286
P.L. Colin
9.1 Introduction
As a biological and oceanographic phenomenon, spawning aggregations provide a
window into the natural complexity of the processes that maintain populations.
Their study and monitoring normally requires fi eldwork and involves a wide variety
of physical and biological methods. This chapter is not a complete guide on how to
study fi sh spawning aggregations, but is intended as a summary of some methods
that have been used, recently developed methods (since 2003) and what might be
done in the future. The SCRFA (Society for the Conservation of Reef Fish
Aggregations) Methods Manual (Colin et al. 2003 ) , available online at www.
SCRFA.org , is supplementary, more comprehensive for some techniques and is
to be updated at regular intervals. This chapter touches on the challenges of
studying aggregations and highlights the need to better understand and properly
monitor them.
Once the existence of a spawning aggregation is established (and even this seemingly
simple task requires a strictly applied methodology) the type of information desired
about the aggregation varies with its intended use. Academic scientists may be
interested in “hard” data to address questions such as ‘how and why’ while the
management and conservation community may focus solely on obtaining information that tells them the status of aggregating fi shes, changes over time, and how to
reverse negative trends in exploited populations. Monitoring is important and needed
to assess the impact of management, yet like establishing the existence of aggregations, the meaningful monitoring of large temporary gatherings of fi sh can often be
a major challenge.
Once the information needs are identifi ed, the appropriate methods can be
selected. Choosing the wrong method often results in dubious and inconsistent data while losing the opportunity to establish baselines and squandering
resources. Careful selection of what is possible (and what is not) will hopefully
result in information and results that are accurate, repeatable and informative.
Standardization of methods will allow comparison of aggregations across geographic areas or of those examined by different workers over time. This has often
been lacking in the past, but SCRFA has been diligent (with some success) in
encouraging researchers to use consistent methods. Comparability of information
is improving.
Work on spawning aggregations is still largely in the “discovery phase”, in places
where these phenomena are just beginning to become known. For a number of species
and aggregation sites, knowledge has advanced to the point that more rigorous
scientifi c investigations can now be undertaken. This requires collection of accurate
data using suitable methods so the results from individual and geographically separate
sites are comparable over time. Aggregations have usually been discovered by
fi shers, followed in some cases by site visits by biologists for confi rmation of aggregation existence as well as basic data acquisition. This still continues, particularly
to validate traditional ecological knowledge (Chap. 10 ). Sites are beginning to be
P.L. Colin
9.1 Introduction
As a biological and oceanographic phenomenon, spawning aggregations provide a
window into the natural complexity of the processes that maintain populations.
Their study and monitoring normally requires fi eldwork and involves a wide variety
of physical and biological methods. This chapter is not a complete guide on how to
study fi sh spawning aggregations, but is intended as a summary of some methods
that have been used, recently developed methods (since 2003) and what might be
done in the future. The SCRFA (Society for the Conservation of Reef Fish
Aggregations) Methods Manual (Colin et al. 2003 ) , available online at www.
SCRFA.org , is supplementary, more comprehensive for some techniques and is
to be updated at regular intervals. This chapter touches on the challenges of
studying aggregations and highlights the need to better understand and properly
monitor them.
Once the existence of a spawning aggregation is established (and even this seemingly
simple task requires a strictly applied methodology) the type of information desired
about the aggregation varies with its intended use. Academic scientists may be
interested in “hard” data to address questions such as ‘how and why’ while the
management and conservation community may focus solely on obtaining information that tells them the status of aggregating fi shes, changes over time, and how to
reverse negative trends in exploited populations. Monitoring is important and needed
to assess the impact of management, yet like establishing the existence of aggregations, the meaningful monitoring of large temporary gatherings of fi sh can often be
a major challenge.
Once the information needs are identifi ed, the appropriate methods can be
selected. Choosing the wrong method often results in dubious and inconsistent data while losing the opportunity to establish baselines and squandering
resources. Careful selection of what is possible (and what is not) will hopefully
result in information and results that are accurate, repeatable and informative.
Standardization of methods will allow comparison of aggregations across geographic areas or of those examined by different workers over time. This has often
been lacking in the past, but SCRFA has been diligent (with some success) in
encouraging researchers to use consistent methods. Comparability of information
is improving.
Work on spawning aggregations is still largely in the “discovery phase”, in places
where these phenomena are just beginning to become known. For a number of species
and aggregation sites, knowledge has advanced to the point that more rigorous
scientifi c investigations can now be undertaken. This requires collection of accurate
data using suitable methods so the results from individual and geographically separate
sites are comparable over time. Aggregations have usually been discovered by
fi shers, followed in some cases by site visits by biologists for confi rmation of aggregation existence as well as basic data acquisition. This still continues, particularly
to validate traditional ecological knowledge (Chap. 10 ). Sites are beginning to be