Effects of migration distance on whole-body and tissue-specific energy use in American shad (Alosa sapidissima)

1999 ◽  
Vol 56 (7) ◽  
pp. 1159-1171 ◽  
Author(s):  
Jill BK Leonard ◽  
Stephen D McCormick

We examined total and tissue-specific energy content of upstream-migrating American shad (Alosa sapidissima) in the Connecticut River. Total energy depletion over the course of the 228-km migration ranged from 35 to 60%. The approximate contributions of different tissues to energy use during migration were white muscle 57%, subdermal fat 27%, red muscle 8%, viscera 6%, and liver 2%. American shad preferentially use energy stores in the skin and its subdermal fat layer (depleted by 63%) while sparing red muscle protein. Both lipid and protein were used as energy sources throughout migration, although lipids were depleted to a greater extent (e.g., white muscle lipid decreased 48% and protein 30%). Large fish expended 2-21% more energy during migration than small fish. Migrating to upriver sites (198-228 km) is 50-100% more energetically expensive than to lower river sections for females. This suggests that upriver range expansion may be limited by females in that they may have reached a threshold level of energy expenditure in this upriver area. American shad may possess physiological mechanisms for tissue-specific energy use allowing maintenance of critical tissues necessary for postspawning survival.

1972 ◽  
Vol 29 (10) ◽  
pp. 1495-1499 ◽  
Author(s):  
Raymond C. Levesque ◽  
Roger J. Reed

Food habits of young American shad (Alosa sapidissima) were studied in the Connecticut River above Holyoke, Massachusetts, 1969. Diurnal feeding data revealed a peak in stomach content volume at 8:00 PM during midsummer. Larval shad fed mainly on aquatic crustaceans and tendipedid larvae and pupae. Juveniles ingested the most abundant organisms: crustaceans, tendipedid larvae and pupae, hydropsychid larvae and adult insects. Electivity data indicated positive selection for tendipedid pupae and crustaceans and negative selection for hydropsychid larvae and tendipedid larvae. Selection of Trichoptera larvae by young shad in significant amounts was documented for the initial time.


1973 ◽  
Vol 30 (12) ◽  
pp. 1847-1860 ◽  
Author(s):  
Julian J. Dodson ◽  
William C. Leggett

The migratory behavior of American shad (Alosa sapidissima) approaching their natal river during the final saltwater stage of the spawning migration was studied using ultrasonic tracking and conventional tagging procedures. Initial displacement of most sonic-tagged shad released without displacement adjacent to and 10 km west of the Connecticut River was not in the direction of the home river. These fish, however, homed successfully to the Connecticut River as did dart-tagged shad released in the same areas.Shad exhibited two major behavior patterns; countercurrent orientation in response to the reversing tidal current and adjustment of swimming speed to changes in tidal velocity. Countercurrent orientation was equally significant during daylight and darkness, whereas the adjustment of swimming speeds to tidal current velocity was more significant during daylight than darkness.Shad tracked to the west exhibited a westerly bias inherent in the basic open water behavior patterns. Shad exhibited a greater degree of directed movement when oriented against the ebb tide and adjusted their swimming speeds to exceed the ebb tide velocity and to approximately equal the flood tide velocity. Shad tracked to the east exhibited the same major behavior patterns but with the opposite directional bias.A hypothesis is presented suggesting that the location of the home river is achieved by means of a nonrandom search. Environmental clues indicative of the Connecticut River act to establish a preferred direction of displacement while the actual unidirectional displacement is achieved by reference to the rate and direction of tidal currents.


1990 ◽  
Vol 47 (8) ◽  
pp. 1570-1577 ◽  
Author(s):  
Michael H. Prager ◽  
Mary C. Fabrizio

We examined the applicability of logistic regression to stock identification studies and compared its performance on two data sets to that of linear and quadratic discriminant functions. Logistic regression can be used to model a categorical dependent variable associated with continuous or discrete independent variables, and is preferred to discriminant analyses when the explanatory variables are not multivariate normal. Our examples were American shad (Alosa sapidissima) from the Connecticut River and Hudson River estuaries, and striped bass (Morone Saxatilis) from the Hudson River, Chesapeake Bay, and Roanoke River estuaries. In the examples we used a resampling method to assess classification and allocation errors of the two methods on new data. For the shad data, the logistic model classified significantly more fish correctly, and provided a significantly better estimate of stock composition. For the striped bass data, the two methods classified about the same proportion of fish correctly, but the logistic model gave a significantly better estimate of stock composition.


2002 ◽  
Vol 205 (14) ◽  
pp. 2067-2077 ◽  
Author(s):  
Jeff G. Richards ◽  
Ashley J. Mercado ◽  
Cheryl A. Clayton ◽  
George J. F. Heigenhauser ◽  
Chris M. Wood

SUMMARY A biochemical approach was employed to examine the oxidative utilization of carbohydrate and lipid in red muscle of rainbow trout (Oncorhynchus mykiss) during sustained swimming at 30 and 60% of their critical swimming speed (Ucrit; for 2, 15 and 240 min) and during non-sustainable swimming at 90% Ucrit (for 2, 15 and 45 min). Measurements included pyruvate dehydrogenase (PDH) activity, creatine phosphate, ATP, glycogen, glycolytic intermediates, acetyl-CoA, acetyl-,total-, free-, short-chain fatty acyl- and long-chain fatty acyl- carnitine,intramuscular triacylglycerol and malonyl-CoA concentrations, and whole body oxygen consumption(ṀO2). During the first 2 min at 30 and 60% Ucrit, oxidation of endogenous glycogen by PDH activation increased 4- and 8-fold, respectively, yielding 1.5- to 2.5-fold increases in acetyl-CoA and 2- to 6-fold increases in acetyl-carnitine concentrations. Within 15 min, PDH activity returned to control values (153.9±30.1 nmol g-1 wet tissue min-1); after 240 min there were small 1.7- to 2.6-fold increases in long-chain fatty acyl-carnitine and approx. 50% decreases in malonyl-CoA concentrations, indicating an overall enhancement of lipid oxidation. Sustainable swimming at 30 and 60% Ucrit was further characterized by 1.5- and 2.2-fold increases in ṀO2,respectively. Non-sustainable swimming at 90% Ucrit was characterized by a sustained tenfold (approx.) elevation of red muscle PDH activity (approx. 1600 nmol g-1 wet tissue min-1). Significant 67% decreases in white muscle creatine phosphate and 73% decreases in glycogen levels, without matching increases in lactate levels, point to significant recruitment of white muscle during high-speed swimming for power production, and the potential export of white muscle lactate to red muscle for oxidation. Overall, sustainable exercise at 30 and 60%Ucrit is supported by approximately equal contributions of carbohydrate (approx. 45%) and lipid (approx. 35%) oxidation, whereas non-sustainable swimming is supported primarily by carbohydrate oxidation with only moderate contributions from lipid oxidation.


2013 ◽  
Vol 111 (8) ◽  
pp. 1361-1372 ◽  
Author(s):  
Guillaume Salze ◽  
Helene Alami-Durante ◽  
Shai Barbut ◽  
Massimo Marcone ◽  
Dominique P. Bureau

Adaptations in growth dynamics in fish, i.e. how fish prioritise tissue accretion between organs, remains poorly understood. In the present study, we investigated the effects of graded feed restriction levels on nutrient deposition in 1·3 g fingerlings and 70 g juveniles. At the whole-body level, highly restricted juveniles strove to maintain body protein while mobilising lipid reserves and compensating for mass loss by increasing water content. In contrast, fingerlings maintained body water and energy contents. Additionally, we investigated deposition patterns in four body compartments (red and white axial muscles, viscera and rest of the carcass) in juveniles and changes in the cellularity of the white and red muscles in fingerlings. We provide evidence of priorities in growth and nutrient deposition in body compartments in response to low feeding levels. In juveniles, feed intake (FI) primarily affected the white muscle, while the red muscle and the viscera appeared to be preserved. Specific proteins (45 and 173 kDa) were preferentially deposited in the white muscle, while others (22 and 32 kDa) were preferentially mobilised. In fingerlings' muscle anterior to the anus, the cross-sectional surface areas increased with increasing FI in a logarithmic fashion in the white muscle, and in linear fashion in the red muscle. The maximum diameter of white fibres decreased linearly with fish length, while that of red fibres remained stable. This suggests an adaptation mechanism by decreasing white muscle hyperplasia in favour of hypertrophy when feed is restricted. Overall, these results indicate some mechanisms by which fish cope with low food availability. Our findings also suggest different adaptation strategies employed by fish of different body weights.


1985 ◽  
Vol 42 (10) ◽  
pp. 1640-1648 ◽  
Author(s):  
Victor A. Crecco ◽  
Thomas F. Savoy

We examined the hypothesis that temporal oscillations in zooplankton abundance, river flows, and temperatures in the Connecticut River affect the survival and growth rates of larval and juvenile American shad, Alosa sapidissima, among 5-d cohorts. The relative survival rates between newly hatched shad larvae and juveniles were low among early cohorts (May 21 – June 15), but rose rapidly among later cohorts (June 21 – July 6) when river flows were low and temperatures and zooplankton densities were high. Age of larval and juvenile shad was estimated by counting daily rings on sagittal otoliths and age-specific length increments determined by backcalculation techniques. Cohort-specific growth rates of larval shad increased linearly with rising zooplankton densities, and asymptotically with rising river temperatures and declining flows. By contrast, juvenile growth rates among 5-d cohorts showed no significant linear or nonlinear relationships to water temperatures and flows.


1984 ◽  
Vol 41 (8) ◽  
pp. 1216-1223 ◽  
Author(s):  
Victor A. Crecco ◽  
Thomas F. Savoy

We evaluated a parent–progeny relationship for Connecticut River shad, Alosa sapidissima, with population data from 1966 through 1982. The hypothesis that shad year-class strength is established during larval development mainly by abiotic factors was assessed by correlation analysis between environmental variables, year-class strength, weekly zooplankton densities, hydrographic conditions, and larval feeding success among the 1979 through 1982 year-classes. No significant parent–progeny relationship was found for American shad even after recruitment variations due to river flow and water temperatures were removed. All three environmental variables (mean river discharge, water temperatures, and total monthly precipitation) were significantly correlated with shad year-class strength for the month of June, the period when most American shad larvae emerge.


1971 ◽  
Vol 28 (8) ◽  
pp. 1167-1171 ◽  
Author(s):  
William C. Leggett ◽  
Robert A. Jones

During tracking of 13 adult American shad (Alosa sapidissima) with ultrasonic transmitters in 49 approaches to commercial drift gillnets in the lower Connecticut River, only one shad was captured. Typically, shad moved to within 1–2 m of the net before sensing its presence, then turned and swam along the net, close to the mesh, to its end, where they turned and continued their upriver migration. Sight appeared to play an important role in net detection. However, 14 avoidances were observed when light intensities were inadequate to allow visual detection of the mesh. It was concluded that other senses, perhaps the lateral line, also function in net avoidance, especially when sight is impaired.


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