Fish Markets
Noting the catch at fish markets can be a free and easy way to get valuable spawning aggregation information. Photo © K. Warren-Rhodes
Where markets are available, periodic visits can provide free and easy information on spawning times for individual species. Information about spawning times, species and even FSA sites may be gathered from fish markets by looking at the fish, talking to the marketers or interviewing the fishers selling their catch1. For example, in many instances, when aggregation fishing is occurring, markets are saturated with gravid (egg-bearing) fish. Gravid individuals are recognized by swollen bellies, and generally have milt or eggs apparent to the naked eye. Just prior to spawning, extrusion of eggs or milt is possible by applying light pressure to the abdomen.
Markets also provide a good forum to talk to fishers and market owners. Market owners are often quite knowledgeable of fish life history and fisher habits. Be sure to ask when examinations of fish require handling, including gonads, since these are often sold separate from the fish and may even fetch higher prices than the fish itself.
Where there is a live reef-food fish operation, sudden increases in the number of fishes of a single species within holding pens, or in export statistics, could signify increased catches from fishing on active spawning aggregations. Remember to always ask permission from market owners or fishers before handling their fish.
Talking to fishers at the market in Micronesia. Photo © K. Warren-Rhodes
Whole fishes being cleaned and gutted at the market, or at the catch site, provide an excellent opportunity to examine and weigh gonads, and assess whether reproductive activity seems imminent within the adult population. It should be noted, however, that spawning seasons can vary within an area or region even for individual species. To ensure that management is effective, it is imperative to connect the spawning season to the individual FSA site(s) and species.
Resources
1 Rhodes et al. 2008