Detection of predation on Australian native fishes by Gambusia holbrooki

1999 ◽  
Vol 50 (5) ◽  
pp. 467 ◽  
Author(s):  
Walter Ivantsoff ◽  
Aarn

Clearing and staining of Gambusia holbrooki facilitated identification of juvenile fishes among the gut contents, and a feeding trial with captive Gambusia allowed assessment of gut transit time and degradation of melanotaeniid larvae. Regurgitated fishes and eggs in fixative solutions were also investigated. These techniques, extending to 12 h the post-feeding interval in which fishes may be found and differentiated among Gambusia gut contents, were tested on 631 wild-caught Gambusia collected in eastern Australia; an ingested native fish could be identified in the gut of 18 Gambusia, and a cannibalized fish in the gut of three.

1982 ◽  
Vol 62 (4) ◽  
pp. 1199-1209 ◽  
Author(s):  
V. A. POUTEAUX ◽  
G. I. CHRISTISON ◽  
C. S. RHODES

Two experiments were conducted to evaluate the involvement of dietary protein and short-term chilling on the incidence of diarrhea and on transit time of digesta in pigs weaned at 3–4 wk of age. The three protein sources used were buttermilk powder (BMP), soybean meal (SBM) or pea protein concentrate (PPC), which provided 85% of the dietary protein. In exp. 1, 72 pigs were exposed to a 16 °C decrease in ambient temperature for 8 h on day 4 of a 9-day feeding trial; 72 pigs were not chilled. The pigs on the PPC diet gained less (539 g) (P < 0.05) than pigs on BMP (1183 g) or SBM (952 g) although intakes were similar. Neither diet nor chilling affected fecal moisture content or the incidence of diarrhea. The PPC ration increased (P < 0.05) transit time (slowed rate of passage) on day 8. Chilling on day 4 decreased (P < 0.05) transit time (18.7 vs. 25.6 h) on that day. Neither protein source nor chilling caused differences in total or coliform bacteria isolated from fecal samples on blood agar or MacConkey's agar. In exp. 2, eight chilled and nine control pigs were euthanized and the quantity of three markers in six segments of the gastrointestinal tract was determined. The PPC diet passed more slowly than the other diets. In chilled pigs, the chromic oxide front was closer to the anus, indicating an increased rate of passage. It was concluded that the severity of the cold exposure was not suffficient to induce diarrhea and that there was no interaction between the effects of chilling and of dietary protein. There was, however, a tendency for chilling to increase the rate of passage of digesta which could have an additive effect on the severity of nutritional diarrhea. Key words: Pigs, weaning, diarrhea, protein, cold, transit time.


Author(s):  
Tatia Kuljanishvili ◽  
Levan Mumladze ◽  
Bella Japoshvili ◽  
Namig Mustafayev ◽  
Shaig Ibrahimov ◽  
...  

The South Caucasus (SC) region is recognized for its high biological diversity and various endemic animal taxa. The area has experienced many fish introductions over the years, but the overall information about non-native fishes in the three SC countries, Armenia, Azerbaijan, and Georgia did not exist. Although these three countries belong to the Kura River drainage, Caspian Sea basin (only the western half of Georgia drains into the Black Sea), the legislative framework for each country regarding introduction of non-native fish species and their treatment is different and poorly developed. The goal of the present study was to make an initial inventory of non-native fish species in the three SC countries, and summarize the existing knowledge as a basis for future risk assessment models and formulation of regional management policies. Here, we present a unified list of 27 non-native species recorded in the wild in Armenia, Azerbaijan, and Georgia. Among these 27 species, eight were translocated from the Black Sea basin to the Caspian Sea basin. Out of these 27 non-native fishes, 15 species have become established (three of them being considered invasive) and six fish species could not survive in the wild.


2020 ◽  
Vol 71 (11) ◽  
pp. 1464
Author(s):  
John D. Koehn ◽  
Stephen R. Balcombe ◽  
Lee J. Baumgartner ◽  
Christopher M. Bice ◽  
Kate Burndred ◽  
...  

The Murray–Darling Basin (MDB) is Australia’s food bowl, contributing 40% of agricultural production and supporting a population of over 4 million people. Historically, the MDB supported a unique native fish community with significant cultural, subsistence, recreational, commercial and ecological values. Approximately one-quarter of the MDB’s native species are endemic. Changes to river flows and habitats have led to a &gt;90% decline in native fish populations over the past 150 years, with almost half the species now of conservation concern. Commercial fisheries have collapsed, and important traditional cultural practices of First Nations People have been weakened. The past 20 years have seen significant advances in the scientific understanding of native fish ecology, the effects of human-related activities and the recovery measures needed. The science is well established, and some robust restoration-enabling policies have been initiated to underpin actions. What is now required is the political vision and commitment to support investment to drive long-term recovery. We present a summary of 30 priority activities urgently needed to restore MDB native fishes.


2010 ◽  
Vol 61 (1) ◽  
pp. 23 ◽  
Author(s):  
Ivor G. Stuart ◽  
John D. Koehn ◽  
Tim A. O'Brien ◽  
John A. McKenzie ◽  
Gerry P. Quinn

A major environmental issue for hydro-electric power generation is passage of fish through turbines, or entrainment onto trash racks. At Yarrawonga Weir, on the upper Murray River in south-eastern Australia, the positioning of a fish lock resulted in the potential for upstream migrating fish to be swept back into the adjacent power station by cross flows. In 2004, a 4.5-m long steel extension flume was attached to the exit to alleviate this problem. To determine the fate of native fish after exiting the extension flume, 72 individuals (305–1015 mm long) were implanted with radio-transmitters and released into the fish lock exit channel. In 2004 (power station inflows 10 300 ML day–1), the majority of fish exited successfully (44 of 45) and only a single fish (2%) was entrained into the power station. In 2005 (power station inflows 12 000 ML day–1), fish again exited successfully (26 of 27) but with a higher proportion entrained (5 of 27; 18%). This reduced success appeared to be related to strong transverse flows with high water velocities adjacent to the fish lock exit. The efficiency of fish passage at this site might be improved by altering water management strategies, integrating engineering and fish biology, and through field-testing of proposed solutions.


1980 ◽  
Vol 31 (1) ◽  
pp. 61 ◽  
Author(s):  
PD Jackson ◽  
WD Williams

Eight species of native fish and two of introduced fish were found during studies of the distribution of fishes in streams in three areas of southern Victoria; namely in the upper part of the catchment of the Yarra River, in the Otway Ranges, and on Wilsons Promontory. S. trutta does not occur on Wilsons Promontory, but does occur in the other two areas. Results provide circumstantial evidence that S. trutta has deleteriously affected the occurrence of Galaxias olidus and possibly G. brevipinnis. Some native fishes appear able to coexist with S. trutta.


2021 ◽  
Vol 25 (02) ◽  
pp. 565-587
Author(s):  
Diego Azevedo Zoccal Garcia ◽  
◽  
Fernando Mayer Pelicice ◽  
Marcelo Fulgêncio Guedes de Brito ◽  
Mário Luís Orsi ◽  
...  

Biological invasions are among the main causes of biodiversity loss on planet. Losses are accentuated in streams, which are sensitive to human impacts, since they have specialized fauna and higher degree of endemism. Despite this, studies on invasions by non-native fish in streams are incipient in Brazil. In this review, we present an introduction on the process (i.e., stages) of biological invasion, the environmental factors that influence the establishment and the impacts of non-native species in streams. A methodological step-by-step is also presented as a way to guide the conduct of studies on non-native species in Brazilian streams. In addition, management actions measures are presented to prevent new cases of introductions and suggestions for studies on invasions in streams. Avoiding propagule pressure and environmental education, as well as legal aspects of Brazilian legislation, are management actions that can prevent new introductions. Finally, gaps in knowledge and perspectives are raised as an incentive for interested parties to enter the subject and develop new studies on non-native fishes in Brazilian streams.


2019 ◽  
Author(s):  
Erick Loayza

ABSTRACTLake Titicaca (∼3800 m a.s.l.), an emblematic tropical-mountain ecosystem is the major source of fish for people on the Altiplano. The Andean killifish genus Orestias, represent an important resource for local fisheries in Lake Titicaca. It has been suggested that exist an effect of segregation in the Lake Titicaca in order to avoid competition for food resource between native fish species, due most of Orestias species share the littoral habitat, which is now also share with introduced species. Such scenario increases the pressure for food resource. Here I examined the gut content of O. luteus, O. agassizii and O. mulleri (Cuvier & Valenciennes, 1846) from a bay of Lake Titicaca during rainy (April) and dry season (July) with the predominance method, frequency of occurrence and numerical percentage to describe the diet and dietary overlap between these native fish. I also applied a PERMANOVA test in order to determine diet variations related to depth and seasonally, as well as the Levins and Pianka’s index to test diet breadth and dietary overlap respectively. 396 gut contents were evaluated, identifying a high frequency of amphipods and molluscs in the three Orestias native species. Diet breadth revelled a selectivity for a few preys and the composition of the diets was influenced mainly by depth, followed by seasonality (PERMANOVA, P = <0.05). Dietary overlapping between O. luteus and O. agassizii was evidenced in the rainy season. During the dry season, the three species undergone dietary overlapping. This study provided a detail knowledge on the diet variations of native species in Lake Titicaca, especially for Orestias mulleri, a little-known species. Here I also discussed the importance of the amphipods as a food resource in Lake Titicaca not only for fish community, but for the food web in general. The seasonal and depth diet variations here discussed are relevant for fisheries management and conservation and could be used to guide aquaculture development in Lake Titicaca.


2021 ◽  
Vol 48 (5) ◽  
pp. 311-327
Author(s):  
R. T. Sani ◽  
H. O. Okin-Aminu ◽  
W. Idowu ◽  
N. P. Achi ◽  
S. A. Ahmed ◽  
...  

The need to observe the changes taking place in the animal's body in response to external factors such as nutrition, housing system and microclimate as it affects intake, rumen metabolite, haematological and biochemical parameters cannot be over-emphasized. Against this background, a study was conducted to evaluate the effect of feeding diets containing graded levels of Palm Kernel Cake (PKC) on feed intake, rumen metabolites, haematological and biochemical characteristics of yearling Bunaji bulls. Twenty yearling Bunaji bulls with average weight of 130kg and aged 1-1.5 years were balanced for weight and allotted to five dietary treatments with four bulls per treatment in Completely Randomized Design. They were individually penned and fed diets containing graded levels of PKC at (0, 10, 20, 30 and 40%) and Digitaria smutsii (Wholly finger grass) hay at 4% body weight (2% concentrate and 2% hay). The feeding trial lasted for 90 days. Blood samples were collected at the beginning, middle and end of the feeding trial to determine some haematological and biochemical changes. Rumen fluid were collected at 0, 3, 6 and 9hrs intervals to determine the rumen pH, rumen ammonia nitrogen(RAN) and rumen total volatile fatty acids(TVFA) for the yearling bulls. The CP contents of the experimental diets varied between 14.19 and 17.75% while ME ranged from 11.79 to11.81MJ/kg DM. The crude fibre varied from 26.36-38.77%. Average feed intake ranged between 5.38-5.61Kg/day with animals on 10%, 20% and 40% PKC being statistically similar (P>0.05).Rumen parameters were significantly (P<0.05) affected by sampling time, such that at 0hrRumen pH was highest (7.08) and lowest at 3hrs post feeding(6.66),RAN value was similar at 0hr pre feeding (10.44 mg/100mL) and 3hr post feeding (9.93 mg/100mL) but differ at 6hr (8.25 mg/100ml) and 9hrs post feeding (8.34mg/100mL).There was significant difference (P< 0.05) among treatments for all the haematogical and biochemical parameters measured. Highest urea value was obtained at 0% PKC inclusion, animals on diets containing 20,30 and 40%PKC were statistically similar (P>0.05), Total protein ranged from 70.83 - 78.92 g/l and highest value was obtained at 30% PKC inclusion, animals on diets containing 10% and 20%PKC were statistically similar (P>0.05) but differ from 40%. The study concluded that up to 40% inclusion level of PKC could be added to the diets of yearling Bunaji bulls with no adverse effect on their feed intake, rumen metabolite and some of their blood parameters.     La nécessité d'observer les changements qui se déroulent dans le corps de l'animal en réponse à des facteurs externes tels que la nutrition, le système de logement et le microclimat, car il affecte l'apport, le métabolite du rumen, les paramètres hématologiques et biochimiques ne peuvent pas être surestimés. Dans ce contexte, une étude a été menée pour évaluer l'effet de l'alimentation des régimes alimentaires contenant des niveaux classés de gâteau au noyau de palmier (GNP) sur l'apport alimentaire, les métabolites rumen, les caractéristiques hématologiques et biochimiques des taureaux de Bunaji d'Annulation. Vingt Bunaji Bunaji avec poids moyen de 130 kg et de 1 à 1,5 ans ont été équilibrés pour poids et alloué à cinq traitements diététiques avec quatre taureaux par traitement dans une conception complètement randomisée. Ils ont été individuellement engagés et nourris à des régimes alimentaires contenant des niveaux classés de GNP à (0, 10, 20, 30 et 40%) et digitariasmutsii (à 100% de l'herbe à doigts) à 4% de poids corporel (concentré de 2% et 2% de foin). L'essai d'alimentation a duré 90 jours. Les échantillons de sang ont été collectés au début, au milieu et à la fin de l'essai d'alimentation afin de déterminer des changements hématologiques et biochimiques. Les liquides de rumen ont été recueillis à des intervalles de 0, 3, 6 et 9hrs pour déterminer le pH de rumen, l'azote d'ammoniac rumen (AAR) et les acides gras volatils rumen (AGVV) pour les taureaux yearling. Le contenu du CP des régimes expérimentaux variait entre 14,19 et 17,75%, tandis que je suis allant de 11,79 à 11,81 MMJ / kg DM. La fibre brute variait de 26,36-38,77%. L'admission moyenne d'aliments allait entre 5,38 et 5,61 kg / jour avec des animaux sur 10%, 20% et 40% GNP étant statistiquement similaires (p> 0,05). Rumen Les paramètres étaient significativement (p <0,05) affectés par le temps d'échantillonnage, tel que à 0hr rumen Le pH était le plus élevé (7.08) et le plus bas à 3 heures d'alimentation post (6,66), la valeur de AAR était similaire à 0HR pré-alimentation (10,44 mg / 100 ml) et 3hrs post-alimentation (9,93 mg / 100 ml) mais diffèrent à 6h (8,25 mg / 100 mg). et 9 heures après l'alimentation (8h34 mg / 100 ml) était une différence significative (p <0,05) parmi les traitements pour tous les paramètres hématogiques et biochimiques mesurés. La valeur la plus élevée de l'urée a été obtenue à 0% d'inclusion de GNP, les animaux sur les régimes contenant 20,30 et 40% de GNP étaient statistiquement similaires (p> 0,05), une protéine totale allait de 70,83 - 78,92 g / l et une valeur la plus élevée a été obtenue à 30% de GNP. L'inclusion, les animaux sur les régimes contenant 10% et 20% de GNPétaient statistiquement similaires (p> 0,05) mais diffèrent de 40%. L'étude a conclu que jusqu'à 40% de niveau d'inclusion de GNP pouvait être ajouté au régime alimentaire des taureaux de la Bunaji qui n'y a pas d'effet défavorable sur leur consommation d'alimentation, le métabolite du rumen et certains de leurs paramètres de sang.


Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1217
Author(s):  
Kangshun Zhao ◽  
Chao Li ◽  
Tao Wang ◽  
Bowen Hu ◽  
Min Zhang ◽  
...  

Controlling the invasion of non-native fish species necessitates a complete understanding of the distribution of these species and the key factors that influence such distribution. In order to research the situation of non-native fish and the relevant influencing factors in the Liao River Basin, we investigated and analyzed the characteristics of the distribution and the trophic levels of non-native fish species, as well their response to different types of factors in the basin. Nine non-native fish species were found during the investigation, and the trophic levels of these species ranged between 2.00 and 3.84. The results of generalized linear models indicate that the distribution of non-native fish species in the basin is mainly related to anthropogenic activities, socioeconomic development, and climate. The southeastern part of the Liao River Basin is conducive to the distribution of non-native fish species. Furthermore, on a spatial scale, we also found that the mean trophic level of non-native fish species was not correlated with anthropogenic activities and socioeconomic development in the Liao River Basin. By providing evidence for the links between non-native fishes and different types of factors, our study contributes to increasing the relevant references for and experiences in the early detection and management of non-native fishes on a basin scale.


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