Daily Vertical Migration Research Articles

Pressure as a Limit to Bloater (Coregonus hoyi) Vertical Migration

Bloater Coregonus hoyi are one of the Great Lakes ciscoes, an incipient species flock of seven recognized fishes (Todd and Smith, 1992). The vertical migration of adult bloater has been documented in day-night catch-per-unit-effort comparisons on the lake bottom (Brandt et al., 1991; Argyle, 1992) and in hydroacoustic observations (Fleischer et al., 1997). Bloater stay on or near the bottom during the day, whereas at night, a portion of the population ascend in the water column (Brandt et al., 1991; Argyle, 1992). Vertical migrators with swimbladders cope with frequent buoyancy changes due to pressure-induced volume changes of the swimbladder. Maintaining neutral buoyancy by gas secretion and resorption is time consuming and not practical for daily vertical migrations (Jones and Scholes, 1985; Alexander, 1993). Frequent adjustments of swimbladder volume are also energetically expensive, especially in environments with low temperatures and high pressure gradients (Alexander, 1972, 1993; Jones and Scholes, 1985). Alexander (1972) suggested that vertical migrators with gas-filled swimbladders may cope with the problem of swimbladder adjustment by using their swimbladder for neutral buoyancy only at the shallowest depths of their migration, whereas at the deepest depths of their migration, Alexander (1972) hypothesized these fish would be negatively buoyant and either rest on the bottom or use another buoyancy mechanism such as hydrodynamic lift to remain above the bottom. Observations of Merluccius bilinearis

Daily vertical migration of dense deep scattering layers related to the shelf-break area along the northwest coast of Baja California, Mexico

Echo signals were collected with a Simrad 200 kHz transducer across the shelf-break features off the northwest coast of Baja California (30°05'-30°42'N, 115°50'-116°26'W) during two diel cycles (July 1995) with the objective of describing vertical migrations of two dense deep scatter- ing layers (DSL) found near the shelf break. DSL records were made within an area -±50 m in the neritic zone, ±200 m at the shelf break and ±1000 m depth in the offshore station. Using an Isaacs-Kidd midwater net and Bongo nets, we inferred that the DSL were composed mainly of juveniles and adults of the euphausiids Nyctiphanes simplex Hansen and Euphausia pacifica Hansen. These aggregations have a close interaction with the ocean bottom during the daytime and display a vertical migration, rising near to the surface at night where a progressive horizontal dispersion then occurs. The DSL measured -3.5-6.0 km horizontally during the night. The ascent and descent migra- tions of the DSL were significantly fitted to a polynomial function of the second order, suggesting different swimming behavior during these two processes. Vertical migrations of the DSL were between 60 and 90 m. During the descent migration, maximum instantaneous speeds reached -0.7 cm s~', and during the ascent, maximum instantaneous speeds were -0.3 cm s~'. These coastal euphausiid species, along with other macrozooplankton and nektonic organisms, have a daily close interaction with the ocean bottom and also with the pelagic environment, suggesting that they play an important role providing food for demersal and pelagic organisms on the slope and shelf break in the upwelling region off the northwest coast of Baja California.

Vertical migration of Coregonid larvae in the first two months of development

Using an acoustic system in a 9 m deep enclosure, the daily vertical distribution patterns of whitefish larvae were studied from hatching to the age of two months. Four patterns of daily vertical distribution and migration were observed in accordance to different developmental stages: 1) Newly hatched larvae dispersed in the enclosure during the day and congregated at the water surface at night. 2) After 2 weeks of age larvae stayed close to the water surface during day and night. 3) At 15 to 18 mm length, larvae showed distinct vertical migration at dawn and dusk, they stayed close to the surface during the day and dispersed at night. 4) At 28 mm length the depth pattern was reversed. These fish frequented greater depths during the day than at night.

The influence of hematocrit, temperature and shear rate on the viscosity of blood from a high-energy-demand teleost, the yellowfin tuna Thunnus albacares

The high cardiac output, arterial blood pressure and cardiac energy demand of tuna make it likely that blood viscosity has an important influence on cardiovascular function. Furthermore, tuna regularly subject themselves to ambient temperature changes of 10°C or more during their daily vertical migrations. They can also maintain muscle temperatures several degrees Celsius above ambient and reach maximum muscle temperatures of approximately 15°C above ambient. The blood of tuna is, therefore, subjected to more frequent and rapid temperature changes than those that occur in other teleosts. Nothing is known, however, about the effects of temperature, shear rate or hematocrit on the viscosity of tuna blood. Viscosity of yellowfin tuna blood (hematocrits of 0­55 %) was measured at 15, 25 and 35°C and at shear rates of 45, 90, 225 and 450 s-1 using a cone-plate viscometer. As found for the blood of other vertebrates, viscosity increased with increasing hematocrit. Viscosity also increased nonlinearly with decreasing shear rate, until a shear rate of 90 s-1 was reached. There was no significant increase in viscosity when shear rate was decreased further, to 45 s-1. Because of the relatively flat hematocrit­viscosity curves, predicted optimal hematocrit curves were nearly flat above a hematocrit of approximately 30 %.

Seasonal variation of the daily zooplankton migration in the Greenland sea

Moored Acoustic Doppler Current Profilers (ADCPs) were used to analyse the daily vertical zooplankton migration and its seasonality. One-year records of vertical velocity and acoustic backscatter were obtained at four stations in the Greenland Sea. Both parameters exhibited a diurnal cycle typical for vertically migrating zooplankton. Upward and downward migration occured in short periods approximately 5 h long, and peak migration velocities were around 1.5 cm s−1.Similar structures were observed at all four mooring sites in the 200–300 m depth range. Farther down, between 1000 and 1400 m, no daily migration was observed.Strong seasonal variations are evident, and both the phase and intensity of the migration pattern change with daylight as the season progresses. In summer and during the polar night the migration became very weak and was only detectable in the displacement of scattering layers. When the day/ night contrast was large, intense upward or downward motion was accompanied by sloping backscatter isopleths.We observed two main scattering layers, a deep layer that varies in depth with season and an almost invariable shallow scattering layer at about 150 m depth. The deep layer was interpreted as the “resting depth” of the migrating plankter, and the latter as their “feeding horizon”. Changes in the “resting depth” from about 400 m in autumn and spring to about 200 m in winter lead to seasonal variations in the migration distance. This behaviour is discussed with respect to environmental conditions.

Prey species and nutritive value of food fed during summer to King Penguin Aptenodytes patagonica chicks at Possession Island, Crozet Archipelago

The diet of King Penguins Aptenodytes patagonica at Possession Island was studied in February 1989 by analysis of 20 stomach contents collected from adult birds, just before they fed their single chicks. The mean mass of the samples was 1.84 kg, equivalent to 15% of the unladen adult body‐mass. Fish accounted for 99.8% and squids for 0.2% by mass. The main prey were mesopelagic myctophid fish which live in dense shoals and perform a daily vertical migration. Subadults/adults of Electrona carlsbergi and juveniles and subadults/adults of Krefftichthys anderssoni represented 73.7 and 13.4% of the diet by mass, respectively. No difference was found in the diet of male and female King Penguins. Comparison of individual samples suggests that these birds catch a large quantity of fish from only a limited number of shoals. The mean caloric content of the food was 7 kJ/g wet mass. The total energy requirement of each chick during its initial period of growth was estimated to amount to 328,000 kJ, equivalent to 55 kg of food. The rate at which energy was delivered to the chick was calculated to be 50 W during this period.

Diel Pelagic Foraging by a Pandalid Shrimp (Pandalus montagui) off Resolution Island (Eastern Hudson Strait)

The vertical distribution and diet of shrimp (Pandalus montagui) were investigated using a multistage plankton sampler (BIONESS) and were compared with those of shrimp captured on the bottom using a trawl. Massive nocturnal vertical migrations of shrimp were observed in association with intense pelagic feeding activity. The sex ratio, size frequency distribution, and diet of shrimp caught in the water column differed markedly from shrimp caught during their stay on the bottom. Pelagic migrants were mostly males (75%), extending their planktonic foray into morning hours, whereas ovigerous (12%) and nonovigerous (13%) females returned to the bottom at dawn. In the trawl, the representation of males (43%) and ovigerous females (45%) differed, but also fluctuated on a diel cycle. Stomachs of shrimp captured in the BIONESS were fuller and the contents were in better condition than found in shrimps captured in the bottom trawl. Pelagic shrimp fed opportunistically on a variety of zooplankters, using copepods as a staple food. Stomachs of shrimp from the bottom trawl contained chitinous debris, sand grains, and small amounts of benthic organisms. The occurrence of daily vertical feeding migrations results in the unavailability of a variable proportion of the total shrimp biomass to bottom trawls.

Shallow‐Water Gasohydrothermal Vents of Ushishir Volcano and the Ecosystem of Kraternaya Bight (The Kurile Islands)

Abstract. A marine ecosystem in the crater of the Ushishir Volcano (Kraternaya Bight, Yankich Island, the Kuriles) showing gasothcrmal activity was studied for hydrographical, hydrochemical, and biological characteristics. Maximal changes in chemical and biological characteristics were observed in the surface water layer of 0–5 m. This layer had higher water temperature, was saturated with volcanogcnic carbon dioxide (up to 2000 10‐6 torr), ovcrsaturatcd with oxygen (up to 200 %), and contained high concentrations of chlorophyll a. Hydrogen sulfide was found in the surface water layer and at a depth of 15 m in the area of maximal effect of volcanic effluents.The planktonic community is characterized by high rates of production and destruction of organic matter only in the 0–5 m layer. Daily vertical migrations of the ciliatc Mesodinium rubrum were observed, which caused “red tides”.Bacterial, algobacterial, and diatom mats developed on the bottom of the bight in the zone of gasohydrothermal vents and in areas of volcanic water seeping. The rate of organic matter production in algobacterial mats reached 33.4g C‐rrr2‐d‐l, chcmolithotrophy predominating. Bottom settlements had high population density and great animal biomass, which reached 10 kg m‐2 in gasohydrothermal fields. They obtain sufficient energy from primary production of microphy‐tobenthos, algobacterial, and bacterial mats. Bcnthic species dominant in the bight were not found off the Ushishir Islands.Some species of macrobenthos inhabiting the Kraternaya Bight differ markedly in size and biomass from the same species found beyond the bight.

Haemolymph magnesium levels in some oceanic crustacea

1. 1. Data are presented for the haemolymph magnesium levels of a number of amphipod and decapod species from oceanic mid-waters of the northern South Atlantic. 2. 2. The values are compared with neritic brachyuran haemolymph magnesium levels. 3. 3. No obvious correlation was apparent between the presumed general activity levels of the oceanic Crustacea and their haemolymph magnesium concentrations; non migrating forms had not dissimilar concentrations to those species known to undertake substantial daily vertical migration.

A Circadian Rhythm of Population Behavior in Gonyaulax polyedra

Like other flagellates, Gonyaulax polyedra exhibits diurnal vertical migration and pattern formation. Shape and size of the aggregations depend on container type, light intensity, and cell density. In Petri dishes, cells form oval "swarms"; within these, cells move downward in the highly dense center and rise up at the periphery. We have investigated the daily rhythm of this swarming activity in Petri dishes illuminated from the side, using time-lapse video recordings. At night, a "lawn" of cells forms at the bottom of the dish toward the light source (independent of light intensity). Before dawn, cells rise toward the surface and aggregate in swarms. The daily vertical migration occurs independent of light direction and intensity. The diurnal swarms, however, form every day at the same location within the dish, at a distance from the light that depends on light intensity, indicating a self-selection of light intensity. In constant light and temperature and with negligible vertical nutrient differences, all aspects of the rhythm continue to oscillate for up to 3 weeks, when the rhythm of the population becomes desynchronized. Under cycles of bright white-dim red light (WR), cell entrain to WR 10:10 but free run in WR 8:8 and shorter cycles, showing relative coordination (von Holst, 1939) to the driving light cycle. They also entrain to the 24-hr multiple of WR 6:6. Under nonentrained conditions, swarming activity is still influenced by light changes, and in spite of the apparent free run, the phasing of the averaged activity varies systematically with different T-cycle frequencies.

Swimbladder‐depth relationships of fish causing volume reverberation in the Cariaco Trench

Oceanic volume reverberation in the frequency range of 1 to 20 kHz is caused primarily by scattering from swimbladders of small midwater fish. As these fish undergo daily vertical migrations, the scattering characteristics of their swimbladders change, due to changes in ambient pressure. Two simple swimbladder‐depth relationships have been postulated. The first is that fish work to keep their swimbladders at constant volume in order to remain neutrally buoyant at all times. The second is that fish conserve energy by passively allowing their swimbladders to remain at constant mass, or PV = constant. In order to investigate swimbladder‐depth relationships, we have collected acoustic and biological volume reverberation data in the Cariaco Trench, where only two species of midwater fish were found. Acoustic results were reported previously [J. Acoust. Soc. Am. Suppl. 1 73, S97 (1983)]. Measured scattering strengths were compared to values obtained by applying a swimbladder scattering model to fish caught in discrete‐depth biological trawls. Results of this comparison show that swimbladder‐depth relationships in the Cariaco Trench are more complex than the constant volume or constant mass postulates. [Work supported by NORDA.]

Diurnal changes in the vertical distribution of phytoplankton in hypertrophic Lake Kasumigaura, Japan

The daily vertical migration of five species;Microcystis aeruginosa (Kutz.) Trevis,Anabaena spiroides Klebahn f.crassa (L.) Elenkin,Aphanizomenon flos-aquae (L.) Ralfs,Melosira granulata (E). Ralfs, andCoscinodiscus lacustris Grun. was studied using a close-interval water sampler on a calm summer day in Lake Kasumigaura. Many colonies ofMicrocystis were observed at the middle of the water column (approx. 1.5 m depth) in the afternoon, and at the surface in the early morning.Anabaena occurred mostly in the upper layer whileAphanizomenon tended to be uniformly distributed. The difference in migration patterns suggests thatMicrocystis is superior toAnabaena andAphanizomenon in obtaining both light and nutrients from this lake. Among diatoms,Melosira remained at the bottom of the water column throughout day and night, but Coscinodiscus was uniformly distributed.

A multivariate analysis of planktonic molluscan distribution in the Middle Atlantic Bight

Faunal structure is described for the planktonic molluscs of the Middle Atlantic Bight based on two years of seasonal data from the continental shelf. Collection and taxa groups are constructed using numerical classification and reciprocal averaging ordination. Discriminant analysis is used to relate surface collection groups to physical variables, then taxa group distribution among these collection groups is analyzed by nodal fidelity analysis. The areal distribution of dominant species is presented by season, as is their surface temperature-salinity distribution. Four communities are recognized on the continental shelf. A subarctic community, including Limacina retroversa, Paedoclione doliiformis, and Clione limacina, is advected down the central shelf region from the northeast. A Gulf Stream community of weak vertical migrators, including Limacina trochiformis, Cavolinia longirostris, Creseis conica, Atlanta peroni, and A. gaudichaudi, is introduced onto the shelf in occasional intrusions across the shelf-edge front. A depth-limited warm-water community of strong vertical migrators, including Limacina inflata, L. bulimoides, L. lesueuri, and Cavolinia inflexa is generally confined offshore of the 100-m isobath since the extent of their daily vertical migration is greater than the bottom depths on the continental shelf. A coastal community, including the larvae of Loligo pealei and of Ensis directus is found in coastal water of local origin and is generally confined within a coastal boundary layer.

Vertical migration, hatching rates, and distribution of egg stages in freshwater zooplankton

In shallow, thermally stratifield lakes, the developing eggs carried by pelagic crustacean zooplankton are exposed to regularly alternating higher and lower temperatures during daily vertical migration. Rate summation techniques for determining the duration of egg developiment suggest that (1) the distribution of egg stages in the population will not change because of the alternating temperatures, and (2) the majority of young animals will not be hatched or released in the warmer, upper waters of the lake. This latter result is probably positively adaptive, but it may be brought about entirely mechanistically by the more rapid development in warmer waters.

Metabolic responses to temperature change in a tropical freshwater copepod (Mesocyclops brasilianus) and their adaptive significance

Metabolic rates of Mesocyclops brasilianus from Lake Valencia, Venezuela, were determined at several temperatures spanning the environmental range (22-28° C). The QO2's (oxygen consumption per unit weight) of all Mesocyclops stages from Lake Valencia are higher than most but not all QO2's from temperate copepod species that have been studied. The QO2 is essentially static through naupliar development and shows a sudden jump between N6 and CI, which probably results from the major change in morphology and behavior at this point in the life history. QO2 declines steadily between CI and adult stages. Acclimated copepodite and adult Mesocyclops show a decreasing metabolic rate with increasing temperature (i.e. Q10< 1.0) over the temperature range 26-28° C. This is the range of temperatures normally encountered during the daily vertical migration when the lake is thermally stratified (April-November). Since vertical migration would result in a compromise between a fully acclimated and an acute response, a nearly constant metabolic rate or a slight decline in metabolic rate in the warmer water would be expected in field populations. The results thus show that the metabolic rate of Mesocyclops is not reduced when it moves into deeper (cooler) water, as would be predicted by certain energy-based hypotheses that have been used to explain vertical migration. In contrast to the low Q10's between 26 and 28° C, copepodites and adults have very high Q10 values in the range 22-26° C. This indicates an adaptive decrease in metabolic rate which is thermally programmed to coincide with the cooler temperatures that are encountered during the mixing season (December-March), when a drastic change in ecological conditions occurs in the lake.Nauplii show evidence of the same seasonal response but without the superimposed plateau at high temperatures, which they would not need because they are weak migrators. Nauplii show a plateau at the lowest temperatures, however, which suggests that a fixed metabolic reduction occurs at the onset of mixing and metabolism is not altered thereafter with declining temperature.The change in QO2 with temperature generally supports the hypothesis that all Mesocyclops stages are adapted to hold a high, constant metabolic rate through the diel cycle but experience a seasonal reduction in metabolic rate in response to major ecological changes in the lake at the time of seasonal mixing.

Rythmes nutritionnels et organisation trophique d'une population de crustac�s p�lagiques (Euphausiacea)

The nature of the food (animal, plant or mixed) and the fullness of the stomachs at different times of the day have been studied through dissection of 18620 specimens representative of almost all the euphausiid species of the Central and Western Tropical Pacific Ocean. Animal food predominates in 22 of the 28 species studied, while 12 can be considered as omnivorous; only 4 are mainly phytophagous. The trophic level of a given species is more or less the same in different zones, but scarcity of phytoplankton in oligotrophic tropical regions results in an increase of the trophic level of herbivorous and omnivorous species. There is no correlation between trophic level and vertical distribution of a species. Each species follows a clearly defined feeding rhythm, usually characteristic for each genus: nutrition most active by night in Euphausia, continuous in Thysanopoda, restricted to light hours in Stylocheiron, mainly from noon to midnight in Nematoscelis and Nematobrachion. As a rule, it is obvious that the smaller the daily vertical migration, the more pronounced the feeding rhythm: the range of fluctuations in fullness of stomachs over 24 h is weak or non-existent in migrating species, maximum in non-migrating ones. Nevertheless, daily vertical migration does not appear to be “advantageous” from the point of view of trophic efficiency: assuming that the stomachal transit is the same for all species (a speculative proposition), it is shown that the ratio “total biomass of species: food consumed during 24 h”, i.e., “biomass permanently available for the upper link: biomass eaten daily at the expense of the lower link” is 4 times higher in non-migrating than in migrating species. It is thus considered that daily vertical migration is an expensive manner to transfer energy from link to link, and therefore fulfills other functions, amongst which diffusion throughout the whole water column of the biomass produced in the upper levels is probably one of the most important.

The lipids of some lantern fishes (family myctophidae)

1. 1. Of eight species examined four contained less than 4·3 per cent (fresh wt.) lipid and four at least 14·2 percent. 2. 2. C 30C 38 wax esters with one and two double bonds were the major lipid in three species with high total lipid; C 36 and C 38 homologs with five and six double bonds were detected in two of these species. 3. 3. The alcohol moieties of the wax esters were largely (74–82%) 1-hexadecanol, and octadecenoic was the predominant (72–76%) fattcy acid. 4. 4. The high was ester content correlates with deeper living and a pattern of daily vertical migration.

Daily Vertical Migration of Lucifer, Planktonic Numbers in Relation to Solar and Tidal Cycles

The daily variation in planktonic numbers of mature and juvenile Lucifer faxoni Borradaile has been determined for two neritic locations in the northern Gulf of Mexico. The planktonic numbers are apparently related to both solar and tidal cycles. There are more Lucifer in the sampled water column during the night than during the day and more during the flooding tide than during the ebbing tide. The flood to ebb ratios are higher than the nocturnal to diurnal ratios at both locations. It is suggested that the daily vertical migration of Lucifer at these locations is being modified to achieve landward transport by the tendency of Lucifer to swim up into, or remain up in, the water column during a flooding tide and to drop out of the water column during an ebbing tide.

Daily Vertical Migration of Lucifer (Decapoda, Sergestidae). Egg Development, Oviposition and Hatching

Daily Vertical Migration of <i>Lucifer</i> (Decapoda, Sergestidae). Egg Development, Oviposition and Hatching

Observations on Treehopper Behavior (Homoptera, Membracidae)

Observations were made on one or more aspects of the behavior of 36 species at Lake Itasca, Minnesota, and Ada, Oklahoma, 1960-62. The treehoppers did not show decided preference for any particular height or for the shady or sunny side of trees. No daily vertical migration was detected. Thirty-two of 77 Enchenopa binotata responded to lights, more so to either white or black than to various colors. Thirteen species came to both black and white light traps, three to a black light trap only, four to a white light trap only. A discussion of observations on righting, response to mechanical stimuli, protective coloration and shape, resting time, feeding, minor movements, and defecation is included.