Use of Population Modeling to Enhance the Gulf Sturgeon Recovery Plan PDF Download
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Author:
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ISBN:
Category : Fish populations
Languages : en
Pages : 40
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Book Description
The Gulf sturgeon population in the Pearl River was monitored from 1992 through 1996 and compared to historical data sets from the 1960s and 1980s. The estimated population sire iii 1996 was approximately 300 fish with adults comprising about 3 percent of the population. Annual mortality rates in the late 1960s were about 9 percent; these rates increased to almost 40 percent in 1985 and decreased to about 26 percent during 1992 through 1996. Population modeling was used to evaluate the sturgeon's status and recovery potential. Results of models suggest that this population can only withstand mortality rates in the range of 13 to 18 percent, depending upon recruitment assumptions. Population models indicated that catch and fishing effort data specified in the Gulf Sturgeon Recovery Plan may not detect a declining population. Population models can be used to simulate annual variation in population sire under different rates of mortality. Recovery goals can address a specific source of mortality simulated in the model and monitoring can determine the success of recovery efforts. Population modeling does not require considerably more effort or expertise over that already required to conduct monitoring studies.
Author:
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 40
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Book Description
The Gulf sturgeon population in the Pearl River was monitored from 1992 through 1996 and compared to historical data sets from the 1960s and 1980s. The estimated population sire iii 1996 was approximately 300 fish with adults comprising about 3 percent of the population. Annual mortality rates in the late 1960s were about 9 percent; these rates increased to almost 40 percent in 1985 and decreased to about 26 percent during 1992 through 1996. Population modeling was used to evaluate the sturgeon's status and recovery potential. Results of models suggest that this population can only withstand mortality rates in the range of 13 to 18 percent, depending upon recruitment assumptions. Population models indicated that catch and fishing effort data specified in the Gulf Sturgeon Recovery Plan may not detect a declining population. Population models can be used to simulate annual variation in population sire under different rates of mortality. Recovery goals can address a specific source of mortality simulated in the model and monitoring can determine the success of recovery efforts. Population modeling does not require considerably more effort or expertise over that already required to conduct monitoring studies.
Author: H. Jared Flowers
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ISBN:
Category :
Languages : en
Pages :
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ABSTRACT: Gulf sturgeon Acipenser oxyrinchus desotoi is a U.S. federally threatened species found throughout the northern Gulf of Mexico. The viability of the Apalachicola River, Florida Gulf sturgeon population is a concern to fishery managers because of the small population size, slow rate of population recovery, and numerous threats to recovery, including habitat loss and interstate water allocation battles. Although Gulf sturgeon harvest has been illegal since 1985, managers and researchers are concerned that the population is not recovering at the desired rate to meet the recovery criteria objective of delisting by 2023.
Author: Gulf Sturgeon Recovery/Management Task Team (U.S.)
Publisher:
ISBN:
Category : Endangered species
Languages : en
Pages : 170
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Author:
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ISBN:
Category : Government publications
Languages : en
Pages : 58
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Author: Page Elizabeth Vick
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ISBN:
Category : Anadromous fishes
Languages : en
Pages : 96
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Critical spawning and feeding habitat was designated for federally threatened, anadromous Gulf Sturgeon (GS) to aid in population recovery. This study examined GS occupancy, habitat use, and movement through critical habitat monitored by the Ship Island (SI) acoustic array during overwintering periods from 2011 to 2015, prior to MsCIP SI restoration. An occupancy index analyzed patterns of spatial and temporal habitat use of both western and eastern population segments (WPS and EPS, respectively) of GS on the SI array. The ends of SI along with the passes and cuts of the island, especially Dog Keys Pass (DKP), were occupied by GS. Further, the index was determined to be strong and robust as it was able to adapt as the array expanded. There was no significant difference in mean active days of population segments of GS on the SI array, and both population segments were concentrated within DKP and nearshore Western Horn Island. Travel rate (km d[-1]) to the SI array from natal drainages was observed, and population segments differed significantly with EPS individuals traveling at a higher rate, on average, compared to WPS individuals; Blackwater fish had a significantly higher travel rate compared to Pascagoula fish. Clearly, both population segments use areas associated with the SI array as critical habitat during the overwintering period, regardless of the distance traveled from natal rivers. Gulf Sturgeon use multiple marine and freshwater habitats throughout their lifetime; critical habitat should be protected and expanded to possibly assist in population recovery for this species. --Page ii.
Author: Merrill B. Rudd
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ISBN:
Category :
Languages : en
Pages : 130
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This study utilized the data collected from a standardized acoustic telemetry tagging program and historic mark-recapture database to resolve uncertainties in Gulf sturgeon mortality and movement rates at spatial scales relevant to management. Using multi-state models with river mouth acoustic receiver detections over a two year period, I estimated detection probabilities greater than 0.50 across all rivers and time periods. River and marine survival rates were similar in all regions except the western Gulf, where riverine survival was lower. Gulf sturgeon exhibited non-random fidelity to their natal rivers, and were more likely to enter their natal river or genetically related riverine population. High fidelity rates to rivers or genetically distinct units combined with differential mortality rates spatially provides support for considering Gulf sturgeon stocks as distinct population segments. This delineation could be important if population segments show divergent evidence of recovery. Using estimates of mortality from the telemetry study and a historic mark-recapture database, I updated the Gulf sturgeon stock assessment using an age-structured mark-recapture (ASMR) model. I fit initial marking and recapture data from the Suwannee, Apalachicola, and Choctawhatchee Rivers, incorporating uncertainty in initial age assignment, to estimate a time series of abundance, recruitment, and survival in each riverine population. Assuming a negative binomial probability distribution, model results were possibly divergent depending on pulsed or constant effort sampling designs. These results demonstrate important tradeoffs between monitoring time, size of the marked population, and capture probability, which are necessary to consider in managing a protected species.
Author: Mark Angelo Dugo
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 174
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Author:
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 344
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Author: United States. Office of the Assistant Secretary of the Army (Civil Works)
Publisher:
ISBN:
Category : Borgne, Lake (La.)
Languages : en
Pages : 916
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Author: Jo Anne Siskidis
Publisher:
ISBN: 9780355334111
Category :
Languages : en
Pages : 64
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Three quarters of the world's fisheries are classified as overexploited or depleted. Management programs have mainly focused on reducing the fishing pressure on these stocks. However, some stocks fail to rebound even after fishing effort is reduced and hatchery programs may be used to facilitate population recovery. Despite substantial investment in hatchery supplementation, failed programs outnumber successful ones. It therefore seems vital to explore the abiotic and biotic factors that hinder their success. This thesis addresses the performance of several active recovery policies through the use of multispecies microcosms. Specifically, I ask 1) whether one or several supplementation efforts are needed before a sustainable stock population is established and 2) what factors influence the success or failure of recovery in these microcosms. My results show that the community within an ecosystem may strongly influence a recovery program's likelihood of success and that multiple small additions may offer a better chance of success than one or several large additions. My results support previously made arguments that community ecology is an important framework for fisheries management. Moreover, commercial fishing alters community structure and this may happen in a way that inhibits population recovery. I suggest reconceiving population recovery as 'facilitated invasion' may provide useful guidance for designing future recovery programs.
