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71.
A new species of corophiid Amphipoda, Cheiriphotis trifurcata, collected from the seagrass bed of the Lower Gulf of Thailand, is described. Cheiriphotis trifurcata is characterized by its trifurcated tip of the modified setae on the outer ramus in male pleopod 3. In this paper, the new species is fully described and compared with related species and a complete key of the 16 valid species in the genus Cheiriphotis is given. 相似文献
72.
广西西端海岸四种红树植物天然种群生境高程 总被引:2,自引:0,他引:2
在广西防城港市东湾渔洲坪、石角、交东3个样地平行海面方向共设置18条剖面对4种红树植物白骨壤(Avicenniamarina)、桐花树(Aegiceras corniculatum)、秋茄(Kandelia obovata)、木榄(Bruguiera gymnorhiza)在沿海滩涂生长带高程测量和群落调查。调查结果表明:由于人类活动造成东湾渔洲坪和交东两个样地的坡度变化较大,分别从-0.37变化为-0.05和-0.72变化为-0.10,而地处北仑河口保护区内的石角样地受到保护,没有人为因素的影响,坡度从-0.23变化为-0.10变化不大。石角和交东两个样地中的桐花树集中出现在高程15至40 cm和33至36 cm范围内;秋茄集中出现在高程43至60 cm和37至51cm范围内;木榄集中出现在高程94至106 cm和111至119 cm范围内。所有样地中的白骨壤在高程60至80 cm范围内,树高最高达到220 cm,且分布密集;桐花树在高程20至40 cm范围内,树高最高达到200 cm,且分布密集;秋茄在高程40至80 cm范围内,树高最高达到200 cm,且分布密集;木榄在高程60至100 cm范围内,且分布密集,树高最高达280 cm。通过对各样地剖面上红树植物种类出现频度的分析和林木高度的测量,4种红树植物天然林临界滩涂高程分别为:桐花树为-7 cm;秋茄为+33 cm;白骨壤为+23和+26 cm;木榄为+44 cm。对应的浸淹时间分别为8.5、7.0、7.0、6.0h。在石角和交东分别有30.0%和56.7%的桐花树分布于平均海平面以下,秋茄也能分布在此高程下,平均株高也达1.75 m。根据现场实际调查结果,桐花树、秋茄可以大量生存在平均海平面以下的滩涂上。 相似文献
73.
74.
Grant Murray Barbara Neis Craig T. Palmer David C. Schneider 《Human ecology: an interdisciplinary journal》2008,36(4):581-598
Some recent scholarship has focused on integrating local and/or traditional knowledge with conventional scientific information
in fisheries management to improve the factual foundation of and strengthen support for management decisions. This article
compares a sequence of historical and contemporary scientific texts and maps about the migrations and stock structure of cod
in the Northern Gulf of St. Lawrence with texts and maps generated by the authors through the collection, aggregation and
interpretation of commercial fish harvesters’ ecological knowledge. We find that the relationship between fisheries science
and harvesters’ ecological knowledge is dynamic and has changed over time, and that both are ‘situated’ socially and ecologically.
Overall, each paints an incomplete picture of cod movements and stock structure but the knowledge of harvesters provides a
valuable complement to scientific information, particularly at the local scale, and has the potential to contribute to the
identification of local cod stocks that are new to science and management. We end by considering how this case study informs
the larger discussion about the challenges and potential benefits of the so-called integration project to bring together science
and the ecological knowledge of fish harvesters.
相似文献
Grant MurrayEmail: |
75.
Timothy T. Wynne Richard P. Stumpf Michelle C. Tomlinson Varis Ransibrahmanakul Tracy A. Villareal 《Harmful algae》2005,4(6):224
Blooms of the toxic dinoflagellate, Karenia brevis, have had detrimental impacts on the coastal Gulf of Mexico for decades. Detection of Karenia brevis blooms uses an ecological approach based on anomalies derived from ocean color imagery. The same anomaly product used in Florida produces frequent false positives on the Texas coast. These failures occurred during wind-driven resuspension events. During these events resuspension of benthic algae significantly increases chlorophyll concentrations in the water, resulting in confusion with normal water column phytoplankton, such as Karenia. A method was developed to separate the resuspended chlorophyll from the water column chlorophyll, decreasing the false positives used with the detection method. 相似文献
76.
Kari K. Lehtonen 《Aquatic Ecology》2004,38(3):441-456
Seasonal variations in the physiological condition of two benthic deposit-feeding amphipods were studied in two environmentally differing areas in the Gulf of Riga (Baltic Sea) with the purpose of estimating their role in benthic mineralisation. At the shallower (26 m) nearshore station, Monoporeia affinis exhibited low ammonia excretion rate (VNH
4
+
) throughout the year. After intensive accumulation of lipids in spring, the lipid reserves of the individuals became rapidly depleted during autumn. Gravid females in winter-early spring showed exceedingly low lipid and triacylglycerol (TAG) levels compared to studies carried out in open-sea areas. Pontoporeia femorata studied at the deeper (43 m) offshore station exhibited a higher VNH
4
+
at all times with no significant seasonal variation. Lipid and TAG accumulated continuously until November, reaching higher levels than recorded previously for this species. Experiments showed that the temperature coefficient Q
10 determined for VNH
4
+
is likely to depend on the recent feeding history of the amphipods. Mineralisation of nitrogen and carbon by the amphipod populations at the study sites was estimated to be 1.7-3.0 g C and 11.3-13.5 mmol NH
4
+
m–2 yr–1. Conclusively, both biotic and abiotic factors affect the condition of the amphipods, while the species also have genuine differences in their metabolic characteristics. 相似文献
77.
Jose Luis León-de la Luz José J. Pérez-Navarro Reymundo Domínguez-Cadena 《Brittonia》2002,54(2):72-77
Marina victoriae andM. brevis are newly described species from the southern Baja California peninsula, Mexico. The former is a perennial herb locally abundant
in the eroded hillsides at the foothills of Sierra de la Victoria, where an oak woodland and a dry tropical forest meet. The
latter is an elusive ephemeral inhabiting a narrow strip of land between the mangroves and the desert scrub on an island in
the Gulf of California. These two new species belong to the seriesChrysorrhizae, a group native to the Gulf of California basin. 相似文献
78.
Effects of brackish water on growth, feed conversion and energy absorption efficiency by juvenile euryhaline and freshwater stenohaline fishes 总被引:3,自引:0,他引:3
Among six species of juvenile fishes (<6 months old), stenohaline species (channel catfish Ictalurus punctatus and goldfish Carassius auratus ) had their highest specific growth rate ( G ) and most efficient food conversion ratio ( E C ) and energy absorption efficiency ( I E ) in fresh water. Three of the euryhaline species (rainbow trout Oncorhynchus mykiss , striped bass Morone saxatilis and Gulf sturgeon Acipenser oxyrinchus desotoi ) had higher G and had more efficient E C and I E in 3 and 9‰ salinities than in lower salinities (fresh water and 1‰). For brown trout Salmo trutta (age 3–4 months), 9‰ was above the optimum level for G and E C. However, I E for brown trout was not significantly different at 3 and 9‰ salinities. Over the salinity range tested, channel catfish had the largest change in G , E C and I E , while changes for euryhaline species were relatively small. Although all species tested survived and grew in all treatments, salinities as low as 1‰ adversely affected the stenohaline species, and 9‰ adversely affected brown trout. 相似文献
79.
THE ABUNDANCE OF HARBOR SEALS IN THE GULF OF ALASKA 总被引:1,自引:1,他引:0
Peter L. Boveng John L. Bengtson David E. Withrow Jack C. Cesarone Michael A. Simpkins Kathsyn J. Frost John J. Burns 《Marine Mammal Science》2003,19(1):111-127
The abundance of harbor seals ( Phoca vitulina richardii ) has declined in recent decades at several Alaska locations. The causes of these declines are unknown, but there is concern about the status of the populations, especially in the Gulf of Alaska. To assess the status of harbor seals in the Gulf of Alaska, we conducted aerial surveys of seals on their haul-out sites in August-September 1996. Many factors influence the propensity of seals to haul out, including tides, weather, time of day, and time of year. Because these "covariates" cannot simultaneously be controlled through survey design, we used a regression model to adjust the counts to an estimate of the number of seals that would have been ashore during a hypothetical survey conducted under ideal conditions for hauling out. The regression, a generalized additive model, not only provided an adjustment for the covariates, but also confirmed the nature and shape of the covariate effects on haul-out behavior. The number of seals hauled out was greatest at the beginning of the surveys (mid-August). There was a broad daily peak from about 1100–1400 local solar time. The greatest numbers were hauled out at low tide on terrestrial sites. Tidal state made little difference in the numbers hauled out on glacial ice, where the area available to seals did not fluctuate with the tide. Adjusting the survey counts to the ideal state for each covariate produced an estimate of 30,035 seals, about 1.8 times the total of the unadjusted counts (16,355 seals). To the adjusted count, we applied a correction factor of 1.198 from a separate study of two haul-out sites elsewhere in Alaska, to produce a total abundance estimate of 35,981 (SE 1,833). This estimate accounts both for the effect of covariates on survey counts and for the proportion of seals that remained in the water even under ideal conditions for hauling out. 相似文献
80.
TWO TYPES OF BLUE WHALE CALLS RECORDED IN THE GULF OF ALASKA 总被引:1,自引:0,他引:1
At one time blue whales were found throughout the Gulf of Alaska, however, none have been sighted there in post-whaling era surveys. To determine if blue whales ( Balaenoptera musculus ) might now occur in the Gulf of Alaska, an array of hydrophones was deployed there in October 1999. Data were retrieved in May 2000 and in June 2001. Spectrograms from a random subsample comprising 15% of the ∼63,000 h of data were visually examined for blue whale calls. Call types attributed to both northeastern and northwestern Pacific blue whales were recorded. Both of these call types were recorded seasonally from the initial deployment date in October 1999 through the third week of December 1999 and then from July 2000 through mid-December 2000. Both call types were regularly recorded on the same hydrophone at the same time indicating clear temporal and spatial overlap of the animals producing these calls. Two blue whale call types were recorded in the Gulf of Alaska suggesting that perhaps two stocks use this area. The northeastern call type has now been documented from the equator up to at least 55°N in the eastern North Pacific. 相似文献