Joel K. Llopiz
RSMAS, University of Miami jllopiz@rsmas.miami.edu

I am presently a postdoctoral researcher in the lab of Dr. Robert Cowen, but also working closely with Dr. Su Sponaugle. My current research is building upon the work of my dissertation that focused generally upon the trophic ecologies of larval fishes in the oceanic Straits of Florida. Some of the general conclusions of that work included the observation that, despite having to find food in these low-latitude oligotrophic waters, larval fish feeding was often very selective and the diets were notably narrow and specific to the larval fish taxon. Thus, in Straits of Florida waters where there is a high diversity of larval fishes and potential zooplankton prey, there is distinct trophic niche partitioning among co-occurring larvae.

Another finding was the important role that appendicularians have in the diet of several taxa, including three genera of tunas and three families of coral reef fishes. Such a high reliance upon appendicularians, which exhibit rapid growth by consuming bacteria and other nano- and picoplankton, indicates appendicularians provide a critical link in these oligotrophic waters from the microbial food web to higher trophic levels.

Some of my recent work has incorporated our findings on the coral reef fish the bluehead wrasse and istiophorid billfishes into an examination of growth variability. We found that although these larvae appear to be feeding rather successfully (with potentially little starvation mortality), there is some influence of both environmental prey abundance and prey type availability on larval growth. We are also expanding on the 21 taxa already examined for feeding analyses to include the most dominant taxa in the Straits of Florida. With these data we will be able to put together a quantitative subweb for almost the entire larval fish community that takes into account both their abundance and diets. This will allow for a thorough and unprecedented look at the dominant energy pathways that go to this previously ignored component of planktonic food webs.

These are just a few of my interests and ongoing efforts. Some other work and areas of interest include questions related to prey patchiness, larval piscivory, sources of larval mortality, zooplankton distributions and implications that many of our findings have for population connectivity. While we are working on many of these questions in the Cowen and Sponaugle labs, I am certainly open to additional collaborations or simply answering any questions--just send me an email.