Premium
Some observations on the ecology of Galeus piperatus Springer and Wagner, a little known shark endemic to the Northern Gulf of California *
Author(s) -
Mathews C.P.
Publication year - 1975
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1975.tb04577.x
Subject(s) - demersal zone , fishing , biology , geography , fishery , abundance (ecology) , population , ecology , oceanography , geology , demography , sociology
Galeus piperatus Springer & Wagner, the peppered shark, is a dwarf shark found in the Gulf of California north of the City of Guaymas, Sonora. It has been taken in June and August 1971 and in February and March 1972, and is found from 130–550 m with maximum abundances from 170–420 m deep. Numbers are higher in June and August (up to 110 individuals/ha) than in February and March. In June and August 1971 the area of distribution included all the waters north of Isla Tiburón and Isla Angel de la Guarda, and below the 130 m isobath. During these months Galeus piperatus was found at 12 and 33 stations respectively, but was taken at only one station in the same area during February and March 1972. The fishing effort expended during these periods was 16, 42 and 60 units respectively. It seems likely that a strong migratory movement causes these differences in abundance and distribution. Galeus piperatus has been taken from 50–100 m off the bottom in mid‐water trawls at night and is clearly a mid‐water and demersal form. Sexually mature females carrying olive green egg cases were taken in large numbers in June 1971 and were also present in reduced numbers in August 1971. Only females 18 cm or more in total length carried egg cases. The migration of Galeus piperatus into the North Gulf of California appears to coincide with sexual maturity.