Commentary: "Commentary: Stable isotopes of carbon (δ 13 C) and oxygen (δ 18 O) from vaquita (Phocoena sinus) bones as indicators of habitat use in the Upper Gulf of California."

Mónica Yanira Rodríguez Pérez¹Laura Sánchez-Velasco¹Martha Patricia Rosas-Hernández²Claudia Janetl Hernández Camacho¹Juan Pablo Gallo Reynoso³Fernando A. Cervantes⁴Francisco Arreguin Sanchez^1*Victor M Godínez⁵

• ¹Centro Interdisciplinario de Ciencias Marinas (IPN), La Paz, Mexico
• ²Facultad de Ciencias Biológicas y Agropecuarias, Universidad Veracruzana, Región Poza Rica-Tuxpan, Veracruz, México, Poza Rica, Mexico
• ³Centro de Investigación en Alimentación y Desarrollo, A. C., Guaymas, Mexico
• ⁴Universidad Nacional Autónoma de México, Ciudad de México, Mexico
• ⁵Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Mexico

Flessa and Dettman's comments in their article "Commentary: Stable isotopes of carbon (δ 13 C) and oxygen (δ 18 O) from vaquita (Phocoena sinus) bones as indicators of habitat use in the Upper Gulf of California" appear disproportionate and seem intended to divert attention from the main focus of the article. They criticize a sentence unrelated to the article's main contributions, using a magnifying lens and terms such as "improves the scientific rigor" and "erroneous and misleading." The authors believe that, in order to contribute constructively to scientific discourse, a reasoned argument could have been presented without derogatory qualifiers that risk discrediting the article.The article "Stable isotopes of carbon (δ 13 C) and oxygen (δ 18 O) from vaquita (Phocoena sinus) bones as indicators of habitat use in the Upper Gulf of California" documents, for the first time, a shift in the vaquita's food sources, likely related to changes in Colorado River flow. It points out that changes in the food chain likely stemmed from variations in primary productivity, which impacted vaquita feeding patterns, as suggested mainly by the carbon isotope. The article also notes that, in the case of oxygen, no differences were found between the two temporal groups, which correspond to the largest episode of water input from the Colorado River (1984)(1985)(1986)(1987)(1988) and a period of zero freshwater input (1989)(1990)(1991)(1992)(1993). "The enrichment in species such as Mulinia coloradoensis (Rodriguez et al., 2001), Cynoscion othonopterus (Rowell et al., 2005), and Totoaba macdonaldi (Rowell et al., 2008)