Ecology

Gulf of California

Also known as the Sea of Cortez, is located at the end of the Colorado River and spans between the Baja California Peninsula and the mainland of Mexico. It is over 900 miles worth of turquoise water that is home to an extraordinary diverse marine life, many of which are endangered. This is why it is Mexico's most important commercial fishing region as well as sport fishing region. Another concern is tourism. People flock to the coastlines due to splendid beaches and to the water for the colorful coral reef as well as being a biodiversity hotspot. It has been referred to as the aquarium of the world.

The upper tip of the Gulf of California at 30 degrees 45 minutes north, 114 degrees 20 minutes west near San Felipe around The Rocas Consag in about a 120 square miles area is the Vaquita's habitat. This has shrunk from original range of approximately 2500 square miles with heaviest concentration in 1400 square miles. The Vaquita prefers the estuary and warmer (55 - 88 degrees F), shallower (between 33 to 92 feet deep) water within 16 miles of the shoreline so its biome is coastal. The Vaquita is a very unique porpoise which has adapted to warm water with large fluctuations in temperature and lives in small groups of up to 3 individuals. They are the only endemic species of cetacean to Mexican waters. They are extremely shy, secretive in nature, and afraid of boats which has made it difficult to study. Also, it does not migrate.

The Vaquita plays a small role in its ecosystem. They have a contribution rate of 4.7 % which puts them in the top ten of the principal components group of their ecosystem. (Riofrio-Lazo, 2012). Their contribution to the order of the ecosystem is maintenance and structure which is similar to apex predators such as California sea lions (Zalophus californianus). They have developmental capacity which indicates they have organization and resilience. So they contribute to the sustainability of their ecosystem. They are a high contributor to the ecosystem recovery after a natural disturbance. Therefore, they are a keystone species. However, their role is not specialized and their functional role is very limited.

It's ecological niche is as predator and prey. As predators, they assist in keeping lower food chain species in check. They are carnivores of high trophic level and secondary consumers that feed mainly on benthic zone and small pelagic zone prey such as crabs, squids, and teleosts. However, they are opportunistic feeders and are known to eat a variety of fish and plants. Scientists have found the remains of Guld croakers inside dead Vaquita stomachs on examination. One dead Vaquita was found to have 17 fish species in its stomach proving they are not selective. They are diurnal therefore, they hunt and feed during the day. They communicate and locate prey by utilizing echolocation.

As prey, they are an important food source for the top predators such as sharks especially the great white shark and killer whales.

As a side note, the Vaquita is often entangled in nets meant for the totoabo which has lead to its endangerment listing, but may also be seen as a negative impact on the fishing industry by reducing the number of intended species being caught in the net. Also, the Vaquita are extremely shy and avoid boats so very little interaction with humans which limits our knowledge of them.

References:

Aquarium of Pacific. (2022). Vaquita. Retrieved on May 25, 2022 from https://aquariumofpacific.org/onlinelearningcenter/species/vaquita

Belanger, M., Askin, N., & Wittnich, C. (2015). Vaquita (Phocoena sinus) - The Little Known Porpoise. Journal of Marine Animals and Their Ecology. 8(1), 10-14.

Biological Diversity. (n.d.). Natural History: Vaquita. Retrieved on May 20, 2022 from https://www.biologicaldiversity.org/species/mammals/vaquita/natural_history.html

Landes, D. (2000) "Phocoena sinus". Animal Diversity Web. Retrieved on May 20, 2022 from https://www.animaldiversity.org/accounts/phocoena_sinus

Riofrio-Lazo, M., Arreguin-Sanchez, F., Zetina-Rejon, M., & Escobar-Toledo, F. (2012). The Ecological Role of the Vaquita, Phocoena sinus, in the Ecosystem of the Northern Gulf of California. Ecosystems, 16, 416-433.

Rodriguez-Perez, M., Ruiz-Cooley, R., Aurioles-Gamboa, D., Sanchez-Velasco, L., Lavin, M., & Gallo-Reynoso, J. (2021). Deciphering the trophic niche of the nearly extinct vaquita (Phocoena sinus) and its variability through time. Progress in Oceanography, Vol. 199. Retrieved on June 10, 2022 from https://www.sciencedirect.com/science/article/pii/S0079661121001786/

Word Press. (n.d.). The Vaquita Porpoise: Ecological Niche. Retrieved on June 10, 2022 from https://thevaquitaporpoise.wordpress.com/ecological-niche/

World Wildlife. (2022). Gulf of California. Retrieved on June 10, 2022 from https://worldwildlife.org/places/gulf-of-california

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