Nekton use of marsh-surface habitats in Louisiana (USA) deltaic salt marshes undergoing submergence

Self Cite

We used a spatially explicit individual-based model to investigate the relative influences of inundation and habitat fragmentation on brown shrimp Farfantepenaeus aztecus production in northern Gulf of Mexico (NGOM) salt marshes. The model simulates the mortality, growth, and movement of a population of brown shrimp from their arrival in Spartina salt marsh as post-larvae in spring to their emigration as sub-adults in summer and fall. We quantified production in terms of subadult export, growth production (a measure of total shrimp growth), and trophic transfer (total shrimp mortality). We utilized a factorial design to simulate shrimp on all combinations of 4 maps that represented an idealized progression of habitat fragmentation and 4 inundation regimes from each of 2 locations in the NGOM (Louisiana and Texas). We also quantified the configuration of the marsh landscape to determine if specific metrics could be utilized as a proxy for shrimp production within a single inundation regime. Our results indicate that inundation is more important than habitat fragmentation for determining sub-adult export, growth production, and trophic transfer, but that marsh configuration has a strong influence on shrimp production within a single inundation regime. Inundation affected all 3 measures of shrimp production, primarily due to decreased mortality incurred when shrimp have access to vegetation through marsh flooding. We conclude that simple metrics of marsh configuration are capable of adequate predictions of shrimp production in static landscapes, but future research must consider the dynamic relationship between inundation and marsh fragmentation to fully assess how these forces affect shrimp production.KEY WORDS: Farfantepenaeus aztecus · Fragmentation · Inundation · Production · Spartina · Salt marsh · Gulf of Mexico · Estuaries · Individual-based model Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 359: [185][186][187][188][189][190][191][192][193][194][195][196][197][198][199][200][201][202] 2008 marsh. Several studies from the NGOM and elsewhere have documented a positive relationship between fishery landings and the extent of intertidal vegetation , Jackson et al. 2001, Loneragan et al. 2005. Vegetation provides increased foraging opportunities and shelter from predators , Beck et al. 2001, Kraus & Secor 2005. Thus, the productivity of many species is tied to their ability to access intertidal vegetation (Weinstein 1979, Kneib 1997, that is, in turn, controlled by both the amount of edge habitat (intersection of vegetation and water) and the local pattern of inundation (Weinstein et al. 2000, Minello et al. 2003. Patterns of nekton use related to marsh edge (e.g. Minello et al. 1994, Peterson & Turner 1994, Minello & Rozas 2002 and the role of inundation on species productivity , Rozas 1995, Minello et al. 2003 are well documented. The relative importance of marsh fragmentation (i.e. marsh edge) versus inundation for species productivity, however, h...

Section: Discussionsupporting

confidence: 79%

Relative influence of habitat fragmentation and inundation on brown shrimp Farfantepenaeus aztecus production in northern Gulf of Mexico salt marshes

Roth

Rose

Rozas

et al. 2008

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“…Nonetheless, most species of nekton frequently taken on the marsh surface were concentrated in low marsh located at the marsh-water interface. Thus, for these species, apparent habitat selection within emergent marsh was influenced most by 2 factors: marsh elevation and the proximity of the marsh to open-water areas (Zimmerman & Minello 1984, Rozas 1993, Rozas & Reed 1993, Peterson & Turner 1994. In our study, high densities of brown shrimp, white shrimp (fall), daggerblade grass shrimp, naked goby, and darter goby (fall) were strongly associated with low, shoreline marsh sites.…”

Section: Discussionmentioning

confidence: 62%

“…Striped mullet, daggerblade grass shrimp, brown shrimp, and blue crab also were more numerous in edge S. alterniflora marsh than Juncus marsh. Similarly, in a previous study, brown shrimp and white shrimp seemed to prefer low S, alterniflora marsh, whereas gulf killifish and diamond killifish appeared to favor high Distichlis spicata marsh over low S. alterniflora marsh (Rozas & Reed 1993). In another study, densities of daggerblade grass shrimp and brown shrimp were 1.2 to 4.3 times higher on low than high S. alterniflora marsh, but elevation did not seem to affect the abundance of white shrimp (Minello et al 1994).…”

Section: Discussionmentioning

confidence: 92%

Small-scale patterns of nekton use among marsh and adjacent shallow nonvegetated areas of the Galveston Bay Estuary, Texas (USA)

Rozas¹,

Zimmerman²

2000

Self Cite

128

We quantified and compared nekton and infauna1 densities among vegetated (edge Sparhna alterniflora, inner Spartina alterniflora, Scirpus maritimus, Juncus roemenanus, and Spartina patens marsh) and shallow nonvegetated (marsh pond, marsh channel, cove, and shallow bay) areas of upper Galveston Bay and East Bay, Texas. In 2 seasons (spnng and fall) of h g h nekton abundance, and over 2 yr, we collected 267 quantitative samples (upper Galveston Bay, 1993 = 127 and East Bay, 1994 = 140) using a 1 mZ drop sampler. The vegetated marsh surface consistently contained more species (i.e. higher species richness) and total numbers of decapod crustaceans than nonvegetated areas. In contrast, fish species richness and densities of total fishes on the marsh and in nonvegetated areas were not sigrdicantly different in most comparisons. Most numerically dominant species of nekton seemed to exhibit at least some degree of habitat selection. Within vegetation, 2 factors, elevation and proximity to open water, were most important in influencing the distribution of nekton. Low marsh edge dominated by Spartina alterniflora or Sciq~us maritirnus was apparently selected by most species that used the marsh surface including brown shrimp Farfantepenaeus aztecus, blue crab Callinectes sapidus, and daggerblade grass shrimp Palaemonetes puglo. White shrimp Litopenaeus setlferus and striped mullet Mugil cephalus also were concentrated in low edge marsh; although in one comparison, densities of these 2 species in edge and Inner S. alterniflora were not significantly Uferent In contrast, gulf killifish Fundulus grandis and sheepshead minnow Cyprinodon vanegatus were most abundant on inner S. alterniflora or S. patens marsh. Other fishes (gulf menhaden Brevoortia patronus, spot Leiostomus xanthurus, bay anchovy Anchoa mitchill~, blackcheek tonguefish Symphurusplagiusa, and Atlantic croaker Micropogonias undulatus) had higher densities over nonvegetated bottoms than on the marsh surface. Specific habitat types that these pelagic species seemed to favor were marsh channels (gulf menhaden, bay anchovy), marsh ponds (spot), and coves (Atlantic croaker, blackcheek tonguefish). Overall, marsh-surface and adjacent nonvegetated habitat types contalned much higher densities of most nekton than the shallow bay. Infaunal densities were estimated from sedlment cores, and taxa (mainly annelids, crustaceans, molluscs, and insects) were most abundant in nonvegetated areas contiguous with marsh in the spring. Factors that influenced infaunal abundance are complex and may include predation, flooding patterns, elevation, and distance to edge. Our study has important implications for designing marsh-creation projects. Based on our results, we recommend creating a variety of marsh and contiguous shallow-water areas to enhance nekton biodiversity. To maximize fishery habitat, priority should be given to constructing low marsh edge by creating large areas of low marsh interspersed with a dense network of shall0.w channels and interconnected ponds.

“…The prawn densities were higher in the natural, more frequently inundated salt marshes. Higher densities of P. aztecus and P. setiferus were also found in salt marshes on lower ground by Rozas & Reed (1993), but the results were complicated by different densities of vegetation.…”

Section: Other Intertidal Habitatsmentioning

confidence: 92%

Distribution of juvenile penaeid prawns in mangrove forests in a tropical Australian estuary, with particular reference to Penaeus merguiensis

Vance

Haywood²,

Heales³

et al. 2002

Several species of prawns, including juveniles of Penaeus merguiensis, will move into mangrove forests when the forests are inundated by flood tides. However, we do not know how extensively the prawns use the forests or whether some parts of the forests are more valuable to the prawns than others. We assessed the distribution of juvenile prawns in 3 different mangrove communities in intertidal forests adjacent to a small creek and a river in northern Australia between December 1993 and February 1995. The 3 mangrove communities were dominated, respectively, by the structurally complex Rhizophora stylosa, and the more open Ceriops tagal and Avicennia marina. We used stake nets (100 m long, 2 mm mesh) to sample discrete areas of the mangrove forests, and fyke nets (2 mm mesh) to sample prawns moving through the forests. The area of each stake net site ranged from 430 to 650 m 2 and the distance of the midpoint of each site inland from the creek or river mangrove fringe ranged from 13 to 225 m. A large size range of juvenile P. merguiensis (2 to 21 mm carapace length, CL) was caught in the mangroves and prawns were caught as far as 200 m into the forests. In the creek forest, there was no clear relationship between mangrove community type and prawn catches. The highest densities of P. merguiensis were recorded in the creek and were 28.1 and 27.6 prawns 100 m -2 in Rhizophora sp. and Ceriops sp. forest respectively. The highest mean catches were taken 59 m from the creek mangrove fringe. In contrast to the creek, in the river mangrove forest, there was a clear pattern of catches: the number of P. merguiensis caught decreased with distance into the mangroves and at shallower water depths. We have hypothesised that the distribution of juvenile P. merguiensis inside the mangroves depends largely on the local topography and pattern of water currents within each forest. Large numbers of unidentified Metapenaeus spp. and smaller numbers of M. ensis and P. monodon were also recorded from the samples inside the mangrove forests.