scholarly journals Using winter flounder growth rates to assess habitat quality in Rhode Island's coastal lagoons

2000 ◽  
Vol 201 ◽  
pp. 287-299 ◽  
Author(s):  
L Meng ◽  
C Gray ◽  
B Taplin ◽  
E Kupcha
1971 ◽  
Vol 28 (8) ◽  
pp. 1153-1165 ◽  
Author(s):  
V. S. Kennedy ◽  
D. H. Steele

Monthly samples of winter flounder taken in Long Pond from November 1962 to October 1963 indicated that the flounder moved into deeper water (7–10 m) during the summer and returned to shallow water (1–2 m) from September to June. These movements corresponded to the end of the spawning season and the ripening of the gonads respectively. Spawning occurred from March until early June, most of it in May and early June. Most males were mature at age 6 and most females at age 7. Fifty percent of the males and females were mature at 21 and 25 cm respectively. The growth rates of the males and females were similar until the age of 8, after which the females apparently outgrew the males. Early growth and fecundity were similar to those reported for other areas. No feeding took place in December or January but the flounder fed in March and continued to feed throughout the summer; food intake decreased in the fall. They were omnivorous and the type of food eaten varied with the locality. Polychaetes, plant material, and molluscs were the most common food items throughout the year. Capelin eggs and fish remains were found only during a few months of the year but were eaten in great quantities.


1991 ◽  
Vol 48 (10) ◽  
pp. 1862-1871 ◽  
Author(s):  
Susan M. Sogard

In winter flounder (Pseudopleuronectes americanus), sagittae developed secondary origins of calcium carbonate deposition during metamorphosis just prior to completion of eye migration. Sagittae and lapilli of larvae were bilaterally symmetrical, but those of postmetamorphic individuals showed increasing morphological asymmetry between the left and right side. In juveniles marked with oxytetracycline and maintained in field enclosures for 10 d, increment deposition on sagittae was daily if somatic growth following marking was good (> 0.25 mm∙d−1), but less than daily in individuals with poor or negative somatic growth (< 0.25 mm∙d−1). Narrowly spaced increments or divergence of otolith growth from the main rostral–postrostral growth axis, where counts were made, may have limited detection of daily deposition. Lack of detectable daily increments occurred primarily in larger juveniles (> 50 mm total length), which had lower absolute growth rates than newly settled juveniles. In oxytetracycline-marked fish there was a significant correspondence between otolith growth and somatic growth in both length and weight. The strength of this relationship, which varied with the specific radius used, was highest (r = 0.854) for the rostral radius of the left sagitta; increment widths along this radius are reliable estimators of prior somatic growth rates.


The Condor ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 301 ◽  
Author(s):  
Melinda G. Knutson ◽  
Randy K. Hines ◽  
Larkin A. Powell ◽  
Mary A. Friberg ◽  
Gerald J. Niemi

Author(s):  
C. J. Meise ◽  
D. L. Johnson ◽  
L. L. Stehlik ◽  
J. Manderson ◽  
P. Shaheen

1993 ◽  
Vol 20 (5) ◽  
pp. 579 ◽  
Author(s):  
A Poiani

The breeding biology of the bell miner (Manorina melanophrys, Meliphagidae) at a site 60 km east of Melbourne, Victoria, is described. Bell miners showed a clear seasonal pattern of nesting, moulting and development of brood patch. Increased food availability and number of helpers were not associated with increased nesting success. This is partially explained by increased predation on nests in colonies with more helpers. Growth rates of nestlings did not increase with increased number of helpers and habitat quality, although these variables may affect postfledging survival rates. Breeding females organised into neighbourhoods seemed to be able to synchronise nesting. Egg shape differed among females but egg size did not, although egg volume increased as the breeding season progressed.


The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 505-515 ◽  
Author(s):  
William B. Kristan

Abstract Abstract. Habitats are composed of multiple variables, each of which may affect one or more population demographic rates. The patterns of correlation among habitat variables can introduce correlations among demographic rates, even if any single habitat variable affects only a single demographic rate and is independent of others. I present a simple model in which habitat is composed of two continuous habitat variables, one of which affects fecundity but not survival, and the other of which affects survival but not fecundity, such that correlations between survival and fecundity are due exclusively to correlations between the habitat variables. When individuals are able to select habitat with complete information about habitat quality, habitat selection always leads to higher growth rates at small population sizes. With complete information about habitat quality, patterns of distribution and population growth rates are strongly affected by the correlation between habitat variables. In contrast, when individuals have information about only fecundity or survival but not both, distributions become insensitive to correlations among habitat variables, which can lead to an ecological trap. This simple model demonstrates why explicitly distinguishing between habitat choices and the consequences of choices will be necessary if the complex interplay between habitat structure, habitat choice, and habitat quality is to be fully understood.


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