Assemblages and biogeography of demersal fishes of the east coast of North America

1998 ◽  
Vol 55 (7) ◽  
pp. 1704-1738 ◽  
Author(s):  
Robin Mahon ◽  
Stephen K Brown ◽  
Kees CT Zwanenburg ◽  
D Bruce Atkinson ◽  
Kenneth R Buja ◽  
...  
Keyword(s):  
North America ◽  
East Coast ◽  
Fish Assemblages ◽  
Single Species ◽  
Distribution Patterns ◽  
Demersal Fish ◽  
Trawl Survey ◽  
Distribution Maps ◽  
Cape Hatteras ◽  
Management Approaches

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.

scholarly journals Trends in cpue and related changes in spatial distribution of demersal fish species in the Kattegat and Skagerrak, eastern North Sea, between 1981 and 2003

2005 ◽  
Vol 62 (4) ◽  
pp. 671-682 ◽  
Author(s):  
Michele Casini ◽  
Massimiliano Cardinale ◽  
Joakim Hjelm ◽  
Francesca Vitale
Keyword(s):  
Spatial Distribution ◽  
Fish Species ◽  
General Pattern ◽  
Demersal Fish ◽  
Average Weight ◽  
Trawl Survey ◽  
Catch Per Unit Effort ◽  
Distribution Maps ◽  
Increasing Trend ◽  
Commercial Species

Abstract We explored the trends in ln-transformed catch per unit effort, defined as average weight (kg) per 1 h trawling, and the spatial distribution of 32 demersal fish species in the Kattegat and Skagerrak using International Bottom Trawl Survey data collected between 1981 and 2003. As in other areas, the biomass of roundfish species such as cod, pollack, hake, and ling drastically decreased during this period most likely owing to fishing pressure. However, other commercially important fish species, e.g. haddock, whiting, and some flatfish, showed a constant or increasing trend during the same period. Non-commercial species showed no or an increasing trend in ln-cpue, by as much as 40 times in hagfish. Furthermore, analyses of the spatial distribution of 14 selected fish species by means of distribution maps of ln-cpue suggested that fish stocks contracted and expanded in response to decrease and increase of the stock biomass, respectively, with some flatfish species (i.e. plaice and flounder) and hagfish representing the exceptions to this general pattern.

Tenure of individual larval trematode infections in an estuarine gastropod

2003 ◽  
Vol 83 (5) ◽  
pp. 1047-1051 ◽  
Author(s):  
Lawrence A. Curtis
Keyword(s):  
North America ◽  
Salt Marshes ◽  
East Coast ◽  
Single Species ◽  
The Other ◽  
Trematode Species ◽  
Infection Status ◽  
Ilyanassa Obsoleta ◽  
Larval Trematode ◽  
Trematode Infections

Ilyanassa obsoleta (Mollusca: Gastropoda) is an abundant inhabitant of salt marshes and tidal flats on the east coast of North America. Populations of this snail may be heavily infected by larval trematodes. Three species were observed in this work, Himasthla quissetensis, Lepocreadium setiferoides, and Zoogonus rubellus. Mostly as single-species infections, all occupy snail tissues as parthenitae that produce cercariae, which are released from the snail to infect the next host. By periodically testing snails for cercarial emission, single-species infections are here shown to persist over six summers and double-species infections are also noted to be long-lived. Among the 32 snails followed, 25 released the same (or no) cercariae throughout observation periods averaging three years. The other seven indicated infection changes, but only two of these are judged to reflect actual changes. The probability that a snail changed infection status in this study is thus 2.1% y−1. Ilyanassa obsoleta individuals, and apparently their trematode infections, can persist for decades. Because species colonize and get evicted infrequently, sets of trematode species infecting I. obsoleta individuals (infracommunities) are concluded to be isolationist in character.

scholarly journals Spatial and temporal trend in the abundance and distribution of gurnards (Pisces: Triglidae) in the northern Mediterranean Sea

2020 ◽  
Vol 83 (S1) ◽  
pp. 101
Author(s):  
Francesco Colloca ◽  
Giacomo Milisenda ◽  
Francesca Capezzuto ◽  
Alessandro Cau ◽  
Germana Garofalo ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Fish Assemblages ◽  
Linear Trend ◽  
Temporal Trends ◽  
Temporal Distribution ◽  
Demersal Fish ◽  
Western Mediterranean ◽  
Trawl Survey ◽  
Coastal Species ◽  
The Impact

In this study we investigated the spatio-temporal distribution of gurnards (8 species of Triglidae and one species of Peristediidae) in the northern Mediterranean Sea using 22 years of MEDITS bottom trawl survey data (1994-2015). Gurnards showed significant differences in terms of abundance, dominance and composition among geographical sub-areas and ecoregions, with the highest relative biomass (BIy) being found in Malta, eastern Corsica, the Balearic Islands and the eastern Ionian Sea. The lowest gurnards BIy were observed in the highly exploited areas of the western Mediterranean and the Adriatic Sea, where the largest number of species with a negative linear trend in BIy was also found. The temporal trends in species abundances highlighted a general decrease for the coastal species (C. lucerna, C. lastoviza, C. obscurus) as compared with the species inhabiting the deep continental shelf and slope (T. lyra, P. cataphractum). The results provide for the first time an overview of the spatiotemporal trend in the abundance of gurnards over the wide spatial scale of the northern Mediterranean Sea, also suggesting the possible use of these species as indicators for monitoring the impact of fishing pressure on demersal fish assemblages.

Distribution of the Parasitic Isopod Hemioniscus balani with Special Reference to the East Coast of North America

1968 ◽  
Vol 25 (6) ◽  
pp. 1161-1167 ◽  
Author(s):  
D. J. Crisp
Keyword(s):  
North America ◽  
Small Area ◽  
World Wide ◽  
East Coast ◽  
Wide Distribution ◽  
American Variety ◽  
North Wales ◽  
Cape Hatteras ◽  
Balanus Balanoides ◽  
Parasitic Isopod

Hemioniscus balani Spence Bate, a parasitic isopod with a world-wide distribution in temperate waters, was not found among intertidal populations of Balanus balanoides examined between 1959 and 1965 on the east coast of North America from Newfoundland to Cape Hatteras, except for a small area near Halifax, Nova Scotia.The North American variety of Balanus balanoides, when transplanted from Woods Hole to North Wales, was found to be much more susceptible than the European variety to parasitisation by H. balani.

Description of the subareas of Ragay Gulf, Philippines, and their fish assemblages by exploratory data analysis

1992 ◽  
Vol 43 (2) ◽  
pp. 379 ◽  
Author(s):  
RR Federizon
Keyword(s):  
Data Analysis ◽  
Exploratory Data Analysis ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Demersal Fish ◽  
Trawl Survey ◽  
Fish Stocks ◽  
Catch Data ◽  
Exploratory Data ◽  
Comparison Of The Results

Exploratory data analysis using four different techniques of classification and ordination was applied to the catch data from a 15-month demersal trawl survey in Ragay Gulf, Philippines, in order to characterize the area. The four techniques yield almost identical results and therefore lend confidence to the three subareas identified: shallow, coralline and deep. Species characteristic of the subareas were also identified. The observed pattern remained consistent during the study period, suggesting that seasonal variability is not pronounced. This study provides further empirical evidence of the zonation of fish communities by depth. Preliminary comparison of the results of this study with those of studies of demersal fish community assemblages in the Samar Sea shows that boundary depths defining zonation are different in the two areas because of their different depth ranges and spatial scales. This comparison leads to the question of whether the boundary depths as identified via classification and ordination methods could be a function of the shape of the depth distribution of the samples. The use of a bootstrapping method to investigate this question is suggested. The importance of applying exploratory data analysis to the catch data from a demersal trawl survey done to assess fish stocks is also discussed.

Phylogeny of the Crepidula plana (Gastropoda: Calyptraeidae) cryptic species complex in North America

2000 ◽  
Vol 78 (8) ◽  
pp. 1500-1514 ◽  
Author(s):  
Rachel Collin
Keyword(s):  
North Carolina ◽  
North America ◽  
Species Complex ◽  
East Coast ◽  
Sequence Data ◽  
Single Species ◽  
The United States ◽  
Molecular Techniques ◽  
Dna Sequence Data ◽  
Cryptic Species Complex

The taxonomy of Crepidula species with flat white shells is particularly difficult. These animals from the east coast of North America have generally been classified as a single species, Crepidula plana Say, 1822. Based on allozyme and developmental data, however, Hoagland (K.E. Hoagland. 1984. Malacologia, 25: 607-628; K.E. Hoagland. 1986. Am. Malacol. Bull. 4: 173-183) concluded that two species of flat white-shelled Crepidula live along the east coast of the United States, but she did not apply any name to the second species. Herein I use molecular techniques to characterize populations of flat white-shelled Crepidula species from Texas, Florida, Georgia, North Carolina, and |Massachusetts, and describe their morphology and development. DNA-sequence data support the existence of three species. One species is readily distinguished on the basis of morphology and development, but the other two are very similar. To clarify the nomenclature of these species, I designate neotypes for C. plana Say, 1822 and Crepidula depressa Say, 1822, and describe Crepidula atrasolea sp.nov.

Bryogeography and the bryophytic characterization of biogeoclimatic zones of British Columbia, Canada

1988 ◽  
Vol 66 (12) ◽  
pp. 2673-2686 ◽  
Author(s):  
W. B. Schofield
Keyword(s):  
British Columbia ◽  
North America ◽  
Nutrient Cycling ◽  
Anthropogenic Disturbance ◽  
Distribution Patterns ◽  
Western North America ◽  
Distribution Maps ◽  
Representative Species ◽  
Forestry Practice

Although nearly 85% of the bryophytes of the known flora of British Columbia show wide world distributions, they, plus the remaining 15% confined to western North America, segregated into at least eight distinguishable patterns. These patterns have been shaped by the coincidence of climate, historical events, substratum, and topography and have been altered more recently through anthropogenic disturbance. The distribution patterns form the basis for the bryophytes that characterize the biogeoclimatic zones. Lists of these bryophytes are provided for the 12 biogeoclimatic zones recognized for British Columbia by V. J. Krajina. Distribution maps are provided for 16 representative species. Other applications of bryophyte ecology in forestry practice include site evaluations, nutrient cycling, and successional interpretation.

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