[Coral-List] A Brief Survey on Methodologies for Fish Assemblages

Jerald S. Ault jault at rsmas.miami.edu
Tue Apr 12 08:21:25 EDT 2011

Hi Zach,

You will be interested in our recently published paper that appeared in
Fisheries Research that outlines our approach to fishery-independent
survey assessment of multispecies reef fish dynamics:

Smith, S.G., J.S. Ault, J.A. Bohnsack, D.E. Harper, J. Luo, and D.B.
McClellan. 2011. Multispecies survey design for assessing reef-fish
stocks, spatially-explicit management performance, and ecosystem
condition. Fisheries Research 109(1): 25-41. 

Principles of statistical sampling design were used to guide refinement of
a 30-year multispecies fishery-independent diver visual survey of
population abundance and size structure of more than 250 exploited and
non-target fishes in the Florida coral reef ecosystem. Reef habitat
features and no-take marine reserves (NTMRs) were used to partition the
885km2 sampling domain into sub-areas (or strata) to control the variation
of fish density. For the period 1999–2008, survey precision of population
density and abundance (CV, coefficient of variation, ratio of standard
error to mean) ranged from 7% to 20% for the majority of 13 primary
exploited species in the Florida Keys and Dry Tortugas regions. Population
sustainability metrics like species average length in the exploited life
stage were comparable between our fishery-independent survey and
fishery-dependent catch-sampling. The survey design also performed well
for non-target fishes, yielding CVs between 6% and 15% for population
density for the majority of 36 species. Sampling efficiency was improved
over time via an iterative learning process by which past survey data was
used to refine the stratification and allocation schemes of future
surveys. We show how survey data are used to support multispecies stock
assessments, evaluate the effectiveness of NTMRs, and assess ecosystem
condition for the reef fish community.

Best regards, Jerry

> If possible, I would appreciate a few minutes of your time in my effort to
> survey and synthesize the perspectives of the marine ecological community
> regarding fish survey protocols.
>  Quantitative surveys that assess and monitor reef fish assemblages have
> been identified as a critical element in understanding over all reef
> health. Despite the pervasive use of this approach, lack of continuity
> and standardization of survey methodology has limited the ability of the
> data to be widely applicable or transferable between studies.  Numerous
> academic, governmental, and non-governmental institutions conduct these
> surveying programs, and their methods may vary depending on multiple
> factors, such as: the research question, species’ ecology, spatial
> distribution, environment, and institutional capacity. As such, the
> results obtained from each method are oftentimes incomparable due largely
> to variation in spatial and temporal scales chosen.  The development of a
> standardized census method could provide lasting benefits to the research
> and conservation community.
>  The attached survey is designed to gather information toward the
> development of a standardized census method for reef fish assemblages, and
> should take approximately 10 minutes to complete.  The first section
> gathers input on how reef fish population data are being collected and
> where particular methods are being used.  The second section is focused on
> better understanding the research community’s thoughts on the development
> of a standardized reef fish survey method.  You have been chosen as a
> participant in this survey because of your involvement in the field of
> reef fish assessments. To ensure that as much information is collected as
> possible, please feel free to forward this email to any colleagues
> conducting reef fish surveys.
>  The results of this survey will be presented at a symposium at Scripps
> Institution of Oceanography in June 2011, and will be posted online on
> the Center for Marine Conservation and Biodiversity website.
>  Thank you so much for your time, your contribution to this project is
> invaluable and will serve as a critical element in global reef surveying
> efforts.
>  To access the survey click on the link:
> https://qtrial.qualtrics.com/SE/?SID=SV_0kYyT0h4omX3SSg
> Zach Caldwell
> Masters Candidate
> Marine Biodiversity and Conservation
> Scripps Institution of Oceanography
> University of California, San Diego (UCSD)

Jerald S. Ault, Ph.D.
Professor of Marine Biology and Fisheries
Rosenstiel School of Marine and Atmospheric Science
University of Miami,  4600 Rickenbacker Causeway
Miami, FL 33149        jault at rsmas.miami.edu
(305)421-4884  ph      (305)421-4791  fax

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