299
9 Studying and Monitoring Aggregating Species
have used conventional anchor type tags to assess site fi delity, movement between
aggregations and home ranges for groupers (Colin 1992 ; Luckhurst 1998 ; Nemeth
2005 ; Starr et al. 2007 ) and snappers. Interestingly, the two longest distance migration records for Nassau grouper, Epinephelus striatus, (250 and 220 km) were the
result of fortuitous recovery (when captured fi sh were cleaned) of implanted acoustic
tags (Carter 1994 ; Bolden 2000 ) . This is not surprising since external tags often
only last for a few months before being lost (Shapiro et al. 1994 ) . There are numerous
considerations with regard to conventional tagging to increase tag retention and
readability. Ideally external tags can have some type of numbering or coding system,
such as specifi c placement on the body, which can be deciphered by a diver seeing
a fi sh, so its presence can be noted without capturing it inside or outside of aggregations. Freeze branding is one method that holds promise for quickly tagging fi sh
at an aggregation site for easy visibility by divers (Koenig and Coleman 1998 ) .
Nemeth (Chap. 2 ) includes additional information about considerations for conventional tagging studies. It is extremely important that a campaign to notify and inform
fi shing communities and to encourage/reward returns is extensively conducted in
relation to tagging projects.
TN – Traditional Knowledge Through Interviews
Nearly all spawning aggregations have been discovered by fi shers and in many
communities fi shers continue to acquire increasingly detailed knowledge of aggregation timing and locations. Fishers, particularly older individuals generally referred
to as “patriarch” fi shers, have a wealth of information and many are willing to share
it, especially so it will not be lost when they pass away. A protocol for conducting
fi sher interviews was described by Johannes ( 1981 ) and adapted by others (Hamilton
2005 ) in which questions are asked in a manner that helps to produce accurate
responses comparable to information gathered from other individuals and locations.
Efforts are often made to also validate such information. Chapter 10 in this volume
includes more detailed information on the use of traditional knowledge (Local
Ecological Knowledge or LEK) of spawning aggregations and the importance of
this approach for other types of information exchange as well as its challenges
and limitations.
TS – Tape and Compass Survey
This crude method is sometimes the only alternative for producing maps showing
the general relationships of features and habitats and for calculating area in a
spawning aggregation. Distance and bearing between chosen points at the site are
determined with measuring tape and a hand bearing compass and recorded on
underwater slates (Fig. 9.4a ). Any features along the survey line, such as the reefsand interface, are sketched relative to the survey line (Fig. 9.4b ) and this information is later used to prepare a rough map an area and plot the relationship of objects
(Fig. 9.4c ). It is useful in areas where bottom features are not visible in aerial or
satellite photos and can allow mapping of home ranges of fi shes and determining
the outer limits of aggregation sites. The method is discussed in more detail in
Colin et al. ( 2003 ) .
9 Studying and Monitoring Aggregating Species
have used conventional anchor type tags to assess site fi delity, movement between
aggregations and home ranges for groupers (Colin 1992 ; Luckhurst 1998 ; Nemeth
2005 ; Starr et al. 2007 ) and snappers. Interestingly, the two longest distance migration records for Nassau grouper, Epinephelus striatus, (250 and 220 km) were the
result of fortuitous recovery (when captured fi sh were cleaned) of implanted acoustic
tags (Carter 1994 ; Bolden 2000 ) . This is not surprising since external tags often
only last for a few months before being lost (Shapiro et al. 1994 ) . There are numerous
considerations with regard to conventional tagging to increase tag retention and
readability. Ideally external tags can have some type of numbering or coding system,
such as specifi c placement on the body, which can be deciphered by a diver seeing
a fi sh, so its presence can be noted without capturing it inside or outside of aggregations. Freeze branding is one method that holds promise for quickly tagging fi sh
at an aggregation site for easy visibility by divers (Koenig and Coleman 1998 ) .
Nemeth (Chap. 2 ) includes additional information about considerations for conventional tagging studies. It is extremely important that a campaign to notify and inform
fi shing communities and to encourage/reward returns is extensively conducted in
relation to tagging projects.
TN – Traditional Knowledge Through Interviews
Nearly all spawning aggregations have been discovered by fi shers and in many
communities fi shers continue to acquire increasingly detailed knowledge of aggregation timing and locations. Fishers, particularly older individuals generally referred
to as “patriarch” fi shers, have a wealth of information and many are willing to share
it, especially so it will not be lost when they pass away. A protocol for conducting
fi sher interviews was described by Johannes ( 1981 ) and adapted by others (Hamilton
2005 ) in which questions are asked in a manner that helps to produce accurate
responses comparable to information gathered from other individuals and locations.
Efforts are often made to also validate such information. Chapter 10 in this volume
includes more detailed information on the use of traditional knowledge (Local
Ecological Knowledge or LEK) of spawning aggregations and the importance of
this approach for other types of information exchange as well as its challenges
and limitations.
TS – Tape and Compass Survey
This crude method is sometimes the only alternative for producing maps showing
the general relationships of features and habitats and for calculating area in a
spawning aggregation. Distance and bearing between chosen points at the site are
determined with measuring tape and a hand bearing compass and recorded on
underwater slates (Fig. 9.4a ). Any features along the survey line, such as the reefsand interface, are sketched relative to the survey line (Fig. 9.4b ) and this information is later used to prepare a rough map an area and plot the relationship of objects
(Fig. 9.4c ). It is useful in areas where bottom features are not visible in aerial or
satellite photos and can allow mapping of home ranges of fi shes and determining
the outer limits of aggregation sites. The method is discussed in more detail in
Colin et al. ( 2003 ) .