Managing Centrarchid Fisheries in Rivers and Streams

<em>Abstract.</em>—Coastal rivers provide important fishing opportunities throughout the southeastern United States. Black bass <em> Micropterus </em>spp. are major components of these fisheries and are highly valued by anglers, especially in northwest Florida, where few impoundments exist. In the Escambia and Yellow rivers, as in most other rivers on the northern Gulf Coast, salinity is low in the upper segments but may exceed 13‰ in the lower, mesohaline sections. Both rivers are located within the natural intergrade zone between Largemouth Bass <em> M. salmoides </em>and Florida Bass <em> M. floridanus</em>, and the age and size structure of fish inhabiting riverine reaches differ considerably from those in salt marsh habitats. We collected tissue samples from fish in both the riverine and salt marsh habitats in the Escambia and Yellow rivers and conducted genetic analyses to determine whether individuals from the two habitat types exist as a single randomly mating (panmictic) population in each system. Analysis of 15 microsatellite loci identified significant differences in the allele frequency distributions of samples collected from riverine versus salt marsh habitats in each river. Both rivers were found to be inhabited by intergrade populations that included pure Largemouth Bass and hybrids between Largemouth Bass and Florida Bass. Fish in the salt marsh habitats tended to have more Largemouth Bass alleles than fish in riverine habitats in both systems. Together, these findings indicate fish in the salt marsh and river habitats do not exist in panmixia and have different genetic compositions. Environmental differences between the riverine and estuarine habitats may have led to divergent selection and limited mating between subpopulations within the same river system. Largemouth Bass alleles may confer greater fitness than Florida Bass alleles in estuarine environments of the northern Gulf Coast, which could explain the greater frequencies of Largemouth Bass alleles in these unique habitats.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 516b-516
Author(s):  
James N. McCrimmon

Zoysiagrass has great potential for use in the Gulf Coast states as a turfgrass. There has been minimal research on the nitrogen (N) and potassium (K) fertility response of zoysiagrass and the effect on turf color, quality, and nutrient content. The objective of this study was to evaluate the effects of N and K fertility on zoysiagrass. A study was conducted on three zoysiagrasses: Zoysia japonica × Z. tenuifolia Willd. ex Trin. (`Emerald'); Z. japonica Steud. (`Meyer'); and Z. matrella. The N and K treatment combinations consisted of high (H) and low (L) rates of N and K at the following levels: N levels of 454 and 227 g N/92.9 m2 per month and K levels of 454 and 227 g N/92.9 m2 per month. The treatment combinations were (N and K): HH, HL, LH, and LL and were applied in two split applications monthly from July through November. The study was a randomized complete-block design with three replications. All plots received two applications of a micronutrient fertilizer (late June and August), were irrigated as needed, and maintained at a height of 3.8 cm. Color, density, texture, uniformity, and quality were determined visually for each month. Plant tissue samples were collected (September) and analyzed for macronutrient and micronutrient contents. There were significant differences for color, density, and quality in the following months: September (color and density); October (quality); and November (color and quality). There were differences in leaf texture for all months. There were significant differences for N, magnesium (Mg), and K contents but there were no differences for any micronutrient. This study indicated that all three zoysiagrasses provided acceptable color and quality during the summer and fall, and that N and K rates affected N, K, and Mg contents in the plant.


2019 ◽  
Vol 30 (2) ◽  
pp. 275-293 ◽  
Author(s):  
Joshua M. Goodwin ◽  
Kenneth E. Sassaman ◽  
Meggan E. Blessing ◽  
David W. Steadman

Prevalent as bird imagery is in the ritual traditions of eastern North America, the bony remains of birds are relatively sparse in archaeological deposits and when present are typically viewed as subsistence remains. A first-millennium ad civic-ceremonial centre on the northern Gulf Coast of Florida contains large pits with bird bones amid abundant fish bone and other taxa. The avian remains are dominated by elements of juvenile white ibises, birds that were taken from offshore rookeries at the time of summer solstices. The pits into which they were deposited were emplaced on a relict dune with solstice orientations. The timing and siting of solstice feasts at this particular centre invites discussion of world-renewal rituality and the significance of birds in not only the timing of these events but also possibly as agents of balance and rejuvenation.


Coral Reefs ◽  
2021 ◽  
Author(s):  
Liam Lachs ◽  
Brigitte Sommer ◽  
James Cant ◽  
Jessica M. Hodge ◽  
Hamish A. Malcolm ◽  
...  

AbstractAnthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.


Shore & Beach ◽  
2021 ◽  
pp. 56-64
Author(s):  
S. McGill ◽  
C. Sylvester ◽  
L. Dunkin ◽  
E. Eisemann ◽  
J. Wozencraft

Regional-scale shoreline and beach volume changes are quantified using the Joint Airborne Lidar Bathymetry Technical Center of Expertise’s digital elevation model products in a change detection framework following the passage of the two landfalling hurricanes, Hurricanes Sally and Zeta, along the northern Gulf Coast in late fall 2020. Results derived from this work include elevation change raster products and a standard set of beach volume and shoreline change metrics. The rapid turn-around and delivery of data products to include volume and shoreline change assessments provide valuable information about the status of the coastline and identification of areas of significant erosion or other impacts, such as breaching near Perdido Key, FL, from Hurricane Sally’s impact. These advanced change detection products help inform sediment budget development and support decisions related to regional sediment management and coastal storm risk management.


1981 ◽  
Vol 32 (4) ◽  
pp. 605 ◽  
Author(s):  
CF Chubb ◽  
IC Potter ◽  
CJ Grant ◽  
RCJ Lenanton ◽  
J Wallace

The age structure, growth rates and movements of M. cephalus and A forsteri in the Swan-Avon river system have been investigated using data obtained from beach seining and gill netting carried out between February 1977 and June 1980. Length-frequency data and scale readings show that the populations of both species consist predominantly of 0+ and 1 + fish. From the times when the smallest fry (20-30 mm) were present in the lower part of the river system, and from the condition of the gonads of older fish, the breeding seasons of the sea and yellow-eye mullets have been estimated as extending from March to September and from March to August respectively. The bimodality or polymodality exhibited by the length-frequency distributions for the 0 + year classes suggest that in both species groups of individuals spawn at slightly different times. The range of mean total lengths and weights of animals caught in May near the end of the first year of life was 178-222 mm and 64-119 gin M. cephalus and 136-154 mm and 19-30 g in A. forsteri, which shows that the growth of each of these two species of mullet is relatively very rapid in the Swan-Avon river system. 1 + and 2 + fish tend to leave the estuary for varying periods. Although 0+ fish of both species utilized the shallow banks of the estuary throughout the year. the sea mullet moved further upstream and were not as consistently abundant in the lower estuary. Since 0+ yellow-eye mullet 40-100 mm long were also abundant in marine coastal waters between January and May. and sea mullet of comparable age were rarely observed in these regions, it would appear that M. cephalus is the more estuarine-dependent of the two species. Commercial catches of M. cephalus were greater than those of A. forsteri. This feature can be related in part to the much faster growth rate of M. cephalus, which results in a larger proportion of its youngest year classes reaching the minimum legal size for capture prior to the time when they leave the estuary in large numbers.


1984 ◽  
Vol 3 (4) ◽  
pp. 609-616 ◽  
Author(s):  
Christopher J. Smith ◽  
Ronald D. Delaune ◽  
William H. Patrick ◽  
J. W. Fleeger
Keyword(s):  

<em>Abstract</em>.—Hurricanes Katrina and Rita critically impacted the northern Gulf Coast. Shrimping and other commercial fishing industries saw large scale destruction of vessels and shore based facilities in addition to a deposition of large amounts of debris on fishing grounds from Alabama to Louisiana. In 2006, the National Oceanic and Atmospheric Administration’s (NOAA’s) Office of Coast Survey and Office of Response and Restoration started the implementation of a large scale hazards survey program to map the coastal waters of Louisiana, Mississippi, and Alabama. The first phase of the effort involved surveying more than 600 square nautical miles of coastal bays and nearshore waters with sidescan and single beam acoustic sonar. Survey findings are posted each week on a NOAA public Web site displaying the location of each hazard and debris found. The survey work is also updating the NOAA navigation charts for coastal areas that are used heavily by fishing vessels, the navigation industry, and recreational boaters. Survey planning and implementation is conducted cooperatively with the marine fisheries agencies of Alabama, Mississippi, and Louisiana.


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