Evaluation of the beds of Macrocystis pyrifera (Phaeophyta, Laminariales) in the Baja California Peninsula, Mexico. III. Summer 1986 and seasonal variation

Abstract

The beds of Macrocystis pyrifera (L.) C. Agardh of the west coast of the Baja California peninsula were assessed during the summer of 1986, employing aerial photography with infrared film to determine areas and field samplings in five localities to estimate surface biomass. The total yield was estimated through the statistical analysis for a stratified random sampling. In the northern zone as far as Punta San Antonio, B.C., the distribution of the beds increased slightly compared to spring 1986 (Hernández et al., 1989b). There is a discontinuity from this point to Islas San Benito, where the beds reappear and extend to Punta San Pablo, B.C.S. The area between this last site and Punta San Hipólito, B.C.S., continued without beds of Macrocystis pyrifera. A bed covering of 18,682,018 m² and a yield of 97,804 ± 6,331 tons were calculated in the summer of 1986. Of this yield, 67.74% was located to the north of the discontinuity of Bahía Vizcaíno, B.C., and 35.23% was located to the South. Seasonal variations of the resource for each study zone and global seasonal variation were analyzed, finding that the most productive seasons are spring and summer.