An assessment of the introduced mosquitofish (Gambusia affinis holbrooki) as a predator of eggs, hatchlings and tadpoles of native and non-native anurans

2000 ◽  
Vol 27 (2) ◽  
pp. 185 ◽  
Author(s):  
Spogmai Komak ◽  
Michael R. Crossland

The introduced mosquitofish (Gambusia affinis holbrooki) is a pest species in Australia and has been implicated in the decline of populations of native fishes and anurans. However, few quantitative data exist regarding interactions between Gambusia and native aquatic fauna. We used replicated laboratory experiments to investigate predation by G. a. holbrooki on eggs, hatchlings and tadpoles of native (Limnodynastes ornatus) and non-native (Bufo marinus) anurans. Our aims were to determine (1) whether the susceptibility of anurans to predation by G. a. holbrooki changes during larval development, and (2) the potential for G. a. holbrooki as a predator of the introduced toad B. marinus. Gambusia were significant predators of all aquatic life-history stages of L. ornatus, but were significant predators of B. marinus only at the hatchling stage. When offered both species simultaneously, Gambusia consumed tadpoles of L. ornatus but avoided those of B. marinus. The differences between the responses of Gambusia to L. ornatus and B. marinus are probably due to differences in palatability and toxicity of eggs, hatchlings and tadpoles of these species. The results indicate that G. a. holbrooki is unlikely to significantly affect larval populations of B. marinus via predation. However, Gambusia has the potential to significantly affect larval populations of L. ornatus in natural water bodies where these species co-occur.

1998 ◽  
Vol 25 (4) ◽  
pp. 373 ◽  
Author(s):  
Michael R. Crossland

Few quantitative data exist regarding the impact of the introduced cane toad, Bufo marinus, on native Australian fauna. This study investigated predation by tadpoles of B. marinus and two native anurans (Limnodynastes ornatus and Litoria rubella) on eggs, hatchlings and larvae of native anurans that co-occur with these tadpoles in temporary and semi-permanent water bodies in northern Queensland. During controlled laboratory experiments, neither small nor large B. marinus tadpoles were significant predators of native anuran eggs, hatchlings or tadpoles. Small tadpoles of L. ornatus also did not prey significantly upon native anuran eggs, hatchlings or tadpoles. However, large tadpoles of L. ornatus and, to a lesser extent, L. rubella were often significant predators of native anuran eggs and hatchlings, but were not significant predators of native tadpoles. The results suggest that native tadpoles are often likely to have a greater impact on the survival of early life history stages of native anurans via predation than areB. marinus tadpoles.


2014 ◽  
Vol 281 (1795) ◽  
pp. 20140878 ◽  
Author(s):  
Kathryn McMahon ◽  
Kor-jent van Dijk ◽  
Leonardo Ruiz-Montoya ◽  
Gary A. Kendrick ◽  
Siegfried L. Krauss ◽  
...  

A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For example, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.


2020 ◽  
Vol 8 (10) ◽  
pp. 808
Author(s):  
Sara M. Garcia ◽  
Kevin T. Du Clos ◽  
Olivia H. Hawkins ◽  
Brad J. Gemmell

The eastern oyster Crassostrea virginica is an ecologically and economically important species that is vulnerable to oil pollution. We assessed sublethal effects of soluble fractions of crude oil alone (WAF) and crude oil in combination with Corexit 9500 dispersant (CEWAF) on oysters at three life history stages. Veliger swimming, pediveliger settlement, and adult clearance rates were quantified after 24 h exposures to the contaminants. Veliger swimming speeds were not significantly impacted by 24 h exposures to WAF or CEWAF. A larger proportion of veligers were inactive following WAF and CEWAF exposure as compared to the control, but the effect was greater for pediveligers, and pediveliger settlement in the highest concentration CEWAF treatment decreased by 50% compared to controls. Thus, pediveligers may be particularly vulnerable to oil exposure. In the adults, we found significant clearance rates reductions that persisted 33 days after acute exposure to CEWAF. Knowledge of sublethal effects of oil and dispersant at multiple life history stages aids understanding of how this important species will respond to an oil spill.


1991 ◽  
Vol 48 (10) ◽  
pp. 1820-1828 ◽  
Author(s):  
Pierre Pepin ◽  
Ransom A. Myers

Recruitment variability is commonly associated with fluctuations in abundance of marine fish populations. Previous studies have focussed on stock-specific correlative or mechanistic models or on comparisons of recruitment variations of several stocks or species. The purpose of this study is to determine whether recruitment variability of commercial marine fish populations is associated with either size or the duration of early life history stages. The analysis was performed with data from 86 stocks representing 21 species of commercial marine fish. Univariate analysis shows that neither egg size nor the length at hatch is significantly correlated with recruitment variability. The change in length during the larval phase, which is representative of the duration of the stage, is significantly positively correlated with recruitment variability. Multivariate analysis shows that recruitment variability increases with increasing length at metamorphosis but that recruitment variability is poorly associated with length at hatch. The degree of serial correlation is related to the relative duration of egg and larval stages. The results clearly indicate that recruitment variability is linked to characteristics of early life history stages.


2012 ◽  
Vol 277 ◽  
pp. 54-66 ◽  
Author(s):  
Uromi M. Goodale ◽  
Mark S. Ashton ◽  
Graeme P. Berlyn ◽  
Timothy G. Gregoire ◽  
B.M.P. Singhakumara ◽  
...  

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