Population biology and growth of the hermit crab Dardanus insignis at Armação do Itapocoroy, southern Brazil

2002 ◽  
Vol 82 (4) ◽  
pp. 597-603 ◽  
Author(s):  
Joaquim Olinto Branco ◽  
Alexander Turra ◽  
Flávio Xavier Souto
Keyword(s):  
Population Biology ◽  
Outer Part ◽  
Growth Function ◽  
Hermit Crabs ◽  
Reproductive Pattern ◽  
Southern Brazil ◽  
Von Bertalanffy Growth Function ◽  
Temporal Oscillation ◽  
Males And Females ◽  
Unimodal Pattern

This study was conducted between January and December 1995 at Armação do Itapocoroy, Penha, Santa Catarina, southern Brazil. Monthly samples were carried out in the morning, afternoon, and evening using two over-trawls with 6 m at the opening, 3·0-cm mesh at the outer part and 2·0-cm mesh in the bag. Dardanus insignis was collected year round but with higher densities in September and October. The hermit crabs were more abundant during the evening than the afternoon but no differences were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes (<1·8 cm) while males outnumbered females in the largest ones (>2·2 cm). The individuals of this population of D. insignis have a mean cephalothoracic length of 1·89±0·40 cm (range 1·00 to 3·90 cm) and a mean weight of 40·26±27·06 g. The size distribution showed an unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Dardanus insignis showed a seasonal reproductive pattern with a peak from September to November and complete absence of ovigerous females from April to August. The von Bertalanffy growth function (VBGF) with temporal oscillation fitted for this population of D. insignis had the following parameters: L∞=4·40 cm, K=0·60, C=0·95, WP=0·35. Recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2·21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both cephalothoracic width and crab weight.

scholarly journals Reproduction and feeding ecology of Amphisbaena munoai and Anops kingi (Amphisbaenia, Amphisbaenidae) in the Escudo Sul-Rio-Grandense, southern Brazil

2011 ◽  
Vol 101 (1-2) ◽  
pp. 93-102 ◽  
Author(s):  
Rafael L Balestrin ◽  
Lize H Cappellari
Keyword(s):  
Feeding Ecology ◽  
Original Data ◽  
Adult Males ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Gut Content ◽  
Insect Larvae ◽  
Males And Females ◽  
Sexually Mature ◽  
Unimodal Pattern

This study presents original data on the reproduction and feeding ecology of two syntopic amphisbaenians, Amphisbaena munoai Klappenbach, 1969 and Anops kingi Bell, 1833, from southern Brazil. Sampling was carried out from April 2004 to April 2006 at a highland area located in São Jerônimo and Barão do Triunfo municipalities, Rio Grande do Sul, Brazil. A total of 647 amphisbaenians were collected, 510 specimens of A. munoai and 137 specimens of A. kingi, of which 130 and 93, respectively, had their gonads and gut content analyzed. Both species presented a unimodal pattern of seasonal distribution, sexually mature females with significantly larger snout vent length (SVL) than sexually mature males, and seasonal reproductive cycle. Adults of A. kingi had significantly larger (SVL) than those of Amphisbaena munoai. Both species had generalist diets, but termites (Isoptera) was a staple item in their diet. Greater predominance of insect larvae was observed in the diet of A. kingi, which may be due to its larger body in comparison to A. munoai. Insect larvae ingested by A. kingi were significantly larger than those ingested by A. munoai. Diets of adult males and females of both species were not significantly different. The ontogenetic diet comparison in both species revealed significant numerical differences, with adults consuming higher numbers of prey.

Population biology and growth of three sympatric species of intertidal hermit crabs in south-eastern Brazil

2000 ◽  
Vol 80 (6) ◽  
pp. 1061-1069 ◽  
Author(s):  
Alexander Turra ◽  
Fosca P.P. Leite
Keyword(s):  
Population Growth ◽  
Hermit Crab ◽  
Population Biology ◽  
Size Structure ◽  
Growth Function ◽  
Sympatric Species ◽  
Growth Patterns ◽  
Hermit Crabs ◽  
South Eastern ◽  
Eastern Brazil

Hermit crab populations have been described in different habitats and latitudes but few studies focused on coexisting populations. Such information is especially important to evaluate the effect of coexistence in the population biology of such organisms. This study was done in the intertidal region of Pernambuco Islet, São Sebastião Channel, south-eastern Brazil. Random samples of crabs were taken monthly during one year to evaluate their size and sex. The three coexisting Clibanarius populations (C. antillensis, C. sclopetarius, and C. vittatus) showed similar patterns of sex ratio (skewed for females), sexual dimorphism (males larger than females), recruitment (February to June) and population growth but differed in size structure (Cs>Cv>Ca) and reproductive activity over the year. Population growth was estimated using the von Bertalanffy growth function (VBGF) and revealed that the growth of these three populations was strongly reduced from August to January and that longevity varied from 42 to 48 months. Clibanarius antillensis showed continuous reproduction with high frequency of ovigerous females over the year while C. sclopetarius and C. vittatus had a reproductive peak in April and absence of ovigerous females in August/September. Coexistence seemed to influence population biology of these hermit crabs, given the relationship of their reproductive periods and growth patterns to the shell adequacy to the crabs. The overlap in reproductive peaks and recruitment periods may strengthen competition for shells. Comparisons of the reproductive patterns of the hermit crab populations recorded to date emphasize that reproduction and, consequently, life strategies of hermit crabs are not directly dependent on taxonomic or geographical proximity, but on their evolutionary histories and on local processes acting on each assemblage or population.

scholarly journals Population biology and reproduction of the hermit crab Clibanarius vittatus (Decapoda: Anomura) in an estuarine region of southern Brazil

2009 ◽  
Vol 89 (4) ◽  
pp. 761-767 ◽  
Author(s):  
Bruno Sampaio Sant'Anna ◽  
Álvaro Luiz Diogo Reigada ◽  
Marcelo Antonio Amaro Pinheiro
Keyword(s):  
Hermit Crab ◽  
Population Biology ◽  
Reproductive Activity ◽  
Hermit Crabs ◽  
Reproductive Pattern ◽  
Size Frequency Distribution ◽  
Clibanarius Vittatus ◽  
Shield Length ◽  
Bell Shaped Curve ◽  
Modal Size

The population dynamics and reproduction of the hermit crab Clibanarius vittatus were evaluated on Pescadores Beach, located on the estuarine channel of São Vicente (São Paulo), Brazil. The hermit crabs were captured by hand during low tide, from May 2001 to April 2003. A total of 2554 hermit crabs were captured, of which 701 were males, 1741 non-ovigerous females, 48 ovigerous females and 64 intersex individuals. The size–frequency distribution of the males was represented by a platykurtic bell-shaped curve, which differed from the leptokurtic bell-shaped curve of the females. The smaller and intermediate classes were composed mainly of females (modal size 6.5–7.5 mm carapace shield length (CSL)), and the larger classes only by males (modal size 9.5–10.5 mm CSL). The overall sex-ratio was skewed toward females (0.39:1/M:F), differing significantly from the expected 1:1. A seasonal reproductive pattern was recorded for C. vittatus in this location, with more intensive reproductive activity in the warmer months. The absence of juveniles suggests that their recruitment area is different than the area inhabited by adults, possibly another area with more protection and specialized or different resources for young.

Population Biology of Liocarcinus Depurator (Brachyura: Portunidae) In Mussel Raft Culture AreasIn The Ría De Arousa (Galicia, Nw Spain)

1991 ◽  
Vol 71 (2) ◽  
pp. 375-390 ◽  
Author(s):  
L. Fernández ◽  
E. González-Gurriarán ◽  
J. Freire
Keyword(s):  
Growth Rate ◽  
Sex Ratio ◽  
Population Biology ◽  
Carapace Width ◽  
Outer Part ◽  
Growth Function ◽  
Breeding Cycle ◽  
Raft Culture ◽  
One Year ◽  
Density And Biomass

The population biology of the crab Liocarcinus depurator was studied for one year in the mussel raft culture areas of the Ria de Arousa. The density and biomass of this species is much higher in the raft areas, especially in the outer part of the ria, than in the central channel area. Maximum abundance occurred during the winter months (up to 8-80 g wet weight m and 0-44 individuals m.Maturity size in females was set at 28-30 mm carapace width, (based on ovigerous females) and is attained in the first year of life. The ovigerous females were most abundant in January (approximately 70% of the mature females), but another less important maximum value was observed in May, attributable to a second spawning. Modifications in the sex ratio from 1:1 affected individuals larger than the maturity size during the season when there was a greater number of ovigerous females present. Data on sex ratio and breeding cycle indicate that ovigerous females move towards the raft areas located in the outer part of the ria. Trawl recruitment took place in the stations located in the outer Ria, and mainly in August-September, although it continued to a lesser extent in autumn.The Von Bertalanffy growth function was fitted to both sexes in the two outer stations. Growth rate was higher in males than in females, while variability between stations was less important. However the growth rate and reproductive output of L. depurator in the Ria de Arousa was higher than in populations from other geographical areas, possibly because of the availability of food from the rafts and or the oceanographic conditions in the ria.

An Antarctic shelf population of the deep-sea, Pacific brachiopod Neorhynchia strebeli

1997 ◽  
Vol 77 (2) ◽  
pp. 399-407 ◽  
Author(s):  
David K.A. Barnes ◽  
Lloyd S. Peck
Keyword(s):  
Deep Sea ◽  
Growth Function ◽  
Weddell Sea ◽  
Von Bertalanffy ◽  
Growth Rings ◽  
Von Bertalanffy Growth Function ◽  
Annual Periodicity ◽  
A Site ◽  
The Antarctic ◽  
Order Rhynchonellida

Thirty-five specimens of the articulate brachiopod Neorhynchia strebeli were collected from a site at 814 m in the Weddell Sea. This was only the second species of the order Rhynchonellida to be found in Antarctica. Formerly N. strebeli was known solely from abyssal Pacific Ocean localities. A circumantarctic distribution is suggested in addition to the known deep-sea Pacific range. The specimens of this collection showed considerable commissure variation, suggesting that the previously proposed erection of two subspecies on the basis of this character is erroneous, and emphasises the phenotypic plasticity of some articulate brachiopods. The valve lengths and the number of alpha growth rings in the sample showed a normal distribution and a von Bertalanffy growth function was fitted to the data: Lt = 23 (1-exp[-0·228t]). If the alpha growth rings were of annual periodicity, the ages attained by the Antarctic N. strebeli of 11 y would be substantially lower than those reported for other Weddell Sea brachiopods. The epibiotic communities occurring on the valves of N. strebeli were impoverished, which is characteristic of deep water Antarctic brachiopods. The few specimens collected with their substratum were attached to small pebbles, but the typical attachment substrata may be different.

scholarly journals Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

2010 ◽  
Vol 90 (8) ◽  
pp. 1493-1500 ◽  
Author(s):  
Silvina Botta ◽  
Eduardo R. Secchi ◽  
Mônica M.C. Muelbert ◽  
Daniel Danilewicz ◽  
Maria Fernanda Negri ◽  
...  
Keyword(s):  
Growth Models ◽  
Growth Curves ◽  
Small Sample ◽  
Age And Growth ◽  
Buenos Aires Province ◽  
Von Bertalanffy ◽  
Southern Brazil ◽  
Data Set ◽  
Males And Females ◽  
Pontoporia Blainvillei

Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

Leaf demography and decline of Panicum racemosum populations in coastal foredunes of southern Brazil

1991 ◽  
Vol 69 (7) ◽  
pp. 1593-1599 ◽  
Author(s):  
César S. B. Costa ◽  
Ulrich Seeliger ◽  
César V. Cordazzo
Keyword(s):  
Population Biology ◽  
Sand Dunes ◽  
Salt Spray ◽  
Nutrient Status ◽  
Southern Brazil ◽  
Leaf Demography ◽  
Growth Vigour ◽  
Sand Movement ◽  
Mobile Dune ◽  
Sand Deposition

We studied the effect of nutrient status and sand movement on the population biology of Panicum racemosum Spreng. over a 5-year period (1982–1986) on mobile, semifixed and fixed coastal foredune habitats in southern Brazil. The soils were deficient in nitrate, phosphate, and potassium (<0.5, 0.2–1.2, and 3–5 mg/kg, respectively) in all habitats, and a gradient of decreasing availability existed from the mobile to the fixed dunes. Half-lives of leaves were shorter in the fixed dune as compared with the mobile dune. Similarly, half-lives of leaves were shorter in summer than in winter. Experiments using cuttings of P. racemosum tillers showed that as P. racemosum plants grew, so did the deposition of sand on mobile foredunes. The mechanical deposition of sand itself did not stimulate P. racemosum growth. The deposition of saline sand provided a substrate that supported vertical growth of P. racemosum rhizomes and tillers and was a source of adsorbed nutrients. Also, active sand deposition limited the invasion of frontal dunes by other species. Panicum racemosum populations changed from "invader" to "mature" to "regressive" age states over a 5-year period, apparently in response to the spatial patterns of sand deposition and salt spray input. Key words: Panicum, leaf demography, growth vigour, sand dunes, temporal changes.

Age, Growth and Sex Ratio of the Azorean Rock-Pool Blenny, Parablennius Sanguinolentus Parvicornis

1995 ◽  
Vol 75 (3) ◽  
pp. 751-754 ◽  
Author(s):  
Ricardo Serrão Santos ◽  
Richard D. M. Nash ◽  
Stephen J. Hawkins
Keyword(s):  
Sex Ratio ◽  
Growth Function ◽  
Early Growth ◽  
Reproductive Season ◽  
First Year ◽  
Von Bertalanffy ◽  
Rock Pool ◽  
Total Length ◽  
Von Bertalanffy Growth Function ◽  
One Year

The age and population structure of Parablennius sanguinolentus parvicornis (Valenciennes) (Pisces: Blenniidae) from the Azores have been studied. Total length and weight relationships are given for each sex. Age study was based on otoliths readings. The von Bertalanffy growth function was applied to describe the growth in total length with age. At the end of the first year mean (±SD) total length was significantly different in males (7.1 ±1.5 cm) and females (6.1 ±1.2 cm). One-year-old males participate in reproduction as satellites, whereas females do not. The implications of this in early growth rate of the males is discussed. During the two most important months of the reproductive season (i.e. June and July), the sex ratio was significantly biased towards males, particularly in the larger size classes.

scholarly journals Age, growth and mortality of the anchovy Stolephorus commersonnii (Lacepède,1803) (Clupeiformes) caught off the coast of Tanga, Tanzania

2021 ◽  
pp. 95-104
Author(s):  
Albogast T. Kamukuru ◽  
Shigalla B. Mahongo ◽  
Baraka C. Sekadende ◽  
Joseph S. Sululu
Keyword(s):  
Software Tool ◽  
Growth Function ◽  
Fishing Effort ◽  
Northern Coast ◽  
Management Intervention ◽  
Von Bertalanffy Growth Function ◽  
Relationship Model ◽  
June July ◽  
Spawning Periods ◽  
Length Frequency Data

The population dynamics of Stolephorus commersonnii (Lacepède, 1803) from a ringnet fishery operating off the northern coast of Tanga Region were evaluated based on monthly length-frequency data collected from August 2016 to August 2017. The total length (TL) and total weight (TW) of 14,410 individuals ranged from 22 to 130 mm and from 0.39 to 14.64 g respectively. S. commersonnii exhibited a negative allometric growth pattern with the length-weight relationship model: W = 0.00001 x L2.886. The von Bertalanffy growth function was Lt = 86.03 x (1 – e–1.19(t – (–0.01))) using ELEFAN I from the FiSAT II software tool package. Growth performance index and longevity were estimated at (ɸ) = 3.9 and Tmax = 2.5 yrs, respectively. The total (Z), fishing (F) and natural (M) mortalities were determined at 1.39, 0.53 and 0.86 yr-1, respectively. The current exploitation rate (Ecur) was estimated at 0.38. S. commersonnii exhibited a year-round breeding pattern, with two recruitment peaks in March and June/July. Length-at-first-capture (Lc50) and length-at-first-sexual maturity (Lm50) were 40.51 and 57.35 mm TL, respectively, suggesting growth overfishing. The stock of anchovy indicates an overfishing scenario requiring management intervention such as reducing fishing effort levels, increasing mesh sizes and introducing seasonal closures during peak spawning periods.

scholarly journals Population and reproductive traits of a freshwater amphipod (Crustacea, Peracarida, Hyalellidae) from northwest of the state of Rio Grande do Sul, Brazil

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Daniela da Silva Castiglioni ◽  
Marcio Limberger ◽  
Vanessa da Silva Castro ◽  
Francieli Ubessi
Keyword(s):  
No Reduction ◽  
Natural Populations ◽  
Reproductive Traits ◽  
Bimodal Distribution ◽  
Southern Brazil ◽  
Natural Pond ◽  
Males And Females ◽  
The Mean ◽  
Anthropic Influence ◽  
Almost All

Abstract The study of population and reproductive traits provides information about the ecological structure of natural populations. This study aimed to characterize dynamics and reproductive traits of Hyalella palmeirensis from a natural pond from southern Brazil. The amphipods were sampled monthly (August 2012 to July 2013) by a person with the aid of a hand net for 20 minutes. Ovigerous females and pre-copulatory pairs were individualized in the field. A total of 12,325 individuals were sampled, being 1,421 males, 6,983 females (including 215 ovigerous females) and 3,921 juveniles. Paired and unpaired males were significantly greater in size than females. There was a positive correlation between body size (CL) of paired males and females. Males and females showed bimodal distribution. Total sex ratio favored females, and these were more frequent in almost all months. Ovigerous females and precopulatory pairs were found throughout the year, but with high frequency in winter and autumn, respectively, characterizing a seasonal reproduction. Juveniles were sampled throughout the year, with greater intensity in the spring. The mean fecundity was 19.6 ± 4.34 eggs. No reduction in the number of eggs was observed during embryonic development. The results observed in H. palmeirensis demonstrate that this species has a population and reproductive dynamics very similar to other species of Hyalella already analyzed in southern Brazil. Moreover, it can be seen that although the H. palmeirensis occurs in an environment with anthropic influence (soy cultivation,) the population is managing to remain in the area, with reproduction and recruitment in most months of year.

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