Life History of the Mottled Scorpionfish, Pontinus clemensi, in the Galapagos Marine Reserve
The Mottled Scorpionfish (Pontinus clemensi) is an ecologically and economically important species endemic to the Eastern Tropical Pacific. Despite its importance, little is known about its life history traits. In order to close this knowledge gap, we analyzed otoliths and gonads to describe age and reproduction, fit the von Bertalanffy, logistic, and Gompertz growth models, and selected the most parsimonious model using Akaike Information Criterion. We collected 420 samples from fishing trips throughout the archipelago and fish landed at Pelican Bay dock in Santa Cruz Island from 2013–2015. Fork length of fish ranged from 19–67 cm, with males being significantly larger than females, age ranged from 9 to 17 years (n = 203), with similar ranges for both genders, and the logistic model was the most parsimonious growth model (k5 = 0.46 in males, 0.28 in females, 0.31 for the species). Spawning-capable females were observed in all months, suggesting fish can reproduce year round, with size at first maturity (L90) occurring at 33.6 cm or 11.8 years for females, and 43.4 cm or 13.7 years for males. Our results suggest that, similarly to other species in this family, P. clemensi is a slow-growing fish that begins reproducing later in life. Considering P. clemensi represents an important resource, a management plan should be urgently introduced to ensure a sustainable fishery and the survival of the population.
Sampling locations for adult Pontinus clemensi collected from 2013–2015 in the Galapagos Marine Reserve.
Relative frequency distribution of female and male adult Pontinus clemensi collected from May 2014 to August 2015 in the Galapagos Marine Reserve. Size classes (fork length) represent 5 cm bin sizes.
Relation between length and age for adult Pontinus clemensi collected from May 2014 to August 2015 in the Galapagos Marine Reserve. Three growth model curves are also presented.
Photomicrographs (40 and 100X) of gonad cross sections of female Pontinus clemensi collected in the Galapagos Marine Reserve from May 2014 to August 2015. (A) Immature 27 cm fork length (FL) individual collected in December 2014. (B) Developing 36 cm FL individual collected in September 2014. (C) Spawning-capable 42 cm FL individual collected in December 2014. (D) Regressing 40 cm FL individual collected in August 2014. (E) Regenerating 31 cm FL individual collected in September 2014. A = Atresia; CA = Cortical alveolar; MB = Muscle band; PG = Primary growth; POF = Postovulatory follicles; Vtg1,2,3 = Vitellogenic stage 1,2,3. Scale bar = 0.1 mm (A, B, and D, 40X) and 0.01 mm (C and E, 100X). See description of stages in Table 3.
Proportion of developmental stages of female Pontinus clemensi by month. Individuals (n = 117) were collected in the Galapagos Marine Reserve between August 2014 and June 2015. Only two individuals were collected in July 2015, one in August 2015, and none in February and March 2015, and were therefore not presented.
Monthly average Gonadosomatic Index values (±SD) for female and male Pontinus clemensi collected in the Galapagos Marine Reserve from July 2014 to August 2015.
Size (A and C) and age (B and D) at first maturity for female (top) and male (bottom) Pontinus clemensi collected in the Galapagos Marine Reserve between May 2014 and August 2015. Size and age are defined as L90, or the value at which 90% of the population are mature.
Contributor Notes
Associate Editor: M. T. Craig.