scholarly journals Seasonal and ontogenetic variations in the diet of Cichla kelberi Kullander and Ferreira, 2006 introduced in an artificial lake in southeastern Brazil

2010 ◽  
Vol 70 (4) ◽  
pp. 1033-1037 ◽  
Author(s):  
LM Gomiero ◽  
GA Villares Junior ◽  
F Naous

The diet of Cichla kelberi introduced in an artificial lake in Leme-SP was predominantly composed of common fish species (Oreochromis niloticus and C. kelberi). In the spring and summer, the most consumed item was O. niloticus. However, cannibalism was very common for this species. The high frequencies of O. niloticus and C. kelberi reveal that this species is adapted to a seasonal cycle, feeding on the most common prey in each period of the year, with a reduction of foraging activity during the winter. The diets were different among the immature and mature individuals suggesting that there are ontogenetic differences, mainly related to prey type, such as: Ephemeroptera consumed by the immature peacock bass and fish by the mature ones, besides the size of the prey.

2009 ◽  
Vol 69 (1) ◽  
pp. 175-183 ◽  
Author(s):  
LM. Gomiero ◽  
GA. Villares Junior ◽  
F. Naous

The objective of this study was to characterize the reproduction of Cichla kelberi in an artificial lake, located in the municipality of Leme, in the state of São Paulo, Brazil. Breeding occurred in spring, and summer. The L50 and the L100 of this species were 192 and 235 mm (L50), for males and females, respectively, and 290 mm (L100) for both sexes. Spawning was parceled. The oocytes matured at a size of 428.4 µm, reaching their maximum at 2,203.2 µm. A mean of fecundity were of 12,129.2 oocytes, with the mean of oocytes in each batch of 4,897.7. This species has external fertilization, is nonmigratory, and with parental care of the young. Various attributes of the peacock bass make their introduction a temptation. However, due to their feeding and reproductive characteristics, they have no natural predators, making it difficult to control their population growth or eradicate them.


2005 ◽  
Vol 65 (2) ◽  
pp. 211-215 ◽  
Author(s):  
R. M. Bonaldo ◽  
J. P. Krajewski ◽  
I. Sazima

The banded butterflyfish (Chaetodon striatus) from the tropical and subtropical western Atlantic is a territorial, diurnal forager on benthic invertebrates. It is usually seen moving singly or in pairs, a few meters above the sea floor. We studied the foraging activity of C. striatus on rocky reefs in southeastern Brazil. This fish spent about 11 h and 30 min per day on feeding activities, and preferred colonies of non-scleratinian anthozoans over sandy and rocky substrata while foraging. The lowest feeding rates were recorded in the early morning and late afternoon, but we found no further differences between feeding rates throughout the day. We also found no differences between the feeding rates of paired and single individuals.


2012 ◽  
Vol 102 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Lívia B. Santos ◽  
Nelio R. dos Reis ◽  
Mário L. Orsi

Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) is a semi-aquatic animal spread through the Central and South America, except in Chile. The implantation of a hydroelectric power plant along a river alters the dynamics of the watercourse, transforming a lotic environment into a lentic or semilotic one, what can damage the otter's feeding. From April 2008 to March 2009 we analysed the otter's food habits in lotic (streamlet) and semilotic (hydroelectric reservoir) environments of Paranapanema Valley, in southeastern Brazil. Aiming to compare the otter's diet of these two environments, we analyzed statistically the frequency of occurrence of main items in the scats. Fishes represent the base of the diet both in the reservoir and in the streamlet and, despite of the total otter's diet showing up similarities in the two environments, the results evidenced modifications on the fish species consumed between them. In the reservoir the otters ate more exotic fish Oreochromis niloticus (Linnaeus, 1758) probably because it is an easy capture prey in this place. The fact that the otters get established and feed in the reservoir doesn't mean that this structure is benefic to the species because the food supplied for it consists mainly of exotic fish species.


2010 ◽  
Vol 8 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Fernando Zaniolo Gibran

Based on a fish survey and preliminary underwater observations, 17 "morphotypes" were identified that characterize the morphological diversity found within 27 nektonic fish species sampled at São Sebastião Channel. Such "morphotypes" were studied using an ecomorphological approach, with the intention to investigate similarities and differences in shape and habits. Underwater field observations were also performed, to verify if the lifestyle of these species, such as vertical occupation of the water column and the habitat use, are in accordance with their distribution in the morphospace. The results, complemented with data from scientific literature on the taxonomy and phylogenies of these species, allowed discussing some of the typical cases of convergent and divergent evolution. Some of the ecomorphological clusters had no phylogenetic support although this is probably due to the environmental conditions in which theirs members have evolved. The body shape and fins positions of a fish clearly influence its ecological performance and habitat use, corroborating the ecomorphological hypothesis on the intimate link between phenotype and ecology.


2006 ◽  
Vol 4 (2) ◽  
pp. 291-294 ◽  
Author(s):  
Mark D. Bowen ◽  
Simone Marques ◽  
Luiz G. M. Silva ◽  
Volney Vono ◽  
Hugo P. Godinho

On site human observations and video images were collected and compared at the window of the Igarapava Dam fish ladder (IDFL), rio Grande , Southeastern Brazil, between March 1st and June 30th, 2004. We conducted four experiments with two humans (Observer 1 and Observer 2) observing fish passage in the IDFL window while a Sony 3CCD video camera (Observer 3) recorded fish passage at the same time. Experiments, each one hour in length, were distributed throughout the diel cycle using full spectrum lights. We identified fish species, the number of individuals for each species, and the real time that they passed. Counts from each human observer were compared to the video counts. The fish species most commonly observed in the window were - curimba (Prochilodus lineatus), mandi-amarelo (Pimelodus maculatus), piau-três-pintas (Leporinus friderici) and ferreirinha (Leporinus octofasciatus). The number of species and individuals were indistinguishable for the three observers. But, the number of species and individuals were significantly different among experiments. Thus, the three observers register the same number of species and count the same number of individuals even when these two response variables differ significantly among experiments. Based on these results, we concluded that the video count was an accurate method to assess fish passage at the IDFL.


2018 ◽  
Vol 23 (3) ◽  
pp. 193
Author(s):  
Samuel Samuel ◽  
Yoga Candra Ditya ◽  
Vipen Adiansyah

Introduksi ikan nila atau “serapia” (Oreochromis niloticus) di Danau Paniai bertujuan untuk meningkatkan diversitas hasil tangkapan dan mengurangi tekanan eksploitasi terhadap jenis ikan endemik. Pertumbuhan dan produksi ikan nila yang cepat tanpa diiringi upaya pengelolaan akan mengancam keberlanjutan ikan endemik di danau. Upaya pengelolaan sumberdaya ikan di suatu perairan membutuhkan informasi dinamika populasi. Penelitian dinamika dan pengelolaan populasi ikan nila dilakukan pada bulan Februari sampai Oktober 2016. Contoh ikan dikumpulkan dari hasil tangkapan nelayan dengan menggunakan jaring insang dengan berbagai ukuran mata jaring dan dari 4 (empat) enumerator pada tujuh stasiun pengamatan. Hasil penelitian menunjukkan populasi ikan nila di Danau Paniai didominasi ukuran panjang individu antara 15-25 cm sebanyak 67,24%. Pola pertumbuhan ikan jantan dan betina adalah isometrik, panjang maksimum rata-rata (L) adalah 37,28 cm dan koefisien pertumbuhan (K) adalah 0,50 per tahun. Mortalitas alami (M) dan mortalitas penangkapan (F) masing-masing sebesar 0,99 dan 0,54 per tahun. Tingkat eksploitasi (E) diperoleh nilai 0,35 lebih kecil dari nilai optimum (E=0,5). Ukuran rata-rata ikan nila tertangkap (Lc) adalah 20,55 cm lebih besar dari ukuran pertama matang gonad (Lm) sebesar 14,73 cm. Nilai Lc>Lm mengindikasikan sebagian besar populasi ikan nila di Danau Paniai sempat melakukan pemijahan sehingga pemanfaatan lebih atau sama dengan nilai optimum diharapkan dapat meningkatkan pemanfataan ikan nila di Danau Paniai. Introduction of nile tilapia (Oreochromis niloticus) in Lake Paniai known as “serapia” is aimed for improving the diversity of catches and reducing the exploitation pressure on the endemic fish species. The rapid growth, reproduction and production of nile tilapia without its management efforts is a new threat to the sustainability of the existence and utilization of endemic fish species in the lake. Management efforts of fish resources require population dynamics information. Research on the dynamics and management of nile tilapia populations was conducted from February to October 2016. Fish samples were collected from fishermen catches using nets with various mesh sizes and from four enumerators at seven observation stations. The results showed that the population of nile tilapia in Lake Paniai was dominated by individual length between 15-25 cm with frequency of 67,24%. The growth pattern of male and female fish were isometric, the average maximum length (L) was 37.28 cm and the growth coefficient (K) was 0.50 per year. Natural mortality (M) and fishing mortality (F) were 0.99 and 0.54 per year respectively. Exploitation rate (E) of 0.35 was smaller than the optimum value (E=0.5). The average size of nile tilapia captured (Lc) was 20.55 cm larger than the first size of gonad maturity (Lm) of 14.73 cm. The Lc value was higher than that the Lm value(Lc>Lm) indicating that most of nile tilapia population in Lake Paniai has spawned so that increasing the more or equal to the optimum value was expected to improve the of nile tilapia fish in Lake Paniai.


2019 ◽  
Vol 11 (2) ◽  
pp. 205-209
Author(s):  
Oluwadamilare E. OBAYEMI ◽  
Olusola O. KOMOLAFE ◽  
Oluwakemi V. OKUNOLA ◽  
Sakirat T. ASAFA ◽  
Mary A. AYOADE

This study investigated the length-weight relationships and condition factors of three fish species in an abandoned gold mine reservoir. The fishes were caught on monthly basis between August 2015 and July 2016 using gill nets and traps. The results showed that Coptodon zillii, Oreochromis niloticus and Sarotherodon galilaeus had a mean total length and mean weight of 15.52±4.64 cm and 95.80±66.27 g; 15.27±4.18 cm and 89.54±63.20 g; 15.57±4.80 cm and 102.0±85.81 g respectively. Also, the mean condition factor obtained for the fish species are 2.24±0.52 in C. zillii; 2.26±0.62 in O. niloticus and 2.27±0.46 in S. galilaeus. Similarly, the slope (b) values and correlation coefficient for the three fish species are 2.018 and 0.969 for C. zillii; 1.977 and 0.926 for O. niloticus and 2.436 and 0.965 for S. galilaeus. Furthermore, the total length, weight and condition factor between C. zillii, O. niloticus and S. galilaeus differ significantly (p>0.05). The study concluded that despite being an abandoned gold mine reservoir, the environment is well suitable for the fishes.


2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Adrehem J. Nziku ◽  
Lucy Namkinga

The aim of this study was to examine the availability, concentration levels and bioaccumulation of heavy metals namely; Mercury (Hg), Cadmium (Cd), Lead (Pb), Zinc (Zn) and Molybdenum (Mo) in the waste Stabilization Ponds of the University of Dar es Salaam. A total of 135 samples were analyzed, out of which 27 were samples of water, 27 of sediments and 81 samples of fish tissues. Two types of fishes were used namely; Oreochromis niloticus and Clarias gariepinus. Heavy metal concentration varied significantly between water, sediment, fish species and tissues. Hg, Cd, Zn and Mo concentrations in water and sediment were within WHO safe limits. However, Pb in water and Cd, Pb and Zn concentrations in sediments were found to be above WHO standards (p<0.05). Concentration levels for Cd, Pb and Zn were above acceptable levels in Oreochromis niloticus while Hg was found to be within safe limits in both fish species (p<0.05). Molybdenum was found to be below the detection limits in Oreochromis niloticus. While Cd was not detected, Pb, Zn and Mo were found highly accumulated in Clarias gariepinus (p<0.05). Oreochromis niloticus accumulated metals in the increasing order from dorsal muscles < gills < liver while Clarias gariepinus accumulated metals in the decreasing order from dorsal muscle < gills < liver.Public awareness on the dangers to which fish consumers from the site are exposed is highly suggested and purposeful mitigation measures of stopping all fishing activities in these sites is needed, also animal feeding around the ponds should be forbidden.


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