New Technologies for Observing Marine Life
The Scientific Committee on Oceanic Research (SCOR) Working Group on New Technologies for Observing Marine Life monitors and recommends cutting-edge marine technologies that are mature enough to become routinely useful in the CoML's field projects.

The practical means for achieving improved knowledge of what lives in the ocean, which is an essential requirement for scientific understanding of marine ecology, involves technological challenges. We contend there are many technologies presently in researchers' hands or on the point of implementation, which are badly needed by the larger community of scientists studying and monitoring marine life, yet remain generally inaccessible. There are several reasons for this.

National fisheries interests tend to be very conservative in their approach to measurement. This is understandable, since the setting of fishing quotas and regulations is highly political: consistency in measurement technique from one year to the next is seen as an essential virtue. But such an approach does not always favor development of innovative techniques. For example, the application of acoustic technology to stock assessment remains patchy around the world. Commitment to innovative developments is not just a matter of technological development or economic importance of fish but often has historical, jurisdictional or other reasons.

New techniques, or improved ways of using existing techniques, often arise in research groups that do not have traditional commitment to the measurement of marine life, but depend on innovative application of concepts developed for different reasons. To cite just one example, the development of optical sensing of fish using airborne lidar evolved in a group that was developing optical techniques for atmospheric measurement. Subsequent collaboration with fisheries scientists demonstrated the remarkable potential of this method and its future success will be based on this interdisciplinary link. At present the technology remains largely inaccessible and probably largely unknown to the vast majority of scientists who could benefit from it. But there is no reason why this should remain so, and wider knowledge and discussion of such approaches will almost certainly lead to wider use.

Several emerging measurement approaches were discussed at a CoML funded workshop held at Scripps in 1997 under the chairmanship of Dr. Jules Jaffe. These included the use of acoustic, optical and statistical methods, as well as new deployment approaches such as the use of autonomous vehicles and drifters communicating their results by satellite, DNA sequencing, behavioral approaches such as relating seabird activity to fish populations, concentration of sparsely distributed fish by night time illumination to facilitate assessment and passive detection through bioluminescence stimulated by high fish concentrations.

Inevitably acoustic concepts become an important and generally dominant part of such discussions, since the ocean is relatively transparent to acoustical energy in contrast to electromagnetic radiation. Particularly important advances can be expected from the collaboration of marine biologists and fisheries scientists with specialists in underwater acoustics. At the CoML workshop there were presentations on the study of benthic habitats, 3-d underwater imaging, the use of low frequency attenuation of sound over longer ranges by fish, and horizontally imaging sonars that can identify individual fish at ranges of several km. Acoustical methods show particular promise in overcoming one of the most severe difficulties of measurement: the limited sampling volume achieved by traditional approaches.

Species identification is one of the most challenging aspects of remote fish detection. Multiple frequency sonars have proved highly effective at providing size and other information about zoo-plankton, larval and adult fish. Since fish recruitment is one of the most perplexing fisheries estimation problems, there seems to be special opportunity for developing this approach and making it more readily available. In acoustic measurement, the development of adequate scattering models is just as important as development of measurement hardware, and just as neglected. The combination of better models with new instruments will lead to the greatest advances. This will be especially true with the introduction of low frequency parametric systems that exploit the swim bladder resonance to distinguish size and species.

Innovative deployment technologies will be essential for many of the applications envisaged in the Census. Autonomous underwater vehicles, whether powered or drifting, are becoming available. How will marine biologists use these new platforms? Systems that can maintain a constant height over the sea-floor, allowing the accumulation of high resolution photography, are already being tested and will add immeasurably to our knowledge of benthic communities. Powered vehicles with multi-beam sonars developed for mine detection have obvious application in the study of marine life, and are already available for this use. In summary, there are a great many new concepts and technologies that have become available, but they remain untried and largely unknown by the community of marine biologists who could take advantage of them. Acceptance will only come from detailed assessment of their strengths and weaknesses relative to traditional approaches. Often the newer approaches will prove complementary to established methods. A goal of the Working Group will be to develop assessments of these new technologies and to make them more widely known to the community of scientists who could benefit from their use.

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