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

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.

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

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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