Associations of demersal fish with sponge grounds on the continental slopes of the northwest Atlantic

2013 ◽  
Vol 477 ◽  
pp. 217-230 ◽  
Author(s):  
E Kenchington ◽  
D Power ◽  
M Koen-Alonso
Keyword(s):  
Demersal Fish ◽  
Northwest Atlantic ◽  
Continental Slopes

Hematozoa of deep-sea demersal fish of the Northwest Atlantic Ocean

1992 ◽  
Vol 70 (10) ◽  
pp. 1926-1933 ◽  
Author(s):  
R. A. Khan ◽  
W. Threlfall ◽  
W. S. Whitty
Keyword(s):  
Atlantic Ocean ◽  
Continental Shelf ◽  
Fish Species ◽  
Deep Sea ◽  
Demersal Fish ◽  
Northwest Atlantic ◽  
Physico Chemical ◽  
Chemical Factors ◽  
Total Fish

A total of 410 deep-sea demersal fish comprising 54 species was taken at depths of 1000–3200 m from two locations in the Northwest Atlantic Ocean and examined for hematozoans. Prevalences of 29% of the total fish and 61% of the species examined were observed. Piroplasms (Haemohormidium spp.) were the most common parasites (26% infection), with hemogregarine, trypanosome, and cryptobia infections being considerably lower. Haemogregarina marshalllairdi sp.nov. is described from Nezumia bairdi and Macrourus berglax. An enigmatic intraerythrocytic parasite was observed in one fish. A comparison of prevalences of the infections in fish living in the deep sea, on the continental shelf, and in inshore areas indicates that the percentages of fish species infected are comparable in the three areas and that the prevalence of piroplasm infections is greater in the deep-sea locations. It is likely that transmission of hematozoans, probably by hematophagous leeches, in the deep-sea demersal zone is similar to that on the continental shelf, despite the dramatic changes in biological and physico-chemical factors with increasing depth.

scholarly journals Changes and trends in the demersal fish community of the Flemish Cap, Northwest Atlantic, in the period 1988–2008

2012 ◽  
Vol 69 (5) ◽  
pp. 902-912 ◽  
Author(s):  
Alfonso Pérez-Rodríguez ◽  
Mariano Koen-Alonso ◽  
Fran Saborido-Rey
Keyword(s):  
Fish Community ◽  
Temporal Dynamics ◽  
Moving Average ◽  
Demersal Fish ◽  
Dynamic Factor ◽  
Northwest Atlantic ◽  
Common Trends ◽  
Piscivorous Fish ◽  
The North ◽  
Commercial Species

Abstract Pérez-Rodríguez, A., Koen-Alonso, M., and Saborido-Rey, F. 2012. Changes and trends in the demersal fish community of the Flemish Cap, Northwest Atlantic, in the period 1988–2008. – ICES Journal of Marine Science, 69: 902–912. The Flemish Cap fish community (NAFO Division 3M) has been fished since the 1950s, and major changes in the biomass and abundance of its most important commercial species have been reported since the late 1980s. Variations in oceanographic conditions at the Cap, with alternating periods of cold and warm weather, have also been described. This work examines the existence of common trends in the biomass levels of the main demersal species over time using dynamic factor analysis, and the occurrence of “occasional species” was explored in relation to temperature conditions. Overall, there have been significant changes in community structure involving both commercial and non-commercial species. Common trends among species were identified and overall fishing pressure, environmental conditions (represented by a moving average of the North Atlantic Oscillation, NAO), and predation pressure (represented by the abundance of piscivorous fish) emerged as important drivers of the temporal dynamics. The NAO influence in the dynamics of most species was in agreement with their temperature preference. For occasional species, their pattern of occurrence appears also to be linked to changes in temperature regimes.

Blood parasites from fish of the Gulf of Maine to Cape Hatteras, Northwest Atlantic Ocean, with notes on the distribution of fish hematozoa

1982 ◽  
Vol 60 (3) ◽  
pp. 396-402 ◽  
Author(s):  
R. A. Khan ◽  
M. W. Newman
Keyword(s):  
Atlantic Ocean ◽  
Gulf Of Maine ◽  
Demersal Fish ◽  
The United States ◽  
Infected Fish ◽  
Blood Parasites ◽  
Northwest Atlantic ◽  
Northern Latitudes ◽  
Blood Smears ◽  
Cape Hatteras

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.

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

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