Los copépodos y quetognatos del golfo de california en la primavera de 1985

Abstract

The distribution and abundance of Copepoda and Chaetognatha from the Upper and Middle Gulf of California are determined from samples obtained through oblique tows of a bongo net provided with digital flowmeter and 505-micron mesh. Distribution and abundance patterns are given for the most abundant species of each taxocenosis, from a total of 53 copepod and seven chaetognath species. Community structure is computed through Shannon-Wiener and Patten's indexes, while distinction in between species complexes is accomplished by employing Stander's similarity index for both taxocenosis. Characteristically, the Upper Gulf has an abundant neritic community, with species such as the chaetognath S. euneritica and the copepod Acartia clausi and Labidocera trispinosa.The chaetognaths S. minima and S. decipiens are indicative of vertical mix up the water column, specially at the Middle Gulf and Eastern Coast. As a general trend, specific diversity increases from north to south and from the Eastern to the Western Coast, even if the peak values for chaetognaths were detected at the coastal zone between Laguna of Yavaros and Laguna of Agiabampo. Three chaetognath communities can be distinguished on a latitudinal basis by Stander's index. Community distinctions of copes isn't as clear as that of chaetognaths, due to the dominance of Cotanas pacificas and Rhincalanus nasutus throughout the surveyed area