The Vertical Distribution of the Siphonophores Collected During the SOND Cruise, 1965

Abstract

The siphonophores obtained from the day and night series of horizontal hauls made using a 10 ft Isaacs-Kidd mid-water trawl (IKMT) and a i m 2 ring net (N113), off Fuerteventura in the Canary Islands, have been identified. Because of the low numbers found in some hauls and the possibility that there was some ' hold-up' of material in the nets themselves, the samples from the oblique parts of the IKMT hauls were also examined for siphonophores. A total of 64 species were identified of which there were 51 calycophoran, 12 physonect and 1 cystonect species.The vertical distributions of most of the calycophoran species have been considered in detail, and, where sufficient numbers were present, their diurnal variations analysed. The overall vertical distributions of the physonect species have been compared but because of the difficulty in relating the individual pieces found in the samples to the number of animals present, no attempts were made to analyse quantitatively any of these data. The possible effects on the results on the timing of the hauls and the absence of the catch-dividing bucket in the shallowest ones are discussed in detail for certain species.

Sifonóforos (Cnidaria, Hydrozoa) de aguas superficiales de Isla de Pascua

“…Sin embargo, considerando que las muestras se obtuvieron en un muestreo exploratorio de la capa superficial (0-5 m), se determinó un alto número de especies en comparación con otros resultados obtenidos en el archipiélago de Juan Fernández (Palma, 1985), costa central (Palma, 1973(Palma, , 1994Palma y Rosales, 1995) de estudio y área geográfica mucho más extenso. Esta mayor diversidad observada en isla de Pascua, concuerda con los altos valores estimados para este mismo grupo en aguas cálidas del Atlántico Norte (Pugh, 1974) y de Papua Nueva Guinea (Pagès et al, 1989), así como con las altas diversidades determinadas para los anfípodos hypéridos en las cercanías de isla de Pascua (Vinogradov, 1991).…”

Fauna of the Mediterranean Hydrozoa.

“…Distribution: common and abundant in the warm and temperate regions in the three great oceans, less common in the Mediterranean (Alvariño, 1971). Epipelagic distribution (Pugh, 1974).…”

“…Distribution: quite common in the temperate regions of the three main oceans, and in the Mediterranean (Alvariño, 1971). Epipelagic (Pugh, 1974), but also present in the mesopelagic zone (Gili et al, 1987a).…”

Untitled

“…Daniel (1973Daniel ( , 1985 and Rengarajan (1975) added a few more records for the Indian Ocean; with an illustration of a possible bract appearing in Daniel (1985). Most other records [Pugh, 1974[Pugh, , 1975 (under the heading "Physonect C"); and Stepanjants, 1975] come from the North Atlantic Ocean. Stepanjants (1975) described and figured some bracts and she drew attention to their structural similarity to those found in the family Forskaliidae.…”

“…The most detailed assessment of the depth distribution of Frillagalma vityazi (Physonect "C") was given by Pugh (1974) vicinity of the Canary Islands (c. 28°N, 14°W). He found his 65 nectophores and 63 bracts in 14 hauls at depths ranging from 660 to 950 m, with the bulk of them appearing in the 750-800 m depth range.…”