Panamic Grunt, Rhencus panamensis
Panamic Grunt, Rhencus panamensis, Juvenile. Fish caught within the coastal waters of Magdalena Bay, Baja California Sur, March 2017. Length: 16 cm (6.3 inches).
Panamic Grunt, Rhencus panamensis, Juvenile. Fish caught from coastal waters off Mazatlán, Sinaloa, October 2021. Length: 17 cm (6.7 inches). Catch, photograph and identification courtesy of Bart, The Netherlands (worldangler.eu).
Panamic Grunt, Rhencus panamensis, Juvenile. Fish caught from coastal waters off Mazatlán, Sinaloa, April 2013. Length: 17 cm (6.7 inches). Catch and photograph courtesy of George Brinkman, Guelph, Ontario, Canada.
Panamic Grunt, Rhencus panamensis. Fish provided by the commercial fishermen of Bahía Kino, Sonora, November 2014. Length: 27 cm (11 inches). Photograph courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.
The Panamic Grunt, Rhencus panamensis, is a member of the Grunt or Haemulidae Family, that is also known as the Highfin Grunt and is known in Mexico as roncacho mapache. Globally, there are two species in the genus Rhencus, both of which are found in Mexican waters of the Pacific Ocean.
The Panamic Grunt has an elongated oval body that are strongly compressed with a depth that is 40% to 42% of standard length. They have an overall silvery appearance with a prominent black blotch behind the upper edge of their gill cover and a series of short bars just under their dorsal fin. They have yellowish blotches on their anal and caudal fins, a yellow dorsal fin, and transparent pectoral and pelvic fins. Their head has a convex forehead and a mouth that reaches under the middle of the eyes and features thin lips. Their anal fin has 3 spines, the second being slender, and 7 or 8 rays; their dorsal fin has 12 spines, a deep notch, and 12 to 12 rays; and, their pectoral fins are very long reaching the anal fin base.
The Panamic Grunt is an inshore demersal species that are found over sandy substrate at depths up to 107 m (350 feet). They can also be found within rocky terrain and in mangroves within estuaries on a limited basis. They reach a maximum 39 cm (15 inches) length and 1.0 kg (2 lbs 3 oz) in weight. The Panamic Grunt is a relatively unknown species and is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Panamic Grunt is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from Magdalena Bay, Baja California Sur, northward along the central and northwest coasts of Baja.
The Panamic Grunt can be confused with the Longspine Grunt, Rhencus macracanthus (long thick second anal spine), the Purplemouth Grunt, Rhonciscus bayanus (elongated body; long thick second anal spine), and the Sand Grunt, Rhonciscus branickii (13 dorsal spines).
From a conservation perspective the Panamic Grunt is currently considered to be of Least Concern with stable, widely distributed populations. They are a fairly frequent by-catch of deep water shrimp trawlers in certain areas of the Tropical Eastern Pacific Ocean. They are small in stature to be of interest to most.