novelty of the otolith aging technique, a general warning was sounded that care 

 should be taken with generalizations. Nevertheless, it was agreed that few 

 studies on fish recruitment could effectively proceed without the use of this 

 revealing technique. 



The paper by Lobel and Robinson (1983) reviewed attempts to relate larval 

 drift to mesoscale disturbances in the near surface waters, e.g., local current 

 gyres. For many years various authors have invoked changes in local currents 

 or even steady current conditions to explain how spawning, larval duration, 

 and settlement are integrated to sustain local populations of fishes (Emery, 

 1972; Johannes, 1978, 1980; Sale, 1970). It is only over the last decade, 

 however, that oceanographers have begun to develop instrumentation that allows 

 ready determination of local current eddies, shears, etc., on a sufficiently 

 small scale to be useful in biological investigations (see, for example, 

 Robinson, 1983). Techniques include radio-tracked drogues, expendable rapid 

 acting bathythermographs, current meters, and satellite infrared imagery. As 

 deployed in Hawaii, the initial data appear to support the concept that larvae 

 spawned at a particular site can drift in gyres (at certain times of the year 

 only) and could be returned close to their point of departure in times coin- 

 cident with the general length of larval life. We agreed that it was crucial 

 that local current regimes in various areas of the tropics must be carefully 

 measured at different times of the year and during all phases of the lunar 

 month if the potential drift paths of eggs and larvae are to be ascertained. 

 However, as indicated, daily changes in larval behaviors and the ability to 

 swim and orient can place fishes in different local current regimes. It is 

 possible, therefore, that active directed behaviors (such as vertical movements) 

 could increase the chance(s) that fishes will be dispersed to suitable reef 

 habitats for colonization. Thus, it is critical that subsurface currents as 

 well as surface currents be measured. 



As crucial as the measurements of currents are, they must be coupled to 

 ongoing investigations of spawning, egg and larval distribution, and larval 

 behaviors if they are to result in meaningful conclusions for understanding 

 recruitment dynamics in the tropics. 



As indicated by McFarland and Ogden (this proceeding) data on the actual 

 settlement of reef fishes are sparse. Observations of settlement on a given 

 day usually record the presence of recruits on a specific reef site, from which 

 they were absent the previous day. Daily observations of this sort are useful 

 in establishing recruitment cycles, but they reveal little about actual settle- 

 ment behaviors of local reef fish. Do most reef fish larvae settle at night, 

 or is there diel variation? And if so, are settlement behaviors species specific 

 or plastic? What specific factors trigger settlement, and what attributes of a 

 reef are attractive to each species? Answers to these questions will not yield 

 to casual observation. As an example, during the discussion I indicated that 

 newly recruited French grunts repeatedly established themselves on the same 

 small coral heads and never recruited on closely adjacent heads that had similar 

 configurations. Choice of a site might, thus, be resolved not only by appropriate 

 substrate requirements but also by microscale differences in currents, as noted 

 by Lobel. To know exactly what factors control site selection by new recruits 

 will require carefully controlled manipulative experiments for a broad spectrun 

 of reef species. Answers are critical before generalizations can be made: if 



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