Figure 4 illustrates the distribution of all fish as observed with the acoustic integration system. The unit of fish abundance is 0.1 m2 per nm2 acoustic reflection and the categories of abundance are the same as those used in the previous reports.
Guatemala.
The pattern of distribution is similar to that found during the previous surveys with acoustic detection of fish almost wholly limited to a band along the coast. The dominating species were bumper (Chloroscombrus), barracuda (Sphyraena), threadfin herring (Opistonema), lookdown (Selene), anchovies and various smallsized bottomfish (Haemulopsis, Orthopristis, Peprilus)
Golfo de Tehuantepec, Mexico.
As shown in Figure 4 the inshore belt of pelagic fish along the Guatemalan coast continues along the Tehuantepec Gulf coast unto about 94° W, when the density drops considerably. The dominating pelagic species were anchovy, bumper, threadfin herring and barracudas, and among the demersal fish butterfish and grunts. Several patches of relative high densities were registrated along the coast. They all originate from small pelagic fish, except the aggregation off Salina Cruz, which consist of catfish only.
