Understanding Coastal Ecosystems Room 201D
Jan 24, 2023 01:40 PM - 02:55 PM(America/Chicago)
20230124T1340 20230124T1455 America/Chicago Understanding Coastal Ecosystems Room 201D 2023 Bays and Bayous Symposium mbnep@mobilebaynep.com
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The Greater Amberjack Count: An Overview
01:40 PM - 01:55 PM (America/Chicago) 2023/01/24 19:40:00 UTC - 2023/01/24 19:55:00 UTC
Reef fish management in the Southeastern US has been contentious due to disagreements regarding stock status and catch levels. This has caused the public to question the scientific basis for management decisions. Since stakeholder buy-in is critical to effective management, the US Congress has responded to this situation by funding, to date, two large collaborative studies to help guide future management and build stakeholder confidence by providing independent estimates of the absolute abundance of important fisheries species. The first of these, the Great Red Snapper Count, has been completed successfully. Here we present an overview of the second such study, the Greater Amberjack Count. The primary goals of this ongoing study are (1) to provide an independent estimate of Greater Amberjack (GAJ) absolute abundance in the US Gulf of Mexico and South Atlantic regions using fisheries independent sampling, and (2) to expand our general biological knowledge (spatial ecology, movement, connectivity, growth, mortality, etc.) of GAJ to inform management decision making and to address some of the key assumptions of our abundance estimate. To meet these goals, we have established a phased approach that is adaptable to differences across regions and habitats, scalable from local to regional spatial scales, and efficient in terms of leveraging existing catch data, stakeholder knowledge, and ongoing complementary research.
Presenters
MA
Mark Albins
University Of South Alabama, School Of Marine And Environmental Sciences
Co-Authors
SP
Sean Powers
Dauphin Island Sea Lab/University Of South Alabama
KB
Kevin Boswell
Florida International University
JB
Jeff Buckel
North Carolina State University
MC
Matt Catalano
Auburn University
GC
Grace Chiu
Virginia Institute Of Marine Science
MD
Michael Dance
Louisiana State University
MD
Marcus Drymon
Mississippi-Alabama Sea Grant Consortium
JH
John Hoenig
Virginia Institute Of Marine Science
SM
Stephen Midway
Louisiana State University
SM
Steven Murawski
University Of South Florida
NP
Nicole Phillips
University Of Southern Mississippi, School Of Biological, Environmental, And Earth Sciences
JR
Jay Rooker
Texas A&M University At Galveston
ES
Eric Saillant
University Of Southern Mississippi
SS
Steven Scyphers
University Of South Alabama
LS
Lynne Stokes
Southern Methodist University
GS
Gregory Stunz
Texas A&M University-Corpus Christi
TS
Ted Switzer
Florida Fish And Wildlife Conservation Commission
DW
David Wells
Texas A&M University At Galveston
Estimation of Mortality Rates for the Gulf Menhaden Stock
01:55 PM - 02:10 PM (America/Chicago) 2023/01/24 19:55:00 UTC - 2023/01/24 20:10:00 UTC
Gulf Menhaden, Brevoortia patronus, is the target species of the second largest fishery in the United States. Gulf Menhaden fishery and stock is described using an age-structured stock assessment that has been ongoing since the 1960s. The model is parametrized, in part, using age-specific mortality rates. New advancements in technology have made it possible for modernizing the calculations of many of these parameters in the assessment. In an effort to improve estimates of Gulf Menhaden mortality rates we conducted a study to develop mark-recovery models in AD Model Builder to evaluate recently digitized records of a large-scale tag and recapture study. Recovery data were comprised of adult (n = 90,210) and juvenile (n = 142,013) individuals that were captured, tagged with unique ferro-magnetic tags, and then recovered from the fishery from 1970 to 1988. The models account for the difference in juvenile and adult tagging mortality as well as tag recovery probability. Juvenile dynamics were modeled such that 'transition' into the adult tagged population took place after tagging, with the assumption that all recovered fish were adults. Fishing effort was derived from fishery landings per month throughout the tagging study. Estimating mortality rates based on mark recovery data using contemporary methods will provide validation of current parameters, indicate the annual variation in mortality, and allow an understanding of the range of observed mortality.
Presenters
CW
Catherine Wilhelm
University Of Southern Mississippi, Gulf Coast Research Lab
Depredation on Descender Devices: A Gulf-Wide Investigation
02:10 PM - 02:25 PM (America/Chicago) 2023/01/24 20:10:00 UTC - 2023/01/24 20:25:00 UTC
The post-release survival of discarded reef fishes is often hindered by pressure-related injuries known as barotrauma. Descender devices are effective tools designed to return a fish to the depth of capture, thereby minimizing the effects of barotrauma. While regulations require Gulf of Mexico anglers targeting species in the snapper-grouper fishery management unit to be equipped with descender devices, there is no way to enforce the use of such devices. The widespread acceptance of descender devices by Gulf of Mexico anglers is limited by concerns that these tools merely generate more opportunities for depredation, defined as the partial or complete removal of a captured species by a non-target species. Therefore, we initiated a study to measure the rate of depredation on reef fishes released using descender devices across the U.S. Gulf of Mexico and identify the species responsible for depredation. We incentivized 30 reef fish charter-for-hire captains across the region to collect data during their routine fishing trips. The captains are using downward-facing GoFish® cameras to record reef fish descents on SeaQualizer™ descender devices. Thus far, we have received video footage and accompanying data for 314 descender releases. These videos and data will be analyzed to calculate species-, region-, and depth-specific depredation rates. Ultimately, the results of this project will provide insight into the relationship between the use of descender devices and the occurrence of depredation on these devices in the reef fish fishery across the U.S. Gulf of Mexico.
Presenters
DM
Danielle McAree
Mississippi State University, Marine Fisheries Ecology Lab
Co-Authors
AA
Alena Anderson
Mississippi State University, Marine Fisheries Ecology Lab
AJ
Amanda Jefferson
Mississippi State University/Mississippi-Alabama Sea Grant Consortium
AC
Angela Collins
Florida Sea Grant & UF IFAS Extension
MS
Matthew Streich
Texas A&M University-Corpus Christi
MD
Marcus Drymon
Mississippi-Alabama Sea Grant Consortium
Investigating Salinity and Temperature Tolerances of Grass Shrimp
02:25 PM - 02:40 PM (America/Chicago) 2023/01/24 20:25:00 UTC - 2023/01/24 20:40:00 UTC
Grass shrimp of the genus Palaemonetes are an important prey species for estuarine nekton, transferring energy from producer and decomposer levels to higher consumer levels. Their role as a lower trophic level intermediary makes them a suitable candidate for inclusion in ecosystem models that investigate the effect of changing environmental parameters on food web dynamics. However, few exposure studies exist that are specifically designed for optimal inclusion in a habitat capacity model. The habitat capacity modeling component of the ecosystem modeling tool Ecospace, estimates habitat suitability using species-specific response curves over monthly timesteps. The goal of this study was to determine the tolerance of grass shrimp to different salinities over monthly periods to create response curves in an Ecospace model, at different temperatures to determine if there are salinity x temperature interactions. Over one-month long intervals, grass shrimp were exposed to six treatment levels of salinity (0, 2, 7, 13, 20, and 35 ppt) at three different temperatures (15°, 26°, and 30°C) within a controlled flow-through system. Lethal and sublethal effects were quantified by measuring survival, change in biomass, and caloric content of the grass shrimp at the end of each month. The results will be used to create response curves in an Ecospace model that simulates the effects of changing environmental parameters on an estuarine food web that experiences substantial freshwater inflow events.
Presenters
AM
Adam Murray
University Of Southern Mississippi, Gulf Coast Research Lab
Co-Authors
KD
Kim De Mutsert
University Of Southern Mississippi
The Influence of Changing Environmental and Management Conditions on Past and Present Mississippi Oyster Reefs
02:40 PM - 02:55 PM (America/Chicago) 2023/01/24 20:40:00 UTC - 2023/01/24 20:55:00 UTC
The Eastern oyster (Crassostrea virginica) is an ecologically and economically important species that provides invaluable services for coastal communities. The oyster industry has a long history and tradition in the U.S. Gulf states, but this fishery has declined dramatically in recent years following Hurricane Katrina, the Deepwater Horizon oil spill, and climate change-mediated flooding events. Mississippi was once known as the "seafood capital of the world", but there has been no public harvest of oysters in Mississippi since 2018. Significant resources have been invested in the northern Gulf of Mexico to restore wild oyster populations and re-establish an oyster aquaculture industry, but these projects have faced many challenges, and the baseline to assess restoration progress is not well defined. We conducted a review of the Mississippi oyster industry to establish the history of oyster reefs in this region and gain insights from causes of previous fishery collapses including factors that promoted or hindered oyster population recovery in the Mississippi Sound. This project also synthesizes data related to abiotic and biotic conditions on current Mississippi oyster reefs to improve our understanding of key drivers that influence oyster reef health and resilience to help inform oyster reef restoration efforts in the face of increasing frequency of natural disasters. Successful restoration and persistence of sustainable oyster reefs in Mississippi will require continual investment and implementation of management practices that provide suitable substrate for larval settlement and enhancement of existing stock to promote increased larval supply.
Presenters
JP
Jessica Pruett
University Of Mississippi
Co-Authors
DG
Deborah Gochfeld
University Of Mississippi
KW
Kristine Willet
University Of Mississippi
SS
Stephanie Showalter-Otts
Mississippi-Alabama Sea Grant Legal Program
LF
Luke Fairbanks
University Of Southern Mississippi
KD
Kelly Darnell
University Of Southern Mississippi
University of South Alabama, School of Marine and Environmental Sciences
University of Southern Mississippi, Gulf Coast Research Lab
Mississippi State University, Marine Fisheries Ecology lab
University of Southern Mississippi, Gulf Coast Research Lab
University of Mississippi
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