2001-2004
RESEARCH PROJECTS

Determining the health of small fry food
Assessing the health
of the planktonic food web
in Texas coastal bays
usingRNA:DNA ratios
     Zooplankton are an important link in the food web between phytoplankton and larval fish. It has long been known that an adequate food supply is critical to successful recruitment of marine fish. While a number of studies have looked at the effects of natural and manmade disturbances on fish and shellfish populations, few studies have focused on the lower levels of the food web, which can provide important insights into recruitment processes. Marine copepods are normally the dominant form of zooplankton, and their young are important food for larval fish. Assessing the health of copepod populations in nature can be attempted by measuring growth rates or egg production rates of females, but these methods involve tedious experiments with long incubation times. It would be a significant advance for routinely assessing the health of planktonic food chains if animals could be collected in the field and their condition reliably evaluated using a laboratory analysis such as an RNA:DNA ratio.
Dr. Edward J. Buskey
Marine Science Institute
The University of Texas at Austin
Port Aransas, Texas 78373
(361) 749-6794
buskey@utmsi.utexas.edu

Learning more about the Gulf of Mexico’ssperm whales
Stock assessment,
movement patterns and habitat
of endangered
sperm whalesin the
northern Gulf of Mexico
     The endangered sperm whale, the largest toothed whale on Earth, occurs as an apparently native population or populations in the northern Gulf of Mexico. A gathering of sperm whales of unknown sex, age, number and reproductive status occurs near coastal waters just south of the Mississippi delta in areas that could be affected by coastal and near-coastal toxins, fisheries, industrial traffic and oil and gas exploration and development. This project will attempt to shed light on the population status, habitat use patterns and relationship to human activities of these potentially important members of the Gulf of Mexico’s diverse animal population. The study will use tools, such as photographic identification and photogrammetry studies, genetic analyses, satellite tracking and behavioral observations in consort with satellite remote sensing of oceanographic features.
Dr. Randall W. Davis
Department of Marine Biology
Texas A&M University at Galveston
PO Box 1675
Galveston, Texas 77553-1675
(409) 740-4729
davisr@tamug.tamu.edu

Dr. Bernd G. Würsig
Department of Marine Biology
Texas A&M University at Galveston
PO Box 1675
Galveston, Texas 77553-1675
(409) 740-4729
wursigb@tamug.tamu.edu

Gauging the effects of pesticide run-off on redfish
Contaminants in Texas Bays:
Impairment of red drum
survival skills and the consequences
for their populations
     The use of organophosphate pesticides, especially the herbicide
Atrazine and the insecticide Malathion, for both agricultural and nonagricultural purposes is widespread in the state of Texas. These compounds are present in measurable amounts in Texas bays, but our knowledge of their effects on coastal animal life is negligible. However, the literature suggests both of these compounds will negatively affect behavioral and physiological processes. This project examines the effects of Atrazine and Malathion on the performance and growth of larval red drum, a major recreational fish species in Texas coastal waters. This will be achieved using behavioral and physiological tests to evaluate the survival skills and metabolic performance of larval red drum. This project will refine our understanding of coastal ecosystem health by gauging the effects of Atrazine and Malathion on the survival and growth of the highly sensitive red drum larvae.
Dr. Lee A. Fuiman
Marine Science Institute
The University of Texas
Port Aransas, Texas 78373-5015
(361) 749-6775
lee@utmsi.utexas.edu

Examining the factors that cause hypoxia
Processes responsible
for hypoxia in the Gulf
of Mexico; A re-evaluation
with new data and perspective
     A team of three experienced oceanographers will re-evaluate the factors responsible for the occurrence of hypoxia (dissolved oxygen concentrations low enough to threaten living marine resources) over the northern shelves of the Gulf of Mexico. We will consider background conditions (wind, currents, river discharge, nutrient levels, heating) as well as local factors (nutrients, light levels, phytoplankton concentrations, vertical stratification) in relation to the occurrence of low dissolved oxygen concentration. We will seek quantitative relationships among the factors responsible for lowering oxygen concentrations.
Our results will be combined with those in the literature and compared with those from waters off South Africa. New findings will be disseminated in refereed publications and via the Marine Information Service to improve general understanding of this sensitive marine environmental problem.
Dr. Worth D. Nowlin, Jr.
Department of Oceanography
Texas A&M University
College Station, Texas 77843-3146
(979) 845-3900
wnowlin@tamu.edu

Researchers use earstones to identify sources of red drum
Origins of Red Drum stocks:
Assessing the contribution
of different nursery grounds
using biogeochemical fingerprints
     The study will examine the use of earstone trace element signatures of an estuarine-dependent finfish to quantify the contribution of different nursery areas to adult stocks. Earstones (otoliths) are formed as the adult grows and are made up of elements from the surrounding seawater. By examining the makeup of earstones from different fish, researchers hope to determine where these fish grew up. Researchers will use red drum as a “model” species and characterize trace element signatures of this economically important fish from several nursery habitats in Texas. Researchers also will look for major differences among the earstones of fish gathered from the same area. In addition, scientists plan to determine whether these “fingerprints” are stable over time. They will also use this technique to identify the source of adult red drum stocks in the northern Gulf of Mexico and assess the relative contribution of different nursery grounds. As a result, fundamental questions regarding the value and health of natural ecosystems will be addressed and explained with this novel technique.
Dr. Jay Rooker
Department of Marine Biology
Texas A&M University at Galveston
PO Box 1675
Galveston, Texas 77553
(409) 740-4528
rooker@tamug.tamu.edu

Project examines pollutant uptake by oysters and mussels
Role of natural organic matter
in governing the bioavailability
of potentially toxic metals
to estuarine bivalves
     Bivalves, especially oysters and mussels, have been extensively used as models and bio-indicator organisms in environmental assessment and monitoring programs to assess the bioavailable contaminant concentrations in coastal environments. Natural dissolved organic matter (DOM) is a potentially nutritious food source for bivalves. However, the presence of DOM may significantly alter the bioavailability and biogeochemical cycling pathways of many trace metals in aquatic environments. The role of natural DOM in governing the bioavailability of potentially toxic metals to bivalves is not well understood and has rarely been tested. In order to better use bivalves as pollution indicator organisms, a thorough understanding of metal uptake pathways and mechanisms, as a function of the quality and quantity of DOM, is sorely needed. The primary objectives of this research are to determine how DOM affects the bioavailability of metals to bivalves, including oysters and mussels, and whether DOM can be directly used as a food source by these bivalves. This will be determined using radiotracers and molecular probes in controlled laboratory experiments. The project will provide greater understanding of uptake pathways and mechanisms of potentially toxic and other representative metals in bioavailability and bioaccumulation, providing crucial information that can be used in environmental assessment and monitoring.
Dr. Peter H. Santschi
Department of Oceanography
Texas A&M University at Galveston
Galveston, Texas 77551
(409) 740-4476
santschi@tamug.tamu.edu

Learning about past climates, reef health by studying coral histories
Corals at the Flower Garden
Banks: Monitors of
Environmental Change
     Global-scale climate fluctuations affect the marine environment of the Gulf of Mexico. To anticipate future climate change and develop sensible policies for managing marine resources, we must understand climate variability and its effect on marine life. Our understanding would be greatly enhanced if we had better information about past climate changes and their effects. Such information is preserved in the skeletons of long-lived corals at the reefs of the Flower Garden
Banks. In this project, researchers will construct long, high-resolution records of skeletal density bands and chemistry to determine histories of local environmental conditions and coral growth from them. Importantly, Flower Gardens corals also monitor the dominant pattern of winter climate variability in the extratropical Northern Hemisphere – the Pacific/North American pattern. We will verify coral-derived records with 20th century instrumental data, then use these records to characterize climate variability during the past two and a half to four centuries. Analysis of these results will contribute directly to our understanding of the temporal character of interannual and interdecadal variations of winter climate. The relationship between changes of coral growth and environmental conditions will indicate processes affecting the corals, and long coral records will provide an important baseline perspective on the overall health and vitality of reefs.
Dr. Niall C. Slowey
Department of Oceanography
Texas A&M University
College Station, Texas 77843-3146
(979) 845-8478
slowey@ocean.tamu.edu

Looking at the effects of estuary contamination on croakers
Assessment of feminization
in male croaker and the
presence of estrogenic contaminants
in estuarine environments
     Recent studies indicate widespread feminization of male fish in polluted estuaries in both Europe and Japan because of the presence of estrogenic contaminants (xenoestrogens), which have potentially serious consequences for the reproductive success and long-term viability of fish populations. However, comparable information on male fish in U.S. estuaries is currently lacking. This project will develop and evaluate novel early warning indicators of feminization because of xenoestrogen exposure in Atlantic croaker. These indicators will include: testicular estrogen receptor protein, mRNA levels and androgen production. These indicators will be compared to established feminization biomarkers, plasma vitellogenin and testicular histology. Feminization indicators that are sensitive to xenoestrogens will subsequently be measured in croaker collected from contaminated sites, which are located near sewage and industrial outfalls in Galveston and Corpus Christi Bays. This study will provide an initial evaluation of the extent of xenoestrogen contamination and feminization of croaker populations in two major Texas estuaries. Thus, the research will provide the first information on feminization of male fish and the presence of xenoestrogens in U.S. estuaries and will be of widespread interest to marine resource protection agencies and managers throughout the country.
Dr. Peter Thomas
Marine Science Institute
The University of Texas at Austin
Port Aransas, Texas 78373
(361) 749-6768
thomas@utmsi.utexas.edu

Looking at the effectiveness of erosion prevention strategies
Sediment transport modeling
and assessment of erosion control techniques
on Galveston Island
     This project will be a detailed study of sediment transport and beach change on two critical, three-mile sections of the Galveston Island
(Texas) shoreline – one subject to erosion control (geotubes) and one without erosion control. Researchers will adapt physically realistic sediment transport models for Galveston Island and make use of a novel, jet ski-based surveying system. This study will yield robust (measurement-verified) estimates of long-shore and cross-shore sediment flows and a sediment budget over a three-year period, will provide detailed and extensive baseline (bathymetric) data and will calculate (and/or measure) shoreline/beach change as a consequence of two erosion control measures currently under consideration (offshore breakwater and onshore geotubes).
Dr. Thomas Ravens
Department of Maritime Systems Engineering
Texas A&M University at Galveston
Galveston, Texas 77551
(409) 740-4465
ravenst@tamug.tamu.edu

Developing more precise means of identifying shrimp
Identifying species
of young commercial shrimp
by combining developmental
morphology and molecular genetics
     Prediction of year class strength, accurate assessment of important nursery habitat, the impact of water and wetland management strategies and decisions regarding the effect of coastal development on shrimp populations require correct identification of all life stages of shrimp. While separation of adult brown shrimp from pink shrimp is relatively easy, separation of their postlarval and early juvenile stages remains problematic. We propose a dual approach for identifying, assessing and verifying differences between species that minimizes the impact of morphological variability because of extrinsic factors yet provides confirmation of specimen identification (ID). This procedure combines ontogenetic scaling techniques with ID by molecular genetic testing. Our goals are two-fold: 1) develop an ontogenetic index that permits rapid and reliable separation of postlarval brown from pink shrimp yet allows screening of large numbers of specimens; and. 2) develop relatively inexpensive tests to verify the identity of these two closely related species of shrimp. Ultimately, information provided by this project will contribute to more accurate estimates of year class strength, improve predictive capabilities and provide fishery managers with better information upon which to base recommendations regarding potential annual yield and regulation of the shrimp fishery.
Dr. Jaime R. Alvarado Bremer
Department of Marine Biology
Texas A&M University at Galveston
5007 Avenue U
Galveston, Texas 77551
(409) 740-4958
jaimeab@tamug.tamu.edu

Measuring the success of red drum stocking efforts
Development and application
of hypervariable DNA markers
(microsatellites) to issues
in stock enhancement
and culture of red drum
     The recreational fishery for red drum is a vital resource to economies of Gulf coast communities. In part because of this, Texas Parks and Wildlife operates a vigorous red drum stock enhancement program. This will be an interdisciplinary, interagency project that combines expertise in molecular and quantitative genetics, physiology and aquaculture to address critical issues impacting both stock enhancement and culture of red drum. We will develop the necessary genetic and analytical tools for large-scale efforts to measure success and efficiency of red drum stock enhancement, and we will carry out small-scale experiments to assess performance in the wild of released fish and the hatchery broodstock that produced them. We will use the same genetic tools to assess the genetic component of variation in three important performance traits: growth rate, cold tolerance and marginal metabolic scope (a measure of capacity for generalized physiological performance). Finally, we will take the initial steps towards generating a red drum genetic map. Results of the research will benefit a number of users and stakeholders, including state and federal government entities responsible for marine resources, private (commercial) red drum interests and the scientific and lay public.
Dr. John R. Gold
Department of Wildlife and Fisheries Sciences
Texas A&M University
College Station, Texas 77843-2258
(979) 847-8778
goldfish@tamu.edu

Creating a guide to Gulf of Mexico fish
Survey and inventory
of the fishes of the Gulf of Mexico
     This project will complete a survey and inventory of the fishes of the Gulf of Mexico. The first half of the survey is complete and has been published in book form. About 80 percent of the second and final volume, covering the remainder of the fish fauna of the Gulf, has been completed. A total of 553 of about 700 species, 239 of about 280 genera, 62 of 82 families and two of four orders have been treated thus far. More than 200 species have been illustrated. To complete the inventory and write the remaining species descriptions, it will be necessary to revisit eight of the 11 largest natural history collections that have major holdings of fishes from the Gulf. During these visits the holdings of the fishes from the Gulf will be surveyed and descriptions written. The historical database summarized in this project will facilitate the monitoring of natural and human alterations of the Gulf. Changes in the historical species composition very likely will reflect natural or human alterations, such as weather patterns, habitats, pollution levels or fishing pressures. The historical database will also facilitate monitoring for the presence of non-nativespecies in the Gulf.
Dr. John D. McEachran
Department of Wildlife and Fisheries Sciences
Texas A&M University
College Station, Texas 77843-2258
(979) 847-9332
j-mceachran@tamu.edu

Marine Education: A floating classroom
Acquisition of a specialized
vessel to advance
marine literacy in Texas
     Utilizing a grant from the Texas Coastal Management Program and the Matagorda County Navigation District #1 as well as a generous contribution from Mrs. Virginia Corn of Port Aransas, Texas, the Marine Education Program has acquired a 57 foot vessel to be used as a floating classroom. The vessel, to begin service in Spring, 2001, will be home ported in the central coast area and available for scheduling of school classes, science clubs, coastal education and adventure camps, youth sportsfishing clubs and other suitable groups. Scheduling inquiries should be made to the MAS Marine Education Office at the Texas State Marine Education Center in Palacios, 361-972-5370.
Dr. Russell Miget
Natural Resource Center
Suite 2800
6300 Ocean Drive
Corpus Christi, Texas 78412
(361) 825-3460
rmiget@falcon.tamucc.edu

William Younger
Texas State Marine Education Center
100 Marine Center Drive
P.O. Box 1283
Palacios, Texas 77465
(361) 972-5370
w-younger@tamu.edu