Effects of environmental factors on the abundances of the basket stars Astrocaneum spinosum and Astrodictyum panamense (Ophiuroidea: Gorgonocephalidae) in the northern Gulf of California, Mexico

ABSTRACT

Gorgonocephalid ophiuroids, or basket stars, reside in diverse ecosystems of all oceans, but there is limited information on their basic ecology worldwide; therefore, this study provides the first detailed numerical analysis published to date of the abundances and spatial distributions of gorgonocephalids from the eastern Pacific Ocean. We analysed the relevance of geography (latitude, longitude), oceanographic factors (temperature, chlorophyll a concentration) and bottom type (coral, rock, sand, fleshy algae, coralline algae and turf) on the abundances of Astrocaneum spinosum and Astrodictyum panamense in Los Angeles Bay, Mexico (29°N, 113°W), in 2006–2007. Depth did not influence the number of individuals per census, but an elevated chlorophyll a concentration resulted in a higher abundance during the autumn (possibly the reproductive season of Astrodictyum panamense and Astrocaneum spinosum). The abundances of both species were positively linked to the presence of rocky bottoms and decreased in sandy areas. Additionally, the presence of live coral favoured the occurrence of Astrodictyum panamense, while high macroalgal cover decreased its abundance. The spatial distributions of both ophiuroids were aggregated at most sites, and they were always associated with different species of octocorals, which are abundant in the area. Astrocaneum spinosum is considered among the 30 most important invertebrates in the aquarium trade in Mexico; therefore, its permanence in the study area could be affected by excessive extractions.

RESPONSIBLE EDITOR:

• Dan Smale

KEYWORDS:

• Echinoderms
• reef communities
• Los Angeles Bay Biosphere Reserve
• bottom type
• environmental factors

Acknowledgements

We thank Fermín Smith (Sociedad de Buzos y Pescadores Bahía de Los Angeles) and Esteban Torreblanca (Pronatura Noroeste) for their logistic help in the field. Israel Sánchez, Nuria Torrejón, Saúl González (Universidad Autónoma de Baja California Sur) and Ismael Mascareñas (Centro para la Biodiversidad Marina y la Conservación, A.C.) collaborated in the field work, and Lorenzo Alvarez (Universidad Nacional Autónoma de México, Puerto Morelos), Gustavo de la Cruz-Agüero (Centro Interdisciplinario de Ciencias Marinas), and Andrés López-Pérez (Universidad Autónoma Metropolitana) helped with numerical analyses and the figures.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

María Dinorah Herrero-Pérezrul http://orcid.org/0000-0002-2239-6056

Rebeca Granja-Fernández http://orcid.org/0000-0001-7119-0567

Additional information

Funding

This work was supported by Pronatura Noroeste, A.C. (Gustavo D. Danemann, Director) under grant no. 20052007.