Diel Behavior Research Articles

Changes in species composition of demersal fish fauna of Southeast Gulf of Carpentaria, Australia, after 20 years of fishing

The changes in a tropical demersal fish community in the southeast Gulf of Carpentaria, Australia, were examined by comparing the results of a survey undertaken in 1964 before the area was fished, with two surveys in 1985 and 1986 after 20 yr of commercial trawl fishing. The numerical abundance of 52 of the 82 fish taxa had not changed significantly, but that of 18 had decreased while 12 had increased. One taxon (Paramonacanthus spp.) had decreased by more than 500 times and another (Saurida micropectoralis) had increased substantially in abundance. The changes occurred throughout the area surveyed, but the largest changes were offshore. In the pre-trawling community most taxa were caught mainly during the night, while in the post-trawling community most were caught in the same numbers during day and night. In 10 of the 30 taxa that changed in abundance, changes were within a family and could not be explained. For the remaining 20, the changes could be related to their position in the water column: benthic taxa decreased and bentho-pelagic taxa increased. The changes were assessed in relation to fishing effort, and changes in the mud content of the substrate in the study area. Although the changes did not correlate with the fishing effort among three zones in the study area, it is suggested that fishing effort and discarding of the by-catch caused the change in 18 taxa. The magnitude of the decreases of some species might be related to changes in the sediment or possibly other long-term environmental change. There was also a change in the diel behaviour in the fish community that perhaps may be related to the effects of fishing on a tropical multispecies fish community.

Reproductive behavior of Aplysia californica Cooper: diel patterns, sexual roles and mating aggregations

Reproductive behavior of Aplysia californica Cooper was studied in the field and laboratory. Distinct diel patterns of behavior were found in the field. During the summer > 1 2 of A. california observed at 0300 and 0900 were engaged in reproductive behaviors (precopulatory behavior, copulations, egg-laying); feeding behavior predominated at 1500 and 2100. Relatively little time was spent crawling or being sedentary. This diel behavior pattern was similar during two time periods spanning the sumer peak in A. californica reproduction. A. californica mate in aggregations, which were larger at 0300 and 0900 than at 1500 and 2100. Larger aggregations and aggregations with eggs were more likely to persist to the following day than were small or egg-less aggregations. Despite the relatively high persistence of mating aggregations, individual turnover within the aggregations was high - only ≈ 1 3 of the observed individuals were present in the same aggregation on the following day. Individuals usually joined mating chains as the terminal male, but left from either end or the middle. Mixed-species aggregations of A. californica and the sympatric A. vaccaria Winkler often formed, suggesting that the two species share a common sexual pheromone; however, the two species did not interbreed. A. californica are simultaneous hermaphrodites. The sexual role chosen by an individual was not a function of its mass, relative size compared to its partner, or immediate feeding history. Individuals of some Aplysia species have been reported to specialize in one or the other sexual role; A. californica did not. Egg-laying was associated with subsequent reproduction as a male; reproduction in either role was associated with subsequent egg-laying. The benefits of mating in aggregations probably drive A. californica diel behavior cycles and patterns of social interaction. Major differences in the behavior of different Aplysia species remain to be explained.

Seasonal and diel behaviour of radio‐tagged Clarias gariepinus in Lake Ngezi, Zimbabwe (Pisces: Clariidae)

Seasonal and diel behaviour of six sharptooth catfish, Clarius gariepinus (Burchell), was monitored in Lake Ngezi, Zimbabwe, from May 1986 to February 1987. All specimens were equipped with surgically‐implanted radiotransmi tters, 48–49 mHz, after they were anaesthetized in 6 mg l‐1 quinaldine. This represented the first known use of this methodology in subSaharan Africa.It was determined that C. gariepinus exhibited three movement patterns on a day‐to‐day basis: long‐distance movements ( 2200 m), moderate movements (c. 40–200 m) and local movements (<40 m). Major movements were not restricted to night‐time conditions, nor were inshore/offshore movements related to time of day. Seasonal activity peaks occurred in July/August 1986 and again in January 1987, with rate of swimming exceeding 470 m/h on some occasions. Home range of some individuals encompassed the entire lake (> 5 km2).

Behavioral responses of the marine tintinnid Favella sp. to phytoplankton: influence of chemical, mechanical and photic stimuli

Computerized motion analysis was used to experimentally investigate the locomotory responses of a tintinnid, Favella sp., to phytoplankton and to chemosensory and mechanosensory stimuli associated with the presence of phytoplankton. When exposed to increased concentrations of the dinoflagellate Heterocapsa triquetra (strain HT984), Favella show transient change in behavior which result in a decrease in swimming speed, increase in turning rate and a decrease in net to gross displacement ratio; this should result in the aggregation of Favella in patches of the dinoflagellate. Similar behavioral responses are elicited by exposure to exudates of H. triquetra and to plastic beads of approximately the same size as the alga. When Favella was exposed to other phytoflagellates or their exudates, the behavioral responses were less pronounced or absent. Favella do not respond to beads < 6 μm; for larger beads, the response appears to depend on the concentration of beads. Favella do not exhibit a phototaxis or photokinesis but they do have diel behavior patterns that may be entrained by the light cycle. These diel changes in locomotory behavior may increase the probability of encounter with food patches.

A three day study of the diel behaviour of plankton in a highly humic and steeply stratified lake

A three day study of the diel behaviour of plankton in a highly humic and steeply stratified lake

The Diel Behaviour of Small Demersal Fish on Soft Sediments on the West Coast of Scotland using a Variety of Techniques: with Special Reference to Lesueurigobius friesii (Pisces; Gobiidae)

. The diel behaviour of communities of small demersal fishes was studied in situ on the west coast of Scotland using trawling, diving, underwater television and underwater time-lapse photography techniques. Lumpenus lampretaeformis and Pomatoschistus norvegicus were shown to have crepuscular behaviour patterns. Lesueurigobius friesii was a day active fish, spending the night close to or within its burrow and feeding through the day. Disruptions to this behaviour pattern occurred at high abundances of gadoids and during the spawning season. The fish community as a whole showed a crepuscular periodicity. The various observational methods are discussed. There did not appear to be any close association between Lesueurigobius friesii and the decapod Nephrops norvegicus.

Biology, Morphology and Distribution of the Australian Fossorial Frog Cyclorana cryptotis (Anura: Hylidae)

SCHMIDT-NIELSEN, K. S. 1972. Locomotion: Energy cost of swimming, flying and running. Science 177:222-228. . 1979. Animal physiology: Adaptation and environment. 2nd Edition. Cambridge Press. SCHOLANDER, P. F., AND J. KROG. 1957. Countercurrent heat exchange and vascular bundles in sloths. J. Appl. Physiol. 8:279-292. SCIARROTTA, T. C., AND D. R. NELSON. 1977. Diel behavior of the blue shark, Prionace glauca, near Santa Catalina Island, California. Fish. Bull. 75:519-528. SKUD, B. E. 1962. Measurement of a white shark Carcharodon carcharias, taken in Maine waters. Copeia 1962:659-661.

Diel Behavior of the Tiger Shark, Galeocerdo cuvier, at French Frigate Shoals, Hawaiian Islands

Diel Behavior of the Tiger Shark, Galeocerdo cuvier, at French Frigate Shoals, Hawaiian Islands

Daily, seasonal, and annual fluctuations among zooplankton populations in an unpolluted tropical embayment

During 1973–74 biweekly collections of zooplankton in Jobos Bay, Puerto Rico revealed that major differences in the abundance and variety of several populations were related to water circulation, seasonal rainfall, and diel behavior. Total densities of zooplankton ranged from 225 to 9050/m 3 for night and 30 to 4700/m 3 for day samples. Abundance levels increased about twofold from coastal to isolated regions of the bay but at least twice as many species occurred in the coastal areas. Rapid, short-term changes in abundance, pulses of about one order of magnitude, occurred shortly before and during the wet season. Diel differences in density, most notable among the copepod, Acartia tonsa , coincided with a seasonal increase in abundance. The size and composition of the zooplankton communities in Jobos Bay were similar to those found in one polluted, tropical embayment (Guayanilla Bay, Puerto Rico) but differed greatly from those described in another (Kingston Harbour, Jamaica).

Small-scale pattern of a California current zooplankton assemblage

The small-scale vertical (10′s of meters) and horizontal (100′s to 1000′s of meters) distribution of zooplankton in the California Current near Guadalupe Island, Baja California, Mexico was studied. Vertical distributions were sampled using a vertically-towed Longhurst-Hardy Plankton Recorder (LHPR) which gave a sequence of samples, each integrated over about 5 m, from 250 m to the surface. Because of the sampling biases of the LHPR, details in vertical structure of less than 15 to 20 m were not considered. The pattern of the vertical tows and the variability of the integrated counts of species were used to infer horizontal distribution. Four series of 8 tows each were taken around noon and midnight over a 2-day period. Four of the 8 tows in each series were randomly positioned within 2000 m of a parachute drogue (first day) or a fixed geographic position (second day); four were replicate tows taken at the drogue or the fixed position. Sixty-seven taxonomic categories were counted. The replicate tows, separated by no more than a few hundred meters, gave more similar vertical profiles for species than did the random tows, with separations of 100′s to 1000′s of meters. The night replicate tows showed less variability in depth distribution than did either the night random or any of the day tows, leading to the hypothesis that the vertical distributions observed were generated by interactions of the organisms' diel behavior with internal waves. Variability of abundance estimates using the integrated counts was the same for both replicate and random tows, indicating that horizontal patches may be smaller than 100 m. No evidence was found for a day-night change in patch size, or for a consistent overlapping of patches of different species. Replicate tows gave more similar estimates of community structure (relative proportions of species) than did random tows. Overall day community structure was more similar between tows than night structure. Similarities in species' proportions of any random tow to the replicate tows or to other random tows of a series decreased with increasing distance between the tows being compared. This decrease was greater for the night samples, suggesting that community structure is more heterogeneous at night.

Observations on diel behaviour patterns of North Sea gadoids in the pelagic phase

The general biology of the gadoid fishes of the North Sea after recruitment to the demersal fisheries has received considerable attention, but little is known about their behaviour patterns during the period between metamorphosis and assumption of the demersal habit. In the summer of 1969 the Marine Laboratory, Aberdeen, began a series of annual midwater trawling surveys of the northern North Sea (Hislop, 1970, 1972a, b; Hislop &amp; Bailey, 1971, 1975). During the surveys observations were also made on various aspects of the biology of the species caught. This paper describes the results of a series of trawling experiments carried out on a cruise of F.R.S. ‘Scarba’ (ex ‘Scotia’) between 12 and 29 August 1971.

Rearing Pales Weevils on Soil Beds Containing Pine Bolts1

A rearing technique that approximated field conditions was developed for Hylobius pales (Herbst). Loblolly pine bolts were buried in screened soil beds in the greenhouse or buried with ends exposed in field enclosures, and adult weevils were introduced. Sand, sand-clay, peat, litter, and sawdust were used as bedding materials. Fewer offspring were produced on pine bolts placed in sand than on bolts in other bedding materials. The ratio of females to offspring produced was most efficient when 20 females were introduced per bed. Associated organisms, weights, sex ratios, and diel behavior of bed-reared and field-collected weevils were compared.

Ecological Energetics and Natural History of Hedriodiscus truquii (Diptera) in Two Thermal Spring Communities

The interrelations of flora and fauna of the Ohanapecosh Hot Springs, Mount Rainier National Park, Washington State, were studied during a 4-year period commencing in 1963. The flow of energy and efficiency of its transfer were measured in two springs, one with an annual mean temperature of 35 C (SD 2.0) and the other a constant 47 C. In addition to temperature differences, each spring contained a different flora and fauna.Primary production estimates were obtained together with data relative to many aspects of the natural history of the dominant dipteran herbivore Hedriodiscus truquii (Bellardi), hitherto undescribed in the larval stage, and common to both springs. Aspects of the natural history of Hedriodiscus pertinent to the energetic approach are discussed, including a detailed caloric investigation. Information about the seasonal variation in lipid composition during larval growth was used to explain much of the observed caloric variation. Energy budgets for three of the four instars of Hedriodiscus were determined from estimates of growth, respiration, and rates of food ingestion. This information together with population census data permitted calculation of population energy budgets. Efficiencies of energy transfer in both spring communities are compared and discrepancies in the allocation of assimilated energy between populations are attributed to variation in diel behavior patterns and differences in food ingested. Export of Hedriodiscus larvae and spider predation on newly emerged adults inflicted heavy mortality and were considered the most important sources of population regulation. The annual energy balance for the two springs was tabulated from estimates of energy income and export. The springs fixed far more energy than was expended in any given year. Greatest losses are attributed to algal export, respiration, and travertine deposition; tree leaves represented a significant income of energy to the springs. Primary production accounted for better than 90% of total income and only 0.5–1.0% of algal primary production was channeled to the dominant herbivore, Hedriodiscus. Of algal gross production 20–25% was exported from the system. Photosynthetic efficiency was 1.06% utilization of visible light available to algae.

Effects of Light, Temperature, and Relative Humidity on the Diel Behavior of the Alfalfa Weevil, Hypera postica

Observations made in 1958 showed that adults of the alfalfa weevil, Hypera postica (Gyll.), were more active during the night than during the day. In 1959, replicated sweep samples were taken at regular intervals over 24-hour periods and periods in early morning, to study the effect of light, temperature, and relative humidity on the diel behaviour of the adult weevils. The results strongly suggested that the diel behavior of the adults was related to light intensity, whereas larvae showed no response to either light, temperature, or relative humidity over the 24-hour period.