On the midwater fish faunas of Gulf Stream rings with respect to habitat differences between slope water and northern Sargasso Sea
On the midwater fish faunas of Gulf Stream rings with respect to habitat differences between slope water and northern Sargasso Sea
Date
1976-04
Authors
Jahn, Andrew E.
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Date Created
Location
Gulf Stream
Northern Sargasso Sea
Northern Sargasso Sea
DOI
10.1575/1912/1292
Related Materials
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Keywords
Fishes
Atlantis II (Ship : 1963-) Cruise AII71
Atlantis II (Ship : 1963-) Cruise AII85
Chain (Ship : 1958-) Cruise CH110
Chain (Ship : 1958-) Cruise CH111
Knorr (Ship : 1970-) Cruise KN35
Knorr (Ship : 1970-) Cruise KN38
Atlantis II (Ship : 1963-) Cruise AII71
Atlantis II (Ship : 1963-) Cruise AII85
Chain (Ship : 1958-) Cruise CH110
Chain (Ship : 1958-) Cruise CH111
Knorr (Ship : 1970-) Cruise KN35
Knorr (Ship : 1970-) Cruise KN38
Abstract
Forty-three 1000-in oblique Isaacs-Kidd midwater trawl collections
were made on six cruises. In most cases, these were accompanied by
1500-m hydrocasts and plankton tows to 800 m. The fish collections comprise
19,400 specimens in 129 species, from Slope Water, Gulf Stream,
Northern Sargasso Sea, and four cold-core rings. Temperature, salininty, oxygen, phosphate, and zooplankton biomass information accompany the
collections.
A model predicts that expatriate populations of Caribbean species
can be maintained in the Slope Water and Northern Sargasso Sea in excess
of 15 per cent of their Caribbean population density. With Caribbean
contamination accounted for, the relative abundances of species in
Slope Water and Northern Sargasso Sea are used to assign habitat preferences.
Species clusters derived from an ordination using correspondence
ana1ysis agree well with the habitat preference groups.
The assemblage of species in the rings occupies the middle of a
gradient in faunal composition from winter conditions in Slope Water
to fall conditions in the Northern Sargasso Sea.
The midwater habitat is modeled as two layers, and the ring environment
as a hybrid habitat consisting of a surface layer of Northern Sargasso
Sea habitat and a deep layer of Slope Water habitat. This model is consistent with patterns of species abundance. It is argued that the dramatic change in the depth of the main thermocline on crossing the Gulf Stream is the major physical factor affecting fish distributions with respect to this boundary.
Description
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Woods Hole Oceanographic Institution Apri, 1976.
Appendix C, Biographical notes, not included.
Appendix C, Biographical notes, not included.
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Citation
Jahn, A. E. (1976). On the midwater fish faunas of Gulf Stream rings with respect to habitat differences between slope water and northern Sargasso Sea [Doctoral thesis, Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/1292