Habitat Use Patterns of Newly Settled Southern Flounder, Paralichthys lethostigma, in Aransas–Copano Bay, Texas

Abstract

Southern flounder Paralichthys lethostigma populations have been declining in Texas during the past 25 years. Despite their economic importance, little is known about their juvenile habitat requirements. We examined habitat use patterns of newly settled southern flounder in three zones at varying distances from the Aransas Pass inlet in Aransas-Copano Bay by measuring densities using a beam trawl in replicate estuarine habitat types in each zone. Highest abundance occurred near the inlet in vegetated sandy areas and was lowest in nonvegetated muddy bottom in regions furthest from the inlet. We also examined a 25-year fisheries data set from Texas Parks and Wildlife Department to evaluate long-term spatiotemporal recruitment patterns in Aransas-Copano Bay. These data showed generally low recruitment during the past 25 years with highest abundance near the inlets. Our results support the importance of vegetated habitat types, especially those near tidal passes, and suggest a longterm decline in recruitment densities of southern flounder.

Ecological Aspects of Coastal Sediment Management in the Gulf of Mexico

“…Aggregated spatial distributions related species communities to different habitat characteristics, emphasizing the importance of maintaining a variety of habitat characteristics and distribution in restored areas (Rashleigh et al, 2009). Nanez-James, Stunz, andHolt (2009) and Ross et al (2009) stress the importance of maintaining vegetated, sandy, shallow habitats in the nearshore of barrier islands as compared to unvegetated, muddy bottoms for maintaining populations of southern flounder in Texas and gulf sturgeon in Louisiana, Mississippi, and Alabama. Nordstrom (2000) and Finkl and Walker (2002) emphasize the importance of maintaining beach profile elevation in nourishment projects, many of which employ the use of dredge material.…”

“…Wells et al (2009) documented the use of inshore mud, shell bank, and offshore mud habitats by a variety of fish species on a drowned barrier island along the Texas shelf. Equally important to creating productive nekton habitat is the maintenance of sandy bottom inlets between barrier islands and other shoreline features (Nanez-James, Stunz, and Holt, 2009;Ross et al, 2009). …”

Assessing southern flounder (Paralichthys lethostigma) long-term population trends in the northern Gulf of Mexico using time series analyses

“…The bag seines used in this study were designed to sample juvenile estuarine fish populations (Martinez-Andrade et al, 2009). While formal gear selection studies were not performed, previous studies on this species have shown this to be an effective gear for sampling juvenile southern flounder (Nañez-James et al, 2009 seine) longitude and latitude coordinates were recorded, and total length (TL) of each fish was measured.…”

“…The residuals were fitted using a varIdent variance structure from the "nlme" library in R, where each month was allowed to have a different variance (Zuur et al, 2007). All months were tested for significance against January, due to January being shown as the first month of recruitment in Texas (King, 1971;Stokes, 1977;Nañez-James et al, 2009). Nonparametric bootstrapping with replacement (n = 1000) of the resulting coefficients were used to estimate confidence intervals of the gls model parameters without making assumptions about the population distribution.…”

Sex determination in southern flounder, Paralichthys lethostigma, from the Texas Gulf Coast

“…Southern flounder spawn offshore at depths of 20 to 60 m during winter months (Stokes, 1977). Currents transport the larvae to shallow water estuaries where they settle out at approximately 8 to 12 mm TL and begin life on the bottom (Glass et al, 2008;Nañez-James et al, 2009;Wenner and Archambault, 2005). Histological analysis shows that gonadal tissue differentiation begins at~75 mm TL at approximately 4 to 6 months of age in North Carolina (Luckenbach et al, 2003).…”