Life-history traits of the invasive fish Gambusia ­holbrooki in saline streams (SE Iberian Peninsula): Does salinity limit its invasive success?

Abstract

Knowledge of the adaptive ability of the highly invasive fish Gambusia holbrooki to new habitats is essential for determining its invasion potential. Our main objective was to assess the life-history of G. holbrooki in saline streams by studying its abundance, size and age structure, growth and condition. Two populations inhabiting similar streams of different salinity in the southeastern Iberian Peninsula were monitored over a 2 yr period. In both populations, the lifehistory of the species was characterized by a short life span, a long recruitment period with a massive emergence of young-of-the-year and fast growth of individuals during the first months of their lives. The species showed a less intense recruitment (6.9% of juveniles vs. 46.4% during the recruitment period) and an earlier end of the recruitment period (at least 2 mo) in the hypersaline system, although abundance, hepatic condition and female somatic condition were higher. In addition, temporary increases in salinity diminished population abundance, recruitment, and somatic and hepatic condition. Both populations showed similar seasonal abundance variation patterns, population structures, growth rates, and somatic and hepatic condition cycles. Other environmental factors independent of salinity could have influenced the differentiation in lifehistory of the species between populations, thus disguising direct relationships between salinity and life-history. However, the studied parameters show that G. holbrooki presents a great ability to adapt to lotic systems with high and different levels of salinity. KEY WORDS: Gambusia holbrooki · Invasive success · Salinity · Population dynamics · Growth · ConditionResale or republication not permitted without written consent of the publisher

Trophic overlap between cohabiting populations of invasive mosquitofish and an endangered toothcarp at changing salinity conditions

“…Among others, its tolerance to high temperature, acid and basic pH, or low dissolved oxygen (Homski et al 1994, Pyke 2008 can be highlighted. Mosquitofish is also able to survive a wide range of salinities (Purcell et al 2008), and even established mosquitofish populations have been de scribed in eusaline and hypersaline waters (Alcaraz & García-Berthou 2007a, Ruiz-Navarro et al 2011, 2013. However, salinity is one of the most stressful factors in the viability of mosquitofish populations, and the disrupting effects of salinity on the species' biology have been described (Alcaraz & García-Berthou 2007a, Ruiz-Navarro et al 2013).…”

Diferencias morfométricas de Gambusia holbrooki (Pisce: Poeciliidae) que habitan en los estanques de regadío de los valles de Lluta y Azapa, Chile

“…Los datos obtenidos para caracterizar morfológicamente los ejemplares capturados en ambos ríos demuestran que, independiente del lugar de origen, el marcado dimorfismo sexual que ostenta Gambusia holbrooki se mantiene inalterable, es decir, las hembras son más grandes que los machos (Figura 1), lo que coincide con lo informado por Pyke (2005) en una revisión que hace a la biología de G. holbrooki; de igual forma nuestro estudio concuerda con los tamaños máximos que puede alcanzar esta especie (Ruiz-Navarro et al, 2011).…”

“…El éxito en la colonización de los sistemas acuáticos de este pez se debió a las características climáticas de la Región de Arica y Parinacota que favorece la sobrevivencia de G. holbrooki, por otro lado también es un ambiente ideal para la proliferación del mosquito Anopheles pseudopunctipennis portador de la malaria, por lo que en 1937 se adoptaron medidas para erradicar al estado acuático-larval del insecto (por ende la malaria), lo que incluyó la diseminación de Gambusia holbrooki en los ríos Lluta y San José (Neghme et al, 1947). Por las características predatorias del pez, este fue utilizado como agente biológico controlador de poblaciones de mosquito, no tan solo en Chile sino que en gran parte del mundo, por tal motivo G. holbrooki está prácticamente presente en todos los sistemas límnicos del mundo (Pyke, 2005;Oriol et al, 2012), de hecho se considera como el pez dulceacuícola de mayor abundancia y con rangos de distribución más amplios del planeta, por su plasticidad biológica, capaz de soportar condiciones ambientales altamente estresantes, con registros de poblaciones de G. holbrooki en ambientes salinos de 45 g/l (Pyke, 2005;Ruiz-Navarro et al, 2011).…”

Temporal variations in abundance and biomass of fish species inhabiting the K’sob reservoir (Eastern of Algeria)

“…G. holbrooki presents a clear ability to adapt to lotic systems (Ruiz-Navarro et al, 2011), and it is used in the biological control of mosquitoes. The common carp and bighead carp constitute the majority of the fish biomass in these systems (more than 85%).…”