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Habitat Function of a Restored Salt Marsh: Post-Larval Gulf Killifish as a Sentinel
Citation:
VIVIAN, D., C. F. RAKOCINSKI, AND M. S. PETERSON. Habitat Function of a Restored Salt Marsh: Post-Larval Gulf Killifish as a Sentinel. Chapter 4, Steve Jordan (ed.), Estuaries: Classification, Ecology, and Human Impacts. Nova Science Publishers, Inc, Hauppauge, NY, , 57-74, (2012).
Impact/Purpose:
This chapter describes an approach to monitor marsh restoration success using the gulf killifsh as a sentinel species.
Description:
Successful marsh restoration requires recreating conditions to ensure proper ecosystem function. One approach to monitor restoration success is using a sentinel species as a proxy integrator of salt marsh function. The gulf killifish (Fundulus grandis, Baird and Girard) is a good candidate sentinel, as it provides an important trophic link between marsh surface and subtidal habitats. Accordingly, herein an in-situ approach is presented for assessing marsh function using reared and wild post-larval gulf killifish. Three field experiments conducted in the spring of 2002 and 2003 assessed post-larval growth and survival within cylindrical acrylic microcosms. Marginally significant differences in mean growth rate were apparent between marsh surface and subtidal habitats at Weeks Bayou, MS in 2002, with higher growth in subtidal habitats (6.2 % • d-1) versus surface habitats (3.9 % • d-1). Survival rates of 44.4 % were equivalent within both habitats. Using the same approach, restored and reference sites at the Chevron-Pascagoula refinery, MS were compared in 2003. Survival rates were notably low for both restored (18.75 %) and reference sites (0.0 %) during the first experiment of 2003 (May). Reference mortality most likely reflected high sediment porosity. Survival was considerably higher at the restored site (76.2 %) than at the relocated reference site (29.8 %) in a second 2003 experiment (June); however, growth was poor at both sites (0.1 and –0.47 % • d-1, respectively). Diet analysis showed that enclosed fish were feeding successfully. Estimates of infaunal abundances and daily growth of wild fish were comparable between sites. Growth rates of enclosed fish followed a trajectory more similar to laboratory fish than to wild fish, perhaps reflecting that reared fish within enclosures continued to grow slowly in the field. A number of valuable lessons from this study point to the how an effective multipronged approach for using early stages of fundulids as sentinels of marsh restoration can be further developed.
