Carrageenan yield and properties of Eucheuma uncinatum (Seth. & Gard.) Daw. cultured under natural conditions

Eucheuma uncinatum (Setch. & Gard.) Daw. from the Gulf of California was cultured in 1001 tanks in outdoor conditions. The cultures consisted of a 3 × 3 factorial design of 10, 19 and 33 % incident light and three different conditions of nutrients during winter (0; 20 µM N0₃; and 20:2 µM NO₃:PO₄) and summer (0; 40:4; and 80:8 µM of NO₃:PO₄). Best growth and carrageenan yield conditions were determined under each experiment. Carrageenan extracts were analyzed for total carbohydrates, 3,6-anhydrogalactose anhydrogalactose and sulphates. Higher carrageenan yields were obtained from cultures with fertilized plants under higher light conditions from winter and summer experiments although summer cultures provided the highest yields (48%). During summer a direct relationship between nutrients and sulfate content was observed. This effect was not observed in the winter experiment. An inverse carbohydrate: light relationship was observed in winter but not in summer. Maximum values of 3,6-anhydrogalactose in winter and summer were 23.9% and 18%, respectively. Results indicate that there is the potential to increase yield and quality of Eucheuma uncinatum carrageenan cultured under natural conditions.     

Agar properties of two species of Gracilariaceae from the Gulf of California,Mexico

Agar properties of two potentially commercial important seaweeds from the Gulf of California were studied. Maximum yield in Gracilaria vermiculophylla (45.7%) occurred during the summer months, coinciding with high water temperatures (31°C) whereas minimum yields (11.6%) were obtained during the coldest months of the year when populations of this species diminish in the bay. Gracilariopsis longissima showed two yield peaks, one in spring and another in fall, before the maximum and minimum seawater temperatures. Gel strength in native agar from the two species was low (<22.5 g cm⁻²) for most of the year. G. vermiculophylla native agar showed a slight increase in gel strength from June to August, which were the hottest months. Maximum value was 85 g cm⁻¹ in August. Maximum gel strength in G. longissima was observed in October (91 g cm⁻¹), and an unusual native agar with no detectable gel strength was observed in March and April samples. Gelling temperatures range from 27.7 to 36.5°C in G. vermiculophyla and from 26.6 to 34.9°C in G. longissima, meanwhile melting points were 73.9 – 53.5°C and 75.5 – 56.6°C, respectively. Sulfate content was high, 6.3–13.9% in G. vermiculophylla and 1.9–11.9% in G. longissima, and on the other hand 3,6 anhydrogalactose content was low 12.1–26.7% and 9.1–23%, respectively compared to other species. Results obtained showed that mean native agar yields of Gracilaria vermiculophylla and Gracilariopsis longissima from the Gulf of California are comparable to other tropical Gracilaria. However, the low gel strength, high sulfate content and low 3,6 anhydrogalactose content observed in the native agar extracted from these species make this an agaroid, thus alternative methods of extraction should be used to evaluate the possibility of commercial utilization of both species.     

Open water Chondrus crispus Stackhouse cultivation

Selected strains of Chondrus crispus were acclimated to relativelywarm Pacific waters off the Baja California peninsula, Mexico, and werecultured in semi-exposed oceanic conditions. Specific techniques weredeveloped for culturing this species in semi-exposed oceanic environment,in an effort to establish the basis for its commercial farming. This is the firsttime that Chondrus crispus has been cultured in the ocean and outsideits natural Atlantic environment. The information generated in this studyis being used to feed an economic model to test the feasibility of thecommercial culturing of Chondrus crispus.     

IN SITU GROWTH AND REPRODUCTION OF PORPHYRA PERFORATA IN THE PACIFIC COAST OF BAJA CALIFORNIA

The marine flora of Panama remains poorly described to date, having been described from a few sporadic and species poor (<50 species) collections in the early half of the century and a couple of dedicated surveys in the latter half. With the exception of a few studies that have focused on particular genera or species, only a single marine floral survey has been published in the past three decades. In 1999 we collected marine algae from nearly 100 different collection sites along both coasts of Panama over a 10 month period of time. Over 1500 specimens have been curated, representing 250 Caribbean species and 117 Pacific species. This is an increase in algal diversity of approximately 100 and 50% for the Caribbean and Pacific flora, respectively, relative to Earle's compilation of 1972. We estimate that algal diversity in Panama may approach 450 species as the remaining 30% of the collection is identified and previous records are incorporated. Aspects of biogeography will be discussed in light of such extraordinary diversity over a relatively confined region.     

Brown algae (Phaeophyta) from Bahía de los Angeles,Gulf of California,México

Seven sites in Bahía de los Angeles, northern Gulf of California, were sampled seasonally over a three-year period. Five species of brown algae previously not recorded from this bay were identified: Ralfsia pacifica, Sporochnus balleanus, Hydroclathrus clathratus, Colpomenia sinuosa and Padina mexicana. Of these, H. clathratus also provided a new record for the northern Gulf of California. One species previously recorded from the bay, Dictyopteris undulata, was not observed. On a seasonal basis, temperature and biodiversity showed an inverse relationship: highest species numbers occurred in spring, when temperatures were lowest, and lowest species numbers occurred in autumn when temperatures were highest. Most species of brown algae in Baífa de los Angeles are annuals.