Opossum Shrimp (Mysis relicta) Predation on Zooplankton

1980 ◽  
Vol 37 (6) ◽  
pp. 909-919 ◽  
Author(s):  
Scott D. Cooper ◽  
Charles R. Goldman
Keyword(s):  
Mechanical Efficiency ◽  
Food Selectivity ◽  
Clearance Rates ◽  
Total Consumption ◽  
Mysis Relicta ◽  
Opossum Shrimp ◽  
Consumption Rates ◽  
Food Particles ◽  
Prey Escape ◽  
Comparison Of The Results

Mysis relicta clearance rates were not affected by changes in prey and predator density in single-prey systems where Epischura nevadensis late instars were used as food. A comparison of the results obtained from single-, two-prey, and multiple-prey systems revealed that Mysis clearance rates of E. nevadensis late instars and Diaptomus tyrrelli males were significantly affected by the presence and abundance of alternative prey.When offered natural prey assemblages, the smallest Mysis preyed preferentially on the smallest available prey (Bosmina, Ceriodaphnia, Diaptomus nauplii) while larger Mysis showed an increased preference for larger prey (Epischura, Daphnia). In general, Mysis preferred Daphnia over copepods; Epischura, Ceriodaphnia, Bosmina, and cyclopoid copepods over Diaptomus copepodites and adults; and Diaptomus males over Diaptomus females. Total consumption rates increased with increasing predator size and starvation duration. Food selectivity patterns exhibited by Mysis were attributed to the mechanical efficiency with which the predators captured and handled food particles of different sizes, to the vigor of prey escape responses, and to predator–prey encounter frequencies.Key words: Mysis relicta, predation, zooplankton, feeding preferences, opossum shrimp

Environmental Factors Affecting Predation Rates of Mysis relicta

1982 ◽  
Vol 39 (1) ◽  
pp. 203-208 ◽  
Author(s):  
Scott D. Cooper ◽  
Charles R. Goldman
Keyword(s):  
Feeding Rate ◽  
Bright Light ◽  
Time Of Day ◽  
Clearance Rates ◽  
Mysis Relicta ◽  
Factors Affecting ◽  
Feeding Experiments ◽  
Opossum Shrimp ◽  
Consumption Rates ◽  
Low Levels

Mysis relicta was fed Epischura nevadensis late instars or Diaptomus tyrrelli males in a series of feeding experiments. Mysis clearance rates were not affected by the time of day mysids were collected, the time of day experiments were conducted, or conditioning of experimental water by predators and prey. Mysis fed as efficiently in the dark as in bright light, and exhibited increasing clearance rates with increasing container size. When Diaptomus males were used as prey Mysis clearance rates were significantly higher at 5 °C than 10 and 15 °C; temperature did not affect clearance rates with Epischura as prey. Mean clearance rates tended to decline with increasing prey density, but the only significant differences were recorded when Epischura was used as prey. Prior acclimation to experimental light and temperature conditions had no effect on the results. When presented with an abundant food supply, freshly collected Mysis fed at initially low rates. Subsequent feeding rate peaks were followed by feeding rate declines to low levels over a 24-h period. Individual Mysis consumption rates remained relatively constant from day to day.Key words: Mysis relicta, predation, copepods, clearance rates, opossum shrimp

Effect of Fasting under Different Temperature Conditions on Nucleic Acid Ratios in the Opossum Shrimp Mysis relicta: a Calibration Approach

2008 ◽  
Vol 34 (3) ◽  
pp. 461-471 ◽  
Author(s):  
Christian Schlechtriem ◽  
Ora E. Johannsson ◽  
Kelly L. Bowen ◽  
Richard W. Smith ◽  
Michael T. Arts
Keyword(s):  
Nucleic Acid ◽  
Mysis Relicta ◽  
Temperature Conditions ◽  
Opossum Shrimp ◽  
Calibration Approach

Predation by three glacial opportunists on natural zooplankton communities

1986 ◽  
Vol 64 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Redwood W. Nero ◽  
W. Gary Sprules
Keyword(s):  
Previous Survey ◽  
Clearance Rates ◽  
Mysis Relicta ◽  
Chydorus Sphaericus ◽  
Theoretical Comparison ◽  
Feeding Experiments ◽  
Predatory Impact ◽  
Limnocalanus Macrurus ◽  
Zooplankton Communities

We examine the influence of three glacial opportunist predators, Mysis relicta, Limnocalanus macrurus, and Senecella calanoides, on natural zooplankton communities of central Ontario through a series of feeding experiments in small enclosures (23.6 L). Estimates of in situ clearance rates by M. relicta match previously determined rates, with the following gradation of values: Asplanchna sp. > daphnids and bosminids > Epischura lacustris > large cyclopoids, Chydorus sphaericus and small Diaptomus sp. > L. macrurus > S. calanoides. Clearance rates by M. relicta are similar for all daphnids and bosminids. Hypolimnetic species like Daphnia longiremis and Eubosmina longispina are apparently eliminated by M. relicta, while similarly vulnerable species survive because they have an epilimnetic refuge from M. relicta. Limnocalanus macrurus and S. calanoides prey primarily on copepods, Diaphanosoma spp., and rotifers in the hypolimnion. When both clearance rates and population densities of M. relicta, L. macrurus, and S. calanoides are taken into account, the total predatory impact of M. relicta is much larger than that of the two relict copepods. Based on a theoretical comparison of measured clearance rates by predators with estimated rates of prey recruitment, we conclude that differences in species composition and abundance between relict and nonrelict lakes described in a previous survey are due principally to predation by M. relicta.

scholarly journals Dark-adaptation in the eyes of a lake and a sea population of opossum shrimp (Mysis relicta): retinoid isomer dynamics, rhodopsin regeneration, and recovery of light sensitivity

2020 ◽  
Vol 206 (6) ◽  
pp. 871-889
Author(s):  
Tatiana Feldman ◽  
Marina Yakovleva ◽  
Martta Viljanen ◽  
Magnus Lindström ◽  
Kristian Donner ◽  
...  
Keyword(s):  
Dark Adaptation ◽  
Severe Depression ◽  
Light Sensitivity ◽  
Membrane Turnover ◽  
Low Light ◽  
Photoreceptor Membrane ◽  
Mysis Relicta ◽  
Opossum Shrimp ◽  
Exposure Levels ◽  
Photoreceptor Membranes

Abstract We have studied dark-adaptation at three levels in the eyes of the crustacean Mysis relicta over 2–3 weeks after exposing initially dark-adapted animals to strong white light: regeneration of 11-cis retinal through the retinoid cycle (by HPLC), restoration of native rhodopsin in photoreceptor membranes (by MSP), and recovery of eye photosensitivity (by ERG). We compare two model populations (“Sea”, Sp, and “Lake”, Lp) inhabiting, respectively, a low light and an extremely dark environment. 11-cis retinal reached 60–70% of the pre-exposure levels after 2 weeks in darkness in both populations. The only significant Lp/Sp difference in the retinoid cycle was that Lp had much higher levels of retinol, both basal and light-released. In Sp, rhodopsin restoration and eye photoresponse recovery parallelled 11-cis retinal regeneration. In Lp, however, even after 3 weeks only ca. 25% of the rhabdoms studied had incorporated new rhodopsin, and eye photosensitivity showed only incipient recovery from severe depression. The absorbance spectra of the majority of the Lp rhabdoms stayed constant around 490–500 nm, consistent with metarhodopsin II dominance. We conclude that sensitivity recovery of Sp eyes was rate-limited by the regeneration of 11-cis retinal, whilst that of Lp eyes was limited by inertia in photoreceptor membrane turnover.

Mysid and fish zooplanktivory in Lake Ontario: quantification of direct and indirect effects

2006 ◽  
Vol 63 (12) ◽  
pp. 2734-2747 ◽  
Author(s):  
Gideon Gal ◽  
Lars G Rudstam ◽  
Edward L Mills ◽  
Jana R Lantry ◽  
Ora E Johannsson ◽  
...  
Keyword(s):  
Indirect Effects ◽  
Lake Ontario ◽  
Fish Feed ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Mysis Relicta ◽  
Consumption Rates ◽  
Positive Effect ◽  
Potential Rate

Mysis relicta and planktivorous fish feed on zooplankton in Lake Ontario and form a trophic triangle that includes intraguild predation by fish on mysids. Thus, fish affect zooplankton both directly and indirectly. To evaluate the importance of alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and mysids as zooplanktivores in Lake Ontario, we measured abundances and distributions, assessed diets, and computed mysid and fish consumption rates based on bioenergetics models. We further estimated indirect effects by comparing clearance rates given observed and potential mysid distributions. Estimated consumption rates varied widely with season and water depth and ranged between 2.6 × 10–3 and 1.3 g·m–2·day–1 for mysids and between 1.4 × 10–3 and 0.5 g·m–2·day–1 for fish, representing a daily removal of zooplankton of up to 10.2%·day–1 and 2.0%·day–1 by mysids and fish, respectively. Mysid planktivory exceeded fish planktivory in May and August, but fish planktivory dominated in October. Estimated mysid planktivory rates were 2- to 90-fold lower than the potential rate if mysids moved to temperatures that maximized their predation rates, suggesting an indirect positive effect of fish on zooplankton.

Impact of the Introduction of Kokanee (Oncorhynchus nerka) and Opossum Shrimp (Mysis relicta) on a Subalpine Lake

1978 ◽  
Vol 35 (12) ◽  
pp. 1572-1579 ◽  
Author(s):  
Mark D. Morgan ◽  
Stephen T. Threlkeld ◽  
Charles R. Goldman
Keyword(s):  
Population Dynamics ◽  
Lake Trout ◽  
Oncorhynchus Nerka ◽  
Food Sources ◽  
Mysis Relicta ◽  
Kokanee Salmon ◽  
Opossum Shrimp ◽  
Cladoceran Species ◽  
Subalpine Lake ◽  
The Impact

Introductions of opossum shrimp (Mysis relicta) and kokanee salmon (Oncorhynchus nerka) are common management tools for improvement of local sport fisheries. This paper summarizes published information from varied sources and presents supplemental data on the impact of these introductions on the Lake Tahoe zooplankton and fish communities. Concomitant with peak spawning runs of kokanee and the establishment and high densities of Mysis was the disappearance of the three pelagic cladoceran species in the lake. Population dynamics analysis of the cladoceran populations indicate that their elimination was due to increasing death rates (related to Mysis and kokanee predation) and decreasing birth rates (possibly related to cultural eutrophication). Changes have also been observed in the fish populations. Lake trout have altered their food habits to include large quantities of Mysis, but this has been done to the exclusion of other prey types. Thus, improvement in lake trout condition has been indicated only in years when Mysis is abundant. Recent evidence of a sustained decline in the mysid population suggests that unless lake trout shift back to more traditional food sources, their condition could deteriorate to below pre-mysid levels. Finally, mean weight and abundance of kokanee spawners have declined since the cladoceran disappearance, suggesting a negative impact on the whole population which fed heavily on cladocerans. Key words: opossum shrimp, kokanee salmon, population dynamics, cladoceran decline, introductions, subalpine lake

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