Estimating the abundance of clustered and cryptic marine macro-invertebrates in the Galápagos with particular reference to sea cucumbers

Shepherd, Scoresby. A. and Toral-Granda, Veronica and Edgar, G.J. (2003) Estimating the abundance of clustered and cryptic marine macro-invertebrates in the Galápagos with particular reference to sea cucumbers. Noticias de Galapagos, 62, pp. 36-39.

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Abstract

Estimating the abundance of marine macro-invertebrates is complicated by a variety of factors: 1) human factors, such as diver efficiency and diver error; and 2) biological factors, such as aggregation of organisms, crypsis, and nocturnal emergence behavior. Diver efficiency varied according to the detectability of an organism causing under-estimation of density by up to 50% in some species. All common species were aggregated at scales from 10-50 m. Transects need to be long enough to transcend the scale of patchiness to improve accuracy. Some species of sea urchins and sea cucumbers (pepinos) which are cryptic by day emerged at night so that daytime censuses underestimated their abundance by up to 10 times. In the sea cucumber fishery, estimates of abundance need to be made at the scale of the population, i.e. at hundreds of km. A strategy for this is proposed.

Item Type: Article
Title: Estimating the abundance of clustered and cryptic marine macro-invertebrates in the Galápagos with particular reference to sea cucumbers
Personal Creator/Author:
CreatorsEmail
Shepherd, Scoresby. A.
Toral-Granda, Veronica
Edgar, G.J.
Journal or Publication Title: Noticias de Galapagos
Volume: 62
Page Range: pp. 36-39
Date: December 2003
ISSN: 0550-1067
Latitude: -0.425
Longitude: -91.1167
Issuing Agency: Fundacion Charles Darwin Foundation
Uncontrolled Keywords: sea cucumbers;Stichopus fuscus;Eucidaris;sea urchins;Lytechinus;sampling methods;surveys;diver efficiency;Isla Isabela;Isla Fernandina;Galápagos
Subjects: Biology
Conservation
Fisheries
Item ID: 8589
Depositing User: Ms Sally Taylor
Date Deposited: 16 Apr 2012 19:50
Last Modified: 16 Apr 2012 19:50
Related URLs:
URI: http://aquaticcommons.org/id/eprint/8589

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