Search

The reproductive aspects of populations are important determinants of their ability to maintain themselves throughout time. In the case of amphipods from the genus Hyalella Smith, 1874, the reproductive period is easily determined by the presence of ovigerous females and pre-copula pairs in the population. This study evaluated the fecundity, pairing patterns and reproduction period of Hyalella carstica Bastos-Pereira and Bueno, 2012 in a karst environment in the West of Minas Gerais, Brazil. Monthly, from April, 2010 to April, 2011, amphipods were sampled using a hand net with 15 cm diameter and 250 µm mesh size. In the laboratory, animals were sexed and measured, and the ovigerous state of females was evaluated. Couples in pre-copula and ovigerous females were found throughout the year, with the exception of the dry months (September−November). During drought, the stream's superficial water dried out, and only a few refuges for the population remained. Although couples were found in all months with a water flow, a higher number of unpaired males and females was found after the dry season. In all months, ovigerous females were more abundant than non-ovigerous, and the relationship between head length and the number of eggs in the marsupium was positive. Most eggs were in the first developmental stage, although all other stages were found before the dry season. Considering the frequency of pre-copula pairs, as well as ovigerous females, the reproduction in this H. carstica population seems to be continuous throughout the year, without a distinct peak.

O caranguejo de manguezal Ucides cordatus é uma espécie endêmica de manguezais com expressiva importância econômica no litoral brasileiro, mas a sobrepesca e a devastação dos manguezais vêm reduzindo drasticamente as suas populações. Estudos nacionais sobre a biologia reprodutiva têm sido realizados em algumas regiões, embora sejam escassos ou antigos nos manguezais de Pernambuco. Neste estudo objetivou caracterizar o período reprodutivo do caranguejo através do desenvolvimento gonadal e a frequência de fêmeas ovígeras. Os animais foram coletados manualmente durante a maré baixa em duas diferentes áreas (de 25 m² cada) de abril de 2008 a maio de 2009. Foram amostrados um total de 1.424 exemplares (Mamacabas = 805; Ariquindá = 619). Os espécimes foram sexados e dissecados, e foi avaliado o estágio de desenvolvimento das gônadas através de seu tamanho e de sua coloração. Os caranguejos com gônadas imaturas e rudimentares foram considerados imaturos sexualmente, enquanto aqueles pertencentes aos demais estágios reunidos (em desenvolvimento, desenvolvido, avançado e esgotado) foram classificados como maduros. Os machos com gônadas maduras ocorreram durante todo o ano, sendo mais frequentes na primavera e no verão, independentemente da área de manguezal estudada (Mamucabas ou Ariquindá). As fêmeas com gônadas maduras ocorreram ao longo do ano, com maior frequência no outono e no verão, enquanto as ovígeras ocorreram apenas no verão e no outono, em ambas as localidades. Tais resultados caracterizam uma reprodução sazonal do caranguejo-uçá nos manguezais analisados, seguindo o padrão reprodutivo já descrito para a espécie em outras regiões do Brasil. The mangrove crab Ucides cordatus is a typical species of the estuarine environment with significant economic importance in the Brazilian coast, but overfishing and destruction of mangroves have dramatically reducing their populations. Studies about reproduction have been conducted in several regions, although those papers carried out in the mangroves of state of Pernambuco are scarce or old. Thus, this study aimed to characterize the reproductive period of Ucides cordatus through the analysis of gonadal development and the frequency of ovigerous females. The crabs were collected manually during low tide in two different areas (each 25 m²) from April 2008 to March 2009. A total of 1,424 specimens (Mamacabas = 805; Ariquindá = 619) were sampled. The sampled crabs were observed for sex, dissected and evaluated for stages of development of the gonads through the size and color. Crabs with immature and rudimentary gonads were considered immature and the remaining crabs were classified as mature. Males with mature gonads occurred throughout the year but they were more frequent in spring and summer in Mamucabas and Ariquindá, respectively. Females with mature gonads were found throughout the year but were more frequently in autumn and summer, as well as ovigerous females occurred only in summer and autumn in both populations. These results characterize seasonal reproduction for Ucides cordatus in the analyzed populations following the reproductive pattern already described for this species in other regions of Brazil.

The blue crab Callinectes sapidus (Rathbun, 1896), a native to western Atlantic coasts, is widely recorded in various Mediterranean regions, including the Gargano lagoons in the Adriatic Sea. This study investigated selected biological traits of Callinectes sapidus females in the Lesina and Varano lagoons during their breeding migration to more saline waters. In total, 19 individuals of Callinectes sapidus, 15 females and four males, were collected in the lagoons near the mouths of the seaward channels. The specimens' Carapace Width ranged from 115 to 230 mm, classifying them as medium to large crabs. In Varano lagoon in April and May 2014, two ovigerous females with egg masses of 63.39 g and 11.65 g respectively were captured. This represents the first record of ovigerous females of C. sapidus in this lagoon. The average Gonado-Somatic Index was 2.91 +/- 1.82 and 1.65 +/- 0.65 for the specimens captured in Varano and Lesina lagoons, respectively. The average Hepato-Somatic Index was 3.88 +/- 0.80 and 4.22 +/- 0.31 for specimens captured in Varano and Lesina, respectively. Egg diameter ranged between 0.23 and 0.35 mm. Histological analysis of gonads showed stages from III to V, with individuals in emission or postissuance stages. This study presents evidence of the establishment of C. sapidus populations in Varano lagoon in the south-west Adriatic Sea and provides additional information on this species in the Lesina and Varano lagoons.

The first record of adult Oriental shrimps Palaemon macrodactylus Rathbun, 1902 in the Venice Lagoon (north Adriatic Sea) is presented based on six specimens collected in a shallow water habitat during May 2012. The record is discussed in the context of the widespread distribution of the species, taking into account the possible ways of introduction and the possible consequences of the presence of P. macrodactylus in the Venice Lagoon.

Zakonitosti razmnožavanja vrsta Niphargus likanus i Synurella ambulans istraživana su nizvodno od HE Lešće uz Gojačku Dobru na povremenom izvoru Gorinci i stalnom izvoru Skukani. Uzorci su prikupljani jednom mjesečno od veljače 2008. godine do svibnja 2009. godine. Cilj ovog rada je bio ustanoviti ekologiju i reproduktivnu biologiju vrsta N. likanus i S. ambulans, dok je posebni naglasak bio na utjecaju abiotičkih čimbenika okoliša na pojavljivanje ovigernih ženki. Gustoća populacija je najveća na izvorima pri vrijednostima temperature vode manjim od 17,7 °C. Ovigerne ženke su zabilježene na oba izvora za vrstu S. ambulans, a za vrstu N. likanus samo na izvoru Skukani s većom brojnošću tijekom zime (prosinac, siječanj, veljača) i u proljeće (svibanj). Jedinke s obilježjima interseksa i jedinke u ampleksusu kod istraživanih vrsta nisu zabilježene tijekom ovog istraživanja. The reproductive traits of the species Niphargus likanus and Synurella ambulans were examined downstream from the HPP Lešće on permanent spring Gorinci and periodical spring Skukani near Gojačka Dobra River. Samples were collected once a month in the period from February 2008 to May 2009. The primary goal was to establish the ecology and reproductive biology of the species Niphargus likanus and Synurella ambulans. Influence of abiotic factors on appearance of ovigerous females was the main focus of the research. The highest population density of the species was recorded in the springs with the water temperature below 17,7 °C. The ovigerous females were recorded in both springs for the species S. ambulans and only in Skukani spring for species N. likanus with high density during the winter (December, January, February) and spring (May). Amplexus and intersex individuals of N. likanus and S. ambulans were not found out in our study.

Very little is known about the epigean niphargid autecology. The aim of this study was to establish the life history traits of the endemic amphipod Niphargus dalmatinus, which regularly inhabits springs, epigean streams and rivers in the Middle Dalmatia. Three replicate samples were collected once a month with benthos net in the period from August 2004 to August 2005 at ten study sites located in the upper, middle and lower reaches of the Cetina River and its tributaries. The highest population density of the species was recorded on two study sites in hypocrenal zone, where the mean water temperature reached 9.7°C with the narrow range of 7.3-12.5°C. Ovigerous females were recorded year-round at the main spring and in the upper course, but were more numerous during the spring (March, April, May) and autumn (October) months. The sex-ratio (males vs. females) was in favour of males almost throughout the all study year. Mean number of eggs was 30 for 100 analysed females, but one female carried maximum of 111 eggs. There was no correlation between fecundity and female body size (total body length). A better insight into the life history strategy of N. dalmatinus will help to interpret the distribution patterns, population structures, and the coexistence with other crustacean species.

Životni ciklus populacija vrste Gammarus balcanicus u rijeci Cetini do sada nije ciljano istraživan, unatoč tome što je vrsta široko rasprostranjena i ima veliku važnost u kruženju tvari u vodotocima koje nastanjuje. Cilj ovog rada bio je istražiti ekologiju i reproduktivnu biologiju vrste. Terenska istraživanja su provedena od kolovoza 2004. godine do kolovoza 2005. godine na šest postaja duž rijeke Cetine. Jedanput mjesečno su mjereni fizikalni i kemijski parametri (temperatura vode, otopljeni kisik, pH, elektrina provodljivost, alkalinitet), te su Surberovom mrežom prikupljani kvantitativni uzorci makrozoobentosa. U laboratoriju su jedinke vrste G. balcanicus za svaku postaju i datum uzorkovanja prebrojavane i razvrstavane u sljedeće starosne (ontogenetske) i razvojne kategorije: odrasli mužjaci, neovigerne ženke, ovigerne ženke, adolescentne mužjake, adolescentne ženke, juvenilne jedinke, interseks i ovigerni interseks. Cilj istraživanja je bio utvrditi raspon abiotičkih čimbenika okoliša, njihov utjecaj na životni ciklus vrste te istražiti strukturu i dinamiku populacija vrste G. balcanicus krenala i ritrala rijeke Cetine. Rezultati su pokazali da vrijednosti abiotičkih čimbenika imaju longitudinalni gradijent tipičan za tekućice. Od izvora prema ušću raste prosječna vrijednost temperature vode kao i temperaturne oscilacije. Koncentracija otopljenog kisika se nizvodno smanjuje, a oscilacije povećavaju. Najniže pH vrijednosti mjerene su na izvorima. U limnokrenom izvoru Cetine voda sporije istječe i duže se zadržava što rezultira većim godišnjim temperaturnim promjenama nego li je u literaturi zabilježeno za izvore. Najveća gustoća populacije vrste G. balcanicus od nekoliko tisuća jedinki po m2 zabilježena je na izvoru Cetine. Longitudinalno, prema ušću, gustoća opada. Mužjaci su bili dominantni tijekom čitavog istraživanog razdoblja što je posljedica njihovog bržeg rasta i ranijeg dostizanja spolne zrelosti. Na postajama izvor Cetine i Obrovac Sinjski vrsta G. balcanicus se razmnožava tijekom cijele godine zato što je u izvoru Cetine temperatura vode ujednačena tijekom godine i zbog povoljnog utjecaja mediteranske klime na temperaturu vode u čitavoj rijeci, pa su i najniže izmjerene temperature na donjoj granici temperaturnih vrijednosti zabilježenih u literaturi za početak razmnožavanja kod ove vrste. Također je zabilježena prisutnost interseksa. Takve jedinke su bile malobrojne, ali s velikim udjelom ovigernog interseksa. So far there are no detailed data on the life cycle of G. balcanicus inhabiting the Cetina river despite its wide range and great importance in matter circulation in streams and rivers. In concordance with that, the aim of this study was to investigate the ecology and reproductive biology of the species. Field studies were carried out from August 2004 to August 2005 at six study sites along the Cetina river. Physical and chemical parameters (water temperature, dissolved oxygen, pH, electric conductivity, alkalinity) were measured and quantitative samples were collected using a Surber net once per month. In the laboratory, the specimens were classified by each month and sampling date in the following categories: adult males, nonovigerous females, ovigerous females, adolescent males, adolescent females, juveniles, intersexes and ovigerous intersexes. The aim was to examine the range of abiotic environmental conditions, their influence on the species' life history traits, and the structure and population dynamic of G. balcanicus in crenal and rhitral of the river. Results have shown that values of abiotic factors have longitudinal gradients typical for streams and rivers. From the spring up to the mouth, the mean water temperature and water temperature fluctuation increase, concentration of dissolved oxygen decreases downstream and its fluctuation increases in the same direction. The lowest pH values were measured at springs. In the limnocrenous Cetina spring, water emerges slower and stays in the pond-like spring for a longer period of time, resulting in higher annual temperature than usually recorded in springs. The greatest population density of G. balcanicus has been recorded at the Cetina spring and reached several thousands of specimens per square meter. A longitudinal decrease in population density was observed. Males were predominant during the whole research period, which can be explained by faster growth and earlier attainment of maturity by males than by females. At the Cetina spring and Obrovac Sinjski study sites, the breeding period of G. balcanicus is ongoing through the whole year because of constant water temperatures at the Cetina spring and the influence of Mediterranean climate on water temperatures along the Cetina river. We recorded the lowest temperatures at which reproduction of G. balcanicus was began The presence of intersex specimens has also been recorded. Intersexes were rare, but with a high ratio of ovigerous intersexes.

Zakonitosti razmnožavanja vrste Niphargus dalmatinus je istraživana na 8 postaja gornjeg, srednjeg i donjeg toka rijeke Cetine te na jednoj od pritoka, rijeci Rudi, u razdoblju od kolovoza 2004. do kolovoza 2005. godine. Iako pripada podzemnom rodu rakušaca, vrsta uglavnom nastanjuje nadzemne vodotoke Srednje Dalmacije. Budući je do sada nepoznata ekologija vrsta istraživanog roda u nadzemnim staništima, cilj ovog rada je prvenstveno bio ustanoviti ekologiju i reproduktivnu biologiju vrste Niphargus dalmatinus, dok je posebni naglasak bio na utjecaju abiotičkih čimbenika okoliša na pojavljivanje ovigernih ženki. Dobiveni rezultati ukazuju na jasnu povezanost longitudinalne rasprostranjenosti, promjene gustoće populacija i pojavljivanja ovigernih ženki s vrijednostima temperature vode. Gustoća populacija je najveća u području eukrenala rijeke Cetine, pri vrijednostima temperature vode manjim od 10°C. Ovigerne ženke su zabilježene samo na postajama gornjeg i donjeg toka rijeke tijekom čitave godine, ali s većom brojnošću tijekom jeseni (u studenom) i proljetnih mjeseci (ožujka, travnja i svibnja). Rezultati provedenog istraživanja upućuju na zaključak da je vrsta bivoltna tj. da spolno aktivne ženke produciraju dva legla godišnje. Jedinke s obilježjima interseksa i jedinke u ampleksusu kod istraživane vrste nisu zabilježene tijekom ovog istraživanja. The reproductive traits of Niphargus dalmatinus were examined from August 2007 to August 2008 at eight study sites located in the upper, middle and lower reaches of the Cetina River and its tributary the Ruda River. Although the species belongs to the subterranean genus, it inhabits epigean streams in the Middle Dalmatia. Whereas the ecology of the species in the epigean habitats remains unknown, the primary goal was to establish the ecology and reproductive biology of the species. Influence of abiotic factors on appearance of ovigerous females was the main focus of the research. The obtained results pointed out a strong relationship between longitudinal variation in population density, appearance of ovigerous females and water temperature. The highest population density of the species was recorded in the eucrenal zone of the Cetina River, with the water temperature below 10°C. The ovigerous females were recorded year-round in the upper and lower reaches only, with high density during the autumn (October) and spring (March, April, May). The populations studied in this work appears to be bivoltine, but the data are not sufficiently consistent to confirm the hypothesis. Amplexus and intersex individuals of N. dalmatinus were not observed in our study.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:20:33Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:29:21Z : No. of bitstreams: 1 2-s2.0-0036936709.pdf: 219924 bytes, checksum: e5085f8cdc5e4e9d6a7d207c02405037 (MD5) Made available in DSpace on 2014-05-27T11:20:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-12-01 Moina minuta, a tropical species of Cladocera, was selected for the study of medium size at maturity and female egg production, due to its abundance and frequency in samples during low-water season in 1997 and high-water season in 1998, in Amapá Lake, Western Amazônia. The primiparous female had a size of 330 μm and 340 μm in low and high water, respectively. Moina individuals reached maximum size during high water (595μm). The medium size of the ovigerous females, in low water was 501 μm, producing an average of 4.41 eggs/female, while in high water, it was 533μm, with an average egg production of 4.84 eggs/female. The results, analyzed by the t test and Fischer's F test, showed that there were no statistical differences in size among individuals (t= -10.69, F=1.20 and P>0.1227), nor among ovigerous females (t= -4.45, F=1.02 and P>0.8906), considering the two seasons. Unesp/SP Campus de Jaboticabal Centro de Aquicultura - Caunesp, Av. Jaime Ribeiro, 14.870.000 Jaboticabal, Sao Paulo Universidade Federal do Acre Campus Universitário, Distrito Industrial, 69.915,900 Rio Branco, Acre Ctro. Pesq. em Biol. Aquatica-CPBA Inst. Nac. de Pesq. da Amazonia-Inpa, Av. Alameda Cosme Ferreira 1756, 69083-000 Manaus, Amazonas Unesp/SP Campus de Jaboticabal Centro de Aquicultura - Caunesp, Av. Jaime Ribeiro, 14.870.000 Jaboticabal, Sao Paulo