[Coral-List] Assessing reef health through fish ID

John McManus jmcmanus at rsmas.miami.edu
Tue Mar 17 12:41:52 EDT 2015

Most people use bottom organisms as the primary indicators of reef health,
often with extra information on certain large fish, or on numbers of small
vs large individuals among species, as indicators of overfishing. However,
if you are focused primarily on fish, one good choice is butterflyfish.
These are fairly easy to identify to species level. Some are highly
dependent on corals. In the 80's and 90's, Ernie Reese and students at the
University of Hawaii, including Tom Hourigan, did great work on relating
butterflyfish to coral reef health. The  abundances by species and their
behaviors are informative, including levels of aggressiveness, feeding
rates, and home ranges. This work, including observer training information,
were nicely summarized in the following manual:
A Manual for Monitoring Coral Reefs with Indicator Species: Butterflyfishes
as Indicators of Change on Indo-Pacific Reefs, by Michael P. Crosby, Ph.D.
and Ernst S. Reese, Ph.D. (1996).
I just found it online at:

I would still be concerned about ratios of juvenile to adult fish among all
species associated with fishing, as these are very useful in identifying
overfishing -- particularly in comparing sites. The Atlantic-oriented AGRRA
methodology includes this (http://www.agrra.org/), though the species in
your area will be much different.   

Good luck!


John W. McManus, PhD
Director, National Center for Coral Reef Research (NCORE)
Professor, Marine Biology and Ecology
Coral Reef Ecology and Management Lab (CREM Lab)
Rosenstiel School of Marine and Atmospheric Science (RSMAS)
University of Miami, 4600 Rickenbacker Causeway, Miami, 33149
jmcmanus at rsmas.miami.edu      http://ncore.rsmas.miami.edu/

"If you lose a diamond ring in the bedroom, don't look for it in the living
room just because the light there is better".

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Gus Fordyce
Sent: Tuesday, March 17, 2015 5:18 AM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Assessing reef health through fish ID

Dear coral-listers,

I'm about to start a position in Mozambique as scientific coordinator for a
marine conservation volunteer program, and could use some guidance. One of
my key roles upon arriving out there will be to design a fish ID training
program that will standardize the way volunteers collect data on species
abundances and locations, all with the aim of assessing the changing health
of the reefs without introducing volunteer bias.

What species (or even taxa) are sensitive to changes in reef health and so
can be a good measure of the health of the reef? My immediate thought was to
look near the top end of the food chain, but I also want volunteers to have
a good chance of seeing them so we can build a large dataset and they can
have a good time!

Advice on successful training techniques would also be helpful.
Any and all help is much appreciated,

Gus Fordyce

MSci Biology student
University of Bristol
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