Marine survival of steelhead (Oncorhynchus mykiss) enhanced by a seasonally closed estuary

2008 ◽  
Vol 65 (10) ◽  
pp. 2242-2252 ◽  
Author(s):  
Morgan H. Bond ◽  
Sean A. Hayes ◽  
Chad V. Hanson ◽  
R. Bruce MacFarlane
Keyword(s):  
Oncorhynchus Mykiss ◽  
Growth Rates ◽  
Adult Population ◽  
Fork Length ◽  
High Growth ◽  
Population Persistence ◽  
Scale Morphology ◽  
Scale Analysis ◽  
Size Dependent ◽  
Dependent Mortality

To investigate the role that estuaries play in the survival of steelhead, Oncorhynchus mykiss , we compared juvenile size at ocean entry with back-calculated measures of size at ocean entry for returning adults in Scott Creek, a representative California coastal stream. During the annual spring emigration, the largest smolts (>150 mm fork length (FL)) move directly to sea, while some smaller smolts remain in the estuary until sandbar formation creates a closed freshwater lagoon. High growth rates in the estuary throughout the summer result in a near doubling of fork length from the time of estuary entry (mean FL of spring migrants = 102.2 mm; mean FL of fall lagoon resident = 195.9 mm). Analysis of the scale morphology of returning adult steelhead indicates that there is strong size-dependent mortality at sea, with estuary-reared steelhead showing a large survival advantage, comprising between 87% and 95.5% (based on tag returns and scale analysis, respectively) of the returning adult population despite being between 8% and 48% of the annual downstream migrating population. Although the estuary forms less than 5% of the watershed area, it is critical nursery habitat, and steelhead population persistence in southern margin ecosystems may well depend upon healthy estuaries.

Estimating larval fish growth under size-dependent mortality: a numerical analysis of bias

2007 ◽  
Vol 64 (3) ◽  
pp. 554-562 ◽  
Author(s):  
Tian Tian ◽  
Øyvind Fiksen ◽  
Arild Folkvord
Keyword(s):  
Growth Rate ◽  
Longitudinal Data ◽  
Growth Rates ◽  
Mortality Rates ◽  
Growth Patterns ◽  
Cross Sectional ◽  
Larval Phase ◽  
Size Dependent ◽  
Recruitment Success ◽  
Dependent Mortality

The early larval phase is characterized by high growth and mortality rates. Estimates of growth from both population (cross-sectional) and individual (longitudinal) data may be biased when mortality is size-dependent. Here, we use a simple individual-based model to assess the range of bias in estimates of growth under various size-dependent patterns of growth and mortality rates. A series of simulations indicate that size distribution of individuals in the population may contribute significantly to bias in growth estimates, but that typical size-dependent growth patterns have minor effects. Growth rate estimates from longitudinal data (otolith readings) are closer to true values than estimates from cross-sectional data (population growth rates). The latter may produce bias in growth estimation of about 0.03 day–1 (in instantaneous, specific growth rate) or >40% difference in some situations. Four potential patterns of size-dependent mortality are tested and analyzed for their impact on growth estimates. The bias is shown to yield large differences in estimated cohort survival rates. High autocorrelation and variance in growth rates tend to increase growth estimates and bias, as well as recruitment success. We also found that autocorrelated growth patterns, reflecting environmental variance structure, had strong impact on recruitment success of a cohort.

Evidence of density- and size-dependent mortality in hatchery-reared juvenile white sturgeon (Acipenser transmontanus) in the Kootenai River

2009 ◽  
Vol 66 (5) ◽  
pp. 802-815 ◽  
Author(s):  
Casey Justice ◽  
Brian J. Pyper ◽  
Raymond C.P. Beamesderfer ◽  
Vaughn L. Paragamian ◽  
Pete J. Rust ◽  
...  
Keyword(s):  
Survival Rates ◽  
Negative Relationship ◽  
Fork Length ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
First Year ◽  
Small Fish ◽  
Size Dependent ◽  
Kootenai River ◽  
Dependent Mortality

We evaluated effects of stocking level and size-at-release on survival rates of hatchery-reared juvenile white sturgeon ( Acipenser transmontanus ) in the Kootenai River using Cormack–Jolly–Seber and related models implemented in Program MARK. A total of 119 768 marked and unmarked hatchery juveniles were released from 1992 to 2006, of which 2938 passive integrated transponder (PIT)-tagged fish were subsequently recaptured. Annual survival rates of marked groups ranged from 0.01 to 0.84 (mean = 0.45) during the first year at large, from 0.48 to 1.0 (mean = 0.84) in the second year, and averaged 1.0 during all subsequent years. First year survival rates declined substantially in recent years, particularly for small fish (<25 cm fork length). Approximately 59% of the variation in first year survival was explained by a negative relationship with estimated juvenile abundance (linear regression, P < 0.01). Length-at-release of individuals explained a substantial proportion of the within-year variation in survival during the first year at large. Our results provide strong evidence of density- and size-dependent mortality in hatchery-reared juvenile white sturgeon in the Kootenai River. Management actions that prioritize the release of fewer, larger-sized fish will likely improve first year survival rates and subsequent recruitment to the spawning-age population.

Reduced swimming performance and increased growth in domesticated rainbow trout, Oncorhynchus mykiss

2009 ◽  
Vol 66 (7) ◽  
pp. 1025-1032 ◽  
Author(s):  
Drew Reinbold ◽  
Gary H. Thorgaard ◽  
Patrick A. Carter
Keyword(s):  
Rainbow Trout ◽  
Body Size ◽  
Oncorhynchus Mykiss ◽  
Body Mass ◽  
Growth Rates ◽  
Swimming Performance ◽  
Large Body ◽  
High Growth ◽  
Hybrid Progeny ◽  
Rainbow Trout Oncorhynchus Mykiss

Domesticated populations of rainbow trout ( Oncorhynchus mykiss ) probably have been selected for high growth rates and large body size, which may have resulted in reduced sprint swimming performance. We hypothesized that more domesticated populations of rainbow trout would have higher growth rates and larger body size, but slower swim speed, relative to semiwild populations. We tested this hypothesis by measuring body mass, body length, and sprint swim speed multiple times over 92 days in progeny from crosses between males from three clonal lines and an outbred female. We found significantly higher body masses and significantly slower swim speeds in the highly domesticated Arlee and Hot Creek progeny groups compared with the semiwild Swanson hybrid progeny group, supporting our hypothesis. Growth rates also differed significantly among groups, but at the ages measured, the Swanson hybrid progeny had an intermediate growth rate. However, given the differences in body mass, either growth rates were higher in the more domesticated progeny groups at young unmeasured ages and (or) they hatched at a significantly larger body mass than the semiwild Swanson hybrid.

Size Selectivity of Coho (Oncorhynchus kisutch) Preying on Juvenile Chum Salmon (O. keta)

1986 ◽  
Vol 43 (3) ◽  
pp. 581-586 ◽  
Author(s):  
N. Brent Hargreaves ◽  
Robin J. LeBrasseur
Keyword(s):  
Chum Salmon ◽  
Prey Size ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Size Selectivity ◽  
Size Dependent ◽  
Juvenile Chum Salmon ◽  
Dependent Mortality

Predation may be a major source of size-dependent mortality of Pacific salmon (Oncorhynchus spp.) during early sea life. Our experiments conducted in large saltwater enclosures demonstrated that coho (Oncorhynchus kisutch) are size selective when preying on juvenile chum (O. keta) salmon. Yearling coho (112–130 mm fork length) consumed significantly more smaller chum over a range in prey size of 43–63 mm fork length. We hypothesize that the intensity of size selectivity by coho and other predators is variable, depending on the relative sizes of the predators and prey.

GROWTH OF PIKE-PERCH SANDER LUCIOPERCA (L., 1758) (PERCIDAE) IN RESERVOIRS OF K. SATPAYEV’S CHANNEL

2018 ◽  
pp. 59-68
Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Vladimir Nickolaevich Krainyuk
Keyword(s):  
Growth Rates ◽  
Growth Dynamics ◽  
High Growth ◽  
Water Bodies ◽  
Volga River ◽  
Trophic Resources ◽  
Pike Perch ◽  
The Amur River ◽  
Back Calculation ◽  
Abiotic And Biotic Factors

Pike-perch is an invader for the water basins of Central Kazakhstan. These species have stable self-reproductive populations in the regional waters. Back calculation method was used to investigate pike-perch growth rates in reservoirs of K. Satpayev’s channel. For comparison, the data from the other water bodies (Vyacheslavsky and Sherubay-Nurinsky water reservoirs) were used, as well as literature data. Pike-perch species from the investigated waters don’t show high growth rates. The populations from the reservoirs of K. Satpayev’s channel have quite similar growth rates with populations from the Amur river, from a number of reservoirs in the Volga river basin and from the reservoir in Spain. Sexual differences in growth have not been observed. Evaluating possible influence of various abiotic and biotic factors on the growth rate of pike-perch in the reservoirs of K. Satpayev’s channel was carried out. It has been stated that the availability of trophic resources cannot play a key role in growth dynamics because of their high abundance. Morphology of water bodies also does not play a role, as well as chromaticity, turbidity and other optical water indicators. It can be supposed that the main factor influencing growth of pike perch is the habitat’s temperature. This factor hardly ever approaches optimal values for the species in reservoirs of K. Satpaev’s channel. The possible influence of fishing selectivity on pike-perch growth rates was also evaluated. Currently, there has been imposed a moratorium on pike-perch catch. However, pike-perch is found in by-catches and in catches of amateur fishermen. It should be said that such seizures have an insignificant role in the dynamics of growth rates.

Biology of Gadus morhua in Ogac Lake, a Landlocked Fiord on Baffin Island

1967 ◽  
Vol 24 (12) ◽  
pp. 2573-2594 ◽  
Author(s):  
David G. Patriquin
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Environmental Variability ◽  
Sea Urchins ◽  
High Growth ◽  
Baffin Island ◽  
Meristic Characters ◽  
Large Size ◽  
Fin Ray ◽  
High Length

Gadus morhua L. occurs in Ogac Lake, a salt, meromictic lake on Baffin Island that receives influxes of seawater only during the highest summer tides. Cod of the order of 10,000 of lengths 25 cm and greater and 500 of lengths greater than 60 cm were present. The size ranges for various ages far exceeded those of oceanic populations. Feeding conditions were poor, and sea urchins predominated in the diet. Large cod (greater than 50 cm) were highly cannibalistic, and it was estimated that they consume of the order of 3500 fish of 20–40 cm annually. Maturation occurred at the unusually large size of 85 cm in females, and at about 65 cm in males. Apparently many of the cod never reach these sizes. Spawning was from late May to early July in 1962, and initiation of spawning appeared to be related to light. The hatching of cod larvae coincided with the appearance of the nauplii of the dominant copepod in the lake. Egg size was highly variable and exhibited a curious bimodalism. Variation in vertebral and fin-ray counts was slight in spite of high environmental variability, and thus appears largely genetically controlled. Possibly the first inhabitants came from Greenland stocks, which have high growth rates similar to the faster growing cod in the lake, and similar high length at maturity. Meristic characters also suggest affinity with Greenland rather than Labrador cod. The hydrography of the area and the possibilities of larval drift or adult migration into the lake are discussed. Cannibalism must exert continuing selection for high growth rates, but very poor feeding conditions and hierarchial dominance effects probably prevent general attainment of high growth rates.

Amorphous silicon deposited at high growth rates near the onset of microcrystallinity

2000 ◽  
Vol 266-269 ◽  
pp. 450-454 ◽  
Author(s):  
Yoram Lubianiker ◽  
Yanyang Tan ◽  
J.David Cohen ◽  
Gautam Ganguly
Keyword(s):  
Amorphous Silicon ◽  
Growth Rates ◽  
High Growth
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