Feeding Modes and Prey Size Selection in the Alewife (Alosa pseudoharengus)

1976 ◽  
Vol 33 (9) ◽  
pp. 1972-1975 ◽  
Author(s):  
John Janssen

Alewives (Alosa pseudoharengus) feed on zooplankton in three modes: 1) particulate feeding on individual prey; 2) filtering with the mouth held agape, accompanied by strong swimming; and 3) gulping, in which the mouth opens and closes more slowly than a particulate feeder and more rapidly than a filterer, and swimming is slower than in a filterer. Individuals that feed by filtering are not size selective; gulpers are size selective; and particulate feeders are more size selective than gulpers. Gulpers and filterers take more than 1 prey per mouth opening and closing; particulate feeders take only 1.

1995 ◽  
Vol 52 (2) ◽  
pp. 358-363 ◽  
Author(s):  
John Janssen ◽  
Warren R. Jones ◽  
Audrey Whang ◽  
Philip E. Oshel

The alewife (Alosa pseudoharengus) is an obligate planktivore which uses a variety of methods for capturing zooplankton. Alewife eat Mysis relicta, especially larger individuals, at night during a vertical migration by both predator and prey. We proposed and tested the hypothesis that alewife use the lateral line to sense prey and feed particulately (single prey at a time) in the dark. We used Daphnia magna and Artemia salina adults as prey. Prey densities were such that they did not elicit filter feeding. Observations using infrared video showed that alewife captured individual prey and bit at a vibrating inert bead. We concluded that under appropriate conditions, alewife were size selective and that streptomycin (which blocks the lateral line sensory cells) eliminated this feeding behavior.


Author(s):  
Jorge Tobajas ◽  
Carlos Rouco ◽  
Javier Fernandez-de-Simon ◽  
Francisco Díaz-Ruiz ◽  
Francisca Castro ◽  
...  

1990 ◽  
Vol 35 (7) ◽  
pp. 1429-1436 ◽  
Author(s):  
Thomas H. Chrzanowski ◽  
Karel Šimek
Keyword(s):  

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ramón Fuentes ◽  
Alain Arias ◽  
María Florencia Lezcano ◽  
Diego Saravia ◽  
Gisaku Kuramochi ◽  
...  

The aim of this study was to analyze the general, geometric, and kinematic characteristics of the masticatory cycle’s movements in a tridimensional way, using a method developed by our study group to provide a new insight into the analysis of mandibular movements due to advancement in the potential of computational analysis. Ten individuals (20.1 ± 2.69 years), molar class I, without mandibular movement problems participated in this study. The movements of the masticatory cycles, frontal and sagittal mandibular border movements, were recorded using 3D electromagnetic articulography and processed with computational scripts developed by our research group. The number of chewing cycles, frequency (cycles/s), chewing cycle areas/mandibular border movements areas ratios, and the mouth opening and closing speeds on the 3D trajectory of the chewing cycle were compared. The cycles were divided and analyzed in thirds. The masticatory cycles showed high variation among the individuals (21.6 ± 9.4 cycles); the frequency (1.46 ± 0.21 cycles/s) revealed a moderate positive correlation (R = 0.52) with the number of cycles. The frontal area ratios between the cycle area and the mandibular border movement presented higher values in the first third (6.65%) of the masticatory cycles, and the ratios of sagittal areas were higher and more variable (first, 7.67%; second, 8.06%; and third, 10.04%) than the frontal view. The opening and closing mouth speeds were greater in the second third of the masticatory cycles (OS, 57.82 mm/s; CS, 58.34 mm/s) without a significant difference between the opening and closing movements when the same thirds were evaluated. Further studies are necessary to improve the understanding of the masticatory cycles regarding the standardization of parameters and their values.


1996 ◽  
Vol 86 (6) ◽  
pp. 633-639 ◽  
Author(s):  
D. Dominic Amalraj ◽  
P. K. Das

AbstractThe foraging behaviour of frequency-dependent prey selection by larval instars of Toxorhynchites splendens (Wiedemann) was studied in the laboratory. Prey size selection (second vs fourth instars of Aedes aegypti Linnaeus or Anopheles stephensi Liston) by third and fourth instar predators was frequency-dependent. However, in the case of second instar predators, prey size selection was not frequency-dependent and the predator preferred second instar to fourth instar prey. When offered second instars of Aedes aegypti and Anopheles stephensi the preference for one species over the other was frequency-dependent in all the three predator instars. The role of frequency-dependent prey selection in the stability of prey—predator interaction at low equilibrium levels is discussed.


1997 ◽  
Vol 75 (9) ◽  
pp. 1508-1518 ◽  
Author(s):  
Dominic J. Tollit ◽  
Paul M. Thompson ◽  
Simon P. R. Greenstreet

This study compared the composition of the diet of harbour seals (Phoca vitulina) feeding in the Moray Firth, Scotland, with the abundance of their fish prey estimated from dedicated fishery surveys in January 1992 and 1994 and June 1992. Prey-size selection was also examined in these three time periods and in January 1991. In each period, the most abundant fish species contributed most to the diet. However, the relative abundances of the remaining species in the sea showed little similarity to their contribution to the seals' diet. Diet composition was almost totally dominated by either pelagic species or species dwelling on or strongly associated with the seabed, depending upon the relative abundance of pelagic schooling prey. Most fish consumed were 10–16 cm in length, although larger cod and herring were taken. With the exception of cod, the extent of size selection was dependent upon the use of correction factors that accounted for otolith erosion due to digestion.


Sign in / Sign up

Export Citation Format

Share Document