Resumption of Feeding by and Survival of Adult Sockeye Salmon (Oncorhynchus nerka) Following Advanced Gonad Development

1963 ◽  
Vol 20 (1) ◽  
pp. 95-100 ◽  
Author(s):  
J. R. McBride ◽  
U. H. M. Fagerlund ◽  
M. Smith ◽  
N. Tomlinson

Adult, migrating, fasting sockeye salmon (Oncorhynchus nerka) were held in captivity in fresh water without spawning well beyond the time when they would normally have done so and died. A few of the fish were then gonadectomized and force feeding was begun. A few unoperated fish were fed similarly while the remainder served as unoperated, unfed controls. The gonads of the operated fish were well developed. After a period of feeding of about four months some fish in each group had survived. The fed fish had regained their green color and much of their weight and vigor, while the surviving unfed fish were extremely emaciated and listless. At this time voluntary feeding by the force-fed fish was observed for the first time, and it was then found that the five surviving unfed controls would also take food voluntarily. While two of these fish died without apparent improvement in their condition, the other three gradually regained green color, weight and vigor.

1989 ◽  
Vol 67 (7) ◽  
pp. 1757-1766 ◽  
Author(s):  
R. E. Bailey ◽  
L. Margolis ◽  
G. D. Workman

Sockeye salmon (Oncorhynchus nerka) smolts were captured from the outlet streams of Cultus Lake, British Columbia, in 1985 and 1986, and from Fraser Lake, British Columbia, in 1986. Samples collected in 1985 were reared in salt water. Samples collected from each lake in 1986 were divided equally into two groups: one group was reared in fresh water, the other was maintained in salt water. Initially biweekly, and later monthly, subsamples from each group were examined for seven parasite taxa: Myxidium salvelini, Diplostomulum sp. metacercaria, Phyllodistomum umblae, Eubothrium sp. (immature), Proteocephalus sp. (immature), Neoechinorhynchus salmonis, and Salmincola californiensis. The maximum life-span was greater than the duration of the experiments (32–40 weeks) for all species in hosts reared in fresh water (except for S. californiensis, which was removed from all freshwater hosts). Survival of M. salvelini, P. umblae, and S. californiensis was reduced in hosts reared in sea water. No differences in survival of each of Diplostomulum sp. metacercaria, Eubothrium sp., Proteocephalus sp., and N. salmonis were observed between hosts held in fresh water or salt water. Implications for the use of these parasites as natural tags are discussed.


1960 ◽  
Vol 17 (3) ◽  
pp. 347-351 ◽  
Author(s):  
J. D. Wood ◽  
D. W. Duncan ◽  
M. Jackson

During the first 250 miles (400 km) of spawning migration of Fraser River sockeye salmon (Oncorhynchus nerka) the free histidine content of the muscle, alimentary tract, and head+skin+bones+tail decreased to a small fraction of the initial value. A further decrease occurred in the levels of this amino acid in the alimentary tract during the subsequent 415-mile (657-km) migration to the spawning grounds, no change being observed with the other tissues. Comparatively small changes in free histidine were found with heart, spleen, liver, kidney and gonads during migration.


1967 ◽  
Vol 24 (8) ◽  
pp. 1791-1810 ◽  
Author(s):  
A. P. van Overbeeke ◽  
J. R. McBride

This communication presents the results of a study of the pituitaries of 150 sockeye salmon in various stages of sexual maturation from the time they entered freshwater till after completion of spawning. In the homologue of the adenohypophysis, nine different cell types were distinguished. On the basis of changes in tinctorial and histochemical properties and relative proportions of each of these cells, it was concluded that the sockeye pituitary contains six different hormone-producing cell types. One of these probably possesses a gonadotrophic function. Degenerative phenomena in the pituitary were found in the sexually ripe and the spent salmon, but only to a limited extent. The implications of the changes in the occurrence of the six different cell types and the degenerative alterations are discussed in relation to gonad development and the death after spawning.


2000 ◽  
Vol 203 (7) ◽  
pp. 1161-1172 ◽  
Author(s):  
I. Novales Flamarique

This study examines the spectral sensitivity and cone topography of the sockeye salmon Oncorhynchus nerka throughout its life history with special emphasis on ultraviolet sensitivity. Electrophysiological recordings from the optic nerve show that ultraviolet sensitivity is greatly diminished at the smolt stage but reappears in adult fish weighing about 201 g. Concomitantly, light microscopy observations of the retina show that ultraviolet cones disappear from the dorsal and temporal retina at the smolt stage but reappear at the adult stage. These changes occur for sockeye salmon raised in fresh water or salt water after smoltification. In contrast to this ultraviolet cycle, the other cone mechanisms (short-, middle- and long-wavelength-sensitive) and the rod mechanism remain present throughout ontogeny. The natural appearance and disappearance of ultraviolet cones in salmonid retinas follows surges in blood thyroxine at critical developmental periods. Their presence coincides with times of prominent feeding on zooplankton and/or small fish that may be more visible under ultraviolet light. It is proposed that the primary function of ultraviolet cones in salmonids is to improve prey contrast.


Parasitology ◽  
1929 ◽  
Vol 21 (1-2) ◽  
pp. 189-219 ◽  
Author(s):  
W. F. Harper

A large number of fresh-water Invertebrates has been examined and the parasites obtained from them include examples of the commoner groups to be met with in any area surveyed. Six larval Trematodes have been described in detail, and by means of direct animal experiment two of them have been definitely related to known adults. Of these two one is the larva of Notocotylus seineti Fuhr., and is doubtfully Cercaria monostomi v. Linst., while the other is the larva of Echinoparyphium recurvatum v. Linst., and is described here in detail for the first time. The four xiphidiocercariae described are new. Data relating to the activity, duration of free life, and process of encystment of cercariae within the bodies of secondary intermediate hosts is also given.Effect of the parasite on the host. The disruption of the tissues brought about by the presence of sporocysts or rediae in the liver of a mollusc injures the host, and in many cases brings about its death. The gonads also are often attacked and completely destroyed. This latter feature of parasitic castration has been observed by Giard (1888) among certain species of Limnaea, Planorbis and Paludina attacked by sporocysts. Brown (1926) states that the gonads are rarely infected. As regards the encysted stages of cercariae these appear to do very little harm to their hosts even when present in large numbers. These observations are in agreement with those of Lebour (1912) for the sporocyst, rediae, and encysted stages of marine Trematodes.Double infection. I have found no instance of a double infection among the species described. In the literature, several records show the parasitism of two or more species of cercariae, within one and the same host. The occurrence of two species is most commonly met with, and as a rule one is in predominance. Sewell (1922) states that double infection is not common in India. Faust (1917), on the other hand, has found as many as four trematode species within the same host individual (Planorbis trivolis). Hesse (1923) states that “every large Limnaea peregra examined was heavily infected with sporocysts of either of the two species, but it was rare to find both together.” Brown (1926) in the neighbourhood of Birmingham has found three examples of associated xiphidiocercariae and furcocercariae, one example of xiphidiocercariae and echinostome cercariae, and two examples of echinostome cercaria, all from Limnaea stagnalis L.


1974 ◽  
Vol 31 (7) ◽  
pp. 1211-1214 ◽  
Author(s):  
Edward M. Donaldson ◽  
J. R. McBride

Injection of a chinook salmon (Oncorhynchus tshawytscha) gonadotropin preparation into gonadectomized sockeye salmon (Oncorhynchus nerka) did not result in any increase in the plasma concentration of cortisol or cortisone, nor did it stimulate the activity of the interrenal tissue. On the other hand, injection of mammalian ACTH (Acthar) did result in an increase in the plasma concentration of cortisol and cortisone, and stimulated the interrenal tissue. The salmon gonadotropin preparation, however, elicited an increase in thyroid activity. The results suggest that in the salmon, ovulation is not caused by gonadotropin induced interrenal corticosteroidogenesis.


1967 ◽  
Vol 24 (1) ◽  
pp. 67-76 ◽  
Author(s):  
J. R. McBride

In unfed adult sockeye salmon, Oncorhynchus nerka, histological examination showed extensive degenerative changes in the thyroid, pancreas, and kidney during gonad development. The more pronounced changes were generally noted in starved fish spawned in the wild. Feeding either prevented (thyroid) or distinctly reduced (pancreas, kidney) these changes in the sexually ripe fish. In fed spent sockeye the thyroid showed little change, the kidney exhibited further deterioration although not as marked as in the corresponding unfed fish, but the pancreas showed marked degenerative changes comparable with those exhibited in the unfed.


1977 ◽  
Vol 34 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Z. Kabata ◽  
B. Cousens

The distribution of the parasitic copepod, Salmincola californiensis, on two size-groups (fry, fork length 3.2–5.8 cm; juveniles, fork length 10.2–27.0) of the sockeye salmon, Oncorhynchus nerka, is described. The existence of preferred sites for both groups is established. The distribution on the smaller fish differs from that on the larger in that on the former the copepods are most abundant in the region of pectoral and pelvic fins, whereas on the latter they are by far most common in the branchial cavity. Macroscopic and microscopic mechanical damage to the fish tissues, resulting from the presence and activity of the copepod, comprises injuries to gills, skin, muscle, and even bone. The "burrowing phenomenon" (failure on the part of the copepod to cease excavation of a completed cavity of implantation, resulting in perforation of body wall and penetration of the viscera) is reported upon for the first time.


Zootaxa ◽  
2020 ◽  
Vol 4896 (1) ◽  
pp. 113-122
Author(s):  
İBRAHÝM KÜÇÜKBASMACI ◽  
SAVAŞ CANBULAT

The Trichoptera include more species than any of the other primarily aquatic orders of insects, which are usually found in clean fresh water. Distribution of the species of an order based on geography can provide guidance for researchers working in the field. In the current study, for the first time, a list of known Trichoptera species in Kyrgyzstan is given along with a new record. The list is prepared based on the relevant literature between 1875 and 2020 and a study conducted in 2012. Literature search revealed that 21 known species of caddisflies of 13 genera and 8 families have been reported from Kyrgyzstan; our research found that Triaenodes reuteri McLachlan 1880 is also present in Kyrgyzstan. We also re-illustrate the male genitalia of T. reuteri and provide a detailed redescription. Based on literature search and our observations, the Kyrgyzstan caddisfly fauna has been poorly studied; it is expected that new records and new species will be found in Kyrgyzstan through further research. 


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