Egg viability of the rotifer Brachionus urceolaris after ingestion by the predatory cladoceran Leptodora kindtii

The predatory cladoceran Bythotrephes longimanus (spiny water flea) has been invading lakes and damaging food webs across the central part of North America since the early 1980s. To understand its niche and that of the taxonomically related and native predatory cladoceran Leptodora kindtii, we investigated species survival after 12 h exposures to low dissolved oxygen (DO) concentrations in the laboratory. Bythotrephes longimanus (n = 690) exhibited a hypoxia tolerance limit (LC50) of 1.65 mg·L−1 DO (95% confidence interval: 1.59, 1.72 mg·L−1) and was significantly less tolerant of hypoxia than L. kindtii (n = 380), which exhibited an LC50 of 0.58 mg·L−1 DO (0.51, 0.65 mg·L−1). These lab-based physiological results are consistent with landscape-scale observations that B. longimanus successfully invades primarily mesotrophic and oligotrophic lakes, while L. kindtii inhabits a wider range of lakes that includes eutrophic ones. Climate change throughout the 21st century may increase the occurrence and severity of hypoxia in the hypolimnia of lakes and may provide a growing barrier to B. longimanus invasion.

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Viability of nematode eggs in high rate algal ponds: the effect of physico-chemical conditions

Water Science & Technology ◽

10.2166/wst.2000.0683 ◽

2000 ◽

Vol 42 (10-11) ◽

pp. 371-374 ◽

Cited By ~ 8

Author(s):

S. Araki ◽

J. M. González ◽

E. de Luis ◽

E. Bécares

Keyword(s):

Hydraulic Retention Time ◽

Pilot Scale ◽

High Rate ◽

Sterile Water ◽

Egg Viability ◽

High Rate Algal Ponds ◽

Helminth Eggs ◽

Physico Chemical ◽

Nematode Eggs ◽

Chemical Conditions

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

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Oocyte Ageing in Zebrafish Danio rerio (Hamilton, 1822) and Its Consequence on the Viability and Ploidy Anomalies in the Progeny

Animals ◽

10.3390/ani11030912 ◽

2021 ◽

Vol 11 (3) ◽

pp. 912

Author(s):

Swapnil Gorakh Waghmare ◽

Azadeh Mohagheghi Samarin ◽

Roman Franěk ◽

Martin Pšenička ◽

Tomáš Policar ◽

...

Keyword(s):

Danio Rerio ◽

Egg Quality ◽

Complete Loss ◽

Egg Viability ◽

Embryo Survival ◽

Hatching Rates

Fish egg quality can be markedly influenced by the oocyte age after ovulation. In this study, we examined the duration of oocyte ageing in the zebrafish (Danio rerio) and whether prolonged ageing is associated with the incidence of ploidy anomalies in the resulting embryos. Oocytes were incubated in vitro for 6 h post-stripping (HPS) at 26 °C and fertilized at 2-h intervals. Meanwhile, for eggs fertilized immediately after stripping, the fertilization, embryo survival, and hatching rates started at ~80%; these rates decreased to 39%, 24%, and 16%, respectively, for oocytes that had been stored for 4 h (p ˂ 0.05), and there was an almost complete loss of egg viability at 6 HPS. Furthermore, almost 90% of the embryos derived from 6-h aged oocytes died prior to hatching, and all larvae originating from 4- and 6-h aged oocytes showed malformations. The proportion of ploidy abnormal embryos was significantly greater at 4 HPS (18.5%) than at either 0 or 2 HPS (4.7% and 8.8%, respectively). The results revealed that zebrafish oocytes retained their fertilization potential for up to 2 h after stripping at 26 °C and indicated the contribution of post-ovulatory oocyte ageing in the occurrence of ploidy anomalies in the resulting embryos.

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Nest microclimate and limits to egg viability explain avian life‐history variation across latitudinal gradients

Ecology ◽

10.1002/ecy.3338 ◽

2021 ◽

Author(s):

Carl G. Lundblad ◽

Courtney J. Conway

Keyword(s):

Life History ◽

Latitudinal Gradients ◽

Egg Viability ◽

Life History Variation ◽

Nest Microclimate

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Changes in the crustacean communities of Lakes Michigan, Huron, and Erie following the invasion of the predatory cladoceran Bythotrephes longimanus

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f04-149 ◽

2004 ◽

Vol 61 (11) ◽

pp. 2111-2125 ◽

Cited By ~ 105

Author(s):

Richard P Barbiero ◽

Marc L Tuchman

Keyword(s):

Zooplankton Community ◽

Crustacean Zooplankton ◽

Bythotrephes Longimanus ◽

Zooplankton Community Structure ◽

Cladoceran Species ◽

Invertebrate Predators ◽

Predatory Cladoceran ◽

Leptodora Kindti ◽

Escape Responses ◽

Zooplankton Communities

The crustacean zooplankton communities in Lakes Michigan and Huron and the central and eastern basins of Lake Erie have shown substantial, persistent changes since the invasion of the predatory cladoceran Bythotrephes in the mid-1980s. A number of cladoceran species have declined dramatically since the invasion, including Eubosmina coregoni, Holopedium gibberum, Daphnia retrocurva, Daphnia pulicaria, and Leptodora kindti, and overall species richness has decreased as a result. Copepods have been relatively unaffected, with the notable exception of Meso cyclops edax, which has virtually disappeared from the lakes. These species shifts have for the most part been consistent and equally pronounced across all three lakes. Responses of crustacean species to the Bythotrephes invasion do not appear to be solely a consequence of size, and it is likely that other factors, e.g., morphology, vertical distribution, or escape responses, are important determinants of vulnerability to predation. Our results indicate that invertebrate predators in general, and invasive ones in particular, can have pronounced, lasting effects on zooplankton community structure.

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