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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Investigations of the Ichthyofauna of Nicaraguan Lakes Papers in the Biological Sciences 1976 Relative Abundance and Distribution of the Mojarra (Cichlasoma citrinellum) in Lake Nicaragua Sergio Martínez C Instituto de Fomento Nacional Follow this and additional works at: https://digitalcommons.unl.edu/ichthynicar Part of the Aquaculture and Fisheries Commons Martínez C, Sergio, "Relative Abundance and Distribution of the Mojarra (Cichlasoma citrinellum) in Lake Nicaragua" (1976). Investigations of the Ichthyofauna of Nicaraguan Lakes. 25. https://digitalcommons.unl.edu/ichthynicar/25 This Article is brought to you for free and open access by the Papers in the Biological Sciences at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Investigations of the Ichthyofauna of Nicaraguan Lakes by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in INVESTIGATIONS OF THE ICHTHYOFAUNA OF NICARAGUAN LAKES, ed. Thomas B. Thorson (University of Nebraska-Lincoln, 1976). Copyright © 1976 School of Life Sciences, University of Nebraska-Lincoln. Relative Abundance and Distribution of the Mojarra (Cichlasoma citrinellum) in Lake Nicaragua Sergio Martinez C. INTRODUCTION location longer than 24 hours and were re-set every SIX Sixteen families and at least forty-five species of fishes hours. have been reported from Lake Nicaragua (Astorqui, 1971; Villa, 1971). The National Development Institute of RESULTS Nicaragua (INFONAC) has investigated the potential fish resources and their distribution in the lake in order to im­ During the trawl operations 12 species were caught plement a program of development and a rational man­ (Table 1), of which C. citrinellum made up 8.7% of the total agement of the fisheries of the lake (INFONAC, 1974). The weight. Sabalete (Dorosoma chaves i) , was the most abundant study at hand was conducted in connection with that inves­ species (Fig. 2) and was distributed almost uniformly in the tigation to define the abundance and natural habitat of the lake. Besides D. chavesi three other species were also more mojarra, Cichlasoma citrinellum. This fish belongs to the fam­ abundant than C. citrinellum: Rhamdia sp., C. nicaraguense ily Cichlidae, which is represented in the lake by several and C. longimanus. Rhamdia sp. and C. nicaraguense were species. found, especially at great depths, in the central zone, while Cichlasoma citrinellum exhibits great intraspecific variabil­ C. longimanus was more abundant in the coastal zone at ity in color and in certain morphological features. The au­ depths of l'i'2 to 5 fathoms. C. citrinellum was present in thor is aware of the difficulties of field identification of the higher frequencies in shallow waters and in areas near the species and its separation from closely allied forms, espe­ coast and was not found in large numbers in the central cially C. labia tum (see Astorqui, 1971; Villa, 1971, 1976; zone. Barlow and Munsey, 1976). He is confident of his identifi­ In Fig. 3 we can observe the distribution of C. citrinellum cations and, in view of conflicting advice, chooses to treat as determined from trawling. Area B, which corresponds to his collected specimens as belonging to the single species, C. the north and northeast coast of the lake, is the most exten­ citrinellum. The major features of the natural history of this sive. Here the bottom is muddy, with some rocky promon­ species have been presented by Barlow (1976) in a study tories. This zone is well protected from the winds that gen­ based on populations living in the crater lakes, not the erally blow from the northeast throughout the year. Zones Great Lakes. C, E and H have similar ecological characteristics; all of them have muddy bottoms and lie near the rocky outcrop­ pings that form the islands of San Bernardo, Mancarron METHODS and Zapatera, respectively. With respect to depth, C. citrinellum was present in high The data were obtained from exploratory fishing cruises percentages in areas from l'i'2 to 5 fathoms. In Fig. 4 we see of the INFONAC vessel, MIN Gaspar. Two types of areas how this factor influences the species' distribution. As the were sam pled in the lake, the central zone, with depths grea t­ depth increases, abundance declines notably, whereas other er than l'i'2 fathoms, and the coastal zone, with depths less patterns are shown by C. nicaraguense and Rhamdia sp. It is than l'i'2 fathoms. presumed that depth is a factor limiting the distribution of In the central zone a 45-ft trawl net of two-inch this species in the lake. (stretched) mesh was used. The trawl was towed at a speed The mojarra catches in the southeast end of the lake were of two knots for a period of 30 minutes. During the study relatively low, but C. longimanus was abundant there. This 94 stations were sampled. They were separated from each other by a distance of five nautical miles (Fig. 1). To obtain the relative abundance of each species, the catch was placed TABLE 1. Species taken in trawls. in 40-lb baskets. One basket was taken as a representative Common name Scientific name Family sample and the rest were discarded. The total catch was Sabalete Dorosoma chavesi Clupeidae determined by multiplying L le number of baskets by the Pimelodidae weight of the representative sample. The species contained Bagre, chulin Rhamdia sp. Moga Cichlasoma nicaraguense Cichlidae in the sample were sorted and weighed to obtain their re­ Carate C. longimanus spective percentages. The apparent distribution of C. cit­ Mojarra C. citrinellum rinellum was determined by plotting the areas of the lake Mojarrita C. centrarchus where the sample percentage was greater than the calcu­ Pica culo N eetroplus nematopus lated average percentage for all stations sampled. Guavina Gobiomorus dormitor Eleotridae In the coastal zone, floating monofilament and multifil­ Sabalito Roeboides guatemalensis Characidae ament gill nets were used. The nets were 50 by 1.6 m and Sabalito Bramocharax bransfordi Characidae had a mesh of 2'i'2, 3'i'2 or 4'i'2 in. The nets were never in one Sabalito Astyanax sp. Characidae 371 MARTINEZ 12°00'----------~--------------.--------------.---------------.--------------~ 10 0 10 20 30 I I KILOMETERS I 5 0 5 10 NAUTICAL MILES 11°001----------+----------.; FIG. L Map of Lake Nicaragua indicating the route of the MIN Gaspar (arrows), collecting stations (closed circles), and stations not reached (triangles). could signify interspecific competition, but a more detailed study must be done to affirm this. TABLE 2. Species taken in gill nets. In the coastal zone, C. citrinellum was common in every Common name Scientific name Family area investigated by gill netting, representing 23.6% of the Gaspar Lepisosteus tropicus Lepisosteidae total number of collected specimens. The gill net stations Guapote Cichlasoma managuense Cichlidae are listed in Fig. 5, along with the number of collected Mojarra Cichlasoma citrinellum Cichlidae specimens from each location. The largest catches of mo- Machaca Brycon guatemalensis Characidae jarras were from the Solentiname Islands. They were found R6balo Centropomus parallelus Centropomidae mainly over rocky bottoms and in areas with floating plants Roncador Pomadasys grandis Pomadasydae such as water hyacinth (Eichornia sp.) Sabalo real Megalops atlanticus Elopidae Seven other species taken by gill net in the coastal zone Pez sierra Pristis perotteti Pristidae are listed in Table 2. 372 I U20 A. DOROSOMA CHAVESI ~ I 8 RHAMDIA SP. U u -.J ~ C. CICHLASOMA NICARAGUENSE D. CICHLASOMA LONGIMANUS ~ 15 ~40 E. CICHLASOMA CITRINELLUM ~ g F. CICHLASOMA CENTRARCHUS l.L G. ROEBOIDES GUATEMALENSIS 0 10 ~20 H. GOBIQMORUS DORMITOR w l? e 0 1 BRAMOCHARAX BRANSFORDI w t:! / J. OTHER SPECIES z e l? w 5 ~ 10 u / z ~ e-e _e_e_e w w u CL ~ W 0 CL A 8 C D E F G H J It-2 2t-5 5t-7t 8+ SPECIES DEPTH (fathoms) FIG. 2. Percentage of total catch, represented by species, taken in FIG. 4. Relation between depth and relative abundance of Cich­ trawls in the central zone of the lake. lasoma citrinellum (solid line) compared with C. nicaraguense (broken line) and Rhamdia sp. (dots and dashes). 10 o 10 20 30 I f KIlOMETERS 5 o I 5 10 NAUTiCAL MILES FIG. 3. Distribution of the mojarra, Cichlasoma citrinellum, determine d by trawling. Hatching indicates areas in which their concentration was greater than 8.7% of the total catch, by weight. 373 MARTINEZ 10 0 10 20 30 fuSS\! &\\\\1 KILOMETERS 5 0 5 10 iii i @ NAUTICAL MILES o Zapatera @~ 801s(05 ~ Sapo6 "''t-;;:~ t47'-=-Morrillo ~:"Q- ~-~ =-_~I/{) L So lep!i.{la me (5)C o~ 3 Boca Ancha 850 00'1 EIR~ FIG. 5. Gill net stations. Numbers encircled are the number of specimens of Cichlasoma citrinellum taken at each location. ACKNOWLEDGMENT poblaciones locales concentradas. La especie prefiere fon­ dos rocosos, que Ie ofrecen las mejores condiciones para su I wish to express my appreciation to Father Ignacio As­ comportamiento reproductor. Ocasionalmente tambien torqui, S. j., for his valuable contribution to the completion habitan areas de fondo lodoso con plantas acuaticas cerca of this study. de la superficie. Prefiere profundidades menores de 5 brazas y, especialmente, areas cercanas a islas 0 promon­ SUMMARY torios rocosos a menos de 1.5 brazas. Su abundancia relativa The mojarra (Cichlasoma citrinellum) is found inhabiting promedio fue del 8.7%, por peso del muestreo total, en las mainly the north and northeast coasts of Lake Nicaragua, estaciones de arrastre en la zona central del Lago. En la areas to the south of Ometepe and Zapatera Islands and to zona coster a, donde se colecto con red de agalla, represento the west of the Solentiname Islands. Small local concentra­ en promedio el 23.6% del total de los especimenes colec­ tions are found near San Bernardo Island and elsewhere.

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