摘要:

The paper presents examples of circatidal rhythms in fishes, reviews the evidence for hydrostatic pressure as a synchroniser for these rhythms, and demonstrates that fish are capable of detecting and responding to slow cyclic pressure changes whose amplitude and duration are similar to those of natural tidal cycles.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<479:HPATRB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Lunar-synchronized spawning has been reported in four orders of fish. Salmoniform, atheriniform, and tetraodontiform species spawn intertidally on spring tides, leaving their eggs exposed to air between tidal inundations. This spawning mechanism may be essential to survival of species that are residents of areas such as tide marshes where dissolved-oxygen concentrations in the water column can be near zero. Spawning cycles of both lunar and semilunar periods have been reported in coral-reef fishes of the Perciformes. Reproduction by these fishes does not include aerial incubation of eggs. It has been hypothesized that the spawning cyclicity in these fishes synchronizes reproduction with moonlight or current conditions that enhance parental care or predator avoidance. The intertidal spawners that have been studied display cyclic changes in gonad maturity consistent with a semilunar periodicity in recruitment of oocytes into final maturation. Oocytes in the early stages of vitellogenesis are present throughout the spawning season. In the mummichog Fundulus heteroclitus, this periodicity is generated by an endogenous mechanism that operates in the absence of diurnal, lunar, or tidal periodicities in light or water movement. Indirect evidence exists for the involvement of both light-and tide-related phenomena in synchronization of semilunar reproductive rhythms in fishes.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<484:LSOFR>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Standard metabolic rate of the pumpkinseed Lepomis gibbosus was estimated from measurements of routine oxygen consumption and random activity at acclimation temperatures of 8–32 C and within each season of the year. Routine and standard metabolic rates increased from winter (January-March) minima to spring (April-June) maxima, independently of acclimation temperature. For example, standard metabolic rate of a 100-g fish increased from 1.8, 3.0, and 4.8 mg O2˙hour−1at 8, 16, and 24 C, respectively, during winter, to 3.5, 5.6, and 9.2 mg O2˙hour−1at the same temperatures, respectively, during spring. The annual energy requirement for standard metabolism, derived from seasonal rate-temperature curves and a simulated annual temperature cycle at 44°N latitude, is 5.01 × 105joules. The annual cycle is anticipatory in that the increase in metabolic rate during spring begins independently of the vernal rise in environmental temperature. Depression of standard metabolism during fall and winter suggests an adaptive metabolic strategy similar to hibernation in endotherms. These findings provide a possible explanation for previously reported thermal zones of metabolic homeostasis in the pumpkinseed and other species, and illustrate the inadequacy of single-season calorimetric determinations for estimation of annual energy budgets in fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<494:TIOTAC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Rainbow trout Salmo gairdneri, statically exposed to 36 μg/liter anthracene (including 9-14C-anthracene), bioconcentrated the polynuclear aromatic hydrocarbon 200 times the exposure concentration over 18 hours. Then, during a 96-hour clearance period, mass-balance analysis of fish and water samples indicated that anthracene was rapidly converted to polar metabolite(s), then eliminated periodically. Maximum depuration occurred during the dark phase of a 16-hour-light:8-hour-dark photocycle. Of the 2–3% contribution of14C metabolite(s) to the total14C residue, nearly half came from the bile. This periodic depuration may be circadian, although this requires confirmation by further work; to the extent it affects metabolic fate of bioconcentrated organics, periodic depuration undoubtedly contributes to differences between predicted and observed bioconcentration factors.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<513:PDOAMB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

When male gulf killifish Fundulus grandis were netted at a consistent time each day for 2–3 weeks, gonad weight and fat stores increased or decreased depending on the time of day the handling occurred. The phases, amplitudes, and patterns of these response rhythms may be influenced by day length and season. In spring, gonad responses were similar at temperatures of 20 and 28 C. In fall, when gulf killifish were placed on a 48-hour diel cycle (12 hours light, 36 hours darkness), fat-response rhythms recycled every 20 hours (for example, similar responses occurred at 0, 20, and 40 hours after the onset of light). Thus, daily photoperiod appears to entrain a circadian rhythm of responsiveness to handling similar to its entrainment of a circadian responsiveness to light.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<521:CROGAF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Goldfish Carassius auratus held on a 14L:10D (14-hour-light:10-hour-dark) photoperiod and fed once daily at unscheduled times during light and darkness had a diurnal activity pattern beginning about light onset; this rhythm lasted at least 3 days when fish subsequently were held in constant light or constant darkness. When goldfish were fed once daily at scheduled times during a 12L:12D photoperiod (the schedule varying among treatments with respect to light and darkness), their activity was entrained by the feeding time, and the activity cycle persisted through 3–10 days of starvation. Serum-cortisol concentrations also were entrained by feeding regimen, peaking 0–6 (often 4) hours before feeding, and mean daily titers were unaffected by the time of day feeding occurred. Serum-thyroxine concentrations, in contrast, were entrained by photoperiod, though daily mean titers were affected by feeding time. Thus, feeding schedule, when it provides a consistent cue, overrides photoperiod to entrain cyclic goldfish activity and serum-cortisol variations–but not serum-thyroxine variations. This implicates a multioscillatory system in the temporal integration of goldfish with their environment. For study of some endocrine rhythms in fish, activity cycles may provide a better reference than photoperiod.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<528:EOPAFS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Goldfish Carassius auratus were maintained on a 12L:12D (12-hour-light:12-hour-dark) photoperiod at 14 C and fed 1% of body weight once daily for 3 weeks. The fish had differences in growth depending on the feeding time relative to the light-dark cycle: Fish fed 18 hours after light onset (6 hours into darkness) grew more than others. Common carp Cyprinus carpio were maintained on a 16L:8D photoperiod at 15 C and fed 2% of body weight at one of six feeding times for 5 months. There were no consistent growth differences among treatments, nor any apparent debilitating effects of long-term enforced feeding times on common carp. The feeding time most conducive to body-weight gain appears to vary with the season and among cultured fish species. Timing the daily meal may be a valuable tool for aquaculture.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<540:CFTAGO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Diel and seasonal changes in the environment directly or indirectly control many biological functions. Chronobiology, the study of biological functions in relation to time of day, time of year, lunar phases, and other consistent cues, could have important applications in aquaculture. Physiological conditions that vary seasonally include feeding time, tolerance of fish to stress, the state of gonad development, lipid and water content of muscle tissue, and the dress-out weight of food fish. The quality of cultured fish may vary with the time of day when fish are fed, seined, graded, treated with therapeutic chemicals, injected with hormones, or physically disturbed. Efficiency of production and quality of aquacultural products might be improved if the activities of fish husbandry were timed to coincide with the biological rhythms of fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1984)113<545:CATA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1984.10493234

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor