scholarly journals Dynamics of reproductive ecology of the fish Ompok bimaculatus (Siluriformes: Siluridae) in six tropical rivers of the Ganges basin, India

2017 ◽  
Vol 9 (1) ◽  
pp. 73-85
Author(s):  
Agnihotri Praveen ◽  
Sarkar Uttam Kumar ◽  
Nagpure Naresh Sahebrao ◽  
Mishra Rahsya Mani ◽  
Kumar Ravindra ◽  
...  

The silurid butter catfish, Ompok bimaculatus (Bloch, 1794), is widely distributed in the plains and sub-mountain regions of India, but not enough is known about its reproductive potential is still insufficient. The present study evaluated the comparative reproductive potential (in terms of sex ratio, spawning season, body size at first go­nadal maturity, gonadosomatic index, fecundity, egg dimension, egg weight etc.) of fish (n=1223) from six tropical tributaries of the Ganges basin during January 2011-December 2013. The females had relatively greater weight and length. The body size at 50% first gonadal matu­rity (L50%) ranged between 228-262mm in females and 198-247mm in males. The population has high and low fecundities. The correlations between absolute fecundity and total length, as well as between body weight and gonad weight, were significant (p<0.05) and positive in all the population.

2009 ◽  
Vol 57 (4) ◽  
pp. 263-272 ◽  
Author(s):  
Hilda Caramantin-Soriano ◽  
Luz Amelia Vega-Pérez ◽  
Miguel Ñiquen

The influence of the 1992-1993 El Niño events on the reproductive behavior of the Scomber japonicus peruanus (Chub mackerel) was studied from samples collected monthly, along the Peruvian coast (3º23'S-14º00'S), from January 1990 to December 1993. The monthly variation of the gonadosomatic index and the frequency of the periods of gonad maturation evidenced that the spawning of the species occurred all year long, being more intense in summer. The values of the gonadosomatic index were higher during the occurrence of the 1992-1993 El Niño, while the body weight and gonad weight decreased. Regarding the condition factor, its values decreased in females over 35 cm in fork length.


2017 ◽  
Vol 11 (4) ◽  
pp. 339 ◽  
Author(s):  
Irin Iriana Kusmini ◽  
Fera Permata Putri ◽  
Vitas Atmadi Prakoso

Eksploitasi ikan lalawak (Barbonymus balleroides) yang berlebihan dari alam mengakibatkan langkanya jenis ikan ini di beberapa perairan aslinya. Sebelum ikan ini diperkenalkan sebagai komoditas budidaya, masih diperlukan lebih banyak lagi informasi mengenai aspek bioreproduksi ikan lalawak yang telah dipelihara pada lingkungan budidaya. Tujuan dari kegiatan ini adalah untuk mengevaluasi produktivitas ikan lalawak yang dipelihara pada lingkungan budidaya melalui pengamatan bioreproduksi dan hubungan panjang-bobot terhadap fekunditas. Sampel induk ikan lalawak betina yang diambil sebanyak 15 ekor, kemudian dipilih lima ekor induk betina yang telah matang gonad dengan ciri-ciri seluruh badannya terasa kasar apabila diraba, perut membesar ke arah posterior dan terasa lunak, genital mengembang, serta berwarna kemerahan. Data yang dikoleksi berupa panjang total, bobot badan, bobot gonad, fekunditas, diameter telur, dan indeks kematangan gonadnya. Hasil penelitian menunjukkan bahwa kisaran fekunditas ikan lalawak adalah 1.920-2.236 butir/g bobot gonad, dan 83-352 butir/g bobot badan induk dengan rata-rata diameter telur 0,87-1,10 mm. IKG berkisar 3,73%-18,36% dari kisaran bobot induk 85,32-264,8 g. Hubungan antara bobot badan dengan bobot gonad ikan lalawak digambarkan dengan persamaan linear y= 5,829ln (x) + 0,691 (r= 0,874); sedangkan hubungan panjang badan terhadap bobot gonad digambarkan dengan persamaan y= 28,52ln (x) - 38,10 (r= 0,7487). Pada ikan lalawak, hubungan bobot badan dengan fekunditas lebih erat dibandingkan dengan hubungan panjang badan terhadap fekunditas. Hasil pengamatan juga menyimpulkan bahwa ikan lalawak tergolong ikan yang memijah secara parsial.Over-exploitation of lalawak (Barbonymus balleroides) from its natural habitat had significant negative impacts on its availability. Before it is introduced as aquaculture commodity, more information about its reproductive biology in aquaculture environment needs to be well observed. The aim of this study was to determine the productivity of lalawak reared in aquaculture environment through observation of bioreproductionand relationship between fecundity and body length-weight of lalawak. Samplewas randomly taken from fifteen individuals female. From those samples, gonads were taken from five mature females for reproduction observation, by which the mature females were selected following specific criteria such as : their body feels rough if touched;enlarged abdomen posteriorly and felt soft; fluffy and reddish genital. Data collection consisted of measurement of the total length, body weight, gonad weight, fecundity, egg diameter and gonadosomatic index (GSI). The results revealed that the fecundity of lalawak ranged from 1,920 to 2,236 eggs/gof gonad weight and 83 to 352 eggs/g of body weight with average diameters of eggs ranged from 0.869 to 1.10 mm. GSI values ranged from 3.73 to 18.36% of 85.32 to 264.8g of body weight. The relationship between body weight and gonad weight of lalawak was described by the linear equation of y= 5,829ln (x) + 0.691 (r= 0.874), while the body length relationship to the gonad weight was described by the equation of y= 28,52ln (x) - 38.10 (r= 0.7487). Fecundity relationship with body weight of lalawak was closer than the length. The observations also concluded that lalawak is classified as partial spawning.


2021 ◽  
Author(s):  
Alena Samková ◽  
Jan Raška ◽  
Jiří Hadrava ◽  
Jiří Skuhrovec

ABSTRACTThe gregarious parasitoid strategy allows multiple larvae to complete development in a single host due to their tolerance and/or lower mobility and thus flexibly adjust their reproductive potential amidst changing environmental conditions. Reproductive success is generally measured as the number of each mother’s offspring. We propose that with scarcity of host, for gregarious parasitoids is important the view on the fertility not only of a mother but also of her offspring (F1 generation). Due to the body size-fitness correlation, each female deliberately adjusts the clutch size, determining the offspring body size and their reproductive potential. In our study, using Anaphes flavipes as a model species, we showed that under a limited number of hosts, the females reduced their fertility. We propose that the lower fertility of mothers can cause higher fertility in the F2 generation using a larger offspring body while halving fertility. The females increase their individual offspring’s fertility by reducing their own fertility. Moreover, we showed that with a scarcity of hosts, the mothers increased the number of their female offspring, and thus, they obtained more offspring in the F2 generation. Additionally, other costs and benefits of the gregarious strategy in relation to superparasitism were tested and discussed.


2019 ◽  
Vol 77 (2) ◽  
pp. 99-105
Author(s):  
Friday Elijah Osho ◽  
Ridwan Abiola Usman

Abstract The length-weight relationship, condition factor, fecundity, gonadosomatic and hepatosomatic indices of Parachanna obscura from the Anambra River were determined between December 2015 and June 2016. Eighty-three live samples of P. obscura were obtained from fishermen. Descriptive statistics, correlation and regression analysis were used to analyze the obtained data. The length-weight relationship had R values of 0.933, 0.843 and 0.896 for male, female and combined sexes, respectively. The b value of 3.133 for male and 2.674 for female were not significantly different (P>0.05). Mean condition factors of 0.89±0.33 and 0.80±0.21 were obtained for female and male, respectively. The largest number of eggs (10,965) was found in a female with the body weight of 154 g, gonad weight of 9.1 g and egg size of 1.3 mm, while the least fecund female with 1820 eggs weighed (94 g) and had a gonad weight 2.1 g with egg size of 1.0 mm. The hepatosomatic indices ranged between 0.55±0.20 and 0.64±0.29 in both male and female, respectively, while female gonadosomatic index average was 2.05±1.44. There was a positive correlation between fecundity and gonad weight.


2017 ◽  
Vol 25 (2) ◽  
pp. 161
Author(s):  
Sławomir Mitrus ◽  
Bartłomiej Najbar ◽  
Adam Kotowicz ◽  
Anna Najbar
Keyword(s):  
The Body ◽  

Author(s):  
Adrian Marciszak ◽  
Yuriy Semenov ◽  
Piotr Portnicki ◽  
Tamara Derkach

AbstractCranial material ofPachycrocuta brevirostrisfrom the late Early Pleistocene site of Nogaisk is the first record of this species in Ukraine. This large hyena was a representative of the Tamanian faunal complex and a single specialised scavenger in these faunas. The revisited European records list ofP.brevirostrisdocumented the presence of this species in 101 sites, dated in the range of 3.5–0.4 Ma. This species first disappeared in Africa, survived in Europe until ca. 0.8–0.7 Ma, and its last, relict occurrence was known from south-eastern Asia. The main reason of extinction ofP.brevirostrisprobably was the competition withCrocuta crocuta. The cave hyena was smaller, but its teeth were proportionally larger to the body size, better adapted to crushing bones and slicing meat, and could also hunt united in larger groups.


2021 ◽  
Vol 246 ◽  
pp. 106659
Author(s):  
Sunil Kumar Jha ◽  
Vinay Kumar Mishra ◽  
Chhedi Lal Verma ◽  
Navneet Sharma ◽  
Alok Kumar Sikka ◽  
...  

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Rungtip Wonglersak ◽  
Phillip B. Fenberg ◽  
Peter G. Langdon ◽  
Stephen J. Brooks ◽  
Benjamin W. Price

AbstractChironomids are a useful group for investigating body size responses to warming due to their high local abundance and sensitivity to environmental change. We collected specimens of six species of chironomids every 2 weeks over a 2-year period (2017–2018) from mesocosm experiments using five ponds at ambient temperature and five ponds at 4°C higher than ambient temperature. We investigated (1) wing length responses to temperature within species and between sexes using a regression analysis, (2) interspecific body size responses to test whether the body size of species influences sensitivity to warming, and (3) the correlation between emergence date and wing length. We found a significantly shorter wing length with increasing temperature in both sexes of Procladius crassinervis and Tanytarsus nemorosus, in males of Polypedilum sordens, but no significant relationship in the other three species studied. The average body size of a species affects the magnitude of the temperature-size responses in both sexes, with larger species shrinking disproportionately more with increasing temperature. There was a significant decline in wing length with emergence date across most species studied (excluding Polypedilum nubeculosum and P. sordens), indicating that individuals emerging later in the season tend to be smaller.


Author(s):  
Kent M. Daane ◽  
Xingeng Wang ◽  
Brian N. Hogg ◽  
Antonio Biondi

AbstractAsobara japonica (Hymenoptera: Braconidae), Ganaspis brasiliensis and Leptopilina japonica (Hymenoptera: Figitidae) are Asian larval parasitoids of spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae). This study evaluated these parasitoids’ capacity to attack and develop from 24 non-target drosophilid species. Results showed that all three parasitoids were able to parasitize host larvae of multiple non-target species in artificial diet; A. japonica developed from 19 tested host species, regardless of the phylogenetic position of the host species, L. japonica developed from 11 tested species; and G. brasiliensis developed from only four of the exposed species. Success rate of parasitism (i.e., the probability that an adult wasp successfully emerged from a parasitized host) by the two figitid parasitoids was low in hosts other than the three species in the melanogaster group (D. melanogaster, D. simulans, and D. suzukii). The failure of the figitids to develop in most of the tested host species appears to correspond with more frequent encapsulation of the parasitoids by the hosts. The results indicate that G. brasiliensis is the most host specific to D. suzukii, L. japonica attacks mainly species in the melanogaster group and A. japonica is a generalist, at least physiologically. Overall, the developmental time of the parasitoids increased with the host’s developmental time. The body size of female A. japonica (as a model species) was positively related to host size, and mature egg load of female wasps increased with female body size. We discuss the use of these parasitoids for classical biological control of D. suzukii.


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