Influences of female body condition on recruitment success of walleye (Sander vitreus) in Wisconsin lakes

2019 ◽  
Vol 76 (11) ◽  
pp. 2131-2144 ◽  
Author(s):  
Zachary S. Feiner ◽  
Stephanie L. Shaw ◽  
Greg G. Sass
Keyword(s):  
Body Condition ◽  
Gonadosomatic Index ◽  
Reproductive Potential ◽  
Relative Weight ◽  
Reproductive Traits ◽  
Large Female ◽  
Female Size ◽  
Sander Vitreus ◽  
Small Female ◽  
Using Data

Stock reproductive potential informs population dynamics and response to harvest. Indices of body condition, like relative weight (Wr), may indicate individual energetic state and provide a mechanistic link between spawning stock traits and recruitment. We tested for relationships among Wr of three female size classes (381–456, 457–557, and ≥558 mm total length), reproductive traits, and age-0 recruitment using data from 92 walleye (Sander vitreus) populations in the Ceded Territory of Wisconsin during 1989–2015 and a lake-specific time series from Escanaba Lake, Wisconsin, during 1958–2014. In Escanaba Lake, Wr was positively related to maturation in small females and was positively related to fecundity and gonadosomatic index in intermediate fish. Among and within populations, Wr demonstrated compensatory density dependence and positive relationships with growing degree-days. Recruitment was positively related to large female Wr variation across lakes and negatively related to small female Wr variation in Escanaba Lake. Improving the condition of large female walleye may promote recruitment, and Wr may serve as an accessible metric of reproductive potential in walleye stock–recruit analyses.

Evolution of sexual dimorphism in the plateau brown frog fails to obey Rensch’s rule

2022 ◽  
pp. 27-33
Author(s):  
Tong Lei Yu
Keyword(s):  
Body Size ◽  
Large Male ◽  
Large Female ◽  
Female Size ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Males And Females ◽  
Brown Frog ◽  
Using Data

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.

scholarly journals Reproductive strategies under different environmental conditions: total output vs investment per egg in the slipper lobster Scyllarus arctus

2021 ◽  
pp. 1-9
Author(s):  
L. Fernández ◽  
C. García-Soler ◽  
I. Alborés
Keyword(s):  
Reproductive Potential ◽  
Reproductive Traits ◽  
Temporal Variations ◽  
Reproductive Period ◽  
Total Output ◽  
Female Size ◽  
Limited Information ◽  
Egg Weight ◽  
Fishery Resource ◽  
North East

Abstract The slipper lobster Scyllarus arctus is an important fishery resource in Galicia (NW Iberian Peninsula), with a large reduction of its populations in recent decades in the North-east Atlantic and Mediterranean, but only limited information on its reproduction. This study provides an analysis of the reproductive potential of this scyllarid during two breeding cycles (2008 and 2009) in the NE Atlantic (43°20′N 8°50′W). We studied several reproductive traits (fecundity, brood weight, egg weight and volume) in broods with eggs both in an early and late embryonic stage, in relation to female size and temporal variations. Total output (fecundity and weight) and egg weight were closely linked to maternal size, and this relationship remained in broods with late-stage eggs. In relation to temporal variations, our data revealed an important seasonal variability in fecundity and egg weight, showing an inverse pattern in the reproductive strategy in the first two seasons of the reproductive period, with a maximum egg weight in winter (December–February) and a maximum number of eggs produced in spring (April–May). A predictive model for realized fecundity was developed: log (FE) = 0.064 + 2.907 log (length)−0.018 Month2 + 0.174 Month, which accounted for over 90% of variation in the total data.

scholarly journals Using the gonadosomatic index to estimate the maturity ogive: application to Chilean hake (Merluccius gayi gayi)

2014 ◽  
Vol 72 (2) ◽  
pp. 508-514 ◽  
Author(s):  
Andrés Flores ◽  
Rodrigo Wiff ◽  
Eduardo Díaz
Keyword(s):  
Gonadosomatic Index ◽  
Reproductive Potential ◽  
Accurate Method ◽  
Reproductive Season ◽  
Multinomial Model ◽  
Unbiased Estimates ◽  
Mature Fish ◽  
Using Data ◽  
Macroscopic Analysis ◽  
Histological Staging

Abstract The proportion of mature fish at age or length is one of the most important population attributes in assessing reproductive potential. This proportion is usually named the maturity ogive. The most crucial step in estimating this proportion deals with maturity staging assessed by macroscopic or histology analysis. Macroscopic analysis is relatively inexpensive but usually introduces large amount of error. Histology is the most accurate method for maturity staging but is expensive and time consuming. Here, we propose using the gonadosomatic index (GSI) as an alternative way to estimate the maturity ogives. A logistic multinomial model was implemented to separate immature, mature-active, and mature-inactive fish, based only on their value of GSI. We evaluated the performance of the GSI-based method by comparing the results with ogives estimated from macroscopic and histological staging using the extensive database available for Chilean hake (Merluccius gayi gayi). Maturity ogives from GSI analysis were evaluated at the start and end of the reproductive season. Results showed that, in all cases analysed, maturity ogives from GSI were closer to the ogives based on histology than those from macroscopic staging. Comparing across periods, those maturity ogives computed at the start of the reproductive season give estimates very similar to those from histological staging. To have unbiased estimates of maturity ogives from GSI analysis, we recommend using data from the start of the reproductive season to minimise the frequency of spent fish. In addition, the assumption of the isometry between gonad and gutted weight across maturity stages needs to be tested before the use of this GSI method. The analyses presented here provide a promising method to estimate maturity ogives when histological staging data are lacking or when macroscopic analysis is suspected to have large amounts of errors.

Demographic life history traits of reproductive natterjack toads (Bufo calamita) vary between northern and southern latitudes

2006 ◽  
Vol 27 (3) ◽  
pp. 365-375 ◽  
Author(s):  
Delfi Sanuy ◽  
Christoph Leskovar ◽  
Neus Oromi ◽  
Ulrich Sinsch
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Large Female ◽  
Breeding Period ◽  
Female Size ◽  
Data Set ◽  
Bufo Calamita ◽  
Trade Offs ◽  
Age Variation ◽  
The Cost

AbstractDemographic life history traits were investigated in three Bufo calamita populations in Germany (Rhineland-Palatinate: Urmitz, 50°N; 1998-2000) and Spain (Catalonia: Balaguer, Mas de Melons, 41°N; 2004). We used skeletochronology to estimate the age as number of lines of arrested growth in breeding adults collected during the spring breeding period (all localities) and during the summer breeding period (only Urmitz). A data set including the variables sex, age and size of 185 males and of 87 females was analyzed with respect to seven life history traits (age and size at maturity of the youngest first breeders, age variation in first breeders, longevity, potential reproductive lifespan, median lifespan, age-size relationship). Spring and summer cohorts at the German locality differed with respect to longevity and potential reproductive lifespan by one year in favour of the early breeders. The potential consequences on fitness and stability of cohorts are discussed. Latitudinal variation of life history traits was mainly limited to female natterjacks in which along a south-north gradient longevity and potential reproductive lifespan increased while size decreased. These results and a review of published information on natterjack demography suggest that lifetime number of offspring seem to be optimized by locally different trade-offs: large female size at the cost of longevity in southern populations and increased longevity at the cost of size in northern ones.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

Ovigeny strategy of the parasitic wasp Cosmocomoidea annulicornis (Hymenoptera: Mymaridae): effect of female age, feeding and host availability on reproductive traits

2021 ◽  
pp. 1-8
Author(s):  
Carolina Manzano ◽  
Eduardo G. Virla ◽  
Maria V. Coll Araoz ◽  
Erica Luft-Albarracin
Keyword(s):  
Body Size ◽  
Parasitic Wasp ◽  
Reproductive Potential ◽  
Reproductive Traits ◽  
Egg Load ◽  
Biological Traits ◽  
Potential Fecundity ◽  
Female Age ◽  
Host Availability ◽  
Egg Maturation

Abstract The reproductive traits of the mymarid wasp Cosmocomoidea annulicornis (Ogloblin) (Hymenoptera: Mymaridae) attacking eggs of the sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae) were evaluated under laboratory conditions. Bioassays were carried out to estimate the realized fecundity and egg load of females. The ovigeny index was calculated and different biological traits, such as body size, oöcyte length, gaster length and wing length, were analysed to assess significant associations between these traits and the species fitness. In addition, the effect of host availability and feeding on longevity and potential fecundity throughout life and the effect of female age on egg maturation dynamics were assessed. The results showed that C. annulicornis is a strongly synovigenic species. A positive correlation was found between fecundity and longevity of the females and between body size and oöcyte length. Contrary to expected, body size was not related to fecundity and longevity. Females lived significantly longer in the presence of hosts and honey than when they were host-deprived and honey-fed or both host and honey deprived. Host availability had a significant effect on the amount of eggs laid by C. annulicornis females. Female age was negatively associated with oöcyte length. Furthermore, females were able to mature additional eggs as they aged, nevertheless, when host-deprived, senescent females presented significantly less mature eggs than younger ones, suggesting a possible egg oosorption. These results might contribute to a better understanding of the reproductive potential of this species as a biocontrol agent.

Sexual Maturity, Spawning Periodicity and Fecundity of Obtuse Barracuda Sphyraena obtusata (Cuvier, 1829) along Karnataka Coast, Southeastern Arabian Sea

2021 ◽  
Author(s):  
M.M. Meshram ◽  
Mridula Rajesh ◽  
K.M. Rajesh ◽  
N.K. Suyan
Keyword(s):  
Gonadosomatic Index ◽  
Management Strategies ◽  
Gravimetric Method ◽  
Reproductive Traits ◽  
Breeding Period ◽  
Southeastern Arabian Sea ◽  
Spawning Periodicity ◽  
Gravid Females ◽  
First Maturity ◽  
Management And Conservation

Background: The success or failure of spawning in any population affects the fishery. Hence, studies on spawning, maturation, fecundity and length at first maturity become essential in drafting management strategies. The detailed information on reproductive traits of Sphyraena obtusata will be helpful in sustainable management and conservation in the study area. Methods: Three hundred and fifty five specimens of S. obtusata were collected fortnightly from Mangaluru and Malpe fishing harbors during August 2019 to March 2020. Maturity of gonads was examined by macroscopic and histological investigations. Spawning periodicity was worked out based on maturity stages and seasonal gonadosomatic index. Gravimetric method of analysis was employed to evaluate the fecundity from randomly collected samples of gravid females. Result: Overall sex ratio revealed that the population had significantly higher (p less than 0.05, X2 test) proportion of females than males. The length at 50% maturity (Lm50) for females and males was estimated at 21.1 and 21.5 cm respectively. The gonadosomatic index (GSI) and the availability of matured individuals for both the sexes in various percentage indicated a prolonged breeding period from October to March with peaks in November and December. The absolute fecundity varied from 91,942 eggs (20.0 cm TL) to 1,34,445 eggs (27.0 cm TL) with an average of 1,12,878 ± 2,984 hydrated oocytes per female.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Gonadosomatic Index ◽  
Reproductive Potential ◽  
Anguilla Rostrata ◽  
Spawning Ground ◽  
Silver Eel ◽  
Migration Distance ◽  
American Eel ◽  
Individual Fitness ◽  
Silver Eels ◽  
Somatic Tissues

<em>Abstract.—</em>The American eel <em>Anguilla rostrata </em>is declining in the St. Lawrence River watershed, where sex ratio is highly unbalanced in favor of females. Since the American eel is a panmictic species, this demographic dominance is implicated in reproductive potential of the species. The major objective of this study was to evaluate the reproductive strategies of five subpopulations of female eels. It was assumed that fecundity varies among subpopulations according to their migration distance because of the tradeoff between energy allocated to gonads and to somatic tissues. Thirty female silver eels were collected from each of five locations in the St. Lawrence watershed 2,850–4,300 km from the spawning area. Among subpopulations, mean length ranged from 67.9 to 104.3 cm, weight from 595 to 2,366 g, fecundity from 6.5 to 14.5 million oocytes, age from 20 to 23 years, gonadosomatic index from 2.9 to 4.1%, and somatic lipid content from 17.5 to 21.7%. Because of panmixia, no genetic influence on intersite variability is expected. Environmental differences in growth habitats and individual fitness might determine acquisition and allocation of resources, as well as subsequent variability in traits that would affect reproduction. In contrast to previous hypotheses, variations in such traits were attributed to eel size rather than migration distance. The number of oocytes per silver eel was positively correlated with length rather than negatively correlated with migration distance. In the St. Lawrence watershed, large eels are highly fecund regardless of their distance from the spawning ground.

scholarly journals What makes lady beetles effective natural enemies in preventative biological control?

2020 ◽  
Vol 21 ◽  
pp. 00018
Author(s):  
Natalia Belyakova ◽  
Yulia Polikarpova
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Reproductive Potential ◽  
Cost Effective ◽  
Ecological Knowledge ◽  
Female Size ◽  
Lady Beetles ◽  
Efficacy Assessment

Based on the reconsideration of traditional criteria for assessing the efficacy of natural enemies, the screening of coccinellids for preventative control of aphids was conducted. The result suggests that there is no causation between the female size (weight) and the reproductive potential of the tested species. Considering that size does not matter in preventative releases, it is more cost-effective to produce small lady beetles. Essential and non-essential ecological knowledge for the efficacy assessment is discussed.

Sign in / Sign up

Export Citation Format

Share Document