Host–Parasite Relationships Between Sockeye Salmon, Oncorhynchus nerka, and Salmincola californiensis (Copepoda: Lernaeopodidae)

1977 ◽  
Vol 34 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Z. Kabata ◽  
B. Cousens
Keyword(s):  
Sockeye Salmon ◽  
Body Wall ◽  
Oncorhynchus Nerka ◽  
Mechanical Damage ◽  
Fork Length ◽  
Parasitic Copepod ◽  
Size Groups ◽  
Branchial Cavity ◽  
Host Parasite ◽  
First Time

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.

scholarly journals The developmental variations of the sagitta otolith in the young and mature male of a hermaphrodite polynemidae fish, Eleutheronema tetradactylum (Shaw, 1804)

2021 ◽  
Vol 61 ◽  
pp. e20216178
Author(s):  
Soumen Roy ◽  
Itika Bardhan
Keyword(s):  
Body Size ◽  
Fork Length ◽  
The Body ◽  
Size Groups ◽  
Protandrous Hermaphrodite ◽  
Ultrastructural Characteristics ◽  
Developmental Variations ◽  
The One ◽  
First Time ◽  
One Way Anova

The Eleutheronema tetradactylum is a protandrous, hermaphrodite, marine perciformes fish. The body length of this fish acts as an important diagnostic marker for male and female discrimination. The present study describes for the first time the ultrastructural characteristics on the medial surface of the sagitta otolith in different body size groups of males of E. tetradactylum (Polynemidae: Perciformes) using scanning electron microscopy. The sagitta is a spindle-shaped structure that includes a well-developed rostrum and a poorly developed antirostrum. The sulcus is ostio-pseudocaudal type, almost straight and devoid of the collum. The ostium is a well-developed, vase-shaped structure. The cauda includes the colliculum and a well-developed caudal bulb with several distinct growth stripes. The length of the caudal bulb is significantly correlated to the growth of the body size of the fish. The excisura major is indistinct and the excisura minor is absent. The cristae are distinct on both sides of the sulcus. The one-way ANOVA test revealed that the development of several sagitta features shows significant differences in various body size groups of E. tetradactylum. The growth of the sagitta length is more closely related to the fork length than the sagitta width. Therefore, the sagitta length and the caudal bulb length can be used as important predictors to evaluate the fish size. The cauda region of the sagitta in E. tetradactylum is unique as well as more decorative than those of another Polynemidae fish and other hermaphrodite, marine perciformes fishes. The sagitta characteristics of E. tetradactylum might be advantageous in the identification of the sex and the taxonomy of the hermaphrodite fish species.

Swimming Thrust of Sockeye Salmon (Oncorhynchus nerka) in Relation to Selectivity of Gillnets

1969 ◽  
Vol 26 (5) ◽  
pp. 1383-1385 ◽  
Author(s):  
R. H. Lander
Keyword(s):  
Significant Relationship ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Fork Length

A significant relationship between girth at the mesh mark and fork length indicates that long sockeye salmon (Oncorhynchus nerka) have more swimming thrust than short ones. This tends to confirm a speculation of Regier and Robson (J. Fish. Res. Bd. Canada 23: 423–454, 1966). Preliminary conjecture relates the observation to the theory of mesh selectivity.

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
Keyword(s):  
Fresh Water ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Gonad Development ◽  
The Other ◽  
Green Color ◽  
Force Feeding ◽  
In Captivity ◽  
First Time

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.

Host–parasite relationships between burbot (Lota lota) and adult Salmincola lotae (Copepoda)

1988 ◽  
Vol 66 (11) ◽  
pp. 2459-2463 ◽  
Author(s):  
Becky A. Lasee ◽  
Daniel R. Sutherland ◽  
Maryjo E. Moubry
Keyword(s):  
Lake Michigan ◽  
Mechanical Damage ◽  
Parasitic Copepod ◽  
Tissue Reaction ◽  
Primary Host ◽  
Lota Lota ◽  
Leucocyte Infiltration ◽  
Parasite Feeding ◽  
Host Parasite ◽  
Host Tissues

The pathology elicited by the parasitic copepod Salmincola lotae and its distribution within the oral cavity of the burbot, Lota lota, is described. Of 50 burbot examined from the Apostle Islands region, Lake Superior, near Bayfield, WI, 18 (36%) were infested with S. lotae. A total of 63 copepods were recovered. Burbot were examined from three Lake Michigan collecting sites: 70 from Sturgeon Bay, 9 from Manitowoc, and 60 from Sheboygan were not infested with S. lotae. Salmincola lotae appears to prefer middle regions of the roof of the mouth. Mechanical damage to host tissues resulting from copepod presence included epidermal shredding from parasite feeding and lesions from bulla excavation and implantation. Epidermal encapsulation of the second maxillae of S. lotae was the primary host tissue reaction. Increased dermal vascularization and leucocyte infiltration occurred in regions of parasite attachment. This is the first report of S. lotae from the Nearctic.

Migration Timing, Size, and Salinity Tolerance of Sea-Type Sockeye Salmon (Oncorhynchus nerka) in an Alaska Estuary

1989 ◽  
Vol 46 (4) ◽  
pp. 633-637 ◽  
Author(s):  
Jonathan Heifetz ◽  
Scott W. Johnson ◽  
K V. Koski ◽  
Michael L. Murphy
Keyword(s):  
Salinity Tolerance ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
River Estuary ◽  
Fork Length ◽  
Habitat Types ◽  
Southeast Alaska ◽  
Fish Size ◽  
Migration Timing

Migration timing, size, and salinity tolerance were determined for sea-type sockeye salmon (Oncorhynchus nerka), which migrate to sea as underyearlings (age-0), in the Situk River estuary, Southeast Alaska. Ten sites in three habitat types were seined monthly from Sate April through August, 1987, and age-0 sockeye from the estuary were tested for salinity tolerance. Age-0 sockeye were most abundant (up to 13∙m−2) from late April through June, and by late July, most sockeye had left the estuary. Mean fork length (FL) was 31 mm in April and increased 0.4 mm∙d−1 to 70 mm in late July when most (72%) remaining sockeye had grown to about the same size as age-1 smolts (69–95 mm) emigrating in May and June. Mean FL of age-0 sockeye in the estuary in July was 23 mm greater than in freshwater areas of the river. Salinity tolerance was directly related to fish size, and a size of at least 50 mm was required for 100% survival in seawater. Because salinity in the estuary ranged 0–30‰, sockeye of all sizes could survive in the estuary. Thus, in 3–4 mo, sea-type sockeye attained a size large enough to adapt to seawater and migrate to sea.

scholarly journals NEMATODES OF GENUS PHILONEMA (PHILONEMIDAE) FROM SOCKEYE SALMON AND WHITESPOTTED CHAR FROM LAKE KISI (OLA RIVER BASIN, OKHOTSK SEA)

2019 ◽  
Vol 197 ◽  
pp. 194-207
Author(s):  
V. V. Pospekhov ◽  
K. V. Kusenko
Keyword(s):  
River Basin ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Nematode Species ◽  
Northern Coast ◽  
Okhotsk Sea ◽  
North East ◽  
Salvelinus Leucomaenis ◽  
First Time

Morphology of phylonems infesting whitespotted char Salvelinus leucomaenis and sockeye salmon Oncorhynchus nerka in Lake Kisi at the northern coast of the Okhotsk Sea is described for the first time. Sockeye was infected with adults of Philonema oncorhynchi Kuitunen-Ekbaum, 1933 and larvae of other nematode species (Philonema sp. II), and char — with adult dracunculoid nematode designated as Philonema sp. I. This Philonema sp. I differs considerably from Ph. oncorhynchi by number of reproductive papillae, their distribution, and structure of cuticular appendices on the caudal end of males. Larvae of Philonema sp. I (1st stage) and Philonema sp. II (3rd stage) are described, as well. These new data allow to reconsider the species belonging of nematodes infesting chars (Salvelinus) in North-East of Russia, which are identified now mostly as Ph. oncorhynchi.

Does mortality select size or growth potential in young sockeye salmon (Oncorhynchus nerka)? A simulation based on otolith - fish size relationships

1998 ◽  
Vol 55 (7) ◽  
pp. 1674-1681 ◽  
Author(s):  
M G Meekan ◽  
DAJ Ryan ◽  
J J Dodson ◽  
S P Good
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Fork Length ◽  
Field Studies ◽  
Growth Potential ◽  
Selective Mortality ◽  
Fish Size ◽  
Conflicting Evidence ◽  
Selection For ◽  
Otolith Size

There is conflicting evidence on the role of size-selective mortality in the demography of populations of young sockeye salmon (Oncorhynchus nerka). A previous field study suggested that increases in mean fork length and otolith size at emergence observed in a cohort of salmon between fry and smolt stages were due to size-selective mortality, such that fry with small fork lengths underwent higher mortality than larger individuals. However, a subsequent study used a simulation to show that such increases could not have been achieved by size-selective mortality without levels of survivorship of the cohort far lower than those that had been observed in the field. To account for field observations, the simulation study proposed that individuals with high metabolic rates had better survivorship, a process that was termed "selection for growth potential." Here, we use a simulation approach to show that size-selective mortality may result in shifts in mean fork length and otolith size at emergence comparable with those observed in the field at total mortalities within the range of estimates of natural values. The contrasting outcomes of earlier simulation work and the present study are probably due to the assumption by the former that otolith and fish size in young salmon were weakly correlated and the use of an inappropriate model of size-selective mortality. We conclude that size-selective mortality can explain the results of previous field studies and that little empirical evidence exists to support the hypothesis of selection for growth potential in cohorts of young salmon.

Evidence for Size-Selective Mortality of Juvenile Sockeye Salmon (Oncorhynchus nerka) in Babine Lake, British Columbia

1987 ◽  
Vol 44 (4) ◽  
pp. 712-721 ◽  
Author(s):  
Cameron J. West ◽  
P. A. Larkin
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Length Distribution ◽  
Fork Length ◽  
Late Summer ◽  
Selective Mortality ◽  
Daily Growth ◽  
Back Calculation ◽  
Spawning Tributaries

Otolith – body length relations and back-calculation procedures were used to test the hypothesis that mortality of juvenile sockeye salmon (Oncorhynchus nerka) in Babine Lake, British Columbia, is size selective. Samples of the 1978 brood of sockeye were collected as fry from spawning tributaries as juveniles in the main basin, and as smolts at the outlet. Total otolith length was chosen as the most useful otolith dimension for back-calculation of fork length at emergence. Sockeye from the various tributaries show different fork length – otolith length relationships necessitating a weighting procedure for comparisons involving samples of mixed stocks from the lake. Instantaneous daily growth rate and In fork length during the early lake-rearing period were significantly correlated. Smaller juveniles grew more slowly than larger individuals in mid-july, and a hierarchy of sizes was maintained. The distributions of total otolith length at emergence for fry, surviving juveniles, and smolts indicate selective mortality of fish with smaller otoliths, hence of small size at emergence. Survivals from the lower and upper halves of the initial total otolith length distribution were 8.9 and 63.6%, respectively. Comparable estimates for back-calculated fork lengths at emergence were 27.2 and 43.4%. Size-selective mortality is most intense in the late summer and early autumn, and may be associated with predation and parasitism.

Egg retention in relation to arrival timing and reproductive longevity in female sockeye salmon (Oncorhynchus nerka)

2011 ◽  
Vol 68 (2) ◽  
pp. 250-259 ◽  
Author(s):  
Kimberly A. Hruska ◽  
Scott G. Hinch ◽  
David A. Patterson ◽  
Michael C. Healey
Keyword(s):  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Fork Length ◽  
Sufficient Time ◽  
Spawning Grounds ◽  
Egg Retention ◽  
Arrival Timing ◽  
Spawning Success

Some female Pacific salmon ( Oncorhynchus spp.) arrive at spawning grounds but fail to complete spawning prior to death. One hypothesis regarding egg retention is that some individuals do not have sufficient time on spawning grounds for successful completion of spawning. We investigated this hypothesis by quantifying the relationships among arrival timing, reproductive longevity, and egg retention in female sockeye salmon ( Oncorhynchus nerka ) from Weaver Creek Spawning Channel (British Columbia, Canada) in 2006. 250 females were tagged over three sampling periods and followed until death. Earlier-arriving females lived longer than later-arriving females (p < 0.001), but patterns of egg retention were not different across sampling dates (p > 0.40). Complete spawners tended to establish a redd sooner after arrival than incomplete spawners (p = 0.001); there was no relationship between spawning completion and reproductive maturity or fork length (p > 0.30). Consistent with the time limitation hypothesis, females retained a lower proportion of eggs with increasing reproductive longevity. Several long-lived females (>7 days) failed to spawn completely before death, indicating that time limitation was not a factor for spawning success in all females. Further research examining the role of individual-specific behavioural physiology on egg retention in sockeye salmon is needed.

Effect of Smolt Size on Smolt-to-Adult Survival for Chilko Lake Sockeye Salmon (Oncorhynchus nerka)

1991 ◽  
Vol 48 (6) ◽  
pp. 988-994 ◽  
Author(s):  
M. A. Henderson ◽  
A. J. Cass
Keyword(s):  
Sockeye Salmon ◽  
Interannual Variation ◽  
Oncorhynchus Nerka ◽  
Fork Length ◽  
Adult Survival ◽  
Threefold Increase ◽  
Limited Variation ◽  
Back Calculation ◽  
The Mean ◽  
Calculation Procedures

Three approaches were used to test the hypothesis that smolt-to-adult survival is independent of smolt size for Chilko Lake sockeye salmon (Oncorhynchus nerka). The mean distance between the focus of the scale and the first annulus, a reliable indicator of smolt size, was greater for adult scales than for smolt scales from the same brood year in two of the three years we examined. This indicated a higher smolt-to-adult survival for larger smolts in these brood years. The abundance of smolts of different fork lengths, based on back-calculation procedures from adult scales, was compared with the abundance of smolts of different fork lengths at the time of outmigration within brood years. In all three years studied, there was a two- to threefold increase in smolt-to-adult survival as smolt length increased. However, there was no significant relationship between smolt-to-adult survival and mean annual smolt fork length based on a 34-yr time series; this lack of relationship was probably caused by limited variation in mean annual smolt fork length over the 34-yr period and other variables, independent of smolt size, that affect survival and exhibit considerable interannual variation.

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