Cichlid Family – Cichlidae

There are currently TWENTY members of the Cichlid or Cichlidae Family, each found in all freshwater systems of Mexico,  presented in this website:

FROM THE FRESHWATER SYSTEMS OF MEXICO (20):

The Cichlids or Cichlidae are a large and diverse family with at least one thousand six hundred fifty documented species that have been placed in two hundred eleven genera making it the second largest fish family. One group of Cichlids, the Tilapias are the subject of ancient Egyptian paintings that show Tilapias being cultured in earthen ponds up to 5,000 years ago. There are about one hundred twenty residents in Mexico with the vast majority being found in shallow fresh water. Only one Cichlid, the Rio Grande Cichlid, Herichthys cyanoguttatus, is native to the United States. Cichlids range in length from 2.5 cm (1.0 inch) to 1.0 m (3 feet 3 inches) and have diverse body shapes; some are strongly laterally compressed and others are cylindrical and highly elongated. The majority, however, have small to mid-sized oval-shaped slightly compressed bodies. Cichlids are found in all possible colors; some are sexually dimorphic with males and females being of different sizes and colors.

Cichlids are unique fish as their lower pharyngeal bones are fused into a single tooth-bearing structure providing them with a second set of jaws used for food crushing; they are thus able to consume a wide variety of food substances. They are primarily herbivores consuming algae and plants supplemented with small invertebrates; others are detritivores consuming organic materials; and others are predatory consuming other fish and insect larvae. Reproduction occurs via monogamy or polygamy (either open polygamy or harem polygamy). In all species some form of parental care for eggs and larvae and for nurturing free-swimming young is provided for up to a month. Parental care is provided by “substratum-spawning” and/or “mouth-brooding”. The spawning sites for eggs laid are found in the open, on rocks, leaves or logs, or in caves, crevices or discarded shells; these sites are vigorously defended by males to ward off predators while the eggs are minded by the females. Alternatively the fertilized eggs can be taken into their mother’s mouths to protect them from predation and they can remain there for up to a month after hatching. Females also often suffer from domestic abuse and end up battered and sometimes killed by males.

Cichlids are of scientific interest due to extensive speciation within their ranks, an evolutionary process by which new species are created. These changes are mostly attributed to variations in diets and food scarcity. In contrast one hundred eight-four species are currently classified as VULERABLE, fifty-two ENDANGERED, one hundred six CRITICALLY ENDANGERED and seven that are now considered to be EXTINCT. A few cichlids are notable game fish and food fish. The Peacock Bass, for example, is a popular game fish that has been introduced in many fresh waters systems around the world including in Mexican waters. Others are utilized in home aquariums (the most popular being the Angelfish, Convict Cichlid, Discus Fish, and Oscar). Many have been introduced in waters outside their native range and have become pests.

In the 1990s Mexico became one of the world’s major producers and consumers of tilapia. They are currently farmed in all states of Mexico, with the exception of Baja California and Baja California Sur, with the largest quantities originating from Veracruz, Tabasco, Michoacan, and Sinaloa. There are currently five species in production: the Blue Tilapia, the Mozambique Tilapia, the Nile Tilapia, the Red Tilapia, and the Wami Tilapia. They are fast growing, reproduce quickly, and can be harvested in 8 to 10 months. They are tolerant to stocking density, have low production costs due to their grain-based vegetarian diet, and are adaptable to multiple environments. China produces more than 50% of the global tilapia. Tilapias (all species included) are the second most important group of farmed fish after carps and the most widely grown of any farmed fish. They are in the top 3 (carp and salmon) farmed fish in the world with production on the order of 2.8 million tons and sales valued at more than $6 billion per year. Behind shrimp and salmon they are the third most imported “fish” into the United States with most originating from Central America. They are the 8eighth most popular seafood in the United States, which imports 90 million tons of tilapia per year of which 100,000 tons originate from Mexico.

Tilapias were introduced to Mexico in 1964 and are consumed domestically with 96% of their current export market being the United States. They are a white fish with a bland flavor that is available year-round live (fresh and frozen) or as frozen fillets. Mexican farmers promote that they do not use chemicals (for better shelf life and sex orientation) or dirty water and therefore produce better tasting fish than their global competitors. Some imported Asian Tilapia are sold as “sashimi-quality snapper” (which they are not). Mexican Tilapia are also sold under the names Cherry Snapper, Lemon Snapper, Mojarra, St. Peter’s Fish, and Nile Perch. They are typically farmed in ponds and small lakes with the use of floating cages on a limited basis. They are fed various materials including numerous protein sources (soybean meal, fishmeal, vegetation, manure, and inorganic fertilizer) with the objective of stimulating the growth of protein-rich phytoplankton. These additives drive up production costs, however, formulated feeds are necessary to produce larger fish and obtain a higher market price. The uncontrolled breeding of tilapia in ponds, however, has led to excessive recruitment, stunting, and a low percentage of marketable-sized fish. The development of hormonal sex-reversal techniques in the 1970s represented a major breakthrough and allowed male monosex populations to be raised to uniform and larger marketable sizes. The Nile Tilapia is the predominant cultured species worldwide. Adding a male sex hormone (17-α-Methyltestosterone) to the diet of fry converts all females to males. There have been reports that tilapia contains high levels of omega-6 fatty acid making them undesirable for human consumption. There is also a widespread view that due to the meat flavor being highly variable they are “trash fish”, thus driving down prices. In Southern California they are sold live at premium prices that guarantee quality and freshness.

Most of the future global production of tilapia is expected to be the Nile Tilapia. Major on-going research is focused on obtaining faster growing strains that are more temperature-tolerant and disease-resistant and can be produced in adequate size using low cost hormone-free feeds.