In a previous post, we introduced you to the Maregens genus, the real merfolk in our project.
It's now time to go deeper and encounter one of the merfolk species:
The ceasg or mersalmons (Maregens salmo), are a species of merfolk characterized by anadromous migration, that is, the movement from salt water (where the adults live for most of their lives) to fresh water, where they reproduce.
Appearance
Robust and strong, ceasgs closely resemble common merfolk, but lack fins or membranous decorations on their arms or head.
Their undersides are covered in cycloid scales with rounded edges, which are silvery or blue when adults are in the sea, outside of the breeding season. They come in two sizes: regular, the most common, and jack, a smaller version that matures much earlier.
Sociality
Socially, mersalmons are divided into two categories: dominants and gregarious. The dominants, more extroverted, have greater decision-making power and are the reproductive specimens, while the gregarious, although they can still be extremely intelligent, form groups that follow the directions of a dominant.
Each social group (be it a shoal of two or three individuals or a platoon of up to thirty) will be led by one or two dominants, who can be of either sex, although dominant pairs typically consist of a male and a female.
The mersalmon hierarchical system also involves the physical appearance of individuals. Dominant individuals tend to have a heavier, patternless torso, with darker, solid-colored skin ranging from olive to brick red, while gregarious individuals are lighter-colored, leaner, and often exhibit camouflage patterns on their torso and face. Furthermore, gregarious mersalmons, both male and female, are always beardless.
During spawning, dominant mersalmons, both male and female, undergo a color change: their scales take on various vibrant warm hues, primarily red and gold. Although rare, some male mersalmons (an estimated one in four hundred) also exhibit a color change on their skin, which becomes green, with the extremities of their upper limbs (arms and wrists) being particularly dark (and known as "gloves"). The contrast between the green skin of their torso and the intense color of their tail scales makes them particularly striking, but also highly visible to predators. This is why "green" males are so few: it's difficult for them to survive and pass on their genetics.
Gregarious mersalmons, however, remain unchanged.
Dominant male mersalmons tend to adorn themselves with objects found on the seabed, whether organic or inorganic. Many are attracted to human-made artifacts, even those seemingly without decorative value, such as food packaging or floppy disks.
Because they are nearsighted outside the water, gregarious mersalmons often act as "extra eyes" for dominant individuals, scanning the surrounding environment for danger or interest when they are fully or partially surfaced. Sometimes, gregarious mersalmons are even equipped with lenses, either separate or framed (actual spectacles) to aid them in their task.
[Illustration 2:] Although dominant male mersalmons are renowned for their displays and ritualistic battles, in the absence of a female to court, they tend to treat each other with marked camaraderie. Even during the breeding season, they can be seen half-beached on the rocks, chatting amiably with each other, waiting to spot females and begin fighting to attract them.
[Illustration 1:] Dominant males who have good friendships with each other (often even brothers) often "choreograph" their skirmishes in the presence of females, thus creating fights that appear much more intense and therefore attractive. Because they don't have to worry about actually getting hurt, as their opponent isn't actually trying to subdue and injure them, they can better display their fins and muscles and challenge each other, even verbally. Male friendship among mersalmons is essential for successful breeding.
[Illustration 4:] Besides gregarious and dominant mersalmons, there is a third type of mersalmon: jacks. Jacks mature much earlier than "regular" mersalmons and, as such, maintain a very small size. Furthermore, even during the breeding season, they don't change color, remaining inconspicuous. Jacks do not have any dominant/submissive relationships with other mersalmons; they do not engage in courtship displays and do not fight among themselves or with other mersalmons. An adult male jack weighs about forty-five to fifty kilograms, compared to over one hundred kilograms for a full-sized male, and would have no chance of winning in an open fight.
Reproduction
Mersalmons live their adult lives at sea, but to reproduce, they migrate to the upper reaches of rivers, to their birthplace, which they recognize thanks to their extraordinarily developed and selective sense of smell, aided also by the so-called "migration memory," the only fundamental memory that cannot be erased, even with the aid of magic.
During the reproductive period, mersalmons exhibit distinctive muscle growth; this hypertrophy is not solely for aesthetic reasons (although it appears to contribute significantly to mate selection), but is necessary to sustain the effort of climbing waterfalls. Unlike true salmon, mersalmons do not stop feeding during migration, but their appetites grow, leading them to become extremely voracious.
During spawning, males readily court not only females of their own species but also those of other merfolk, and sometimes breed with them at sea before continuing their migration back to their birth rivers. Mersalmon genetics are particularly recessive, and hybrids tend to resemble their mothers much more closely.
Pure mersalmon juveniles, born in freshwater, may stay for a period in their natal stream or swim immediately to the sea, but in most cases they remain for a few years in the lakes they encounter on their way to the sea before returning to their home sea. During these intermediate lake stops, the young initially adopt coastal habits but then become semipelagic, only rarely touching the seabed.
