Final Report: Survey of Diamondback Terrapin Populations in Alabama Estuaries

EPA Grant Number: R830651C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R827072
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Alabama Center For Estuarine Studies (ACES)
Center Director: Shipp, Robert L.
Title: Survey of Diamondback Terrapin Populations in Alabama Estuaries
Investigators: Nelson, David D. , Borden, Joel , Coleman, Andrew , Dindo, John , Langford, Gabriel , Marion, Ken , Wibbels, Thane
Institution: University of Alabama at Birmingham , Dauphin Island Sea Lab , University of South Alabama
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 2003 through October 31, 2006
RFA: Alabama Center For Estuarine Studies (ACES) (1999) RFA Text |  Recipients Lists
Research Category: Targeted Research

Objective:

Abstract

Diamondback terrapins (Malaclemys terrapin pileata) were sampled from April to August 2004, from May to August 2005, and from May to August 2006 in salt marshes of southwestern Alabama (Mobile County). Several trapping techniques were utilized: drift fences with pitfall traps, modified crab traps, hoop traps, box traps, nest depredation surveys, and head surveys. Terrapins were individually marked (notching marginal scutes), weighed, and measured (carapace length, carapace width, shell height, plastron length, tail length, and head width). Females were palpated for eggs; anomalies were noted (predation marks, prop scars, barnacle and oyster fouling); and all individuals were digitally photographed. Our goal was to systematically document the abundance and distribution of terrapins in Alabama coastal waters. Only 62 turtles were captured (32 females, 10 males, 12 juveniles, and 8 hatchlings) over the three sampling seasons. Turtle head counts ranged from 24 in 2004, to 25 in 2005, and 40 in 2006. The numbers of depredated nests recorded were 74 in 2004, 15 in 2005, and 109 in 2006. Although our data suggest that terrapin populations appear to be sparse and isolated in Alabama salt marshes, the largest aggregation appears to be near Cedar Point. Smaller populations were evident at Barton Island, Point aux Pines, and Grand Batteurs.

The objective of this study was to document the current status and distribution of the Mississippi diamondback terrapin (Malaclemys terrapin pileata) along coastal Alabama. Compared to other Gulf Coast states, Alabama has a relatively small coastline. However, it appears to be characterized by favorable, relatively undisturbed habitats. Those familiar with the area, however, are aware that terrapin numbers appear to be low. By conducting visual surveys and systematic, conventional trapping programs in local salt marshes, we sought to identify areas where the terrapins occur on Alabama’s Gulf Coast. When possible, we intended to identify viable populations and to characterize their size structures, age distributions, and sex ratios. We planned to establish marked, base-line populations that might provide an on-going source of terrapin monitoring and conservation assessment in the future.

Summary/Accomplishments (Outputs/Outcomes):

Diamondback terrapins were sampled from April to August 2004, May to August 2005, and May to August 2006 along the southwestern coast of Alabama (Mobile County). Several sampling techniques were utilized: drift fences with pitfall traps, modified crab traps, hoop traps, box traps, turtle head surveys, and nest depredation surveys. Hoop traps and box traps were not effective and were discontinued after the first year. Terrapins were individually marked (notching marginal scutes), weighed, and measured (carapace length, carapace width, shell height, plastron length, tail length, and head width). Females were palpated for eggs; anomalies were noted and recorded (predation marks, prop scars, barnacle and oyster fouling); and all individuals were digitally photographed. Over three sampling seasons, only 62 turtles were captured (32 females, 10 males, 12 juveniles, and 8 hatchlings). Eight hatchlings were also encountered, although two were found dead. A total of 89 turtle heads were observed (within marshes) in head-count surveys, and 189 depredated turtle nests were recorded on nesting beaches. The greatest numbers of turtle heads were observed at Cedar Point Marsh, Mon Louis Creek, Little Dauphin Island, and Airport Marsh. Significant nest depredations were recorded at beaches of Cedar Point, Point aux Pines, Grand Batteurs, Barton Island, Airport Marsh, Mon Louis Island, and Heron Bay. The largest populations were apparently recorded (observed and trapped) at Cedar Point and Barton Island. Terrapin populations appear to be sparse and isolated along coastal Alabama. The terrapin is currently listed as a “Priority One” species (highest conservation concern) by the Alabama Department of Conservation and Natural Resources. Apparently, Alabama populations of terrapins have not recovered from excessive harvesting of the past. Further research is needed to identify current threats to terrapin populations in Alabama and to provide for the conservation of the species in its natural habitat.

Journal Articles:

No journal articles submitted with this report: View all 13 publications for this subproject

Supplemental Keywords:

estuarine, marine, aquatic, population, ecology, conservation, Gulf Coast, southeast, turtle, reptile, organism, biology,

Relevant Websites:

http://www.southalabama.edu/aces/ Exit

Progress and Final Reports:

Original Abstract
  • 2004
  • 2005 Progress Report
  • 2006

  • Main Center Abstract and Reports:

    R827072    Alabama Center For Estuarine Studies (ACES)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827072C001 Fluorescent Whitening Agents As Facile Pollution Markers In Shellfishing Waters
    R827072C002 Red Snapper Demographics on Artificial Reefs: The Effect of Nearest-Neighbor Dynamics
    R827072C003 Stabilization of Eroding Shorelines in Estuarine Wave Eliminates with Constructed Fringe Wetlands Incorporating Offshore Breakwaters
    R827072C004 Interaction Between Water Column Structure and Reproduction in Jellyfish Populations Of Mobile Bay (SGER)
    R827072C005 Effects of Variation in River Discharge and Wind-Driven Resuspension on Higher Trophic Levels in the Mobile Bay Ecosystem
    R827072C006 Results of Zooplankton Component
    R827072C007 Benthic Study Component
    R827072C008 A Preliminary Survey of Macroalgal and Aquatic Plant Distribution in the Mobile Tensaw Delta
    R827072C009 Fisheries-induced changes in the structure and function of shallow water "nursery habitats": an experimental assessment
    R827072C010 Effects Of Variation in River Discharge and Wind-Driven Resuspension on Lower Trophic Levels of the Mobile Bay Ecosystem
    R827072C011 Evaluation of Alabama Estuaries as Developmental Habitat for Juvenile Sea Turtles
    R827072C012 Effects of Salinity Stress on Natural and Anthropogenically-Derived Bacteria in Estuarine Environments
    R827072C013 The Role of Land-Use/Land-Cover and Sub-estuarine Ecosystem Nitrogen Cycling in the Regulation of Nitrogen Delivery to a River Dominated Estuary; Mobile Bay, Alabama
    R827072C014 Environmental Attitudes of Alabama Coastal Residents: Public Opinion Polls and Environmental Policy
    R827072C015 Synthesis and Characterization of an Electrochemical Peptide Nucleic Acid Probe
    R827072C016 Determinants of Small-Scale Variation in the Abundance of the Blue Crab Callinectes Sapidus
    R827072C017 Effects of Estrogen Pollution on the Reproductive Fitness of the Gulf Pipefish, Syngnathus scovelli
    R827072C019 A Model for Genetic Diversity Aquatic Insects of the Mobile/Tensaw River Delta
    R827072C020 Evaluating Trophic Processes as Indicators of Anthropogenic Eutrophication in Coastal Ecosystems: An Exploratory Analysis
    R827072C021 Effects of Anthropogenic Eutrophication on the Magnitude and Trophic Fate of Microphytobenthic Production in Estuaries
    R827072C022 Characteristics of Ship Waves and Wind Waves in Mobile Bay
    R827072C023 Methods Comparison Between Stripping Voltammetry and Plasma Emission Spectroscopy for Metals in Mobile Bay
    R827072C024 Changes in Water Conditions and Sedimentation Rates Associated With Construction of the Mobile Bay Causeway
    R827072C025 Cold-Induced Hibernation of Marine Vibrios in the Gulf of Mexico: A Study of Cell-Cell Communication and Dormancy in Vibrio vulnificus
    R827072C026 Holocene Sedimentary History of Weeks Bay, AL: Human and Natural Impacts on Deposition in a Gulf Coast Estuary
    R827072C027 Shelter Bottlenecks and Self-Regulation in Blue Crab Populations: Assessing the Roles of Nursery Habitats and Juvenile Interactions for Shelter Dependent Organisms
    R827072C028 Predicting Seagrass Survival in Nutrient Enriched Waters: Toward a New View of an Existing Paradigm
    R827072C029 DMSP and its Role as an Antioxidant in the Salt Marsh Macrophyte Spartina alterniflora
    R827072C030 A Preliminary Survey of Aerial and Ground-Dwelling Insects of the Mobile/Tensaw Delta
    R827072C031 Natural Biogeochemical Tags of Striped Mullet, Mugil cephalus, Estuarine Nursery Areas in the North Central Gulf of Mexico
    R827072C032 Resolution of Sedimentation Rates in Impacted Coastal Environments Using 137Cs and 210Pb Markers: Dog River and Fowl River Embayments
    R827072C033 Investigation of the Use of Pulse Amplitude Modulated (PAM) Fluorometry as an Indicator of Submerged Aquatic Vegetation Health in Mobile Bay
    R827072C034 Influence of Invasive Plant Species in Determining Diversity of Aquatic Vegetation in the Mobile-Tensaw Delta
    R827072C035 The Influence of Shallow Water Hydrodynamics on the Importance of Seagrass Detritus in Estuarine Food Webs
    R827072C036 Food Web Interactions, Spatial Subsidies and the Flow of Energy Between the Mobile Bay Delta and Offshore Waters: A SGER Proposal to the Alabama Center for Estuarine Studies
    R830651C001 Meteorological Modeling of Hurricanes and Coastal Interactions: A Stability Study For Vertical Pressure Levels
    R830651C002 Characterization of Glycoprotein Cues Used by the Parasitic Rhizocephalan Barnacle Loxothylacus texanus To Identify Its Blue Crab Host, Callinectes sapidus
    R830651C003 Survey of Diamondback Terrapin Populations in Alabama Estuaries
    R830651C004 An Assessment of Environmental Contaminant Levels in Water and Dragonfly Larvae Tissues from the Mobile/Tensaw Delta