Microhabitat and associated biota of abalone juveniles, Haliotis fulgens and H. corrugata, in Bahía Tortugas, Baja California Sur, Mexico

Abstract

Abalone is an important economical resource on the west coast of Baja California. The most important species in this fishery are green and pink abalone (Haliotis fulgens and H. corrugata, respectively). Overfishing has been implicated in the decline of the Mexican abalone fishery. Among the population parameters, recruitment is a highly variable event. To obtain a better understanding of the ecology of abalone juvenile recruitment, the physical and biological characteristics of the microhabitat of juveniles of green and pink abalone were studied at Bahía Tortugas, Baja California Sur (Mexico), during autumn and spring from 1996 to 1998. Two abalone reefs with different depth, relief and wave exposure were surveyed: Clam Bay, with depths of 0.5 to 5 m, and Morro de Adentro, with depths of 6 to 12 m. Four different bottom types were recognized: (a) sheltered and low relief bottom, (b) semiexposed and moderate relief bottom, (c) exposed and high relief bottom, and (d) exposed and moderate relief bottom. Juveniles of green and pink abalone from 3 to 13 mm shell length were observed under small rocks, pebbles and flat stones no longer than 15|00E2|??20 cm, always covered with crusts of coralline algae. Several tiny juveniles of Fisurella, Stenoplax, and Crepipatella of similar sizes (5–10 mm) shared the microhabitat. Juveniles between 15 and 90 mm shell length were found under flat, rhombic or irregular-shaped rocks (20–110 mm length), most of them deployed in imbricate arrangement. Abalone juveniles shared this microhabitat with bryozoans, sponges, ascidians, chitons, and annelids. Bottoms with imbricate arrangement, low wave exposure, and the low depth of Clam Bay were favorable for the high occurrence of juveniles of H. fulgens. Juveniles of H. corrugata showed a high occurrence in exposed and deeper zones of Morro de Adentro.

Assessment of macroalgae coverage in a scarcely studied deep rocky reef in the tropical eastern Mexican Pacific

“…Coral reefs are more commonly protected under this system, while the rocky reefs of the Pacific coast are excluded, specifically those located in the tropical Pacific region (Santander-Monsalvo et al 2018). In coastal areas in the Mexican Pacific, the greatest number of studies have been performed in the temperate and temperate-tropical transition regions (Carreón-Palau et al 2003, Casas-Valdéz & Aguila-Ramírez 2008, Castañeda-Fernández et al 2010, Ulate et al 2016, Favoretto et al 2022). In the tropical region, studies have been performed mainly in rocky intertidal and shallow subtidal areas (León-Tejera & González-González 1994, Mendoza-González & Mateo-Cid 1998, Ávila-Ortiz & Pedroche 2005, Rodríguez et al 2008, Mendoza-González et al 2011, Mateo-Cid & Mendoza-González 2012, Mendoza-González et al 2018, mostly with a floristic or taxonomic approach, leaving deep rocky reefs essentially unexplored, principally due to logistical and funding limitations.…”

Larval and early juvenile development of Tegula eiseni (Jordan, 1936) (Gastropoda: Trochidae)

“…Studies carried out in Baja California on the microhabitat of rocky reef gastropods that focused on the settlement and juvenile recruitment of more conspicuous species (Carreón-Palau et al, 2003) have required to identify early life stages of T. eiseni from field samples. However, identification of these stages on this and other gastropods has proved to be difficult because of the few available descriptions on reproduction and early development of the members of the family Trochidae.…”