'%Healthy Reefs for Healthy People - A Guide to Indicators of Reef Health and Social Well-being in the Mesoamerican Reef Region%'%by Melanie McField and Patricia Kramer%

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FI SH REC RUI T MEN T

What

What Is It?

BENCHMARK

Fish recruitment can be defined in two ways:

To be developed.

· One definition refers to the number of young-of-year

fish entering a population in a given year.

TA R G E T

· The second definition refers to the size at which a

To be developed.

fish can be legally caught, or the size at which a fish

becomes susceptible to a particular fishing gear.

RED FL AG

Why Do We Measure It?

Why

To be developed.

Fish recruitment can indicate the status of a fish

population, especially for important commercial

species like snappers and groupers. It can also be

an indicator of overfishing (when the average size

data are available on the Project website. Few other

declines and/or all of the larger fish are missing).

data are available although a large research effort is

underway (details under Data Needs).

Fish populations are influenced by the source of larvae

Data Needs

Data

and can be larvae-limited, particularly if adult fish

populations have declined, if connectivity between

Several research programs are currently underway

populations has been disrupted, or if nursery areas

that will help to fill the gaps in our understanding of

have been degraded or lost.

the status of fish recruitment in the region and will

In other words, recruitment data will reflect the

help further develop this indicator. Notably, the GEF

influence of many different processes.

Coral Reef Targeted Research and Capacity Building

(CRTR) Program has a component on Large-Scale

How

How Do We Measure It?

Ecological Processes, Recruitment and Connectivity,

chaired by Peter Sale, University of Windsor, Canada,

Fish recruitment can be monitored by setting special

which is conducting research on fish recruitment

traps, such as fish larvae light traps.

within the region11,12.

Recruitment can also be expressed in terms of

juvenile abundances, from counts taken along one-

meter-wide belt transects. These transects can be

the same ones used for adult fish, as detailed in

the MBRS Synoptic Monitoring protocol8. Taxonomic

distinctions in juvenile fish are difficult. Thus, a small

subset of species is counted in the MBRS protocol,

with variable maximum sizes for each species recruits

(2 - 5 cm)8.

Usefulness

To be determined. A high degree of training and

technical expertise are required to identify fish recruits

accurately.

Status

Baseline data for fish recruitment were collected under

the MBRS Project´s Synoptic Monitoring Program at 43

monitoring sites throughout the MBRS region. These