scholarly journals The demographics and morphometries of biogenic reefs: important considerations in conservation management

2017 ◽  
Vol 98 (6) ◽  
pp. 1231-1240 ◽  
Author(s):  
Jenna M. Brash ◽  
Robert L. Cook ◽  
Clara L. Mackenzie ◽  
William G. Sanderson
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Conservation Management ◽  
Tidal Flow ◽  
Growth Curves ◽  
Shell Morphology ◽  
Published Data ◽  
Marine Habitat ◽  
Juvenile Abundance ◽  
Horse Mussel

Modiolus modiolus L. (horse mussel) reefs are a priority marine habitat of high conservation value that is currently listed as endangered and/or threatened across its European distribution. Population structure, density or shell morphology may influence the biodiversity of a reef, either directly or indirectly. Thus, such metrics are important considerations for successful conservation management of these biodiversity hotspots. Population structure, shell morphology and growth rates were examined in M. modiolus reefs across the UK range of the habitat to examine differences between key populations, including those near the Lleyn Peninsula in Wales (southern range), off Port Appin in Western Scotland (mid-range) and in Scapa Flow in the Orkney Isles, Scotland (northern range). Additionally, the influence of physical conditions (temperature and tidal flow) to growth rate and predicted maximum shell length for each population was examined. Growth rates were determined using acetate peels of sectioned shells. Lower juvenile abundance was observed in Scapa Flow. Small, narrow-shaped shells were found to be characteristic of North Lleyn mussels, and larger, globular-shaped shells were characteristic of mussels in Scapa Flow and off Port Appin. Mussels in Scapa Flow were slower growing, yet reached a longer asymptotic length (L∞) than mussels of Port Appin and North Lleyn. Growth curves from sites within this study were analysed with other published data. A trend of higher L∞ at higher latitudes and at lower flow rates was observed. Variations in growth and age are discussed in relation to flow regimes, connectivity to other reefs, density and latitude.

Population structure, age and growth rates of conifer species and their relation to environmental variables at Malam Jabba, Swat District, Pakistan

2018 ◽  
Vol 31 (2) ◽  
pp. 429-441
Author(s):  
Arsalan ◽  
Muhammad Faheem Siddiqui ◽  
Moinuddin Ahmed ◽  
Syed Shahid Shaukat ◽  
Alamdar Hussain
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Environmental Variables ◽  
Age And Growth ◽  
Conifer Species

A STUDY OF RATES OF GROWTH OF YORKSHIRE, LACOMBE, LANDRACE, AND CROSSBRED PIGS FROM BIRTH TO 200 LB

1964 ◽  
Vol 44 (3) ◽  
pp. 315-319
Author(s):  
J. M. Bell
Keyword(s):  
Growth Rates ◽  
Early Life ◽  
Growth Curves ◽  
Rates Of Growth ◽  
Similar Growth ◽  
Crossbred Pigs

Growth records were obtained from 12 research establishments across Canada for pigs fed according to current (1960–63) recommendations of nutrition and management. Growth curves showing age in days and weight in pounds are presented for the various breeds and crossbreds, for between-station comparisons, for comparison of upper and lower quartiles in purebred pigs, and for comparison of growth rates of purebreds with that of Yorkshires of 20 to 25 years ago.Age at 200 lb averaged from 152 to 187 days, among 10 stations for the Yorkshire breed. Pigs of each of the pure breeds reached 200 lb about 3 weeks earlier than that indicated in previous studies. Crossbred pigs of each of four different crosses grew more rapidly than average Yorkshires, some reaching 200 lb in 140 days and having gains in excess of 2.3 lb/day during the finishing period. Yorkshire, Lacombe, and Landrace pigs had similar growth curves. The upper quartile averaged 1.8 and the lower 1.4 lb/day gain between 100 and 200 lb weights. Slow-maturing pigs tended to be below average throughout life but differences in maturity between stations seemed to reflect differing rates of gain in early life, since finishing period gains were similar in 8 of 10 stations.

scholarly journals Host-Directed Evolution of a Novel Lactate Oxidase in Streptococcus iniae Isolates from Barramundi (Lates calcarifer)

2009 ◽  
Vol 75 (9) ◽  
pp. 2908-2919 ◽  
Author(s):  
Roslina A. Nawawi ◽  
Justice C. F. Baiano ◽  
E. Charlotte E. Kvennefors ◽  
Andrew C. Barnes
Keyword(s):  
Molecular Weight ◽  
Growth Rates ◽  
Tidal Flow ◽  
The United States ◽  
Flavin Mononucleotide ◽  
Streptococcus Iniae ◽  
The Novel ◽  
Lactate Oxidase ◽  
Oxidase Gene

ABSTRACT In Streptococcus iniae, lactate metabolism is dependent upon two proteins, lactate permease that mediates uptake and lactate oxidase, a flavin mononucleotide-dependent enzyme that catalyzes oxidation of α-hydroxyacids. A novel variant of the lactate oxidase gene, lctO, in Australian isolates of S. iniae from diseased barramundi was found during a diagnostic screen using LOX-1 and LOX-2 primers, yielding amplicons of 920 bp instead of the expected 869 bp. Sequencing of the novel gene variant (type 2) revealed a 51-nucleotide insertion in lctO, resulting in a 17-amino-acid repeat in the gene product, and three-dimensional modeling indicated formation of an extra loop in the monomeric protein structure. The activities of the lactate oxidase enzyme variants expressed in Escherichia coli were examined, indicating that the higher-molecular-weight type 2 enzyme exhibited higher activity. Growth rates of S. iniae expressing the novel type 2 enzyme were not reduced at lactate concentrations of 0.3% and 0.5%, whereas a strain expressing the type 1 enzyme exhibited reduced growth rates at these lactate concentrations. During a retrospective screen of 105 isolates of S. iniae from Australia, the United States, Canada, Israel, Réunion Island, and Thailand, the type 2 variant arose only in isolates from a single marine farm with unusually high tidal flow in the Northern Territory, Australia. Elevated plasma lactate levels in the fish, resulting from the effort of swimming in tidal flows of up to 3 knots, may exert sufficient selective pressure to maintain the novel, high-molecular-weight enzyme variant.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
Growth Rate ◽  
San Francisco ◽  
Striped Bass ◽  
Growth Rates ◽  
Early Life History ◽  
San Francisco Estuary ◽  
Annual Growth ◽  
Factors Affecting ◽  
Juvenile Abundance ◽  
History Of

<em>Abstract.</em>—We investigated factors affecting growth of larval striped bass <em>Morone saxatilis </em>in the San Francisco Estuary from 1984 to 1993. We estimated ages and growth rates of larval striped bass from daily otolith increments. Mean annual growth rates of 6–14 mm standard length striped bass varied from 0.13 to 0.27mm/d, the lowest rate occurring in 1989 and the highest in 1992. The 1989 growth rate was significantly lower than all other years, and growth rates for 1992 and 1993 were significantly higher than all other years, but did not differ from one another. Differences in annual growth rates apparently were due mainly to differences in mean annual prey densities because growth rate increased as prey density increased. Compared to both laboratory measured growth rates and growth rates of field-caught Chesapeake Bay larvae, growth rates from the San Francisco Estuary appeared to be high for the food available, indicating that larvae can grow at relatively high rates even at low prey densities. Correlation analyses did not support density-dependent control of growth rates. Growth rate was not significantly related to mean annual conductivity, water temperature, mortality rates, or the juvenile abundance index, but was significantly and positively correlated with densities of 1-mm length-groups of 9–14-mm striped bass.

The spatial distribution of illegal logging in the Anavilhanas archipelago (Central Amazonia) and logging impacts on species

2011 ◽  
Vol 39 (2) ◽  
pp. 111-121 ◽  
Author(s):  
ANDRESSA BÁRBARA SCABIN ◽  
FLÁVIA REGINA CAPELLOTTO COSTA ◽  
JOCHEN SCHÖNGART
Keyword(s):  
Growth Rate ◽  
Population Structure ◽  
Spatial Distribution ◽  
Growth Rates ◽  
Market Value ◽  
Southern Region ◽  
Illegal Logging ◽  
Negative Effects ◽  
Human Settlements ◽  
Harvesting Intensity

SUMMARYAmazonia is one of the world's leading suppliers of timber and the Amazonian timber industry is an important source of regional income, however the economic benefits of this market are associated with environmental damage, mainly when the wood is removed illegally. The Anavilhanas National Park, located in the Brazilian state of Amazonas, has been subjected to illegal logging and elaboration of control programmes requires knowledge of the distribution of timber species and the intensity of logging. This study examines the density and growth rate of the five most harvested tree species in the Park, the spatial distribution of illegal logging operations and their effects on population structure. In total, 2332 trees with diameter at breast height greater than 10 cm, as well as stumps of cut trees, were sampled, and dendrochronology was used to estimate growth rates. Some size classes of Virola surinamensis trees and species within the family Lauraceae decreased in abundance as harvesting intensity increased. Growth rates of the most abundant species of Lauraceae, Ocotea cymbarum, were high, indicating stands may recover quickly when harvesting stops. The population structure of Calophyllum brasiliense showed no negative effects due to logging, but its low growth rate and stand distribution suggest that continued exploitation may endanger these populations. Logging had no detectable negative effects on the size structure of populations of Macrolobium acaciifolium or Hevea spp., and their high growth rates suggest that they will not be threatened by current logging rates. Overall growth rates in the Anavilhanas archipelago are higher than those recorded in other black-water floodplain forest (igapó). Logging of most species (except Lauraceae spp., which have the highest market value) is concentrated in the southern region of the Park, which has more human settlements close by. There was no general relationship between harvesting intensity and geographic distance to human settlements, but there was a tendency for harvesting to be higher in sites with concentrations of trees of high market value. Potential strategies to control illegal logging activities in the Anavilhanas archipelago include encouragement of sustainable logging in Park buffer zones and stimulation of ecotourism initiatives in the southern region of the Park. Ecotourism development can provide an economic alternative to illegal logging for local communities and inhibit logging by increasing vigilance.

Age, growth and sex determination in a population of smooth snakes, Coronella austriaca in southern England

2004 ◽  
Vol 25 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Keyword(s):  
Sex Determination ◽  
Age Structure ◽  
Growth Rates ◽  
Growth Curves ◽  
Tail Length ◽  
Daily Growth ◽  
Southern England ◽  
The Difference ◽  
The Relationship ◽  
Coronella Austriaca

AbstractBetween 1992-2001 a study of individually marked smooth snakes Coronella austriaca was done in Wareham Forest, southern England. The sex of individual snakes was determined using the relationship between tail length and snout-vent length, and the presence/absence of a hemi-penes swelling at the base of the tail. Males had longer tails than females at all ages/sizes and the difference between the sexes increased with increasing snout-vent length. Using multiple captures of known individuals over many years, size related daily growth rates were determined for each sex that enabled growth curves to be produced. The age structure of the population was determined for each complete year of the study. Very few young small snakes were captured each year. Of all the females who were potentially able to breed, only the oldest, and therefore largest, did so.

Allometric Models of Simuliid Growth Rates and Their Use for Estimation of Production

1988 ◽  
Vol 45 (2) ◽  
pp. 315-324 ◽  
Author(s):  
Antoine Morin ◽  
Michel Constantin ◽  
Robert Henry Peters
Keyword(s):  
Water Temperature ◽  
Significant Influence ◽  
Growth Rates ◽  
Dry Mass ◽  
Published Data ◽  
Power Relationship ◽  
Square Root ◽  
Allometric Model ◽  
Simulium Vittatum ◽  
Individual Mass

Growth rates of Prosimulium mixtum/fuscum, Stegopterna mutata, and Simulium vittatum are described in relation to individual mass, water temperature, and seston quality in the outlet of Lake Orford (southern Quebec) in the winter of 1985–86. Growth rates in mass (G, per day) of the three species were similar and inversely related to dry mass (DM, micrograms) following the power relationship G = 0.11 DM−0.28; neither water temperature nor seston abundance and quality varied sufficiently during the study period to have a significant influence on growth rates. The allometric model was used to estimate production of the three species, and the resulting estimates are compared with cohort methods and size–frequency estimates. Large larvae were responsible for most of the production, and most of the production occurred before the spring rise in water temperature. Measured growth rates in winter are significantly lower than those reported for simuliids in warmer waters. A reanalysis of published data shows that growth rates of simuliids increase as the square root of water temperature (T, degrees Celsius) (G = 0.08 DM−0.21 T0.48).

Interrelations in the growth and development of Lolium. I. Some effects of vernalization on growth and development

1965 ◽  
Vol 16 (6) ◽  
pp. 903 ◽  
Author(s):  
JH Silsbury
Keyword(s):  
Low Temperature ◽  
Growth Rates ◽  
Growth And Development ◽  
Growth Curves ◽  
High Growth ◽  
Reproductive Development ◽  
Controlled Environment ◽  
Lolium Rigidum ◽  
Vegetative Phase ◽  
Reproductive Phase

The responses of Lolium rigidum Gaud. and L. perenne L. to low temperature seed vernalization were determined by comparing the growth and development of vernalized and unvernalized plants raised in the field and in a controlled environment cabinet. Vernalization did not appear to influence growth in the vegetative phase, but usually induced earlier heading and a greater proportion of reproductive tillers. Comparisons of vernalized (reproductive) and unvernalized (vegetative) plants show increased reproductive development to be associated with higher growth rates, lower tillering, and greater weight per tiller. High growth rates during the reproductive phase are considered to be due to the ability of reproductive tillers to grow more rapidly than vegetative tillers through the growth of true stem functioning as a "sink" for assimilate. Generalized growth curves for vernalized and unvernalized ryegrass grown under long days are presented and discussed.

Experimental study of the stability of boundary-layer flow along a heated, inclined plate

1998 ◽  
Vol 367 ◽  
pp. 1-25 ◽  
Author(s):  
E. J. ZUERCHER ◽  
J. W. JACOBS ◽  
C. F. CHEN
Keyword(s):  
Boundary Layer ◽  
Growth Rates ◽  
Growth Curves ◽  
Leading Edge ◽  
Heated Plate ◽  
Inclined Plate ◽  
Double Pass ◽  
Longitudinal Vortices ◽  
Spatial Growth ◽  
Layer Flow

Experiments are conducted to study the longitudinal vortices that develop in the boundary layer on the upper surface of an inclined, heated plate. An isothermal plate in water is inclined at angles ranging from 20 to 60 degrees (from the vertical) while the temperature difference is varied from 2 to 23°C. A double-pass Schlieren system is used to visualize the vortices and particle image velocimetry (PIV) is used to measure velocities. In addition, a unique method is developed such that both the Schlieren visualization and PIV can be performed simultaneously. The wavelengths of the vortices and the critical modified Reynolds numbers (R˜) for the onset, merging, and breakup of the vortices are determined from Schlieren images for Pr=5.8. The critical values for R˜ and the critical wavelengths are compared to results of previous experiments and stability analyses. The spatial growth rates of vortices are determined by using the PIV measurements to determine how the circulation in the vortices grows with distance from the leading edge. This is the first time that the growth rate of the vortices have been found using velocity measurements. These spatial growth rates are compared to the results of Iyer & Kelly (1974) and found to be in general agreement. By defining a suitable circulation threshold, the critical R˜ for the onset of the vortices can be found from the growth curves.

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