Rapid Growth and Behavioral Proficiency of Individual Larvae: Are They Related?

Fuiman, LA, and JH Cowan

Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373; Department of Marine Sciences, University of South Alabama, Mobile, AL, 36688

Abstract:

Growth rate and behavior appear to play important roles in determining predation mortality of fish larvae. Most computer models of predation mortality show that growth rate determines the span time during which larvae are especially vulnerable to predators ("window of vulnerability") and hence the cumulative predation risk. This is partly because large, well developed larvae have better anti-predator behaviors. However, if some individuals are more proficient in these behaviors than others of comparable size and developmental state, they should suffer lower day-to-day predation risk. Such a combination of rapid growth and behavioral proficiency could be the product of a generally enhanced physiological state and could be the object of natural selection. We conducted laboratory trials on 100 larvae of a limited size range to test two related hypotheses: 1) Some individuals have consistently better survival skills than others; and 2) Individuals with high growth rates also have enhanced survival skills. Analyses show that some individuals are indeed consistently good performers in a particular skill and that fast growers are better than slow growers in some skills.

Created: Fri Feb 23 15:11:39 CST 2001