Density-dependent habitat selection by juvenile haddock (Melanogrammus aeglefinus) on the southwestern Scotian Shelf

1995 ◽  
Vol 52 (5) ◽  
pp. 1007-1017 ◽  
Author(s):  
C. Tara Marshall ◽  
Kenneth T. Frank
Keyword(s):  
Habitat Selection ◽  
Local Density ◽  
Population Analysis ◽  
Melanogrammus Aeglefinus ◽  
Model Parameters ◽  
Total Abundance ◽  
Scotian Shelf ◽  
Density Dependent ◽  
Density Dependent Habitat Selection ◽  
Haddock Melanogrammus Aeglefinus

Positive correlations between total abundance and indices representing distributional area have been reported for several marine fish stocks. Different indices can produce different results for the same stock and many indices scale positively with total abundance. We describe an alternative approach to modelling the distributional response to variation in total abundance using data for juvenile haddock (Melanogrammus aeglefinus) from the southwestern Scotian Shelf. Annual bottom trawl surveys having a stratified random design were used to estimate the local density of haddock age 1 and 2 in each strata. Estimates of total abundance-at-age were obtained from sequential population analysis. The relationship between local density and total abundance-at-age was described for each strata using an exponential model with a Poisson error structure. Systematic variation among strata in the model parameters was indicative of density-dependent habitat selection and supported a previous study showing a positive correlation between distributional area and total abundance. Density-dependent habitat selection by juvenile haddock did not generate correlations between mean length-at-age and total abundance-at-age because the proportional abundance of haddock in areas of differing growth rates remained approximately constant as total abundance-at-age increased.

Density-dependent habitat selection predicts fitness and abundance in a small lizard

Oikos ◽  
2017 ◽  
Vol 127 (3) ◽  
pp. 448-459 ◽  
Author(s):  
James E. Paterson ◽  
Gabriel Blouin-Demers
Keyword(s):  
Habitat Selection ◽  
Density Dependent ◽  
Density Dependent Habitat Selection

Dispersal of early life stage haddock (Melanogrammus aeglefinus) as inferred from the spatial distribution and variability in length-at-age of juveniles

1999 ◽  
Vol 56 (12) ◽  
pp. 2350-2361 ◽  
Author(s):  
Nancy L Shackell ◽  
Kenneth T Frank ◽  
Brian Petrie ◽  
David Brickman ◽  
Jennifer Shore
Keyword(s):  
Early Life ◽  
Life Stage ◽  
Circulation Model ◽  
Early Life Stage ◽  
Melanogrammus Aeglefinus ◽  
Bay Of Fundy ◽  
Shelf Area ◽  
Scotian Shelf ◽  
Frequency Distributions ◽  
Haddock Melanogrammus Aeglefinus

In southwestern Nova Scotia, haddock (Melanogrammus aeglefinus) spawning is centered on Browns Bank where the variability of a partial gyre influences the distribution of eggs and larvae. An unknown proportion of each year-class is advected northward to the Bay of Fundy. We examined the variability in length at age 2 as an index of retention during early life. We assumed that early life stages that are retained in the Scotian Shelf area grow more slowly, while those that are advected into the Bay of Fundy grow more quickly. An optimization program was used to estimate the proportions of Scotian Shelf and Bay of Fundy sized components in length at age 2 bimodal frequency distributions for year-classes 1968-1993. The median proportion of Scotian Shelf sized fish was 0.89. A physical circulation model showed that the majority of particles released on Browns Bank drifted towards the Bay of Fundy. Results of the physical model and the size-based index differ partly because the former predicts the fate of passive particles, while the latter is an integrated measure of the proportion of fish retained and surviving. Survival is associated with high wind stress (r = -0.5, p = 0.011, n = 25) implying a higher probability of survival of those retained in the Scotian Shelf region.

Temporal scales of density-dependent habitat selection in a large grazing herbivore

Oikos ◽  
2014 ◽  
Vol 123 (8) ◽  
pp. 933-942 ◽  
Author(s):  
Anna W. Blix ◽  
Atle Mysterud ◽  
Leif Egil Loe ◽  
Gunnar Austrheim
Keyword(s):  
Habitat Selection ◽  
Temporal Scales ◽  
Density Dependent ◽  
Density Dependent Habitat Selection

Ontogenetic and sex-specific differences in density-dependent habitat selection of a marine fish population

Ecology ◽  
2011 ◽  
Vol 92 (1) ◽  
pp. 189-200 ◽  
Author(s):  
Valerio Bartolino ◽  
Lorenzo Ciannelli ◽  
Nathan M. Bacheler ◽  
Kung-Sik Chan
Keyword(s):  
Habitat Selection ◽  
Marine Fish ◽  
Fish Population ◽  
Density Dependent ◽  
Density Dependent Habitat Selection ◽  
Selection Of

Alimentary tract parasites of haddock (Melanogrammus aeglefinus L.) on the Scotian Shelf

1981 ◽  
Vol 59 (12) ◽  
pp. 2244-2252 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Alimentary Tract ◽  
Parasite Prevalence ◽  
Melanogrammus Aeglefinus ◽  
Bay Of Fundy ◽  
Scotian Shelf ◽  
Young Of The Year ◽  
Parasite Complex ◽  
Haddock Melanogrammus Aeglefinus ◽  
Hysterothylacium Aduncum ◽  
Biological Tags

Nineteen species of alimentary tract (including gall and swim bladders) parasites were found in haddock (Melanogrammus aeglefinus) on the Scotian Shelf, of which eight species were new Canadian records for haddock. Prevalence ranged up to 82.3% for Hysterothylacium aduncum and 70.9% for Echinorhynchus gadi, the most abundant parasites, with Lepidapedon rachion and Echinorhynchus gadi showing highest intensities (14.9 and 76.5, respectively). Prevalence decreased from summer to winter, was not related to sex of host, but showed geographical variation characterizing different geographical areas. The Bay of Fundy showed higher nematode and lower trematode abundance than the offshore Scotian Shelf which showed general clines in abundance of several species from southwest to northeast. There was no evidence of growth-related change in parasite prevalence in adult fish, but the parasite complex of young-of-the-year haddock indicated planktonic feeding, in contrast with benthic feeding in the adult. Site specificity within the alimentary tract was shown by several species. Echinorhynchus gadi changed its site seasonally. Lepidapedon rachion showed size differentiation in the gut, smaller trematodes occupying more anterior sites than larger. Only two parasite species offer prospects as biological tags, L. rachion and Myxidium bergense, but all may provide evidence of ecological, behavioral, seasonal and developmental changes in the host.

Sign in / Sign up

Export Citation Format

Share Document