Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 507568
Title Underwater towed video : a novel method to estimate densities of queen conch (Lobatus gigas; Strombidae) across its depth range
Author(s) Boman, Erik; Graaf, M. de; Nagelkerke, L.A.J.; Rijn, J. van; Meijer Zu Schlochtern, Melanie; Smaal, A.C.
Source Journal of Shellfish Research 35 (2016)2. - ISSN 0730-8000 - p. 493 - 498.
Department(s) Aquaculture and Fisheries
IMARES Onderzoeksformatie
IMARES Regiostation Yerseke
Publication type Refereed Article in a scientific journal
Publication year 2016
Keyword(s) density estimate - video survey - deep-water popultions
Abstract Queen conch (Lobatus gigas) populations living deeper than 20 m are rarely studied, because of the limitations of conventional survey methods using divers [i.e., belt transect (BT), towed-diver].Acrucial management goal for conch populations is to maintain adult densities at adequate levels to ensure reproduction, which is highly density dependent. Therefore, accurate estimates of adult conch densities, both in shallow and deep areas, are essential. The rapid technical progress of video systems has made it possible to develop new cost-effective ecological sampling tools, which can be used to survey areas previously accessible. A lightweight towed video array was used, which was able to survey adult conch throughout the species entire depth range (ca. 0–60 m depth), in a safe and efficient manner. The towed video method (TVM) was compared with a conventional BT method using scuba divers, in its ability to identify adult live and dead conch. A series of intercalibration transects was conducted in a high-complexity (HC) and in a low-complexity (LC) habitat by having the towed video followed by a diver conducting a concurrent standard BT, covering the exact same surface area as the towed video. In both the HC and LC habitat, adult live queen conch had similar counts with both methods. Adult dead conch were not mistaken for live conch but were significantly underestimated with the towed video compared with the BT. The results validate estimate densities of live adult conch in both HC and LC habitats throughout the species depth range.
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