Duration Of Migration Research Articles

Pacific Salmon (Oncorhynchus) Migrations: Orientation versus Random Movement

A computer simulation by Saila and Shappy (1963. J. Cons. Int. Explor. Mer 28: 153–166) indicated that the migrations of Pacific salmon (Oncorhynchus) from high seas feeding areas to the coastal vicinity of their natal stream may be accomplished with only slight homeward orientation. Five assumptions in this important paper are here reexamined to determine the validity of the original conclusion in light of current knowledge of Pacific salmon biology. It appears that assumptions concerning swimming speed, duration of migration, and return success were incorrect. These errors resulted in substantially underestimating the extent of salmon homeward orientation. Thus, contrary to the original conclusion, any hypothesis concerning the high seas migrations of salmon must explain the strong orientation of these fishes in the open ocean.

Conditions and duration of primary hydrocarbon migration

Conditions and duration of primary hydrocarbon migration

Host-Parasite Relationships of Fasciola hepatica in the White Mouse. V. Age of Fluke Responsible for the Induction of Acquired Immunity

Juvenile Fasciola hepatica 12, 14, 18, 20, and 24 days old were successfully transferred to normal recipient mice. Worms entered the common bile ducts when total worm age was 30 or 32 days. Liver migration time was controlled between 16 to 17 and 3 to 4 days. Flukes 12, 14, 16, 18, 20, and 24 days old were transferred to normal recipients in an attempt to relate the duration of liver migration and fluke age to the stimulation of acquired immunity. When transferred worms had a total age of 40 days immunized mice were given a challenge infection of 2 metacercariae per mouse. At 25 days after challenge these mice were killed and worms were recovered. Immunization with 12-, 14-, 16-, and 18-day-old worms produced a significant reduction in challenge worm burdens when compared to natural immunity controls. Immunization with 20and 24-day-old worms did not stimulate a significant acquired immunity. It is suggested that the duration of liver migration, at least 10 to 11 days, by young worms and not the specific age of the young worm is responsible for the stimulation of acquired immunity. Eightand 16-day-old Fasciola hepatica stimulated acquired immunity in recipient mice as measured by a significant reduction in worm burden following a two-worm challenge infection (Lang and Dronen, 1972). Transferred worms migrated in the liver for 21 to 22 days (8-day-old worms) or 13 to 14 days (16-dayold worms). Following an initial metacercarial infection this strain of F. hepatica did not migrate into the common bile duct until 32 days after infection (Lang, 1972). When total worm age was 32 days, regardless of the age of transfer, worms were located in the common bile ducts. Lang and Dronen (1972) did not determine if worms older than 16 days at transfer would complete development in mice and stimulate acquired immunity. The present study attempts to determine if immature worms older than 16 days can be successfully transferred and, if possible, to determine the maximum worm age for inducing acquired immunity. MATERIALS AND METHODS Mice utilized were an isologous strain used in previous studies with this parasite (Lang and Dronen, 1972). The strain of F. hepatica used in the present study behaves similarly to the one used in previous studies (Lang, 1972). Techniques for infection and necropsy of mice and infection of the snail host (Lymnaea bulimoides Received for publication 20 August 1973. * This work was supported by NSF grant GB31745. Lea) have been described (Lang, 1966, 1967, 1970, 1972). Procedures for the transfer of 16day-old and younger worms have been published (Lang and Dronen, 1972). Young worms, 12, 14, 16, 18, 20, and 24 days old, were transferred aseptically to recipient mice. EXPERIMENTAL PROCEDURES AND RESULTS

Host-Parasite Relationships of Fasciola hepatica in the White Mouse. IV. Studies on Worm Transfer and the Induction of Acquired Immunity by Worms of Different Ages

Eightand 16-day-old worms were transferred to normal recipient mice via peritoneal injection, contacted the liver 72 hr after transfer, and migrated into the common bile duct when total worm age was 32 days. Eight-day-old transferred worms were present in the liver parenchyma of recipient mice for 21 to 22 days, while 16-day-old transferred worms were in the liver parenchyma for 13 to 14 days. Transferred worms (8and 16-day-old) were utilized as immunizing infections in 2 groups of normal recipient mice to control the duration of liver migration. When transferred worms had a total age of 40 days, immunized mice were given a challenge infection of 2 metacercariae per mouse. At 25 days after challenge, these mice were killed and worms were recovered. Immunization with 8and 16-day-old worms produced a significant reduction in challenge worm burden when compared to natural immunity controls. Apparently, young flukes are capable of inducing acquired immunity during the entire liver migration period. Studies on the immunology of Fasciola hepatica L. in mice have shown that male mice develop an acquired immunity against a challenge infection after a single two-worm immunizing infection (Lang, 1967; 1968a). Young worms 8 to 17 days old may be responsible for inducing functional acquired immunity in this system (Lang, 1968a). Acquired immunity in this system can be transferred to normal recipients via peritoneal exudate cells from immunized donors (Lang et al., 1967), and it is felt that the lymphocytes seen in the liver by 16 days in a first infection and in immune mice at the time of challenge are effector cells of a specific cellular immunity. As these cells respond almost immediately to the challenge worms after they enter the liver, these 8to 10-day-old worms are no doubt producing the specific antigens. No such response is seen prior to this period in the intestine or body cavity. Young worms removed from livers of normal mice 17 days after infection can be transferred to normal recipients and the worms migrate to and mature in the common bile duct; however, worms of the same Received for publication 15 June 1971. * This work was supported by NSF grant GB8713. t Present address: Department of Biology, New Mexico State University, Las Cruces, New Mexico 88001. age when removed from the livers of immune mice do not complete migration to the common bile duct in normal recipients. Apparently, as these worms were unable to establish, the immune response is against young worms during the liver migratory phase (Lang, 1968b). The present study attempts to determine the age of worm responsible for inducing acquired immunity in the mouse-Fasciola system using the technique of worm transfer. For this work on acquired immunity, a different population of Fasciola (eastern Washi gton) was used; however, it has been shown that it produces nearly the same host responses, with some differences in parasite behavior, in the strain of mouse used for this and previous work. MATERIALS AND METHODS Mice utilized were an isologous strain maintained in the Department of Parasitology, University of North Carolina. Techniques for infection and necropsy of mice, handling of recovered worms, determination of host responses, and infection of snail hosts have been described (Lang, 1966, 1970). In this study, Lymnaea bulimoides Lea was utilized as the snail host. For worm transfer, donor mice were inoculated with 15 to 22 metacercariae and necropsied 8 or 16 days later. Young worms, recovered from the livers and washed in sterile saline at 37 C, were placed in fresh saline at 13 C for 7 min stimulating them to ball up. Two worms were then injected into the body cavity of each recipient mouse using a 16-gauge needle.

Duration of residence and prospective migration: Further evidence

Abstract A basic assumption of the Cornell Mobility Model insofar as it is relevant to inter-community migration is that an individual’s propensity to move is a function of, among other things, his length of residence in the community. Parameters of the functional relationship of migration probabilities to duration status are estimated from migration histories for a sample of residents in Monterrey, Mexico, and compared with estimates reported by P. A. Morrison using data from Amsterdam, The Netherlands. In both data sets a negative nonlinear relation of the probability of migrating to duration status, as well as an interaction between age and duration status, is found. Values of parameters describing the relation within age groups differ sufficiently between the two data sets, however, to suggest that further specification of conditions under which a particular form of functional relation will obtain is necessary if the model is to be useful in migration research.

Social Participation and Social Status

Cohen, Bernard. 1963 Conflict and Conformity: Probability Model and Its Application. M.I.T. Press. De Cani, John S. 1961 On the construction of stochastic models of population growth and migration. Journal of Regional Science 3:1-13. Feller, William. 1957 Probability Theory and Its Applications. Second edition. New York: Wiley. Henry, Neil W., Robert McGinnis and Heinrich W. Tegtmeyer. 1968 A finite model of mobility. Paper presented to the Population Association of America, annual meetings. Hodge, Robert W. 1966 Occupational mobility as a probability process. Demography 3 (1): 19-34. Kemeny, John and J. Laurie Snell. 1960 Finite Markov Chains. Princeton: Van Nostrand. Land, Kenneth C. 1967 The evaluation of a stochastic model of migration: a replication and extension of findings. Paper presented to the Population Association of America, annual meetings. Margenau, Henry. 1950 Nature of Physical Reality. New York: McGraw-Hill. McGinnis, Robert and John White. 1967 Simulation experiments on a stochastic attraction model. Unpublished ms. Morrison, P. A. 1967 Duration of residence and prospective migration: the evaluation of a stochastic model. Demography 4(2):559-560. Myers, George C., Robert McGinnis and George Masnick. 1967 The duration of residence approach to a dynamic stochastic model of internal migration: a test of the axiom of cumulative inertia. Eugenics Quarterly 14:121126. Parzen, Emanuel. 1962 Stochastic Processes. San Francisco: Holden-Day. Perrin, E. B. and M. C. Sheps. 1964 Human reproduction: a stochastic process. Biometrics 20 (March):28-45. Stouffer, Samuel A. 1940 Intervening opportunities: a theory relating to mobility and distance. American Sociological Review 5:945-957. Suppes, Patrick and Richard C. Atkinson. 1960 Markov Learning Models for Multiperson Interactions. Stanford: Stanford University Press. Ter Heide, H. 1963 Migration models and their significance for population forecasts. Milbank Memorial Fund Quarterly 41 (January):57. Whitrow, Gerald J. 1961 Natural Philosophy of Time. London: Thomas Nelson and Sons. Zipf, George K. 1946 The plp2/d hypothesis: on the intercity movement of persons. American Sociological Review 11:377-386.

Migratory Behavior of Sockeye Salmon Fry and Smolts

Considerable new data on the characteristics of sockeye fry and smolt migrations, direct underwater observations of migrating smolts, and a review of the literature are presented here with a synthesis, evaluation, and interpretation of possible survival advantages of these phenomena. Most fry migrations from spawning areas to nursery lakes take place in the spring, when harsh winter conditions in lakes are moderating and the growing season is beginning. Smolt migrations to salt water closely follow spring breakup of the ice and warming of the lake water. The time of smolt migration is correlated closely with latitude: migration is earlier in southern streams than in northern streams. The duration of seasonal migration appears to be strongly related to travel distance to the trunk river outlet. The smolt exodus is rapid and regular in single-lake systems but irregular and extended in multilake or multibasin systems. The frequency distribution of smolts migrating from two-lake or two-basin systems is usually bimodal. Most migrations commence as water temperatures near 40 F and are over when temperatures approach 50 F. Migrations of smolts and especially fry are mainly confined to the darkest hours of the night. In general, in any one season, the oldest and the largest smolts in each age-group migrate first. Other factors, such as the thickness of the ice, effectiveness of solar radiation in melting ice and warming water, and daily weather (including sunlight and wind), also influence seasonal and diel migration patterns. Underwater observations of smolts at night during migration show that they are schooled, travel in the upper water levels in shallow rivers and deeper (but not near the bottom) in deeper rivers, and usually face downstream and swim as they migrate. During migrations, fry and smolts are both often subjected to a depensatory mortality from intense predation by birds and fish. A factor disporportionately affecting different smolt populations is the length and number of restricted passages along the route to the ocean. Smolts migrating in multilake systems must encounter heavier predation than smolts migrating from single-lake systems. Predation is probably minimized en route because of innate migratory behavior patterns. Exceptions to the general migratory behavior of fry and smolts are described to show the wide range in behavioral response to variable environmental situations.

Duration of Residence and Prospective Migration: The Evaluation of a Stochastic Model

The objective of this paper is to evaluate the empirical accuracy of the Cornell mobility model. Migration is formulated as a stochastic process governed by non-stationary probabilities: during a given interval of time, an individual is presumed to undergo a risk of migrating that decreases as he continues to reside in the same community. The major hypothesis, then, is that a person's propensity to move declines as his duration of residence increases.A secondary hypothesis proposes that age interacts with this relationship. Longitudinal data (5,000 residential histories from the Netherlands system of population registers) were analyzed and translated into prospective probabilities that are age- and duration-specific.Both hypotheses were substantiated. Specifically, the relationship is negative, curvilinear, and varies significantly by age. To facilitate simulation analysis of the model, the relationships found in the data are summarized in a set of logarithmic prediction equations.The findings of this paper underscore the fundamental limitation of stationary probability models in portraying migration and suggest that the non-stationary alternative is a more accurate formulation. More generally, processes of change which bear only a formal resemblance to migration (for example, brand switching or attitudinal change) may be governed by a principle of cumulative stability too. The evidence warrants further inquiry into the applicability of the model to other social processes where inertialike factors operate.

THE EFFECT OF SALTS AND ORGANIC SOLUTES ON THE MIGRATION TIME OF THE SLIME MOLD DICTYOSTELIUM DISCOIDEUM

1. In the life history of Dictyostelium discoideum there is a period of migration in which the aggregated cell mass wanders about in the form of a sausage prior to the formation of a final fruiting body.2. The period of migration was known to be variable, and now a limiting factor has been demonstrated. It was possible to show that in the absence of solutes migration will occur for long periods of time, and that the duration of migration decreased approximately exponentially with the concentration of added solute. The effect cannot be accounted for entirely as an osmotic phenomenon because different substances have different degrees of effectiveness, electrolytes being more effective than non-electrolytes.