Michael Lowe

Some coastal habitat types have been established as nursery grounds for estuarine and marine nekton, presumably because these habitats are the template on which population and community dynamics occur. However, the linkage between structured coastal habitat and nekton production is being altered by development; thus, we are studying this linkage while it is changing. Modification to coastal landscapes can have direct and indirect consequences that may lead to reduced or eliminated access to favorable nursery habitat, which is predicted to reduce growth, increase mortality, and/or modify settlement patterns. Cumulative impacts are more problematic because they are not immediately noted and build up over time to produce a more substantial impact to habitat. On a small scale, bulkheads, rip-rap, and levees eliminate or significantly reduce access to intertidal aquatic habitat, but these can accumulate across the landscape and fragment and reduce available habitat. However, the prolifer...

Coastal salt marsh landscapes have undergone rapid urbanization that may impact the suitability of salt marsh ecosystems for the maintenance and regulation of estuarine faunal communities. This paper examines the body condition (a surrogate for growth) of blue crab, brown shrimp, spot, and Gulf killifish in response to increasing levels of urbanization in salt marsh landscapes in coastal Mississippi. Blue crab and brown shrimp condition did not differ among landscapes. Conversely, both Gulf killifish and spot body condition was markedly reduced in highly urbanized salt marsh landscapes, and these differences were likely linked to landscape-specific foraging patterns. In completely urbanized landscapes, empty stomachs were more frequent and larger bodied brown shrimp were characteristic of Gulf killifish diets. In contrast, smaller grass shrimp and fish were key diet components in both intact natural and partially urbanized salt marsh landscapes. Similarly, spot had a greater frequen...

In their seminal paper, Pauly et al. (1998) explicitly described mesopelagic organisms, including both fishes (e.g., families Myctophidae and Sternoptychidae) and krill (order Euphausiacea), as a latent, or unharvested, fisheries resource. Since that publication there have been a number of developing international fisheries targeting mesopelagic organisms for fish feed and human consumption. In the Northwest Atlantic, mesopelagic organisms appear abundant in continental slope waters and, yet, remain relatively ‘data poor’ compared to other regions. In this paper we use several long-term data sets (1973-2013) to examine the spatial distribution of mesopelagic fish and krill along the Northwest Atlantic continental shelf break, their interactions with higher trophic levels, and the large-scale environmental drivers structuring both. Ultimately, mesopelagic fish and krill appear to concentrate along abrupt sub-marine features (i.e., canyons) and are, consequently, being consumed by a v...

ABSTRACT Although largemouth bass is typically thought of as a freshwater species, populations occur in estuaries throughout the US Atlantic and Gulf of Mexico coasts, often with established fisheries. These coastal populations must deal with the physiological stresses associated with salinity variation, and are generally isolated from inland freshwater populations. We quantified individual and population parameters for largemouth bass in the Mobile-Tensaw River Delta, Alabama during 2003-2008 in an effort to understand factors important to these coastal populations to facilitate their management. Large individuals were rare and fish condition increased with increasing salinity influence. Growth responses were more complex; faster growth was observed in the brackish, downstream areas for fish <age-2, while growth of older fish was faster in freshwater upstream sites. Using bioenergetics modeling, we demonstrated that a complex combination of spatial variation in water temperature, prey energetic content, and metabolic cost of salinity was responsible. Largemouth bass of all ages moved very little, even when salinity was 15 ppt in downstream areas. These coastal largemouth bass populations face a number of conservation concerns, and their management will require different approaches compared to their inland counterparts, including different goals, expectations, and likely even requiring consideration as unique populations.