scholarly journals Persistence of Demersal Fish Assemblages Between Cape Hatteras and Nova Scotia, Northwest Atlantic

1992 ◽  
Vol 14 ◽  
pp. 29-46 ◽  
Author(s):  
W L Gabriel
1982 ◽  
Vol 60 (3) ◽  
pp. 396-402 ◽  
Author(s):  
R. A. Khan ◽  
M. W. Newman

Examination of blood smears from 657 marine fish collected from the continental shelf off the east coast of the United States, Cape Hatteras to the Gulf of Maine, revealed hematozoa in 19 of 39 species. Among the infected fish species, hemogregarines were more prevalent (17%) than trypanosomes (5%), piroplasms (4%), or trypanoplasms (1%). Ten species were infected with the virus that causes piscine erythrocytic necrosis. Prevalence of hemogregarines was higher in pleuronectiform and gadiform fish than among perciform species. Sedentary benthic species, especially flatfishes, and some demersal fish, were infected more often than pelagic species. Comparison of this survey with previous studies in the Northwest Atlantic suggests that hematozoa are more prevalent among fish in areas north of Newfoundland and decrease towards the equator. Piroplasms are reported only from fish occurring in temperate Atlantic waters. Piscivorous species of leeches, which are suspected or proven vectors of hematozoa, are more prevalent in the arctoboreal than in the neotropical Atlantic Ocean, and might account for the higher prevalence of piscine hematozoa in the northern latitudes.


1998 ◽  
Vol 55 (7) ◽  
pp. 1704-1738 ◽  
Author(s):  
Robin Mahon ◽  
Stephen K Brown ◽  
Kees CT Zwanenburg ◽  
D Bruce Atkinson ◽  
Kenneth R Buja ◽  
...  

This study describes and maps demersal fish assemblages for the east coast of North America from Cape Hatteras, North Carolina, to Cape Chidley, Labrador, evaluates evidence for interannual shifts in assemblage distribution, and examines the relationship of the assemblages to accepted biogeographical boundaries. Demersal trawl survey data collected from 1975 to 1994 were analyzed. Visual classification of distribution maps for the 108 most abundant demersal species revealed nine species groups, based on both geography and depth distribution. Eighteen assemblage groups were identified using principal components analysis (PCA) and mapped. Assemblage groups were also identified by cluster analysis. Fish assemblages identified by both methods were spatially coherent. Assemblage distribution patterns were not consistent with accepted biogeographical boundaries. The PCA explained only 56.3% of the variance in distribution of the species, indicating that the assemblages should be interpreted as indeterminate, potentially adaptable entities rather than as rigid ecological constructs. Assemblages were persistent in composition through time but appeared to shift in location. The apparent looseness of the assemblages and their persistence through time in spite of severe impacts from fishing suggest that single-species management approaches may not be entirely inappropriate for the major groundfish species in the study area.


Author(s):  
Régis Santos ◽  
Wendell Medeiros‐Leal ◽  
Ana Novoa‐Pabon ◽  
Hélder Silva ◽  
Mário Pinho

Author(s):  
Montserrat Demestre ◽  
Pilar Sánchez ◽  
Pere Abelló

Continental shelf and upper slope fish communities were studied along the Catalan coast based on 66 experimental bottom otter trawls. A total of 79 demersal fish species were studied by means of cluster analysis and multi-dimensional scaling (MDS) ordination for community structure. Analysis revealed the existence of five major location clusters. Similarity percentage analysis (SIMPER) was determined by comparing the dissimilarity between two groups of samples using the discriminating species. Geomorphological characteristics, bottom substratum and depth showed direct influences on species assemblages. High correlation between the biotic data samples and depth was observed. The fish species assemblages identified five main demersal fish associations which corresponded with the five location clusters and with five benthic sediments (mud of the upper slope, sand and gravel, mud of the shelf, muddy-sand and sand with rocky outcrops).


2016 ◽  
Vol 38 (2) ◽  
pp. 189-206 ◽  
Author(s):  
ML Camara ◽  
B Mérigot ◽  
F Leprieur ◽  
JA Tomasini ◽  
I Diallo ◽  
...  

2005 ◽  
Vol 56 (2) ◽  
pp. 133 ◽  
Author(s):  
Rhys A. Edwards ◽  
Stephen D. A. Smith

In marine habitats, the use of geotextile materials as a ‘soft-engineering’ solution is increasingly being considered as an alternative to hard structures. However, very little is known about biological assemblages that develop on geotextile structures. This study provides the first ecological comparison of subtidal assemblages between Narrowneck Artificial Reef (NAR), a geotextile reef in south-east Queensland, Australia, and three nearby natural reefs. Benthic community structure, fish assemblages and habitat complexity were compared between reef types using an asymmetrical design. Although natural reefs supported distinct biotic assemblages, as a class, these reefs differed significantly from NAR. The artificial reef was dominated by macroalgae and supported fewer benthic categories, whereas the natural reefs were characterised by a diverse range of sessile invertebrates. Benthic and demersal fish assemblages were less diverse on NAR, but pelagic fish assemblages were similar on both reef types. The substratum of NAR was less complex than that of the natural reefs; this physical variable was correlated with some of the differences in benthic communities and benthic and demersal fish assemblages. It is likely that the key determinants of the biotic patterns observed in this study are interactions between the age of NAR and the physical properties of geotextile substratum.


Sign in / Sign up

Export Citation Format

Share Document