to 

 bright lights over shallow water at night, but both 

 authors apparently believed they were lured from 

 the bottom. Yet Lindberg (1955) reported that 

 University of Hawaii personnel collected several 

 pueruli of a Panulirus species which were at- 

 tracted to surface night-lights in water several 

 hundred meters deep, thereby eliminating the 

 possibility that they were attracted from the bot- 

 tom. Witham et al. (1968), Sweat (1968), PhiUips 

 (1972), and we have successfully attracted large 

 numbers of pueruli to artificial habitat traps 

 floating at the surface, thereby offering the first 

 strong evidence that the puerulus is primarily a 

 pelagic, surface-dwelling form. 



Preliminary observations made originally by J. 

 C. Van 01st (pers. commun.) in the spring of 1968, 

 demonstrated that puerulus larvae of P. in- 

 terruptus occurring in local coastal waters could 

 be attracted to bright lights suspended under- 

 water near the surface at night. This discovery 

 prompted the following investigation into several 

 aspects of puerulus behavior and ecology. The 

 specific objectives of this study were: 1) to deter- 

 mine the mode of life of the puerulus stage of this 

 species, e.g., whether it is primarily benthic or 

 pelagic; and, having done so, 2) to develop and 

 apply suitable field sampling techniques to study 

 the general dynamics of puerulus recruitment 

 with regard to seasonal, lunar, and daily 

 periodicity, area of settlement, specific habitat 

 preferences, and migratory behavior; and 3) to es- 

 timate the general abundance and possibility of 

 collecting large numbers of this stage for use in 

 aquaculture. Closely related studies were also 

 conducted concurrently to investigate the habitat 

 preferences and the natural growth rates of the 

 early juvenile stages in nature, as well as the 

 growth and survival of the juvenile stages at 

 elevated temperatures in recirculating culture 

 systems (Serfling 1972; Serfling and Ford in press 

 a,b). 



MATERIALS AND METHODS 



The failure of standard sampling methods used 

 by previous investigators to collect the puerulus 



361 



