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Baja California represents the northernmost reproductive area for Lepidochelys olivacea. This region is characterized by its high temperature and low humidity. Thus, nest site selection plays an important role in reproductive success. To evaluate the factors affecting site selection for oviposition Las Barracas Beach, located in the south of the peninsula, was visited, from August to November 2000, in weekly periods. A density of 2.55 nests [ha.sup.-1] was estimated from a total of 55 nests counted. A hatching success of 73.7% was observed, with 23.7% mortality and 2.5% of eggs without apparent development (eggs counted = 4,031). On the day of oviposition, the relative surface humidity (between 0.75% and 1.75%) and temperature (32[degrees]C) preferred by the females for nest construction was determined at the nest site, as well as the mean distance between the nests and the high tide line for that day (17.65 m). Hatching success was affected by humidity and distance. In addition, hatching success was higher between 10 and 30 m above the high tide line measured on the day of oviposition (surface humidity ca. 1%). A total of 874 hatchlings were measured, with an average of 42.1 mm straight carapace length. Larger sizes were found in October and smaller ones in November. Generally speaking, the sizes found here were larger than those obtained in other areas. This is probably due to two factors: (1) the nests in Las Barracas were kept in situ, whereas in other areas nests are sometimes incubated artificially and (2) the nesting population of

Studies into the effects of light quality and photon-fluence rate (PFR) on the photosynthesis, biochemical composition and growth of the red alga Gelidium sesquipedale are described. Carbon molecules collect in the algae if low level PFR of white light (WL) is introduced because nutritional output from photosynthesis is sufficient. However, low PFRs of WL, blue light or red light cause carbon uptake for photosynthesis use. Other experimental observations are given.

Examines the photosynthetic acclimation and biochemical responses of Gelidium sesquipedal cultured in chemostats. Effect of the quality of light and photon-fluence rate; Indications of the changes in C-partitioning between carbon compounds and organic nitrogen compounds; Mobilization and accumulation of carbon in the algae.