Intersexual differences in growth, mortality, and size at maturity in bullfrogs in central Ontario

1993 ◽  
Vol 71 (12) ◽  
pp. 2363-2369 ◽  
Author(s):  
L. J. Shirose ◽  
R. J. Brooks ◽  
J. R. Barta ◽  
S. S. Desser
Keyword(s):  
Standard Length ◽  
Rana Catesbeiana ◽  
Negative Relationship ◽  
Maximum Size ◽  
Logistic Growth ◽  
Size At Maturity ◽  
Age At Maturity ◽  
Frequency Distributions ◽  
Minimum Age ◽  
Intersexual Difference

A population of bullfrogs (Rana catesbeiana) in Algonquin Provincial Park, Ontario, Canada, was studied from May 1985 through October 1987. Of 1187 individuals marked with tattoos, 567 were recaptured at least once. The age of each marked individual was estimated using size–frequency distributions. A negative relationship between age and sex ratio indicated lower survivorship for mature males than for mature females. The average age at maturity was estimated to be 5 years post-transformation (YPT), at 113 mm standard length (snout to urostyle) for females, and 3 YPT, at 91 mm, for males. The minimum age at maturity was 4 YPT, at 94 mm standard length, for females, and 3 YPT, at 90 mm, for males. Age at maturity was greater, and size at maturity smaller, than reported for other populations. A logistic growth model fitted to the data, and comparison of age-specific mean standard lengths, indicate an intersexual difference in the pattern of growth. The asymptotic maximum standard length, as derived from the logistic model, was 181 mm for females and 148 mm for males. The estimated growth constant, r, was greater for males than for females, indicating that males attained their maximum size at a younger age than did females.

The role of thermal environment in determining the life history of a terrestrial salamander

2000 ◽  
Vol 78 (10) ◽  
pp. 1702-1711 ◽  
Author(s):  
Carlos D Camp ◽  
Jeremy L Marshall
Keyword(s):  
Body Size ◽  
Thermal Environment ◽  
Negative Relationship ◽  
Size Variation ◽  
Published Data ◽  
Size At Maturity ◽  
Adult Males ◽  
Age At Maturity ◽  
Adult Body Size ◽  
Adult Body

Largely using previously published data, we analyzed geographic variation in adult body size of terrestrial salamanders of the Plethodon glutinosus complex. Maximum body size of adult males is determined by size at maturity. In turn, size at maturity is determined by a negative relationship with environmental temperature. Moreover, both age at maturity and growth rate are correlated with size at maturity, but apparently only as coincidental correlates through the influence of temperature. The number of degree-days, estimated using temperature data from respective geographic locations, accurately predicts age at maturity for salamanders living in these areas. Development under cooler thermal regimes is more depressed than growth and, consequentially, adult body sizes are greater in cooler climates. This pattern of size variation fits thermal predictive models proposed for larval development in amphibians that breed in ponds. Phenotypic variation in adult body size appears to be accounted for largely by plastic responses to variation in thermal environments and may reflect a single reaction norm for the complex.

Application of the otolith weight – age relationship for the pilchard, Sardinops sagax neopilchardus

1995 ◽  
Vol 52 (4) ◽  
pp. 657-664 ◽  
Author(s):  
W. J. Fletcher
Keyword(s):  
Maximum Size ◽  
Steady Increase ◽  
Average Weight ◽  
Fish Length ◽  
Natural Mortality ◽  
Length Frequency ◽  
Age Classes ◽  
Frequency Distributions ◽  
Southwestern Australia ◽  
Sardinops Sagax

Adult pilchard (Sardinops sagax neopilchardus) from southwestern Australia held in fish cages for 1 year showed minimal increase in mean length but a steady increase in mean otolith weight (1.61–1.83 mg); this increase (0.22 mg) closely parallels the previously calculated mean difference between adjacent age classes (0.24 mg). Modes in otolith weight frequency distributions of fishery-caught pilchards, previously suggested as corresponding with separate year classes, generally persisted and progressed through subsequent samples. By contrast, fish length frequency distributions of these samples showed no consistent modal progression. The average weight of otoliths for year classes 2–8 were used to calculate growth rates: following sexual maturity, at age 2, males grew to a significantly smaller maximum size than females (L∞ = 162 and 172 mm respectively). The otolith weight – age relationship, validated by following a cohort of unusually low abundance as it moved through the fishery, indicated that recruitment to the fishery generally began at age 2 but was not complete until age 4. These data have been successfully used in forecasting the catch rate of the fishery up to 2 years in advance and providing an estimate of the rate for natural mortality of 0.43.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Growth Models ◽  
Adult Population ◽  
Open Water ◽  
Maximum Size ◽  
Population Characteristics ◽  
Residual Effects ◽  
Fish Length ◽  
Frequency Distributions ◽  
Minnesota Lakes ◽  
Spawning Periods

<em>Abstract</em>.—A population assessment of Muskellunge <em>Esox masquinongy </em>in two connected north-central Minnesota lakes allowed evaluation of angler data when assessing various population metrics, including the residual effects of historical stocking efforts, as a nonlocal strain had been introduced into the native population during the 1970s. In 2012, the Minnesota Department of Natural Resources sampled and marked Muskellunge using trap nets during the prespawn and spawning periods and electrofishing during the postspawn period, while anglers collected data from fish caught during the 2012 open-water season. Anglers released all fish after collecting a scale for genetic analysis. Microsatellite DNA genotypes were used to differentiate individuals, thus identifying recaptures, and to estimate ancestry derived from the stocked strain. Anglers reported catching 16% of individuals marked by biologists. Of Muskellunge reported by anglers, 78% were from the lake where they were initially captured while 22% were reported in the lake opposite their initial capture. Postspawn movements suggested that more individuals migrated from the lake characterized as having preferred spawning and nursery habitat to the lake characterized as having preferred summer habitat and prey. The age- and length-frequency distributions of fish captured by anglers and trap nets were similar, while electrofishing sampled younger and smaller fish, likely because it occurred postspawn when many adults had moved off shore. The best estimate of adult population size was produced by a model incorporating fish length as a covariate. Density was estimated at 0.70 adults per ha or 1.92 adults per littoral ha. Higher percentages of nonlocal ancestry were associated with smaller maximum size potential (<em>L<sub></em>∞</sub> ) in von Bertalanffy growth models. Our study described key population characteristics for a Muskellunge population while demonstrating that anglers could reliably collect several specific types of data that supplement data collected by management agencies.

Genetic differences in the interactions of a microsporidian parasite and four clones of its cyclically parthenogenetic host

Parasitology ◽  
1994 ◽  
Vol 108 (1) ◽  
pp. 11-16 ◽  
Author(s):  
D. Ebert
Keyword(s):  
Body Length ◽  
Multiplication Rate ◽  
Juvenile Growth ◽  
Size At Maturity ◽  
Age At Maturity ◽  
Microsporidian Parasite ◽  
Host Parasite Interactions ◽  
Parasite Multiplication ◽  
Host Parasite ◽  
Host Clone

SUMMARYHost–parasite interactions were studied for the microsporidium Pleistophora intestinalis and its host, Daphnia magna. Two host clones were established from the same population from which the parasites were taken (home-1 and 2), and two clones from two other ponds (neighbour and Munich clone). With increasing clutch number infected females from home-1 clone produced relatively smaller clutches than uninfected females. Age and body length at maturity were not affected by the infection, but body length of the sixth adult instar was reduced. In an experiment including all four host clones, the parasite reproduced well in the two home clones and in the neighbour clone, but poorly in the Munich clone. Juvenile growth and age at maturity was not affected in the two home clones, but for the neighbour and the Munich clone age was delayed by 2·2 days and 4·1 days, and juvenile growth reduced by 16 and 23%, respectively. Significant host-clone x parasite-treatment interactions were also found for size at maturity and clutch size. This pattern of host-parasite interactions suggests that there is no general positive relation between disease severity and parasite multiplication rate.

Integrated analysis of sexual maturation through successive growth instars in the spider crab Leurocyclus tuberculosus (Decapoda: Majoidea)

2017 ◽  
Vol 95 (7) ◽  
pp. 473-483 ◽  
Author(s):  
Ximena González-Pisani ◽  
Pedro J. Barón ◽  
Laura S. López Greco
Keyword(s):  
Sexual Maturation ◽  
Sexual Maturity ◽  
Carapace Width ◽  
Integrated Analysis ◽  
Growth Stages ◽  
Spider Crab ◽  
Size At Maturity ◽  
Frequency Distributions ◽  
The Right ◽  
Sexually Mature

An integrative analysis of sexual maturity associated with growth was developed for the spider crab Leurocyclus tuberculosus (H. Milne Edwards and Lucas, 1842). Sexual maturity was characterized based on gonadal, morphological, morphometric, and functional sexual maturity. Progress in sexual maturation was described through 13 growth stages (instars) detected by the examination of size (carapace width) frequency distributions. Mature females displayed mature ovaries, developed vaginae, open gonopores, allometric changes in the abdomen, and ovigerous stage in the transition from instar IX to instar X. Sexually mature males presented spermatophores in the distal vasa deferentia and allometric changes in several measurements of the right chela in the transition from instar X to instar XI. However, two prepubertal phases were recognized in both sexes separated from each other by a prepubertal critical molt. Preceding the second critical molt, gonopores were sealed and vasa deferentia showed no spermatophores, and therefore neither sex was able to mate. The integrated analysis of size at maturity and size frequency distributions showed that in both sexes molt to gonadal, morphological, morphometric, and functional sexual maturity occurred in advance of the terminal molt, in contrast with patterns observed in other Majoidea.

Life history of a small form of the plethodontid salamander Desmognathus quadramaculatus

2003 ◽  
Vol 24 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Christopher Beachy ◽  
Richard Bruce
Keyword(s):  
Growth Rates ◽  
Frequency Distributions ◽  
Plethodontid Salamander ◽  
Plethodontid Salamanders ◽  
Body Sizes ◽  
Minimum Age ◽  
History Of ◽  
Desmognathus Quadramaculatus ◽  
Gravid Females ◽  
Age At Maturation

AbstractWe sampled Desmognathus quadramaculatus, one of the largest species of plethodontid salamanders in eastern North America, from a population exhibiting extremely small adult body sizes in the Bald Mountains of North Carolina (USA). In order to test the hypothesis that miniaturization in desmognathine salamanders is due to early metamorphosis and maturation, we estimated ages and sizes at metamorphosis and maturation. Analysis of size-frequency distributions suggests that most larvae metamorphose after 24 months, with the remainder metamorphosing after 36. The minimum age of sexually mature individuals in the summer months is estimated to be 4 years in males and 5 years in females; some may mature 1 year earlier. This is earlier than other reliable estimates of age at maturation in D. quadramaculatus, and appears to account for the small size of the species at this locality. Larval and juvenile growth rates are within the range of growth rates of other populations. As in other populations of D. quadramaculatus, males are smaller than females at maturation, but grow to larger sizes. Estimates of clutch sizes based on dissection of gravid females are relatively low. The other species of salamanders in this community do not appear to be miniaturized.

Life history schedule and periodic recruitment of female snow crab (Chionoecetes opilio) in the eastern Bering Sea

2012 ◽  
Vol 69 (3) ◽  
pp. 532-550 ◽  
Author(s):  
Billy Ernst ◽  
David A. Armstrong ◽  
Julián Burgos ◽  
J.M. (Lobo) Orensanz
Keyword(s):  
Bering Sea ◽  
Mature Female ◽  
Snow Crab ◽  
Age At Maturity ◽  
Eastern Canada ◽  
Chionoecetes Opilio ◽  
Frequency Distributions ◽  
Eastern Bering Sea ◽  
Crab Abundance ◽  
Mean Size

Snow crab ( Chionoecetes opilio ) populations have fluctuated cyclically in eastern Canada and the eastern Bering Sea, where recruitment to the mature female pool has occurred over a period of three decades (1978–2007) in pulses with a mean period of 7 years. It has been hypothesized that this was the result of a parent–offspring relation between sequentially linked strong cohorts of mature primiparous females, which requires that periodicity matches the time lapsed between egg extrusion by the maternal broodstock and the offspring reaching maturity. We show that female age at maturity (post-settlement) varies between 4.5 and 7.5 years, with most females maturing at 5.5–6.5 years (7–8 years after egg extrusion). Pulses of female recruitment to the mature population do not show a latitudinal trend, consistent with uniformity in age-at-maturity. Results of tracking crab abundance and size–frequency distributions in cod stomach and trawl samples between successive pulses of the cycle are consistent with the hypothesis of serial linkage among pulses. Periodicity is reflected in trends of clutch fullness and average shell condition and in the negative correlation between the strength of primiparous female cohorts and the mean size of their members.

scholarly journals Effects of temperature on individual growth rate and body size of a freshwater amphipod

1998 ◽  
Vol 76 (6) ◽  
pp. 1107-1116 ◽  
Author(s):  
Vadim E Panov ◽  
Donald J McQueen
Keyword(s):  
Growth Rates ◽  
Negative Relationship ◽  
Maximum Size ◽  
Growth Efficiency ◽  
Individual Growth ◽  
Summer Temperatures ◽  
Individual Growth Rate ◽  
Natural Temperature ◽  
Effects Of Temperature ◽  
The Relationship

Individual growth rates of the freshwater amphipod Hyalella azteca (Saussure) were measured in the littoral zone oftwo small oligotrophic Ontario lakes and in growth experiments over a natural temperature gradient (10, 15, 20, and 238C).Field observations showed that a temperature of 208C is important for both the induction and termination of reproductiveresting stages in H. azteca. Growth rates were more affected by temperature in small than in large individuals. Growthparameters are related to rearing temperature by linear regressions, which can be used as a simple model for bioenergeticscalculations in crustaceans. A negative relationship between water temperature and maximum size attained by the amphipodswas found. The largest adults were absent in studied populations when summer temperatures were high, and this phenomenon,which has also been observed in other aquatic invertebrates, was bioenergetically determined. Energy-budget estimationsshowed negative net growth efficiency (K2) in the largest adults at temperatures above 208C. The relationship between K2andtemperature showed a dome-shaped pattern, K2values for larger amphipods being maximal at lower temperatures. Seasonalmigrations of adult H. azteca from shallow littoral to deeper cold habitats, observed in lakes during the warmest periods, appearto be temperature-induced and bioenergetically advantageous, despite probable increases in predation risk experienced inspatially simple deep-water habitats.

Observations on the biology of the common torpedo (Torpedo torpedo, Linnaeus, 1758) and marbled electric ray (Torpedo marmorata, Risso, 1810) from Egyptian Mediterranean waters

1994 ◽  
Vol 45 (4) ◽  
pp. 693 ◽  
Author(s):  
SH Abdel-Aziz
Keyword(s):  
Reproductive Biology ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Strong Correlation ◽  
Maximum Size ◽  
Size At Maturity ◽  
Torpedo Marmorata ◽  
Food Items ◽  
The Common ◽  
Males And Females

The reproductive biology and diets of Torpedo torpedo and T. marmorata from Egyptian Mediterranean waters are described. Males and females reached a maximum size of 39.1 and 40.8 cm total length (TL), respectively, in T. torpedo and 38.6 and 61.2 cm TL, respectively, in T. marmorata. The size at maturity of males of T. torpedo and T. marmorata is 18 and 25.5 cm TL, respectively, and of females, is 22 and 35.5 cm TL, respectively. Both species exhibit aplacental viviparity. T. torpedo has a restricted breeding season, and individual females appear to breed annually, whereas T. marmorata females appear to have a more extended reproductive cycle (probably breeding every two years). In both species, males are capable of mating every year. In T. torpedo, mating occurs between December and February, ovulation in March-April, and parturition in late August and September after five to six months of gestation. Individuals of T. marmorata mate between November and January, ovulate between December and February, and give birth the following December after 10-12 months of gestation. Mean embryos sizes are 7.3 cm TL (range 4.6-8.2 cm TL) for T. torpedo and 8.5 cm TL (range 5.8-10.1 cm TL) for T. marmorata. Observations in Egyptian Mediterranean waters show a strong correlation between ovarian and uterine fecundity and the length of the mother in both species. Fish are an important component of the diet of the two species, as, to a lesser extent, are crustaceans for T. torpedo and cephalopods for T. marmorata. Juveniles eat a wide variety of food items, whereas adults feed only on fish.

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