IR Home
MEPS
Home
Editors
Forthcoming
Information
Subscribe
Journals
Home
MEPS
AME
CR
DAO
ESEP
Search
Subscribe
Book Series
EE Books
Top Books
ESEP Books
Order
EEIU Brochures
(pdf format)
Discussion Forums
Home
Research
Endangered Species Programs
Institutions
International Ecology Institute
Eco-Ethics International Union
Foundation
Otto Kinne Foundation
![](../../../images/pixel.gif) | ![](../../../images/pixel.gif) |
MEPS 254:129-140 (2003)
|
Abstract
|
![](../../../images/hline.gif)
In situ quantification and analysis of large jellyfish using a novel video profiler
William M. Graham1,2,*, Daniel L. Martin1, Jonathan C. Martin2
1Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, Alabama 36528, USA
2Department of Marine Sciences, University of South Alabama, Mobile, Alabama 36688, USA
*Email: mgraham@disl.org
![](../../../images/hline.gif)
ABSTRACT: Ecological studies involving large jellyfish have been limited by the inability of oceanographers to measure the abundance and distribution patterns of these highly aggregated animals at local scales. Conventional plankton nets are undesirable
in these applications because they cannot sample volumes large enough to accurately determine jellyfish concentration, nor do they have adequate spatial resolution to account for the ubiquitous patchiness of most large jellies. Nets are also notorious for
damaging the watery bodies of jellyfish. To overcome these problems, we have developed a video system for use in the in situ study of large jellyfish. The design of our JellyCam is easily replicated since it incorporates commercially available
components within a frame designed to hold hydrographic instrumentation available at most marine laboratories. We present data sets from 2 occasions as a demonstration of the utility of the JellyCam. On one occasion, a vertical profile of medusae of
Pelagia noctiluca revealed intense layering of these jellyfish at the pronounced halocline/pycnocline. Most jellyfish in this layer were swimming toward the surface, and it was hypothesized that retarded forward-swimming velocity at the halocline,
due to salt retention in jellyfish, caused this accumulation. A separate 800 m long horizontal transect of Phyllorhiza punctata medusae revealed distinct concentrated bands of jellyfish associated with increased chlorophyll concentration.
Concomitant hydrographic data from the JellyCam showed that accumulation of both jellyfish and chlorophyll was associated with a hydrographic front. These data sets demonstrate that this system is capable of the desired 2 m3 resolution, which
is adequate for the observation and quantification of jellyfish distributions around small-scale physical discontinuities (e.g. fronts and pycnoclines). A series of side-by-side comparisons with a conventional plankton trawl resulted in comparable
measurements of large jellyfish (Aurelia aurita) concentrations. Though in situ videography by itself is a powerful tool for investigating jellyfish, its use in conjunction with conventional nets or other technologies, such as acoustics and
self-propelled vehicles (e.g. remotely operated vehicles and submersibles), will provide the most comprehensive view of jellyfish distribution in 3 dimensions.
KEY WORDS: JellyCam · Scyphomedusae · Gelatinous zooplankton · Behavior · Fronts · Pycnoclines
Full text in pdf format
![](../../../images/hline.gif)
Published in MEPS Vol.
254
(2003) on June 4
Print ISSN: 0171-8630; Online ISSN: 1616-1599.
Copyright © Inter-Research, Oldendorf/Luhe, 2003
|