The marine otter Lontra felina has been said to prefer wave-exposed habitats over more protected sites in response to a greater prey abundance in exposed habitat. We examined how the foraging activity of L. felina is affected by the regime of wave exposure and prey availability at Isla Choros, northern Chile. Through focal sampling we recorded time spent by otters in foraging, the duration of dives, and the hunting success on a wave-exposed and a wave-protected site on the island. In addition, we quantified the abundance of prey in both habitats. Marine otters spent more time foraging in the wave-protected site compared with the wave-exposed habitat. Successful dives reached 26.9% in the wave-exposed habitats, and 38.2% in the wave-protected habitat. Foraging dives were 18% shorter in wave-exposed as compared with wave-protected habitat. Numerically, available prey did not differ significantly with habitat. Our results are more consistent with the hypothesis that wave-exposed habitats represent a sub-optimal habitat to foraging marine otters. Marine otters' use of wave-exposed patches through northern and central Chile coastal areas probably reflects a low availability of suitable protected areas and greater human disturbance of more protected habitat.

Ciclo reproductivo y fecundidad parcial deAbstract.-This study analyses reproductive aspects of the fish Isacia conceptionis based on 280 females collected at La Herradura Bay, northern Chile, between April 1995 and March 1996, using histological analysis of the ovaries, measurement of gonadosomatic and gonadic indices and the batch fecundity. Five maturity stages for the ovary were described. Mature females were partial spawner because of simultaneous presence of oocytes at different maturity stages. The high frequency of mature females and high gonadosomatic and gonadic indices observed during austral winter and summer suggest two spawning seasons. The estimated batch fecundity (F) for total length (LT) was F = 0.0003LT 3.9701 and for total weight (PT) was F = 0.2255PT 1.1539 .