西北太平洋柔鱼栖息地环境因子分析及其对资源丰度的影响

柔鱼(Ommastrephes bartramii)是西北太平洋海域重要的经济头足类,短生命周期的生活史特征决定其资源丰度易受海洋环境变化影响。根据1998—2010年我国鱿钓船生产统计资料和环境资料,包括海表温度(SST)和叶绿素浓度(Chl-a)数据,结合Nio 3.4区海表温距平值(SSTA),分析了SST和Chl-a浓度的季节和年际变化特征,并分别探讨了SST和Chl-a浓度距平值与Nio 3.4区SSTA及柔鱼资源丰度之间的关系。结果表明,产卵场海域Chl-a浓度冬季高夏季低,SST则夏季高冬季低;育肥场Chl-a和SST均呈夏季高冬季低变化,但6—12月份Chl-a浓度波动明显。产卵场和育肥场SST及Chl-a浓度年际变化明显。同时研究发现,厄尔尼诺、拉尼娜和正常年份时Nio 3.4区SSTA对柔鱼产卵场和育肥场环境的调控机制不同:拉尼娜和正常年份产卵场和育肥场温度上升,叶绿素浓度变化幅度小,有利于资源量补充,产量较高;厄尔尼诺年份温度和叶绿素均降低,尤其育肥场叶绿素浓度,对资源量产生不利影响,产量锐减。研究利用多元线性回归分别建立了基于温度和叶绿素的柔鱼资源丰度的预测模型,两者均能很好的预测柔鱼资源丰度(P0.05),但基于叶绿素的预测模型优于温度模型。     

Temperature-dependent growth and life cycle of Deleatidium (Ephemeroptera: Leptophlebiidae) in two high-country streams in New Zealand

1. Measurements of larval growth rates were used to produce an empirical model for examining factors influencing patterns of size structure and emergence period for populations of the leptophlebiid mayfly Deleatidium ( lillii group) in two high-country streams (South Island, New Zealand). Growth rates were measured in situ by enclosing groups of larvae and natural stream substrata in growth chambers.
2. Multiple regression analysis showed that temperature explained most variation among growth rates in both streams. Growth rates were also significantly related to larval size, although the effect was minor compared with temperature. A significant relationship between larval biomass per chamber and growth rate was shown at only one site.
3. Growth models based on multiple regression equations ( R ² = 0.70–0.84) simulated the extended emergence period and complex size structure observed for populations of Deleatidium in the field. Larvae hatching from eggs deposited before mid-February (austral summer) probably emerge as adults before May (minimum cohort duration ≈ 3 months). Larvae hatching after mid-February probably do not emerge as adults until the following summer because of low growth rates during winter (maximum cohort duration ≈ 11 months).
4. On average, there are probably two generations of Deleatidium per year (bivoltine) at the study sites. The presence of numerous overlapping cohorts throughout summer, however, results in an extended emergence period and complex size structure.     

The growth of brown trout (Salmo trutta) in mild winters and summer droughts in upland Wales

SUMMARY. 1. We compared the observed annual growth of 0- and I-group trout in nine Welsh upland streams, with growth predicted from temperature assuming that this was the only limiting factor.
2. Autumn weights of second year fish were 51–67% of predicted ( G _max) values in 1988, but only 30–40% in 1989 and 1990 when drought occurred. Though initial weights of fry were unknown, simulations suggested that first year growth was also less than G _max, but with no obvious effect of drought.
3. To evaluate the possible effects of future climate change, we simulated stream temperature regimes 1.5–4.5°C above those of a recent year with temperatures similar to the long-term average. Growth was set at 60% G _max for both 0- and I-group, or at 40% for I-group to represent the effect of drought. As winter temperature increased, time to hatching and emergence decreased, for example by 56 and 49 days respectively for a rise of 3°C. 0-group growth was slightly enhanced at up to + 3°C but retarded at + 4.5°C. Simulations of I-group growth suggested that warmer winters could enhance trout growth while warmer summers would only increase growth if there were no adverse effects of drought.
4. We discuss many uncertainties in these simulations, which nevertheless suggest the magnitude of possible effects of climate change.     

A model for predicting the emergence of dragonflies in a changing climate

1. Precise models for the phenology of different species are essential for predicting the potential effects of any temporal mismatch of life cycles with environmental parameters under different climate change scenarios. Here we investigated the effects of ambient water temperature on the onset and synchrony of emergence for a widespread European riverine dragonfly, Gomphus vulgatissimus .
2. Long-term field data on the annual emergence from two rivers in northern Germany, and additional data from a laboratory experiment with different temperature regimes, were used to develop a model that predicted the onset of emergence by using mainly the temperature sum (degree days) as a parameter.
3. Model predictions of the onset of emergence fitted the observations well and could be transferred between localities. This was particularly so when weighting early winter temperature data by using a day length and a temperature-response function, implying potential additional control mechanisms for the onset of emergence.
4. We simulated effects of different winter temperature regimes on the emergence curves in order to predict the effects of climate change. These indicated an acceleration of emergence by 6–7 days per 1 °C temperature increase, which is corroborated by the laboratory data and is in the upper range of data published for other dragonflies.     

The roles of temperature and diapause in the life history of a temperate-zone dragonfly: Argia vivida (Odonata: Coenagrionidae)

Abstract. 1. The life cycle of Argia vivida Hagen generally took longer to complete in the field than was predicted on the basis of the thermal sum accumulated in laboratory rearing.
2. The prediction of a bivoltine life-cycle from geothermal sites with either a constant annual temperature of 26°C or thermal range of 11–31°C was not borne out because the intervention of short-day induced developmental delays in later larval instars extended the life cycle to 1 year.
3. This diapause, which synchronizes adult emergence with favourable summer temperatures, was also present in larvae from sites with annual temperature ranges of 0–33°C and 5–20°C.
4. At these colder sites completion of the life cycle takes 2 and 3 years respectively and dragonflies must be in cold-resistant stages during the winter. A long-day diapause, principally affecting late-instar larvae below a certain size during the summer, achieves this.
5. Large diurnal temperature fluctuations at the 0–33°C site markedly increase the useful thermal energy available to larvae for growth over that predicted by the thermal sum equation.
6. The interaction between the effects of temperatures favourable for growth and day-length-governed diapause, synchronize the emergence of the low-temperature sensitive adult stage of this tropical dragonfly with northern-latitude summers at a variety of habitats.     

Overwintering survivorship of pupae of the mimosa web worm, Homadaula anisocentra (Lepidoptera: Plutellidae), in an urban landscape

ABSTRACT. 1. Overwintering survivorship of pupae of the mimosa webworm, Homadaula anisocentra Meyrick (Lepidoptera: Plutellidae), was examined in several urban habitats in central Iowa during the winters of 1981–82, 1982–83 and 1983–84.
2. Survivorship and supercooling point temperatures were determined throughout the winters. Corroborative laboratory studies were conducted during the winter of 1982–83.
3. Minimum ambient temperatures that equalled or were below the supercooling point of the insect, at any time, were lethal.
4. Prolonged cold exposure below 0°C and above the supercooling point resulted in high mortality levels. To quantify this relationship, a concept of minimum-temperature exposure was developed by tabulating the number of degrees that the daily minimum temperature was below 0°C for a given sampling period.
5. Some mimosa webworm pupae were found to overwinter in highly protected sites (2.5–5.0°C warmer than the ambient air temperatures) in the urban environment, resulting in less minimum-temperature exposure and reducing the probability of reaching the lethal supercooling point temperature.     

Interannual variation in pup production and the timing of breeding in benthic foraging Australian fur seals

Large interannual variations in reproductive success caused by fluctuations in oceanography and prey availability are common to many species of air breathing epipelagic predators. In contrast, little is known about variation in benthic foragers such as Australian fur seals ( Arctocephalus pusillus doriferus ). Between 1997 and 2007, pup production was assessed in 9 yr, while the timing of breeding and adult female condition was assessed in 5 yr at Kanowna Island in Bass Strait, southeastern Australia. Pup production was variable (     = 1,726 ± 42, range = 1,386–2,301), but without temporal trend, as was median birth date (     = 23 November ± 1, range = 21–25 November) and pupping synchrony (period of 90% births:     = 28 ± 2 d, range = 23–31 d). Pup production was negatively correlated with median birth date and positively correlated with female condition, winter sea-surface temperature (SST) and zonal wind strength within Bass Strait. Pup production was also negatively correlated with SST in the previous summer within Bass Strait and in the eastern Great Australian Bight upwelling region. The results suggest that the reproductive success of Australian fur seals is influenced by oceanography but less so than in otariids foraging epipelagically in major upwellings. Despite spanning several El Niño events, no correlation between pup production and the Southern Oscillation Index was observed.     

Chlorella-bearing ciliates dominate in an oligotrophic North Patagonian lake (Lake Pirehueico, Chile): abundance, biomass and symbiotic photosynthesis

1. Large mixotrophic ciliates ( Stentor araucanus , S. amethystinus and Ophrydium naumanni ) were a characteristic component of a temperate, oligotrophic lake in North Patagonia. During a 1-year study, the abundance, biomass and primary production of these large Chlorella -bearing ciliates were compared with those of the total plankton community.
2. Mixotrophic ciliates peaked in spring and from late summer to autumn, accounting for 1.6–43% (annual average: 16.3%) and 67–99% (annual average: 92%) of total ciliate abundance and biomass, respectively. Their contribution to total zooplankton biomass, including flagellates, rotifers, ciliates and crustaceans, was 14–76%, or 47% as an annual average. Endosymbiotic algae accounted for up to 25% of total autotrophic biomass (annual mean: 3.9%).
3. Maximum cell-specific photosynthetic rates of S. araucanus and S. amethystinus at light saturation varied between 80 and 4400 pg C ciliate^–1 h^–1 with high values during autumn and winter, and low values during summer. The depth-integrated rates of photosynthesis (0–40 m) of algal endosymbionts contributed 1–25% to total photosynthesis (annual mean: 6.5%).
4. A comparison of calculated ingestion rates with photosynthetic rates of Stentor indicates that photosynthate produced by endosymbionts generally exceeded heterotrophic food supply of Stentor during autumn and winter, but was much lower during summer, when food supply was high.
5. The mixotrophic ciliates represent an important 'link' between nanoplankton and higher trophic levels within the plankton community because of their high heterotrophic biomass and considerable contribution to total photosynthesis.     

Temperature-dependent growth and life cycle of Deleatidium (Ephemeroptera: Leptophlebiidae) in two high-country streams in New Zealand

1. Measurements of larval growth rates were used to produce an empirical model for examining factors influencing patterns of size structure and emergence period for populations of the leptophlebiid mayfly Deleatidium ( lillii group) in two high-country streams (South Island, New Zealand). Growth rates were measured in situ by enclosing groups of larvae and natural stream substrata in growth chambers.
2. Multiple regression analysis showed that temperature explained most variation among growth rates in both streams. Growth rates were also significantly related to larval size, although the effect was minor compared with temperature. A significant relationship between larval biomass per chamber and growth rate was shown at only one site.
3. Growth models based on multiple regression equations ( R ² = 0.70–0.84) simulated the extended emergence period and complex size structure observed for populations of Deleatidium in the field. Larvae hatching from eggs deposited before mid-February (austral summer) probably emerge as adults before May (minimum cohort duration ≈ 3 months). Larvae hatching after mid-February probably do not emerge as adults until the following summer because of low growth rates during winter (maximum cohort duration ≈ 11 months).
4. On average, there are probably two generations of Deleatidium per year (bivoltine) at the study sites. The presence of numerous overlapping cohorts throughout summer, however, results in an extended emergence period and complex size structure.     

Fishery biology of the seven star flying squid Martialia hyadesi at South Georgia during winter

A scientific research fishing expedition targeting the oceanic/slope ommastrephid squid Martialia hyadesi was undertaken by a Korean-registered squid jigger in CCAMLR area 48.3, near South Georgia, in June 1996, providing the first opportunity to collect data on the fishery biology of this species during the austral winter. Fishing took place over a period of 8 days; a series of eight drifts was undertaken along an approximately east/west transect of about 200 nautical miles to the north and west of South Georgia, over depths ranging from 1,700 to 2,713?m. All fishing was to the south of the Antarctic Polar Front. Data were collected on sea surface temperature, catch per unit of effort, size, sex, maturity status and stomach contents of the catch and a sample of squid was aged by counting putative, daily microgrowth increments in the sectioned statolith. All squid were caught by jigs operating at depths from 80 to 100?m to the surface. Catch per unit of effort per drift varied between 1.0 and 21.9?kg?min^?1 and there was no by-catch. Greatest numbers of squid were caught at dusk and dawn. Mantle length fell in the range 220–350?mm (males) and 212–370?mm (females). Most males were sexually mature (Lipinski's stages IV–V) and most females were immature (stage II). The absence of mature females suggests that no spawning takes place in this area during the austral winter. The squid were up to 1?year of age and had hatched during the previous winter. They were apparently from the same cohort as had been sampled at the Antarctic Polar Front in February 1996. Myctophids were the major prey in the stomach contents and the squid Gonatus antarcticus was also important; crustaceans were relatively unimportant. The results suggest that concentrations of Martialia hyadesi are present in the vicinity of South Georgia, south of the Antarctic Polar Front, during the austral winter. The squid are actively feeding during the austral winter and are susceptible to jigging gear.