Date of this Version
Papers from the Tortugas Laboratory (January 16, 1934)
Preprinted from Carnegie Institution of Washington publication number 435, pages 257-345 (January 16, 1934)
Introduction (first two paragraphs)
The parasitic fauna of ocean depths is practically unknown. Although an extensive fish population occurs at all depths, very little study has yet been made on the helminths of these fish. During the summers of 1930, 1931, and 1932 excellent opportunity was offered for the collection of parasites from fish trawled from depths varying from 40 to 582 fathoms at Tortugas, Florida. A considerable number of systematic hauls by the staff and crew of the Tortugas Biological Laboratory of the Carnegie Institution of Washington yielded an abundance and considerable variety of fish, some of rare forms, many of which were examined for parasites. Most of these hauls were made about 20 miles south of Loggerhead Key.
Fish taken from these depths were commonly parasitized by helminths and especially by trematodes. Preliminary notes already published (Manter, 1930, 1931b, 1932) indicate the richness of this new field. In spite of some circumstances making collection more difficult, it was found that the trematode fauna of the deep-water fish is practically as abundant and as varied as is the rich trematode fauna of the reef fish.
Also includes Hosts, showing general prevalence of trematodes, Descriptions of trematodes collected including those from orders Gasterostomata and Prosostomata, Bathymetric distribution of deep water trematodes, List of hosts with trematode parasites of each, Discussion, Summary, Bibliography, and Plates.
1. A description is given of 49 species of trematodes collected from approximately 90 species of fish from depths of 40 to 582 fathoms. 721 individual fish were examined.
2. Approximately 80 percent of the host species were infected with trematodes, a percentage comparable with the degree of infection found in fish of shallow water. About 30 percent of the individuals examined were infected with trematodes. There was no indication that trematodes became more scarce as depth increased.
3. One new subfamily (of the family Helerophyidae), 11 new genera, and 33 new species are described.
4. Families are represented by the following number of species: Hemiuridae, 15; Allocreadiidae, 13; Fellodistomidae, 11; Bucephalidae, 4; Acanthocolpidae, 2; Zoogonidae, 1; Azygiidae, 1; Heterophyidae, 1; unclassified, 1.
5. These trematodes are markedly distinct from nearby, shallow water, only 2 species collected from below 100 fathoms occurring also in shallow-water hosts. These 2 species are Distomum fenestratum and Sterrhurus floridensis. At about 50 fathoms, Deretrema fusillus, Myzoxenus vitellosus, and Helicometrina nimia, also found in shallow water fish, occurred.
6. Seven species of trematodes known from fish hosts of northern waters were found in deep-water hosts at Tortugas. The deep-water trematode fauna, therefore, is more similar to that of distant, cooler water than it is to the trematode fauna of warm, surface waters of Tortugas. Also, more species of northern trematodes are to be found in deep water than in shallow water at Tortugas.
7. The depths from which collections were made arc indicated in chart form to demonstrate the definite bathymetric distribution of some species of trematodes. This study emphasizes the fact that a gradient of changing environment (such as depth) is reflected not only in the free-living population of a region but also in their parasites.