Presence of Hippocampus patagonicus (Syngnathiformes: Syngnrathidae) in the external estuary of the Negro River, Río Negro Province, Argentina

Abstract

he order Syngnathiformes includes pipefishes and seahorses, with Hi-
ppocampus being the only genus comprising the latter. They exhibit a
global distribution across tropical and temperate regions. Seahorses
face multiple anthropogenic threats, which have led many species to
be classified as Vulnerable by the IUCN. This study reports the presence
of Hippocampus patagonicus in the outer estuary of the Negro River,
Argentina. A stranded female specimen of H. patagonicus was docu-
mented on the coast of the outer Negro River estuary. As the specimen
was incomplete, only the following morphometric measurements were
recorded: trunk length, dorsal fin base length, pectoral fin base length,
head length, snout length, postorbital distance, and orbital distance.
The meristic characters used included: number of trunk rings, number
of anal fin rays, number of pectoral fin rays, and number of dorsal fin
rays. Based on the morphometric values obtained, the specimen was
identified as a small-sized female. This record is significant given the
species’ vulnerable status and the fact that the population in San An-
tonio Bay has declined by approximately 90% over the past 30 years.
Furthermore, it is essential to intensify research efforts in the area to
determine whether this finding represents an isolated occurrence or
evidence of an established population within the study site.