@article{craig_rice_crowder_nadeau_2007, title={Density-dependent growth and mortality in an estuary-dependent fish: an experimental approach with juvenile spot Leiostomus xanthurus}, volume={343}, ISSN={["1616-1599"]}, DOI={10.3354/meps06864}, abstractNote={The abundance of demersal marine fishes is a function of both pre-settlement processes that influence recruitment to benthic juvenile habitats, as well as post-settlement density-dependent processes that act during the juvenile stage. Few studies have investigated density-dependence for fishes that spawn offshore and recruit to inshore estuaries for the juvenile stage prior to returning to offshore waters as adults (i.e. estuary-dependent). We conducted 2 replicated experiments at differ- ent spatial scales to test for density-dependent growth and mortality in juvenile spot Leiostomus xan- thurus, a common estuary-dependent species. In the small-scale experiment, we stocked spot in 1 m 2 cages in a marsh creek at densities of 2, 5, and 10 fish m -2 and determined their growth and mortal- ity after 51 d. In the large-scale experiment, we stocked spot in 79 m 2 pond sections at 2, 5, and 10 fish m -2 and determined their growth and mortality after 52 d. We sampled benthic infauna at the end of the pond experiment to determine if prey availability mediated the effects of density on spot growth and mortality. Average spot growth rates decreased 83 to 97% and mortality increased 2- to 4-fold as density increased from 2 to 10 fish m -2 . The density of benthic infauna at the end of the pond exper- iment was inversely related to spot density, consistent with competition for food as the underlying mechanism. Estimates of spot density compiled from the literature indicate that the density-depen- dent effects we observed occurred within the range of reported field densities. Our results provide strong experimental support for the hypothesis that density-dependent processes during the demer- sal juvenile stage in estuaries can modify patterns in the abundance of spot, and perhaps other estu- ary-dependent species, that are established prior to settlement.}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Craig, J. Kevin and Rice, James A. and Crowder, Larry B. and Nadeau, David A.}, year={2007}, pages={251–262} }
 @article{eggleston_johnson_kellison_nadeau_2003, title={Intense removal and non-saturating functional responses by recreational divers on spiny lobster Panulirus argus}, volume={257}, ISSN={["1616-1599"]}, DOI={10.3354/meps257197}, abstractNote={The effects of recreational fishing often go undetected, yet can lead to the collapse of fishery populations. Fishery managers must understand the dynamics of recreational fishers and their prey to successfully predict the outcome of management actions. We measured the impact of a 2 d exclusively recreational fishery on the Caribbean spiny lobster Panulirus argus in the Florida Keys, USA, and used a theoretical, predator-prey functional response approach to identify whether or not sport diver catch rates were density-independent or -dependent (Types I, II or III functional response), and if catch rates were saturated (i.e. reached an asymptote) at relatively high lobster densities. Herein, we describe how this predator-prey framework could be applied to fisheries management for the spiny lobster. Our approach consisted of SCUBA diver surveys of lobster distribution and abundance patterns immediately before and after the 2 d recreational 'mini-season' coupled with counts of recreational boats and divers to assess the aggregative response of divers to lobster density. During the mini-season, the density of boats along coral patch reefs and patch heads was over 900 × higher than during the regular fishing season ~3 wk later. Overall, there was a 95 and 79% decline in mean lobster densities in the patch reef and patch head habitats, respectively. Fishing effort was 10 × greater on patch heads than on reefs, prob- ably due to ~100-fold higher lobster densities in patch-head habitats. In both patch reefs and heads, the proportion of lobsters removed by divers was density-independent (Type I functional response). Diver catch never reached saturation at natural lobster densities. Thus, recreational divers have a relatively simple predatory response to spiny lobsters, whereby catch rates increase linearly with lobster density such that catch is a reliable indicator of abundance. A major concern is that the current levels of lobster exploitation by sport divers are extremely high (~90%); however, diver predation pressure is not expected to increase proportionally with a decline in lobster density, which could exacerbate local extinction. Management actions that reduce diver effort should have a concomitant reduction in catch. The recreational diver-lobster predator-prey construct in this study provides a useful predictive frame- work on which to build as the spatiotemporal scales of measurements expand, management actions are implemented, and the lobster population varies.}, number={2003}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Eggleston, DB and Johnson, EG and Kellison, GT and Nadeau, DA}, year={2003}, pages={197–207} }