HOME     SCHEDULE     AUTHOR INDEX     SUBJECT INDEX              

PARENT SESSION

Discrimination of Stegastes partitus populations and an assessment of the movement of individuals at Turneffe Atoll, Belize.

Chittaro, Paul*,1, Mora, Camilo1, Fryer, Brian2, Sale, Peter1, 1 Department of Biological Sciences, Windsor, Ontario, Canada2 Department of Earth Sciences & Great Lakes Institute for Environmental Research, Windsor, Ontario, Canada

ABSTRACT- Traditionally, reef fish populations were viewed as open, that is, they received larvae produced primarily by spawning from distant locations. However, evidence has indicated that some reef fish populations are relatively closed; that is, individuals hatched from a given area remain nearby or return to the population at the completion of larval life (often referred to as self-recruitment or local retention). Consequently, an understanding of the extent to which populations are connected (i.e., the demographic link maintained between populations of a species due to the movement of individuals) is relevant to fisheries conservation and management throughout the world. Fortunately, methods exist that have been used to quantify movement of fish among populations. In particular, the microchemistry of calcareous structures are unique in that they incorporate the elemental signature from the environment in which the fish resides, thus allowing for the reconstruction of their spatial movements (much like a flight recorder can be used to reconstruct an airplanes flight history). We examined the microchemistry of otoliths (calcareous structures in fish) from newly settled Stegastes partitus (a common Caribbean reef fish) as a means of discriminating the sites from which they were collected (at Turneffe Atoll, Belize) and assessing the movement of individuals. Results indicated significant temporal (between years and among sampling periods within years) and spatial (among sites within sampling periods within years) variability in the concentrations of several elements, such that it was possible to differentiate the sites from which individuals were collected. Using this spatial and temporal variability in otolith microchemistry, we were able to identify the site from which individuals originated (i.e., the natal site). Our estimates indicated that up to 1/3 of the individuals (i.e., 6-35% of 48-58 individuals) had originated from one of the sites at Turneffe Atoll, across three times in 2002 and 2003, and therefore suggested that populations at this location were neither completely open or closed, but a combination of the two.

Key words: Dispersal, otoliith microchemistry, discrimination

All materials copyright The Ecological Society of America (ESA), and may not be used without written permission.