Green Eggs Research Articles

Artificial reconditioning, spawning and survival of Atlantic salmon, Salmo salar L., kelts in salt water and survival of their Fl progeny

. Atlantic salmon kelts were successfully reconditioned in salinities of 16% and 28%o using a moist pellet diet. Two groups of reconditioned kelts were re-acclimated to fresh water in the autumn tu prevent super chitling in salt water during the winter. The feeding response and growth of salmon kelis. both years, was highest when salinities were maintained at 28% during the winter and 16%during the summer. However, other salinities also provided acceptable growth rates. Two-sea-winter salmon kelts reconditioned at a slower rate in all groups than 1-sea-winter salmon kelts. Kelt survival was 93.1% the first year and 82.7% the second year. Gonnd maturation occurred in 17.9% of the female 1-sea-winter kelts and 40.6% of the male 1-sea-winter kelts after the first year. At the end of the second year. 83.3% of the 1-sea-winter female kelts and 96.3% of the l-sea-winter male kelts matured and spawned. Reconditioned salmon kelts with a mean fork length of 68.4 cm produced 7261 eggs per fish with a mean egg diameter of 5.70 mm and a fecundity of 2262 eggs.kg−1, Survival (Fl) from the green egg stage to the alevin and smolt stages was 73.5% and 38.8% respectively. The smolt to adult return rule based on unadjusted tug recaptures was 2.20%.

Distinguishing Hooded Merganser and Wood Duck Nests by Eggshell Thickness

Although eggshells of hooded mergansers (Mergus cucullatus) and wood ducks (Aix sponsa) are difficult to distinguish by color, I found that eggshell thickness (0.541 vs. 0.255 mm, respectively) provided reliable identification. J. WILDL. MANAGE. 51(3):534 Distinguishing nesting species of ducks during winter maintenance of nest houses can be difficult. The nest remains of hooded mergansers are most often confused with those of wood ducks, especially when only eggshell fragments are available. Many field technicians simply report or frequently misidentify hooded merganser eggshells. The purpose of this paper is to describe a technique to differentiate wood duck and hooded merganser eggshell fragments. I thank S. P. Havera, F. C. Bellrose, B. Bacon, L. E. Nauman, and N. F. Payne for providing comments on the manuscript. While studying wood duck nesting biology and general nest-house use, eggshell fragments were collected from 25 hooded merganser and 8 wood duck nests at Mead Wildlife Area in central Wisconsin and from 22 houses used by wood ducks at Nauvoo Slough in westcentral Illinois. Thickness of 7 eggshell fragments (1-3 mm square in size) from each nest was measured with a tubular micrometer (The Cent. Tool Co., Auburn, R.I.). Fragments from hooded merganser nests averaged 0.541 (SE = 0.0079, range = 0.467-0.630 mm, N = 175) in thickness and those from wood duck nests averaged 0.255 (SE = 0.0039, range = 0.196-0.300 mm, N = 210). No overlap in range of eggshell thickness was observed. Hence, hooded merganser vs. wood duck use can be determined by measuring th thickness of eggshell fragments remaining in nests. Differences in breeding range and site and cavity dimension requirements make use of wood duck houses by other duck species a rare occurrence. However, where common goldeneye (Bucephala clangula), Barrow's goldeneye (B. islandica), or bufflehead (B. albeola) compete for nest sites, eggshell color may aid in species identification. Whereas wood duck eggs are dull white to light brown and hooded merganser eggs are pure white (eggshell fragments often stain to light brown), both goldeneyes have green eggs and those of the bufflehead are ivory yellow to olive buff. Received 18 March 1986. Accepted 7 February 1987. 1 Present address: Illinois Natural History Survey, River Research Laboratory, Box 599, Havana, IL 62644.

Artificial Turf Incubators for Raising Muskellunge to Swim-Up Fry

Abstract Muskellunge Esox masquinongy eggs were incubated in artificial turf incubators in five lakes in Michigan and Wisconsin in 1985. Mean survival of swim-up fry from green eggs was 12% and from eyed eggs was 39%. This technique provides the manager with an economical and rapid method for raising muskellunge in lakes with inadequate spawning habitat.

A Deep-Substrate Streamside Incubation Box for Atlantic Salmon Eggs

Abstract The design, site selection, and operational features of a portable streamside incubation box for Atlantic salmon (Salmo salar) eggs are described. The incubation box was located inside a field laboratory and was evaluated from 1978 to 1980. Performance of the box was then field tested in 1981. Incubation capacity of the box, estimated from this study, was 93,000 salmon eggs at a loading density of 9,000 eggs/m2 of Astroturf; eight layers of Astroturf were used, and flow rate was 1.0 L/min per 1,000 eggs. Mean survival rate from green eggs to fry emergence was 77.2%. Fry emergence occurred from early May to mid June and was partially controlled by manipulating the amount of light allowed to enter the box.

Associative learning, short-term memory, and colour preference during first feeding by juvenile Atlantic salmon

The innate colour preference of 51 groups of 20 fry was examined at resorption of the visible yolk sac. A mixture of equal portions of blue, red, green, yellow, and unstained cod or capeling eggs were given to fry for 10-min feeding intervals after which fry stomach contents were examined and numbers of each colour of egg consumed were tabulated. Fry showed innate colour preference for red eggs; however, this could be changed to any other colour by only one previous feeding with eggs of the desired colour. This single-trial learning was retained up to 6 h after feeding but began to deteriorate after 21 h. Posisble applications in early rearing of Atlantic salmon fry in hatcheries are discussed.

Taste-Aversion Conditioning of Crows to Control Predation on Eggs

Free-ranging crows (Corvus brachyrhynchos) that ate chicken eggs that were painted green and contained a nonlethal toxin subsequently avoided green eggs at various locations, whether or not they contained toxin. The crows also continued to eat unpainted and nontoxic chicken eggs. Illness-induced aversions among predators in nature may be a powerful determiner of the evolution of Batesian mimicry and, in human hands, serve as a practical tool for wildlife ecologists.

Systemic Action of Monitor 10G for Control of Insects on Potatoes, 1981

Abstract ‘Russet Burbank’ potato seed pieces were planted on Apr 22 in Ritzville silt loam soil with a pH of 6.2 and organic matter of 1.6%, at Yakima, WA. On Apr 29 a furrow was opened over the potato seed piece and the insecticide granules were dribbled in the furrow with a hand-held, funnel-type applicator and the seed-pieces and granules were covered with soil. Each plot was 1 row wide (34 inch) and 19 ft long. Each treatment was replicated 4 times in a randomized complete block design. The potato crop was sprinkler irrigated. On Jun 15 (47 days after treatment) the number of Colorado potato beetle (CPB) adults and larvae and Lygus bugs on the plants in 15 ft of row per plot were counted and the percent of plant defoliation by CPB was recorded. On Jun 17 and Jun 26 (49 and 62 days after treatment) 20 compound leaves were collected from each plot and the number of green peach aphids (GPA), potato aphids (PA) and CPB eggs on the leaves were counted. The plants were so severely damaged by CPB by Jun 26 that the leaf samples were unsuitable for aphid counts.

Dispersion and Sequential Sampling of Green Cloverworm 1 Eggs in Soybeans 2

The microspatial patterns of green cloverworm eggs were studied within and among soybean plants. The upper leaf surface generally contained significantly more eggs than the lower surface. Few eggs (2.8%) were found on stem or pod surfaces. The distribution of eggs by relative nodal position was influenced by the stage of plant growth. The third node from the terminal was selected as the best relative nodal position from which to sample egg-bearing leaves. Among-plant data were expressed on the basis of three sample-unit sizes. Four dispersion indices were calculated for each data set expressed on the basis of each sample-unit size. The majority of data sets exhibited a random dispersion pattern, although the proportion of data sets categorized as random increased with increasing sample-unit size. Taylor's power function also indicated a random dispersion pattern for all sample-unit sizes. The results of Iwao's regression technique were inconclusive. A two-stage sequential sampling plan is described that estimates egg densities with a predetermined precision level. This plan consists of random samples of leaves, for which variance-to-cost relationships indicated that the optimal number of leaves per sample was four. Cost estimates indicate that this plan is suitable for ecological population studies.

Incubation of Steelhead Trout and Spring Chinook Salmon Eggs in a Moist Environment

Abstract Fertilized green eggs of steelhead trout (Salmo gairdneri) and spring chinook salmon (Oncorhynchus tshawytscha) were incubated in moist cotton cloth to determine their ability to withstand periods of dewatering. Results indicated that salmonid eggs can develop normally without being submerged in water, if they remain moist. Dewatered hatching survivals in one test equalled those from control (Heath stack) incubation (X = 90.7%). At the time of sampling, alevins resulting from the dewatered incubations were significantly (P \[lessthanorequalto\] 0.05) longer and heavier than control alevins. There was no significant difference in fry lengths or weights after a 71-day rearing period. The apparent ability of salmonid eggs to develop normally without submergence in flowing water may be useful for hatchery design in areas where water supplies are limited.

Comparative Survival from Salmon (Salmo salar L.) Stocking with Eyed and Green Ova in an Upland Stream

The survival rates of salmon stocked as eyed ova and green eggs in an upland trout stream were compared by electrofishing a number of sites during their first summer and at the end of their first complete year. The results were compared with the survival rates in the naturally spawning trout population. It was found that the survival rates from eyed ova were considerably better than that from green eggs and the results were discussed in the context of environmental effects and territorial competition in emerging fry.

In Situ Freezing as a Cause of Mortality in Brown Trout Eggs

Abstract In November 1975, 60 Vibert boxes, each containing 100 green eggs of brown trout (Salmo trutta), were placed in artificial redds in the Laramie River in southeastern Wyoming. Water depths and, velocities were measured, and a representative substrate sample was collected at each site. Because of extensive ice cover in March 1976, only 20 of the 60 boxes of eggs were recovered. Survival of eggs in these boxes was low (average, less than 1%), and only 10 of the 20 boxes contained live eggs (survival range, 0.5 to 3.4%; average, 1.95%). Three boxes were completely frozen, even though they were buried 15 cm in the substrate and covered with 12 to 20 cm of flowing water. Eleven of the 20 redds, including two of the frozen sites, fell within established spawning criteria for brown trout (water depth, 9 cm or more; water velocity, 15-46 cm/s). No correlation was demonstrated between water depth and survival (r = 0.51) or between water velocity and survival (r = -0.21). Extremely low water temperature and...

Notes on Stenopus scutellatus and S. hispidus (Decapoda, Stenopodidae) from Mississippi

Two species of Stenopus were collected in 1976 from a Liberty ship artificial reef near Horn Island, Mississippi. Six specimens of S. scutellatus were collected. This represents an occurrence record for Mississippi. Five specimens of S. hispidus were also collcctcd; thus, extending the range in the Gulf of Mexico by about 400 krn to the northwest. Two species of Stenopus were collected during June through November of 1976 from an artificial reef located in the Gulf of Mexico (3Oo09'00N, 88'44'50W) approximately 10 kni south of Horn Island, Mississippi. The reef consists of a scrapped World War I1 Liberty ship which was sunk on June 10, 1975, in approximately 14 m of water. This hull, designated the Waterhouse Reef, provides approximately 76,200 square meters of artificial substrate. Observations and collections were accomplished by employing SCUBA techniques. Six specimens of S. scutellatus were collected (Table 1) from the artificial reef. In addition many other specimens were observed. They were most frequently seen in rock piles or under pieces of wood or pipe. Over half of those observed were egg-bearing females, easily distinguished by their bright green egg masses. Previous Gulf of Mexico records for S. scutellatus include Rathbun (1919). Holthuis (1946, 1959), and Springer and Bullis (1 956) from Florida, and Dawson (1 963) from Louisiana. The present observations are the first records for Mississippi. Five specimens of S. hispidus were collected during the study (Table 1). Others observed were most frequently seen on pipes or braces along the sides of the Liberty ship hull.

Relationship Between Formamidine Structure and Insecticidal, Miticidal, and Ovicidal Activity

The insecticidal, miticidal, and ovicidal activities of 5 formamidines, including chlordimeform, were examined in laboratory studies against eggs and adults of the twospotted spider mite, Tetranychus urticae Koch, carmine spider mite, T. cinnabarinus (Boisduval), and citrus red mite, Panonychus citri (McGregor), mobile forms of the green peach aphid, Myzus persicae (Sulzer), and eggs and early-stage larvae of the southern armyworm, Spodoptera eridania (Cramer), cabbage looper, Trichoplusia ni (Hubner), bollworm, Heliothis zea (Boddie), and tobacco budworm, H. virescens (F.). In general, excellent ovicidal and larvicidal activity was associated with N′-(2-methyl-4-chlorophenyl) substituted formamidines while the N′-(2,4-dimethylphenyl) analogs were significantly more toxic to adult miles and aphids. In response to treatment by the formamidines, adult mites displayed distinctive behavioral patterns: one, “walkoff” was associated with the nature of the formamidine, the other, “spindown” with the arylthio substituent present on 2 of the compounds. Chemical modifications of insecticidally active parent N-aryl-N-methylformamidines have resulted in the production of more toxic compounds.

Toxicity of Four Toxicants to Green Eggs of Salmonids

Toxicity of Four Toxicants to Green Eggs of Salmonids

Zur Fortpflanzung des Polychaeten Anaitides mucosa

In 1974, spawning polychaetes, Anaitides mucosa (Oersted, 1843), appeared in great numbers (up to 148 individuals/m2) at the surface of an intertidal flat in the German Waddensea from mid-February until 10th April. A. mucosa forms mucous bags which usually contain more than 10,000 green eggs. The eggs measure 113.4±5.4 μm in diameter, including the fructification membrane (18 measurements). Production if these egg bags was observed 5 times in nature and 4 times in the laboratory. Four to 17 males and 1 female form a ball of interlacing bodies. At the same time a mucous mass is secreted by the female — maybe also by the males — which increases to a diameter of as much as 2 cm within about 8 min. Eggs and sperm are shed into this mass of mucus. The worms appeared at the surface of the flat from early sunset until sunrise from about 3 h before to 1 h after low tide. Judging from observations of worms in the laboratory, it seems possible that the rhythm of sexual activity is controlled endogenously.

Some observations on the ecology of Galeus piperatus Springer and Wagner, a little known shark endemic to the Northern Gulf of California*

Galeus piperatus Springer & Wagner, the peppered shark, is a dwarf shark found in the Gulf of California north of the City of Guaymas, Sonora. It has been taken in June and August 1971 and in February and March 1972, and is found from 130–550 m with maximum abundances from 170–420 m deep. Numbers are higher in June and August (up to 110 individuals/ha) than in February and March. In June and August 1971 the area of distribution included all the waters north of Isla Tiburón and Isla Angel de la Guarda, and below the 130 m isobath. During these months Galeus piperatus was found at 12 and 33 stations respectively, but was taken at only one station in the same area during February and March 1972. The fishing effort expended during these periods was 16, 42 and 60 units respectively. It seems likely that a strong migratory movement causes these differences in abundance and distribution. Galeus piperatus has been taken from 50–100 m off the bottom in mid‐water trawls at night and is clearly a mid‐water and demersal form. Sexually mature females carrying olive green egg cases were taken in large numbers in June 1971 and were also present in reduced numbers in August 1971. Only females 18 cm or more in total length carried egg cases. The migration of Galeus piperatus into the North Gulf of California appears to coincide with sexual maturity.

Gravel Incubators: a Second Evaluation on Pink Salmon, Oncorhynchus gorbuscha, Including Adult Returns

A hatchery method designed for mass production of unfed Pacific salmon fry and utilizing a gravel medium during most of the incubation period is being evaluated on successive cycles of a stock of pink salmon, Oncorhynchus gorbuscha, of the Tsolum River, B.C. Possible treatment effects are studied at emergent fry and returning adult stages in artificially and naturally propagated populations. Average growth rate and, hence, efficiency of yolk conversion were unimpeded in the hatchery environment, but fry emerged 11 days prematurely. Survival from green egg to emergent fry averaged 74.9% in the hatchery and 20.6% in the creek, for a gain ratio at emergence of 3.63. Recovery of selectively marked populations of hatchery and creek fish demonstrated almost identical survival rates from fry to adult stages and a final gain ratio of 3.46. Adult lengths and weights, fecundity, and timing of migrations were unaffected generally by the hatchery treatment.

Toxicity of TFM (Lampricide) to Six Early Life Stages of Rainbow Trout (Salmo gairdneri)

The lampricide TFM (3-trifluoromethyl-4-nitrophenol) was tested against the following life stages of rainbow trout (Salmo gairdneri): green eggs, eyed eggs, sac fry, swim-up fry, fry, and fingerlings in four water hardnesses (12, 44, 170, and 320 mg/liter as CaCO3). The eyed-egg stage was one of the most resistant stages tested, and the sac-fry stage was one of the least resistant. Increased water hardness decreases toxicity to all stages. The LC50’s range from 0.532 mg/liter to 40.0 mg/liter depending upon life stage, water hardness, and duration of exposure. The margin of safety for coexisting species exposed to TFM ranges from 3.2 to 4.1 in natural waters. The margin of safety for early life stages of rainbow trout and larval lamprey under controlled laboratory conditions ranges from 4.2 to 12.2. Therefore, all six early life stages of rainbow trout are safe in minimum lampricidal concentrations of TFM.

The Use of Merthiolate on Green Eggs of the Chinook Salmon

The Use of Merthiolate on Green Eggs of the Chinook Salmon

The Spfoilage of Eggs Infected by Pseudomonas Bacteria and Different Methods of Preservation

THE greatest loss in stored eggs is caused by the effect of bacterial spoilage. The source of this spoilage is usually egg shells polluted by mud and excrements. Pennington (1910) was the first to draw attention to eggs in cold storage with green egg white. There were broken, dirty and washed eggs in the lot. In the microflora of the egg content, bacteria of the genus Pseudomonas were prevalent. This kind of egg spoilage has been termed, after its origin, Pseudomonas spoilage and is the most frequent spoilage in stored eggs.Spoiled eggs emanate different bad smells as sourish, musty, or fruit like. Besides becoming greenish, the egg white liquefies, becomes fibrous and a whitish and later brownish, crusty layer forms on the yolk. According to Bryant and Sharp (1934) bacteria of the genus Pseudomonas penetrate into the egg content through the big pores of the shell. If these pores …