COLIN: SPAWNING AND LARVAL DEVELOPMENT OF HOGFISH 



FIGURE 2.— Photograph of spawning pair of Laehnolaimus maximus with the smaller female in front of the male. The fish are 

 turning laterally in the "swim alongside and tilt" action just prior to release of the gametes. Photo by C. Arneson at the study site. 



to create a turbulent eddy where the gametes 

 had been released to aid in their mixing. 



5) Circle and display — When the male broke 

 sharply away from the female, she also turned 

 away, but not as sharply. Both started downward, 

 the male doing a 180° lateral turn while descend- 

 ing. When laterally exposed to the female he 

 initiated a display similar to that used in court- 

 ship. The three dorsal spines were erected, the 

 last two shaken. The soft portion of the dorsal and 

 anal fins, the upper and lower margins of the 

 caudal fin, and the pelvic fins were agitated at a 

 rate of 8-10 times/s. This display continued for 1- 

 3 s as the male approached the female and they 

 continued down. 



6) Swim down — The male separated from the 

 female and swam downward at a steep angle. 

 She did likewise. He may quickly approach 

 another female and engage in courtship behavior 

 or he may simply rise into the water column if 

 another female is ready to spawn. Occasionally 

 he will court the female he has just spawned with 

 after they have returned to near the substrate, 

 but I have never seen a female spawn two times 

 in rapid succession. 



In many instances it was possible to observe 

 the gamete cloud after it had been released. The 

 movements of the fish, particularly the male, 

 produce an area of turbulence where the gam- 

 etes are thoroughly mixed. On occasion the 

 actual sperm cloud was also faintly visible. With- 

 in 15-20 s after release, the gametes will occupy a 

 volume near 1 m 3 . There are usually several hun- 

 dred or more eggs released per rush. In some 

 instances no egg cloud could be found, even 

 though the usual procedures for locating it were 

 followed and the observer arrived within a few 

 seconds to the region in which the eggs should 

 have been. It is possible, but not yet proven, that 

 eggs are simply not released on some rushes. 



Yellowtail snappers, Ocyurus chrysurus, were 

 active predators on the eggs immediately after 

 release. One to as many as ten yellowtail snap- 

 pers would converge on the egg cloud 1-2 s after 

 eggs had been released and would pick individual 

 items, presumably eggs, from the water. This 

 occurred in about 20-40% of rushes. Generally if 

 yellowtail snappers observed a pair of L. maxi- 

 mus rising to spawn, they would attempt to 

 locate and eat the eggs. On occasion individuals 



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