Potential interactive effects of habitat complexity and sub-adults on young-of-the-year red snapper (Lutjanus campechanus) behavior.

摘要

I studied the potential effects of habitat complexity on behavior of young-of-the-year (YOY) red snapper, Lutjanus campechanus, in 2,200 L laboratory tanks. YOY red snapper have a strong affinity for structure, which range in these experiments from open-sand bottom to a more complex, concrete block artificial reef-like habitat.;Average distance of YOY red snapper from the blocks decreased significantly as the number of blocks in the experiment increased. Average distance from a single block was also significantly less than measurements from the center of the tank in the control (0 blocks).;A second set of experiments found that YOY red snapper, in the presence of older sub-adult red snapper, did not stay on or near the artificial structures due to aggressive behavior towards the YOY by the larger snapper. If similar behaviors are prevalent in in situ artificial settings, those YOY that attempt to move onto the reefs from the shrimp grounds, which serves as nursery area for newly settled snapper, may be subject to predation pressures by other piscivorous fishes.;Alternate prey experiments showed that larger snapper preferentially chose to consume the alternate prey, and did not cannibalize the YOY. However, this may be because YOY red snapper were better at avoiding the larger snapper compared to the alternate prey.;Due to the recent declines in red snapper stocks in the Gulf of Mexico, it has become necessary to enhance and protect adult populations. These results suggest the future research should focus on finding suitable sized habitat, placed at certain depths, that maximizes YOY recruitment from the shrimp grounds while minimizing the numbers of larger snapper attracted to these sites.