Liza vaigiensis


        Form, Function, and Adaptations
                            of the
                       Liza vaigiensis


Fish possess many different varieties of fins, and because of such, taxonomists are are able to classify different species similar to how the Liza vaigiensis is categorized as Actinopterygii under class. The most obvious purpose for a fish to warrant fins is its own locomotion though water in order for the species to locate oxygen rich waters (necessary for glycolysis), locate food resources, avoid predation, and locate mates for sexual breeding. Matched with streamlined bodies, an adaptation for rapid movement through aquatic environments, fishes congregate into groups called schools in order to maximize the obstacles encountered within the natural lifecycle.

What may be considered the most important characteristic of most fish including the actinopterygii class is the caudal, or tail fin, which propels the fish though water. Propulsion systems can become constrained given a particular climate (Lauder 1989) Because of those constraints, different species adapt physically. The caudal fin propullsion system of the Liza vaigiensis, to which it is commonly named the squaretail mullet, merits observation. Like many fish, the squaretail mullet contains the hypochordal longitudinalis muscle which originates in the caudal vertebrae stretching to its insertion point on the first dorsal fin ray (Lauder 1989). Such a large muscle grouping coupled with the large surface area of the squaretail allows for greater speed, mobility, and control than other species of fish and aquatic organisms that lack one or both of these physical characteristics.

Relating the Liza vaigiensis, a bilaterally symmetrical, and multicellular organism to unicellular and mobile aquatic protists and fungi can appear to be a stretch of the imagination. Yet, when assuming certain theories of evolution, changes to an organisms environment may lead to tissue formation through endosymbiotic relationships with other organisms. Coexisting with Leigh Van Valen's Red Queen hypothesis, the Liza vaigiensis species formed muscle groups, like those discussed, and structures characterized by the noted classifications, in a rapid state in order to keep pace with competitors in order to avoid massive levels of predation and extinction. Along with the mullet's method of sexual reproduction, large populations and genetic variation promote diverse locations and formidable commonality of the species.

Function: Vision And The Lateral Line of Schooling Species

Like many fish, members of the Liza vaigiensis species congregate in schools in order to avoid predation, and maximize efficiency of travel due to water's dense properties similar to the methods used by migratory animals like geese. Perhaps on of the most incredible features of fish schools may be the ability to synchronize movements with near flawless execution (Partidge and Pitcher 1979). Each individual possesses a lateral nerve line running parallel to the spinal nerve column, a synapomorphy of the chordata phylum. Research has been conducted as to the extent of complicated maneuvers and responses to varying stimuli. Qualitative investigations as to a fish's acute aquatic vision, coupled with the highly sensitive lateral line have been investigated (Partidge and Pitcher 1979). In the qualitative study, the mechanisms to which allow for such uniformity and synchronization are not particularly well understood (Partidge and Pitcher 1979). Many researchers have concluded that the lateral line may not be as important as vision within a school as a whole (Partidge and Pitcher 1979).

A quantitative study conducted on schooling saithe (Pollachius virens), a species possessing a distinct lateral line, researchers severed the lateral line in order to quantify fish movement within schools in comparison to fish that were blinded. The comparison of sensory deprivation techniques sought to determine roles of lateral lines and vision within a normal schooling unit (Partidge and Pitcher 1979). Testing of this particular schooling species desired to uncover fright responses and velocity changes within the school. Often researchers conduct experiments on a particular species where only correlational significance based on phenotype similarities may be concluded. Conclusions derived from particular investigation performed by Brian L. Partrige and Tony J. Pitcher, in the article entitled, “The Sensory Basis of Fish Schools: Relative Roles of Lateral Line and Vision” state that the importance of a fully functioning lateral line be superlative than previously recognized in previous studies (Partidge and Pitcher 1979). The intricacies and and structures rely on both a visual and lateral systems as a whole, with the lateral line as the primary detector of swim speed and direction of travel, and vision primarily for position and angle of an individual operating within a school.


As oceanic temperatures continue to climb around the globe, many organisms are forced to acclimate to new environments in order to maintain homeostasis. The Liza vaigiensis has done so in a fashion warranting attention of researchers conducting investigations in Indo-Pacific regions, predominantly the seagrass nurseries surrounding the small islands of Indonesia. John Eme, Theresa F. Dabruzzi, and Wayne A. Bennet, who've noticed the acclimatization of several aquatic species, conducted such research on two species of distantly related fish sharing like habitats in the research article “Thermal responses of juvenile squaretail mullet (Liza vaigiensis) and jevenile crescent terapon (Terapon jarbua) acclimated at near-lethal temperatures, and the implications for climate change.” In the scientific community, it has been widely assumed that juvenile fishes inhabiting lesser temperatures, have a greater amplitude of adaptation to cycling marine temperatures within known habitats (Eme et al. 2010).

Firgure 3.1 Photograph of Terapon jarbua, note the similarities and differences to Liza vaigiensis

Locals have made observations leading to the hypothesis that the mullet and terapon, exposed to temperatures drastically greater than the perceived maximum of 27 degrees celsius, will continue to inhabit shallow mangroves and seagrass areas conducive to species expansion. The profundity of this hypothesis warrants attention due to overwhelming evidence suggesting such temperatures exceed bio-kinetic limits for vertebral life (Eme et al. 2010). Exhibiting such a unique adaptation has lead to the observance of both species of fishes occupying environments exceeding 40 degrees celsius (Eme et al. 2010). Certainly, such observations and analysis of thermal responses of two distantly related species exemplifies homoplacious character. The incredible acclimatization of the Liza vaigiensis, has warranted further observance of supplementary species dwelling in like environments. Perhaps the most intriguing conclusion constructed from the research links this common species of mullet to the highly specialized Atlantic stingray (Dasyatis sabina), the only other known species to exhibit a similar response temperatures contrary to the perceived norm for the species (Eme et al. 2010). Yet on the contrary, the stingray exhibits an acclimatory response which aids in survival of winter temperatures to the minimal degree not the maximum (Fangue and Bennet 2003).

With both the terapon and mullet exhibiting thermal response to increasing temperatures within the respective natural environment, further study must be conducted as the possible adverse affects to other species may experience. As species adapt and respond to changes within an environment, the mullet may be reproducing in greater numbers, leading to decreases in sources of food or atmospheric oxygen which may be limited if schools become land locked in tide pools.

                      Large fish schools are only useful if
Nutrition can be located.

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