scholarly journals Feeding and food supply of salmons in the Okhotsk Sea in autumn of 2018-2019

2021 ◽  
Vol 201 (1) ◽  
pp. 177-190
Author(s):  
N. A. Kuznetsova ◽  
O. I. Pushchina ◽  
M. A. Shebanova
Keyword(s):  
Chum Salmon ◽  
Pink Salmon ◽  
Species Abundance ◽  
Zooplankton Biomass ◽  
Okhotsk Sea ◽  
Daily Consumption ◽  
Daily Production ◽  
Taxonomic Groups ◽  
Favorable Conditions ◽  
Total Zooplankton Biomass

In the autumn months of 2018-2019, food spectra of salmons were quite diverse in the Okhotsk Sea. Amphipods prevailed in the diet of juvenile pink and chum salmon that corresponded to these zooplankton species abundance in the southern part of the sea; other significant portions of their diet were presented by euphausiids, copepods, arrowworms, pteropods, and oikopleura. Decapods, fish and squids were in the diet of masu, coho and chinook salmon. Portion of zooplankton was about 100 % in the diet of pink salmon fingerlings, but only 98 % in the diet of chum salmon fingerlings with 2 % portion of squids. Grazing by salmons was insignificant: 0.2-0.3 % of the total zooplankton biomass within the periods of observation (18 days in 2018 and 13 days in 2019), or 0.04-2.0 % for certain taxonomic groups, except of pteropods and oikopleura with the consumed portions of 4-7 % and 7-12 %, respectively. However, the daily consumption by salmons relative to daily production of some groups was significant in October, 2018 and reached 97 % for amphipods and > 200 % for euphausiids in the northeastern Okhotsk Sea (biostatistical areas 6-8) and 48 and 27 %, respectively, in the entire surveyed area. This ratio was twice lower in October, 2019, as 24 % for amphipods and 12 % for euphausiids. Daily consumption of copepods and arrowworms never exceeded 2 % of their daily production. The most favorable conditions for nekton feeding in fall of both years were observed in the northwestern Okhotsk Sea, and the worst conditions — in its northeastern part, with moderate conditions without deficit of prey in the central part (biostatistical area 9) and southern part (biostatistical areas 12, 13), where the biomass of forage plankton exceeded the biomass of nekton in 30-97 times in 2018 and in 56-76 times in 2019.

scholarly journals Juveniles of pink and chum salmon in the southern Okhotsk Sea in their late marine stage (August-October 2012). Distribution, feeding, patterns of growth

2014 ◽  
Vol 176 (1) ◽  
pp. 51-61
Author(s):  
Artem Е. Lazhentsev ◽  
Olga А. Maznikova
Keyword(s):  
Growth Rate ◽  
Chum Salmon ◽  
Feeding Activity ◽  
Pink Salmon ◽  
Partial Replacement ◽  
Linear Growth Rate ◽  
Caloric Content ◽  
Okhotsk Sea ◽  
Water Cooling ◽  
Feeding Intensity

Ontogeny of one generation of pink and chum salmons is described for the period after their juveniles redistribution from coastal waters to deep-water areas in the central and southern Okhotsk Sea in August-November, 2012. The juveniles fed very intensively in August when their diet had about 85 % of proteins and 15 % of lipids due to prevalence of hyperiids and oikopleuras with low fat content. Their growth rate was high at this stage, and energy expenditure on growth took about a half of the ration (56-63 % for pink salmon and 40 % for chum salmon). The feeding intensity became lower in October, but caloric content of the food increased because of partial replacement of its protein fraction by lipids, which content exeeded 75 %. Linear growth rate decreased in October in 3.8 times for pink salmon and in 1.8 times for chum salmon, it took 21-27 % of food energy for the pink and almost the same portion as in August for the chum. Both feeding activity, growth rate, and fat deposit depended on temperature. Temperature in August was more favorable for feeding and metabolic processes, in particular for pink salmon that was able to consume daily up to 1/10 of its body weight and spend > 50 % of the energy for the growth, but water cooling in October caused lesser feeding, lower metabolism, and slower growth.

scholarly journals CHEMICAL COMPOSITION AND ENERGY CONTENT OF PACIFIC SALMONS IN THE OKHOTSK SEA

2019 ◽  
Vol 197 ◽  
pp. 152-165
Author(s):  
K. M. Gorbatenko ◽  
I. V. Melnikov ◽  
E. E. Ovsyannikov ◽  
S. L. Ovsyannikova
Keyword(s):  
Total Energy ◽  
Chum Salmon ◽  
Energy Content ◽  
Minimum Energy ◽  
Pink Salmon ◽  
Maximum Energy ◽  
Okhotsk Sea ◽  
The North ◽  
Juvenile Chum Salmon ◽  
The North Pacific

The main bioenergetic parameters of pacific salmons are presented on the data obtained in marine expeditions in 2003–2015. Among the examined species, the minimum energy content is registered in the muscle tissue of chum salmon and pink salmon, and the maximum energy content — in the muscles of king salmon. Total amount of the energy accumulated by juvenile pink salmon during its life within the Okhotsk Sea is estimated as 532 kcal or 27 % of the total energy accumulated in the whole marine period of its life, for juvenile chum salmon this amount is 492 kcal (11 %). The rest is accumulated by adults during their feeding in the ocean: pink salmon, without ranking by age and sex, gains in the North Pacific on average 1 442 kcal or 73 % of the total energy accumulated in the marine period of life, chum salmon — 4 071 kcal (89 %).

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

scholarly journals Influence of net-cage fish farming on zooplankton biomass in the Itá reservoir, SC, Brazil

2012 ◽  
Vol 23 (4) ◽  
pp. 357-367 ◽  
Author(s):  
Bruna Roque Loureiro ◽  
Christina Wyss Castelo Branco ◽  
Evoy Zaniboni Filho
Keyword(s):  
Fish Farming ◽  
Dry Weight ◽  
Control Area ◽  
Zooplankton Biomass ◽  
Total Density ◽  
Total Zooplankton ◽  
Net Cage ◽  
Uruguay River ◽  
Cage Fish ◽  
Total Zooplankton Biomass

OBJECTIVES: This study aimed to verify the influence of net-cage fish farming on zooplankton biomass in the Itá reservoir (Uruguay River, Brazil). METHODS: Samples were collected monthly from October/2009 to May/2010 at the surface and at the bottom in two sampling stations, the net-cage area and in a control area using a Van Dorn bottle and a plankton net (68 µm). RESULTS: The Cladocera and Copepoda biomass was estimated by dry weight using a micro-analytical balance, and the Rotifera biomass by Biovolume. Total zooplankton biomass varied between 6.47 and 131.56 mgDW.m-3 Calanoida copepod presented the highest value of biomass (127.56 mgDW.m-3) and rotifers, despite having an important contribution to total density, showed a maximum biomass of 2.01 mgDW.m-3. Zooplankton biomass at the net-cage area surface was higher when compared with the control area during the months of October to January. However, the zooplankton biomass was similar at the bottom of the two areas throughout the studied period. From February until May, zooplankton biomass decreased in both sampling stations, a fact probably associated with the flushing of the reservoir, followed by an increase in water transparency and a decrease in chlorophyll-a concentration in the following months (February to May). CONCLUSIONS: The influence of fish farming on zooplankton biomass was detected at the surface of the net-cage area only from October to January. From February to May this influence was not found, probably by the influence of the flushing of the reservoir.

scholarly journals Resources and fishery of Pacific salmon in Magadan region in the beginning of the 21st century

Trudy VNIRO ◽  
2020 ◽  
Vol 179 ◽  
pp. 90-102
Author(s):  
M. N. Gorokhov ◽  
V. V. Volobuev ◽  
I. S. Golovanov
Keyword(s):  
Chum Salmon ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Spawning Grounds ◽  
Magadan Region ◽  
Spawning Areas ◽  
Optimal Values ◽  
In The Beginning ◽  
Salmon Fishery

There are two main areas of pacific salmon fishing in the Magadan region: Shelikhova Gulf and Tauiskaya Bay. The main fishing species is pink salmon in the region. Its share of total salmon catch by odd-year returns reaches 85 %. Data on the dynamics of escapement to the spawning grounds of pink salmon of the Shelikhova Gulf and Tauiskaya Bay are presented. The displacement of the level of spawning returns of pink salmon into the Shelihova Gulf with the simultaneous reduction of its returns to the Tauiskaya Bay is shown. Data on the dynamics of the fishing indicators of pink salmon for the two main fishing areas are provided. The Tauiskaya Bay as the main pink salmon fishery area loses its importance is shown. Graphical data on the escapement of producers pink salmon to the spawning grounds are presented and the optimal values of spawning escapements are estimated. Chum salmon is the second largest and most fishing species. Information on the dynamics of the number of returns, catch and escapement to the spawning grounds of chum salmon is given. The indicators of escapement to the spawning areas and their compliance with the optimal passes of salmon producers are analyzed. The issues of the dynamics of returns number, catch and the escapement to the spawning grounds of coho salmon producers are considered. The level of the escapement to the spawning areas is shown and the ratio of actual to optimal values of passes is estimated. The role of coho salmon as an object of industrial fishing and amateur fishing is shown. The extent of fishing press on individual groups of salmon populations is discussed. It is concluded that it is necessary to remove the main salmon fishery from the Tauiskaya Bay to the Shelikhova Gulf.

scholarly journals Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

1993 ◽  
Vol 62 (4) ◽  
pp. 215-226 ◽  
Author(s):  
Juliana H.M. Kouwenberg
Keyword(s):  
Seasonal Variation ◽  
Coastal Region ◽  
Zooplankton Biomass ◽  
High Abundance ◽  
Total Biomass ◽  
Total Zooplankton ◽  
Copepod Abundance ◽  
Bottom Depth ◽  
Total Zooplankton Biomass ◽  
Northwestern Mediterranean

Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish programme Pélagolion/Leopel in the near-coastal region (≤ 25 m bottom depth), the Rhone dilution zone, the neritic region (≤ 200 m bottom depth), and the oceanic region (200–2000 m bottom depth). Abundance of other zooplanktonic groups was estimated and total zooplankton biomass was determined for the upper 50 m. Copepod abundance was highest during September 1986 (all regions) and July 1987 (neritic). Total biomass was highest during July 1987 and May/June 1988, caused by high abundance of many other zooplankters.

Production of the Euphausiid Crustacean Thysanoëssa raschii in the Gulf of St. Lawrence

1977 ◽  
Vol 34 (3) ◽  
pp. 443-446 ◽  
Author(s):  
F. Berkes
Keyword(s):  
Field Data ◽  
Zooplankton Biomass ◽  
Total Zooplankton ◽  
Loss Of Weight ◽  
Annual Biomass ◽  
The Mean ◽  
Total Zooplankton Biomass ◽  
Population Numbers

From field data on growth and population numbers, production of Thysanoëssa raschii, excluding molts, was calculated to be about 1.8 mg dry wt∙m−3∙yr−1 in the Gulf of St. Lawrence. The mean annual biomass of T. raschii was 0.47 mg dry wt∙m−3, comprising about 1% of the total zooplankton biomass in the Gulf, and giving a production to biomass (P:B) ratio of about 4. Production and biomass were probably underestimated due to some sampler avoidance, lack of egg to nauplius–metanauplius interval of population production and loss of weight due to leaching in preserved samples.

Zooplankton and Trophic State Relationships in Florida Lakes

1983 ◽  
Vol 40 (10) ◽  
pp. 1813-1819 ◽  
Author(s):  
J. S. Bays ◽  
T. L. Crisman
Keyword(s):  
Trophic State ◽  
Size Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Crustacean Zooplankton ◽  
Trophic State Index ◽  
Total Zooplankton ◽  
Eutrophic Lakes ◽  
Florida Lakes ◽  
Total Zooplankton Biomass

Zooplankton, including ciliated protozoans, were collected from 39 Florida lakes of widely ranging trophic state. Annual mean biomass values for different zooplankton groups were regressed against Carlson's Trophic State Index based on annual mean chlorophyll a concentration. Whereas total zooplankton biomass yielded a significant regression with increasing trophic state, microzooplankton (ciliates, rotifers, and nauplii) accounted for more of the relationship than macrozooplankton (cladocera, calanoids, and cyclopoids). Within the microzooplankton, the regression improved with decreasing body size. Macrozooplankton biomass exhibited a weak statistical relationship with lake trophic state, but the different component groups were variable in their response. The dominance within the zooplankton community shifts from macrozooplankton to microzooplankton with increasing trophic state, and the microzooplankton can constitute between 50 and 90% of the total zooplankton biomass in eutrophic lakes. Changes in zooplanktivore community structure with increasing trophic state show that whereas total fish biomass increases, dominance shifts from visually oriented predators, such as bass and bluegill, to pump filter-feeding planktivores, such as gizzard shad (Dorosoma cepedianum). While Florida zooplankton communities are similar in size structure to tropical communities, no statistically significant differences were found between empirical equations of crustacean zooplankton biomass and trophic state determined from temperate and Florida data bases.

Genetic Effect on the Dynamics of a Model of Pink (Oncorhynchus gorbuscha) and Chum (O. keta) Salmon

1984 ◽  
Vol 41 (10) ◽  
pp. 1446-1453 ◽  
Author(s):  
William W. Smoker
Keyword(s):  
Chum Salmon ◽  
Pink Salmon ◽  
Genetic Effect ◽  
Genetic Mechanism ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Chum Salmon Oncorhynchus Keta ◽  
High Heritability ◽  
Maturation Age

Different stock dynamics result from genetic and nongenetic mechanisms of determination of maturation age of chum salmon (Oncorhynchus keta) in a model of interacting pink (O. gorbuscha) and chum salmon stocks. When the model is disturbed from equilibrium by low survival in one pink salmon line, the genetic mechanism (high heritability of maturation age) leads to biennial cycles of numbers of even-aged chums and of numbers of pinks, similar to observed cycles. The nongenetic mechanism (zero heritability of maturation age) results in a new equlibrium at which neither stock cycles. When one pink salmon line is completely removed the genetic mechanism leads to biennial cycles of abundance of even-aged chums; the nongenetic mechanism does not lead to such cycles. These effects persist at intermediate values of heritability of maturation age and in spite of stochastic variability. The model is an adaptation of the Ricker curve to two interacting stocks, the recruitment for each depending on the density of both.

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