scholarly journals Reproductive strategy of common dentex Dentex dentex: management implications

2016 ◽  
Vol 17 (2) ◽  
pp. 552 ◽  
Author(s):  
A. GRAU ◽  
F. SABORIDO-REY ◽  
E. PASTOR ◽  
M. PALMER ◽  
E. MASSUTÍ-PASCUAL ◽  
...  
Keyword(s):  
Sex Differences ◽  
Life History ◽  
Reproductive Strategy ◽  
Egg Production ◽  
Gonadosomatic Index ◽  
Life History Strategy ◽  
Minimum Size ◽  
Small Scale ◽  
Female Size ◽  
Dentex Dentex

Common dentex Dentex dentex is an iconic endangered species in the Mediterranean where is a sought after target species for small-scale, recreational and spearfishing fisheries. The reproductive biology of D. dentex in the natural environment is poorly known; therefore the reproductive strategy of the species was assessed by combining reproductive traits with the growth characteristics (estimated from length-at-age data), the size/age of sexual maturity and the energetic dynamics. A total of 358 wild fish were sampled on Mallorca Island (W Mediterranean) from March 1996 to June 1999 with a 19 to 84.7 cm total length (LT) range. The sex ratio was skewed towards females (1.361) albeit the length composition was not different between sexes (p = 0.551). Three young immature individuals (< 28 cm LT, 0.8% individuals) were rudimentary hermaphrodites supporting the late gonochoristic species classification. The age composition determined from sagitta otolith interpretation ranged from 0 to 26 years (yr). Concerning growth, between sex differences in von Bertalanffy parameters were not relevant, even after accounting for potential between-year differences. The most noticeable difference was found for L∞ (64.7 cm for females versus 61.6 for males) but even in this case, the bayesian credibility interval of between-sex differences included zero.  Maturity ogives at size and age showed that females achieved 50% maturity at 34.9 cm LT and 3.3 years, while males did at 33.8 cm LT and 2.5 years. The onset of gonad developing phase took place in December, while it progresses until April. The spawning peak was in April and May for both sexes. A generalized linear model showed that female size didn’t affect significantly the spawning season, whilst there was a strong seasonality in the spawning. Most of the evidences showed that fecundity is likely determinate, with an asynchronous oocyte development before spawning and a clear ovarian bimodal organization after the onset of spawning. Female weight explained 84% of the observed variance for fecundity. The gonadosomatic, hepatosomatic and condition indexes varied significantly with the reproductive season for females and only the gonadosomatic index for males. Storage in muscle seemed to be the primary source of energy for reproduction, although liver appeared to play a short-term role in egg production, suggesting a combination of capital and income breeding. The results indicate that the life history strategy of common dentex possess consist on maturing well before reaching maximum size, investing in growth after maturation, and therefore the reproductive effort is distributed through a longer lifespan and related with the size attained after maturation. At present no management measures are directed to D. dentex; given its life history strategy we suggest that a slot limit should be implemented, i.e. a minimum and a maximum landing size, with a minimum size of 35 cm. The upper threshold, to protect the higher reproductive potential of older and larger fish, should still be defined.

Laboratory culture of Dreissena polymorpha larvae: spawning success, adult fecundity, and larval mortality patterns

2004 ◽  
Vol 82 (9) ◽  
pp. 1436-1443 ◽  
Author(s):  
James A Stoeckel ◽  
Dianna K Padilla ◽  
Daniel W Schneider ◽  
Chris R Rehmann
Keyword(s):  
Life History ◽  
Dreissena Polymorpha ◽  
Egg Production ◽  
Larval Mortality ◽  
Field Studies ◽  
Laboratory Culture ◽  
Minimum Size ◽  
Critical Periods ◽  
Brood Stock ◽  
Wide Range

Understanding the entire life history, especially critical periods during the life cycle of a species, is important for understanding population dynamics and is crucial for control of nuisance species. Errors in estimates of growth rates and recruitment in field and modeling studies are likely to occur if one assumes uniform rather than size- or stage-specific mortalities for larval stages. Similarly, effects of brood-stock health on adult fecundity and larval mortality patterns might affect results of laboratory studies investigating larval life history. We maintained zebra mussels, Dreissena polymorpha (Pallas, 1771), in spawning condition in the laboratory for 24 weeks. Healthy larvae were produced for 18 weeks. However, induction of spawning and egg production declined through time. Fecundity increased with size per female, but sperm production did not for males. We found no correlation between clutch size and egg size across a wide range of clutch sizes. Survivorship was greater when larvae were reared at lower densities. Daily larval mortality was strongly size dependent; the average size of dead larvae was similar to the minimum size of live larvae. Highest daily larval mortality occurred during the transition from D stage to umbonal stage, supporting the suggestion of a developmental bottleneck as found in previous field studies.

Physiological Characterization of Hatchery-Origin Juvenile Steelhead Oncorhynchus mykiss Adopting Divergent Life-History Strategies

2011 ◽  
Vol 2 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Kyle C. Hanson ◽  
William L. Gale ◽  
William G. Simpson ◽  
Benjamen M. Kennedy ◽  
Kenneth G. Ostrand
Keyword(s):  
Life History ◽  
Fresh Water ◽  
Gonadosomatic Index ◽  
Life History Strategy ◽  
Life History Strategies ◽  
Migratory Fish ◽  
Physiological Characterization ◽  
Subunit Expression ◽  
Mature Fish

Abstract Smoltification by juvenile Pacific salmonids has been described as a developmental conflict whereby individuals face several life-history decisions. Smoltification occurs as a result of interactions between organismal condition and environmental cues, although some fish may forgo ocean migration and remain in freshwater streams for some time (residualize). We compared the physiological profiles of steelhead that were actively migrating to the ocean (migratory fish) and those that remained in fresh water (residuals) for at least a period of between 2 wk and 3 mo after release from a hatchery facility. In addition, we investigated the physiological characterization of residuals that further differentiated into precocial freshwater residents or parr that will either precocially mature in fresh water or migrate to the ocean in the future. Residuals had higher condition factors and gonadosomatic index than migratory fish and were characterized as less prepared for saltwater due to low levels of gill Na+,K+-ATPase activity and Na+,K+-ATPase α1b-subunit expression. Residuals tended to be males with the highest condition factors. Sex-specific differences are probably reflective of male fish adopting an alternative life-history strategy foregoing outmigration as a result of condition at the time of release. Collection of residuals throughout the fall suggested that residual hatchery fish further diversify into precocially mature fish that will presumably attempt to spawn without ever migrating to the ocean or into parr that will precocially mature or migrate in a future year.

scholarly journals Differing Life-History Strategies of Two Mycoheterotrophic Orchid Species Associated with Leaf Litter- and Wood-Decaying Fungi

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 161
Author(s):  
Yuki Ogura-Tsujita ◽  
Kenshi Tetsuka ◽  
Shuichiro Tagane ◽  
Miho Kubota ◽  
Shuichiro Anan ◽  
...  
Keyword(s):  
Life History ◽  
Leaf Litter ◽  
Mycorrhizal Fungi ◽  
Life History Strategy ◽  
Life History Strategies ◽  
Small Scale ◽  
Nutrient Depletion ◽  
Saprotrophic Fungi ◽  
Orchid Species ◽  
Mycoheterotrophic Plants

Mycoheterotrophic orchids depend completely on mycorrhizal fungi for their supply of carbon. The life-history traits of mycoheterotrophic plants (MHPs) can differ according to the characteristics of the associated mycorrhizal fungi. We compared the life-history strategies of two mycoheterotrophic orchids associated with wood- and leaf litter-decaying fungi over a maximum of six years of field monitoring. Seventy percent of the aboveground stems of Erythrorchis altissima, associated with wood-decaying fungi, disappeared from the host wood within two years after tagging, likely due to nutrient depletion. In contrast, Gastrodia confusa, associated with leaf litter-decaying fungi, occurred continuously (18 to 108 fruiting stalks) every year within a small-scale plot (12 × 45 m) for six years through seed and clonal propagation. Our results support the idea that mycoheterotrophic orchids associated with wood-decaying fungi disappear from their habitats due to nutrient depletion after their host wood has mostly decayed, while mycoheterotrophic orchids associated with leaf litter-decaying fungi can survive in small-scale habitats where substantial leaf fall regularly occurs to sustain the associated fungi. Our study provides basic information about a unique life-history strategy in MHPs associated with saprotrophic fungi and an understanding of the variation in life-history strategies among MHPs.

scholarly journals Life-history of the South American darter, Characidium pterostictum (Crenuchidae): evidence for small scale spatial variation in a piedmont stream

2008 ◽  
Vol 6 (4) ◽  
pp. 591-598 ◽  
Author(s):  
Fernando Gertum Becker ◽  
Silene de Carvalho ◽  
Sandra Maria Hartz
Keyword(s):  
Life History ◽  
Spatial Variation ◽  
Life History Theory ◽  
Spatial Scales ◽  
Gonadosomatic Index ◽  
Sampling Site ◽  
Small Scale ◽  
Upstream Site ◽  
Trade Off ◽  
Disturbed Site

The present study compares the reproduction, condition and size of the small characiform fish, Characidium pterostictum, sampled at close sites differing in severity of flash flood effects. Data were obtained from seasonal samples in two sites situated 8 km apart in the same stream. In the upstream site, habitat is more severely affected by flash floods than in the downstream site, and this difference was hypothesized to produce differences in life history and individual reproduction trade-off patterns, as predicted by life-history theory. The results provided evidence for small-scale spatial variation in life-history and trade-off patterns within the studied population. At the most severely disturbed site, C. pterostictum displayed a trade-off pattern that favored reproductive life-span (e.g., larger size, higher and seasonally stable condition, larger mean size of mature females) over instantaneous reproductive output (lower gonadosomatic index), while the opposite pattern was observed in the less disturbed site. Because of the differences in disturbance effects between each sampling site, these results suggest that within-stream variability in the severity of hydrological disturbance can influence life-history patterns at small spatial scales. An implication of the results is that fish occupying areas that are hydrologically more variable within a stream are not necessarily at an energetic or reproductive disadvantage, but may be simply under environmental conditions that favor distinct patterns of energy allocation (or trade-offs) and population persistence, as predicted by life-history theory. Therefore, plasticity in life-history is expected to be common in stream fish populations that are widespread in a stream system with spatially variable or patchy habitat characteristics.

Attachment and life history strategy

2009 ◽  
Vol 32 (1) ◽  
pp. 26-27 ◽  
Author(s):  
Aurelio José Figueredo ◽  
Jon A. Sefcek ◽  
Sally G. Olderbak
Keyword(s):  
Sex Differences ◽  
Life History ◽  
Attachment Styles ◽  
Life History Strategy ◽  
Theoretical Issue

AbstractDel Giudice addresses a complex and pertinent theoretical issue: the evolutionary adaptiveness of sex differences in attachment styles in relation to life history strategy. Although we applaud Del Giudice for calling attention to the problem, we regret that he does not sufficiently specify how attachment styles serve as an integral part of a coordinate life history strategy for either sex.

scholarly journals Sex Differences in Moral Reasoning: The Role of Intelligence and Life History Strategy

2016 ◽  
Vol 31 (2) ◽  
pp. 5-16 ◽  
Author(s):  
Curtis S. Dunkel ◽  
Paul R. Gladden ◽  
Eugene W. Mathes
Keyword(s):  
Sex Differences ◽  
Life History ◽  
Moral Reasoning ◽  
Life History Strategy

scholarly journals Reproductive Strategy and Sexual Conflict Slow Life History Strategy Inihibts Negative Androcentrism

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Paul R. Gladden ◽  
Aurelio José Figueredo ◽  
D. J. Andrejzak ◽  
Dan Nelson Jones ◽  
Vanessa Smith-Castro
Keyword(s):  
Life History ◽  
Sexual Conflict ◽  
Reproductive Strategy ◽  
Life History Strategy

scholarly journals Reproductive biology of Plesionika narval in the SE Aegean Sea (Eastern Mediterranean)

2017 ◽  
pp. 454 ◽  
Author(s):  
AIKATERINI ANASTASOPOULOU ◽  
PANAGIOTA MAKANTASI ◽  
KOSTAS KAPIRIS ◽  
CHRIS J. SMITH ◽  
CHRISTOS MARAVELIAS ◽  
...  
Keyword(s):  
Reproductive Biology ◽  
Carapace Length ◽  
Gonadosomatic Index ◽  
Aegean Sea ◽  
Reproductive Period ◽  
Small Scale ◽  
Female Size ◽  
Depth Range ◽  
Depth Zone ◽  
Widespread Species

Plesionika narval is a widespread species of the Pandalidae family, of particular high economic importance for small-scale shrimp trap fisheries in the Dodecanese Islands (SE Aegean Sea). Understanding its biology and reproduction are crucial for stock management. Reproductive biology aspects were studied through data collected during monthly experimental surveys with baited shrimps traps from November 2014 to October 2015 at a depth range of 10 - 150m. A total of 3436 individuals within the size range of 6.46 to 20.20 mm carapace length (CL) was analyzed. Overall, mean female size was significantly higher than mean male size, while the mean size of ovigerous females was higher than that of non-ovigerous females. Mean carapace length of ovigerous and non-ovigerous females was significantly correlated to depth. Ovigerous females were observed throughout the study period; however, monthly proportions revealed April to October as the main reproductive period of the species in the area. The sex ratio showed a clear predominance of females in the shallow depth zone (10-25 m) and was found to be affected by sampling area and depth zone. Immature females were found from November to March. Mature females were found all year round, exhibiting higher percentages in March, June, July and September, coinciding with the main reproductive period. P. narval seemed to spawn more than one time within the annual reproductive cycle. Gonadosomatic index obtained its highest mean values in May, June and September, thus revealing the main reproductive period. Size at first maturity for females was estimated at CL50=11.7 mm.

scholarly journals Revisiting the concept of Beverton­­–Holt life-history invariants with the aim of informing data-poor fisheries assessment

2014 ◽  
Vol 72 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Jeremy Prince ◽  
Adrian Hordyk ◽  
Sarah R. Valencia ◽  
Neil Loneragan ◽  
Keith Sainsbury
Keyword(s):  
Life History ◽  
Meta Analysis ◽  
Reproductive Potential ◽  
Life History Strategy ◽  
Marine Species ◽  
Small Scale ◽  
Implicit Assumption ◽  
Fish Stocks ◽  
Assessment Techniques ◽  
The Relationship

Abstract The complexity and cost of assessment techniques prohibits their application to 90% of fisheries. Simple generic approaches are needed for the world's small-scale and data-poor fisheries. This meta-analysis of the relationship between spawning potential and the normalized size and age of 123 marine species suggests that the so-called Beverton–Holt life-history invariants (BH-LHI; Lm/L∞, M/k, M × Agem) actually vary together in relation to life-history strategy, determining the relationship between size, age, and reproductive potential for each species. Although little realized, the common assumption of unique values for the BH-LHI also implies that all species share the same relationship between size, age, and reproductive potential. This implicit assumption is not supported by this meta-analysis, which suggests that there is considerable but predictable natural variation in the BH-LHI ratios and the relationships between size, age, and reproductive potential that they determine. We believe that this reconceptualization of the BH-LHI has potential to provide a theoretical framework for “borrowing” knowledge from well-studied species to apply to related, unstudied species and populations, and when applied together with the assessment technique described by Hordyk et al. (2015b), could make simple forms of size-based assessment possible for many currently unassessable fish stocks.

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