Changes in the Age Structure of Nearshore Adult Red Drum off West-Central Florida Related to Recruitment and Fishing Mortality

Murphy, Michael D.; Crabtree, Roy E.

doi:10.1577/1548-8675(2001)021<0671:citaso>2.0.co;2

Cited by 28 publications

(60 citation statements)

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“…At the macro scale, observed age and growth during 2007 was comparable to estimates of seatrout growth along the western Gulf of Mexico. Prior to 2006, age and growth estimates from Alabama were, however, more similar to locations along the northern and eastern Gulf of Mexico (see review in GMFMC, 2001;Nieland et al, 2002;Murphy and McMichael, 2003). Changes at this scale may be indicative of changes at the ecosystem level rather than at the local level.…”

Section: Discussionmentioning

confidence: 93%

“…Identifying the underlying reason for these population trends may be critical to expanding our understanding seatrout populations in this region. Because our back-calculated regression estimates were 4% less than the regressions derived from the observed data and we limited our analysis to fish 5 yr old or younger, backcalculated lengths appearing smaller for older fish (Lee's phenomenon) was not problematic in these data (Duncan, 1979;Murphy and McMichael, 2003). Difference in models may also be indicative of the recent changes in population structure toward smaller fish.…”

Section: Discussionmentioning

confidence: 99%

“…This shift in growth seems to be sudden, as it was not evident in the ADCNR's 2002-06 survey (ADCNR, 2007). Minimum and/or maximum size are commonly used management tools for spotted seatrout (GMFMC, 2001;VanderKooy and Muller, 2002;Hendon and Warren, 2003) and population structure of seatrout and other sciaenids can be highly influenced by fishing pressure and size limits (Murphy and Crabtree, 2001;Hendon and Warren, 2003). Removal of the fastest-growing fish could result in shifts in population structure (Zhao et al, 1997;Hsieh et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…All values were transformed using a log transformation to meet the homogeneity of variance assumption (Sokal and Rohlf, 1981). Because previous studies indicate differences in size-at-age for spotted seatrout (Murphy and Taylor, 1990;Nieland et al, 2002), Student's t-tests were used to examine observed size-at-age between sexes to identify the age when differences in size become evident. A nonparametric binomial response test (SPSS, v. 11) was used to examine sex ratios between Mobile Bay and Mississippi Sound.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the limited number of older spotted seatrout collected, results were restricted to fish , 5 yr old. Sexes were also analyzed separately because they grow at different rates (Murphy and Taylor, 1990;Murphy and McMichael, 2003;Nieland et al, 2002). To compare the parameters of our actual and back-calculated VBGEs with ADCNR's previously estimated parameters from 1995-96 and 2000-06, we used a likelihood ratio test using Solver function in Microsoft Excel 2007 (Kimura, 1980;Cerrato, 1990;Haddon, 2000).…”

Section: Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Population Changes and Location-Specific Differences for Otolith-Derived Age and Growth of Recreationally Harvested Spotted Seatrout (Cynoscion nebulosus) From Alabama in 2007

Johnson

Bortone

Klement

et al. 2011

goms

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Population Changes and Location-Specific Differences for Otolith-Derived Age and Growth of Recreationally Harvested Spotted Seatrout (Cynoscion nebulosus) From Alabama in 2007

Johnson

Bortone

Klement

et al. 2011

goms

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Genomic signals found using RNA sequencing show signatures of selection and subtle population differentiation in walleye (Sander vitreus) in a large freshwater ecosystem

Thorstensen

Jeffrey

Treberg

et al. 2020

Ecology and Evolution

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RNA sequencing is an effective approach for studying aquatic species yielding both physiological and genomic data. However, its population genetic applications are not well‐characterized. We investigate this possible role for RNA sequencing for population genomics in Lake Winnipeg, Manitoba, Canada, walleye ( Sander vitreus ). Lake Winnipeg walleye represent the largest component of the second‐largest freshwater fishery in Canada. In the present study, large female walleye were sampled via nonlethal gill biopsy over two years at three spawning sites representing a latitudinal gradient in the lake. Genetic variation from sequenced mRNA was analyzed for neutral and adaptive markers to investigate population structure and possible adaptive variation. We find low population divergence ( F ST = 0.0095), possible northward gene flow, and outlier loci that vary latitudinally in transcripts associated with cell membrane proteins and cytoskeletal function. These results indicate that Lake Winnipeg walleye may be effectively managed as a single demographically connected metapopulation with contributing subpopulations and suggest genomic differences possibly underlying observed phenotypic differences. Despite its high cost relative to other genotyping methods, RNA sequencing data can yield physiological in addition to genetic information discussed here. We therefore argue that it is useful for addressing diverse molecular questions in the conservation of freshwater species.

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Rapid changes in age structure, mortality, and escapement accompanied stock recovery of the estuarine Red Drum population of Texas

Anderson,

Fisher,

Weixelman

et al. 2023

Mar Coast Fish

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ObjectiveWe analyzed a fishery‐independent catch time series in the context of predicted historical age structure of Red Drum Sciaenops ocellatus for the years 1980–2019. This time series roughly coincided with closure of the commercial fishery in Texas (in 1981) and federal waters (in 1987). Changes in size and age were used to estimate changes in mortality and offshore escapement.MethodsOtoliths collected from Red Drum between 1997 and 2015 in Texas were used to create seasonal length‐at‐age growth functions, which were then used to estimate ages (based on total length) of all Red Drum encountered in fishery‐independent gill‐net samples collected by the Texas Parks and Wildlife Department during 1980–2019 (total n = 311,150). Temporal changes in observed body size and overall catch were used to predict annualized changes in mean age, mortality, and offshore escapement of the estuarine population.ResultThe initial 14‐year period (1980–1993) was characterized by rapid increases in mean catch per hour and mean total length (mm) in fishery‐independent samples, followed by relative stability for the remainder of the time series. There was a 55% increase in estimated mean age of Red Drum when comparing 1980 (mean age = 0.84 year) to 2019 (1.30 years). There were also rapid and significant declines in total mortality (Z; estimated via catch curves) and increases in offshore escapement (estimated indirectly from mortality) in the initial recovery period.ConclusionThe current estuarine population of Red Drum in Texas is significantly larger and older than it was at the onset of fishery management measures, and offshore escapement is annually well above the current target level of 30% set by the federal fisheries management plan. These findings suggest that regulations put into effect starting in the 1980s have succeeded in recovering the estuarine Red Drum population in Texas.

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Changes in the Age Structure of Nearshore Adult Red Drum off West-Central Florida Related to Recruitment and Fishing Mortality

Cited by 28 publications

References 2 publications

Population Changes and Location-Specific Differences for Otolith-Derived Age and Growth of Recreationally Harvested Spotted Seatrout (Cynoscion nebulosus) From Alabama in 2007

Population Changes and Location-Specific Differences for Otolith-Derived Age and Growth of Recreationally Harvested Spotted Seatrout (Cynoscion nebulosus) From Alabama in 2007

Genomic signals found using RNA sequencing show signatures of selection and subtle population differentiation in walleye (Sander vitreus) in a large freshwater ecosystem

Rapid changes in age structure, mortality, and escapement accompanied stock recovery of the estuarine Red Drum population of Texas

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