Classes:
Marine Ecology (BIOL 529, BIOL 529L, BIOL 592I)
Research Interests
The main goal of my research is to elucidate the causes of variation in abundance of organisms that live in open populations in order to understand and predict their dynamics and spatial patterns. I place particular emphasis on evaluating the relative importance of the various processes that determine patterns of abundance, population dynamics, and community structure. I have worked on reef fishes in temperate (southern California), subtropical (Gulf of California, Mexico), and tropical (Bahamas) systems, and also on estuarine fishes in southern California. Currently, I have three main research programs: (1) population dynamics and community structure of non-exploited reef fishes; (2) density dependence in commercially-exploited reef fishes and implications for fisheries management using marine protected areas; (3) and the ecology of estuarine fishes, particularly as related to wetland restoration projects.
Population dynamics of non-exploited reef fishes
My work at small spatial scales has demonstrated that shelter limitation and predation cause density-dependent mortality in reef fish. I have also found that mortality in some species is density dependent at large scales. In current collaborative work with Graham Forrester at U of Rhode Island, I am testing whether shelter limitation is also the cause of density-dependent mortality at large scales relevant to management by manipulating shelter density on entire large reefs. The prediction is that density-dependent mortality will be eliminated or weakened and population densities enhanced on reefs with added shelter. The results will have important implications for fisheries enhancement and conservation. I am also testing the community level responses to shelter addition. The fieldwork is combined with mathematical modeling (done in collaboration with Dr. Rick Vance at UCLA) to integrate the findings of the empirical studies and predict their consequences at even larger scales.
Evaluating the influence of density dependence on the utility of marine protected areas (MPAs) as tools for fisheries management
Traditional fisheries management theory (e.g., maximum sustainable yield) assumes that fish populations grow in a density-dependent fashion, yet current theory on MPAs typically ignores density dependence or incorporates it in a simplistic and unrealistic way. The strength and nature (e.g., which demographic rates it affects) of density dependence is likely to have important impacts on how well MPAs work as tools for fisheries management. My work seeks first to empirically evaluate the strength of density dependence in exploited coral-reef fishes and, second, to incorporate this information into simulation models to explore how density dependence might be expected to influence the efficacy of MPAs for managing fisheries. 
Explorations of the population and community ecology of estuarine fishes in southern California
This work is currently done in the context of designing effective sampling protocols and statistical approaches for evaluating the success of wetlands restoration projects. I am developing methods for sampling fishes in wetlands and using them to measure the characteristic spatial and temporal patterns of variation in fish abundance in order to develop efficient and accurate sampling designs for fish assemblages. In the course of conducting this work, I am studying the basic ecology of wetland fishes in southern California.
Selected Publications
Steele, M. A., S. C. Schroeter, and H. M. Page. 2007. Preliminary investigation of the effects of purse seine size on estimates of density and species richness of estuarine fishes. Estuaries and Coasts: In press.
Steele, M. A., S. C. Schroeter, R. C. Carpenter, and D. J. Kushner. 2006. Top-down vs. bottom-up effects in kelp forests. Science 313:1738.
Steele, M. A., S. C. Schroeter, and H. M. Page. 2006. Experimental evaluation of biases associated with sampling estuarine fishes with seines. Estuaries and Coasts 29:1172-1184.
Steele, M. A., S. C. Schroeter, and H. M. Page. 2006. Sampling characteristics and biases of enclosure traps for sampling fishes in estuaries. Estuaries and Coasts 29:630-638.
Forrester, G. E., Evans, B., M. A. Steele, and R. R. Vance. 2006. Assessing the magnitude of intra- and interspecific competition in two coral-reef fishes using a response surface experiment. Oecologia 148:632–640.
Steele, M. A. and T. W. Anderson. 2006. Predation. In: L. G. Allen, M. H. Horn, D. J. Pondella II (eds) Ecology of California Marine Fishes, U.C. Press, p. 428-448.
Steele, M. A. and G. E. Forrester. 2005. Small-scale field experiments accurately scale up to predict density dependence in reef fish populations at large scales. Proceedings of the National Academy of Sciences 102:13513-13516.
Forrester, G. E. and M. A. Steele. 2004. Predators, prey refuges, and the spatial scaling of density- dependent prey mortality. Ecology 85:1332-1342.
Forrester, G. E., B. I. Fredericks, D. Gerdeman, B. Evans, M. A. Steele, K. Zayed, L. E. Schweitzer, I. H. Suffet, R. R. Vance, R.F. Ambrose. 2003. Growth of estuarine fish is associated with the combined concentration of sediment contaminants and shows no adaptation of acclimation to past conditions. Marine Environmental Research 56:423-442.
Swearer, S. E., G. E. Forrester, M. A. Steele, A. J. Brooks, and D. W. Lea. 2003. Spatio-temporal and interspecific variation in otolith trace-elemental fingerprints in a temperate estuarine fish assemblage. Estuarine, Coastal and Shelf Science 56:1111-1123.
Forrester, G. E., R. R. Vance, and M. A. Steele. 2002. Simulating large scale population dynamics using small-scale data. In: P. F. Sale (ed) Coral reef fishes: dynamics and diversity in a complex ecosystem. Academic Press, San Diego, p 275-301.
Steele, M. A. and G. E. Forrester. 2002. Early post-settlement predation on three reef fishes: effects on spatial patterns of recruitment. Ecology 83: 1076-1091.
Steele, M. A., J. C. Malone, A. M. Findlay, M. H. Carr, and G. E. Forrester. 2002. A simple method for estimating larval supply in reef fishes and a preliminary test of limitation of population size by larval supply in the kelp bass, Paralabrax clathratus. Marine Ecology Progress Series 235:195-203.
Steele, M. A. and G. E. Forrester. 2002. Variation in the relative importance of sublethal effects of predators and competitors on growth of a temperate reef fish. Marine Ecology Progress Series 237:233-245.
Forrester, G. E. and M. A. Steele. 2000. Variation in the presence and cause of density-dependent mortality in three species of reef fishes. Ecology 81:2416-2427
Steele, M. A. 1999. Effects of shelter and predators on reef fishes. Journal of Experimental Marine Biology and Ecology 233:65-79.
Malone, J. C., G. E. Forrester, and M. A. Steele. 1999. Effects of subcutaneous microtags on the growth, survival, and vulnerability to predation of small reef fishes. Journal of Experimental Marine Biology and Ecology 237:243-253.
Steele, M. A. 1998. The relative importance of predation and competition in two reef fishes. Oecologia 115:222-232.
Steele, M. A., G. E. Forrester, and G. R. Almany. 1998. Influences of predators and conspecifics on recruitment of a tropical and a temperate reef fish. Marine Ecology Progress Series 172:115-125.
Steele, M. A. 1998. Life and Death of Coral Reefs. The Quarterly Review of Biology 73:367. (Book review)
Steele, M. A. 1997. The relative importance of processes affecting recruitment of two temperate reef fishes. Ecology 78:129-145.
Steele, M. A. 1997. Population regulation by post-settlement mortality in two temperate reef fishes. Oecologia 112:64-74.
Steele, M. A. 1996. Effects of predators on reef fishes: separating cage artifacts from effects of predation. Journal of Experimental Marine Biology and Ecology 198:249-267.
Dr. Mark A. Steele 
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