Fisheries Theme Team

Advanced Sampling Technology

Background

Effective management of living marine resources depends on the ability to accurately estimate their distribution and abundance. Information needs have recently become acute because of declining stocks, official definitions of overfishing, growing controversy, increased exploitation of new or alternative fisheries, and extensive litigation. The first two standards of the ten National Standards for Fishery Conservation and Management contained in the 1996 re-authorization of the Magnuson-Stevens Fishery Conservation and Management Act state that "Conservation and management measures shall prevent overfishing while achieving...the optimum yield from each fishery...." and "Conservation and management measures shall be based upon the best scientific information available", respectively. A recent National Research Council report (NRC 1998) recommended the availability of at least one reliable fishery-independent abundance index for every managed stock. Fully implementing this recommendation would require assessing hundreds more stocks than at present, a nearly impossible task given existing technology, personnel, and funding.

Estimates of stock abundance and recruitment are key elements to a stock assessment and are based on fishery-independent surveys coupled with fishery statistics. The direct counting of animals in the sea is an inaccurate and inexact science because of limitations in technology and ship time. Traditional research vessel surveys possess inherent biases such as gear avoidance and selectivity, inability to accurately quantify the volume or area sampled by the gear, substrate/ depth/vessel changes in gear performance, inability to sample all substrates and habitats, and non-uniform distribution of target animals which confound the ability to accurately estimate abundance of all life stages.

Environmental conditions play a key role in estimating stock abundance. The precision of survey-based abundance estimates can be improved, costs reduced, or coverage expanded if the likely distributions of animals can be predicted, through modeling of fish habitat selection and biological-physical interactions or using advanced spatialcharacterization techniques, and if adaptive sampling is employed. Environmental measurements can also be incorporated into a geostatistical sampling design to improve precision, and are needed to establish the link between stock dynamics, distribution, movements, and environmental forcing.

Research Needs

The National Marine Fisheries Service (NMFS) is giving high priority to improving the accuracy and timeliness of its stock assessments. Included in this effort are the development, application, and testing of new advanced sampling technologies, deployment strategies, models, and analytical procedures for: 1) assessing animal abundance and distribution, and 2) assessing environmental conditions, biophysical interactions, and habitat characteristics for fishes. There is a need for developing new technologies, but also applying and integrating existing technologies to a great extent.

Fish Abundance and Distribution

New advances in sampling technology are needed to measure and monitor marine animal stock abundance with the greatest possible statistical precision, lowest survey cost, and minimal bias. These improvements can be achieved with advanced sensing technologies, improved design and deployment of sampling instruments, new models, and the merging of new technologies in physical and biological sampling. Areas for research include:

Environmental Sampling Technologies

Underway sampling technologies are needed that can enhance or supplant shipboard monitoring at fixed grid points and provide a continuous record of environmental variables to accompany continuous records of abundance provided by underway fish sampling techniques. New technologies would allow both environmental variables and fish density measurements to be made at high spatial/temporal resolution. Integrating these data with sophisticated spatial analyses and modeling tools would be a productive areas of research and would lead to a better understanding of the effects of physical processes on fisheries. Acoustics and other evolving technologies may also be useful in producing high resolution characterization of the bathymetry, reef structure, and plant life of fish habitats.

Other Technologies

Other areas of advanced sampling technology requiring development include:

Sea Grant Involvement

The Sea Grant network can best participate in addressing the research needs identified above through collaboration by university researchers with colleagues in interested Federal agencies such as the NMFS Fisheries Science Centers, OAR’s Research Laboratories and Joint Institutes, and OAR’s National Undersea Research Program (NURP).

Literature Cited

National Research Council. 1998. Improving fish stock assessments. National Academy Press, Washington, DC, 177 pp.