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Anadromous salmonids have the ability to live in two very different environments due various physiological and biochemical changes in their as they make their way through their life cycle from eggs to mature salmonids. The complex life of anadromous salmonids begins from eggs laid in redds, a cavity dug by the female salmonid, which can be up to 45cm deep. Roughly after a month from being laid, eyes become visible and they hatch as alevins, tiny creatures with huge eyes attached to bright orange sacs.
These are yolk sacs, which give the alevins a rich supply of nutrients, allowing them to grow rapidly for three to four months before emerging from the gravel as fry. Fry are extremely vulnerable to predators as they are bountiful in numbers and able to swim to hunt for their own food. As they feed and grow, they develop into juvenile fish called parr, identifiable by a pattern of spots and vertical bars that help camouflage them. Eventually this pattern disappears, signaling their transition from parr to smolts, becoming silvery colored through this transition known as smoltification and are then able to survive in saltwater as mature salmonids. Although anadromy is not unique to salmonids, only salmonids have smoltification, a unique preparatory adaption process to survive in both freshwater to saltwater. (Stefansson et al 2008).
Culture conflict theory says that the cause of criminality is caused by different views between socialized groups over what behavior is right or wrong. According to Thorsten Sellin, expectations for human behavior within a social group is acquired early in life through childhood. (Schmalleger, 2018). The clash of these expectations is what results in crime. Sellin describes two types of culture conflict, primary conflict, and secondary conflict. Primary conflict is when a fundamental clash of cultures occurs. Secondary conflict is when smaller cultures within the primary one clash. (Schmalleger, 2018). Subcultural theory is a sociological perspective that emphasizes the contribution made by variously socialized cultural groups to the phenomenon of crime. (Schmalleger, 2018). Subculture is different than the larger cultures because they claim a smaller group of people.
According to Walter Miller, subcultural crime is the consequences from specific values of the subculture. Trouble and crime are most likely to occur in a lower-class culture. The individuals within the lower-class tend to get into trouble, therefore, it is a focal point for those members. Fighting and gambling are crimes often made in a lower-class culture because those who commit these crimes are an excitement for those individuals.
Richard Cloward and Lloyd Ohlin published a report on the activities of juvenile gangs that blended the subcultural thesis and the ideas from strain theory. (Schmalleger, 2018). They identified two types of socially structured opportunities, illegitimate and legitimate. Illegitimate opportunities are when individuals commit crimes when the chances of getting caught are low. Cloward and Ohlin also describe three types of delinquent subcultures, criminal subcultures, conflict subcultures, and retreatist subcultures. Criminal subcultures are when criminal role models available for adoption by those being socialized into the subculture. (Schmalleger, 2018). Conflict subcultures are when participants seek status through violence. Lastly, retreatist subcultures are where drug use and withdrawal from the wider society predominate.
The general theory of crime, also known as self-control theory of crime, focuses on the lack of an individual’s self-control. The general theory of crime looks at the individual’s childhood and whether or not their parental upbringing. It suggests that children under the age of ten did not have good parenting in their life are more likely to have less self-control than those who had good parenting. According to Gottfredson and Hirschi children with behavioral problems tend to grow up to be delinquents because the path of crime comes early in life. (Essays, 2013). Therefore, children who have loving parents who raise and punish them accordingly will develop a sense of self-control. Whereas, those who do not have loving parents tend to impulsive, aggressive, and act out by committing crimes. When an individual’s personal interest is conflicted with a long-term interest, those with a lack of self-control will want the desires of the current moment. (Schmalleger, 2018). Gottfredson and Hirschi also argue that the lack of self-control is not a necessary condition for crime to occur. They believe that there may be other possibilities of the situation that would affect the individual’s likelihood of committing a crime. According to Gottfredson and Hirschi, the belief that a well-developed social bond will result in the effective mechanisms of self-control. (Schmalleger, 2018). The link between crime and self-control depends on the situation that the individual is in.
According to Per-Olof H. Wikstrom’s situational action theory, an individual’s ability of self-control is the outcome of the interaction and situation that they are involved in. (Schmalleger, 2018). One downfall of Gottfredson and Hirschi’s theory is that it is just a general view of crime and ignores the complexity of the criminal process. General Strain TheoryGeneral strain theory is the thought that social structures within a society pressures citizens to commit a crime. Individuals that are experiencing extreme amounts of stress may turn to crime as a coping mechanism. Strain theory is thought of like a pressure that individuals feel to reach a socially determined goal. (Schmalleger, 2018). As a consequence to strain, crime tends to arise because some individuals feel pressured to be successful. However, the tools they need to be successful does not come easy to them, therefore, some individuals turn to crime.
For example, individuals who stress about financial stability may feel the pressure to rob a bank to get the money they need to be successful. Objective strains are events or conditions that are disliked by most individuals in a given group. Subjective strains are events or conditions that are disliked by the people who are experiencing them. (Agnew, 2001). An emotional response to an event is linked to subjective strain. Therefore, the subjective strain is distinct from an emotional reaction to strain. Two individuals can evaluate an event the same way, meaning, they both can dislike the event at an equal amount. Therefore, they have the same amount of subjective strain. Although they may experience the same dislike, the emotional response may be different. For example, one individual may feel angry in response to the strain. Whereas, the other individual may feel depressed in response to the strain.
Convict Criminology is a blend of writings by credentialed ex-inmates and critical criminologists who joined together in distrust of mainstream criminology. (Schmalleger, 2018). It is when ex-convicts become criminologists. Convict Criminology gives a perspective with regards to the justice systems. The convict criminologists have the criminal background and give incite to the inside perspective. Ethnographic is the preferred method used by convict criminologists. They study the culture of inmate society. Ethnographers used their experiences that they lived and write about them. In this case, the convict criminologists have lived the life of a convict.
Therefore, they are now writing about their experience. Luckily, they hours that an ethnographer usually spends learning and experiencing the culture they are studying, the convict criminologists do not have to spend because they have already experienced it because the subject is themselves. Convict Criminology is a source for improving the justice system. (Schmalleger, 2018). Convict Criminology is often critiqued because many say that the authors are white men and some of them are not ex-convicts. Also, most groups of convict criminologists are partisans and activists, therefore, it is a biased approach. Convict criminology differs from other theories discussed in this course because it has the first person view on the inside and is written down based on the criminologist’s point of view.
Smoltification of salmonids involves drastic changes in the physiology, morphology and behavior of the juvenile salmonid to ensure the survival of the salmonid in sea water. To induce these changes, several endocrine glands are activated during the period of smoltification, including the pituitary, thyroid and interrenal tissues. The hormones produced from these endocrine glands cause increased salinity tolerance, increased metabolism, schooling behavior, downstream migratory, silvering and olfactory imprinting (Bjornsson et al 2011). Ensuring osmoregulation is able to function properly is important because of how different the ionic concentrations of the fish is, in relation to the surrounding environment it is in. In freshwater, the fish is a hyperosmotic regulator, meaning the concentration of ions and other solutes in the blood is greater than in the surrounding water. In most cases, the surrounding freshwater is very dilute. Thus, this causes the fish to absorb water passively from their environment which can be lethal. If cells fill up too much they could lyse. On the other hand, in the marine environment, the fish is a hypo-osmotic regulator, meaning the concentration of ions and other solutes in the blood is less than in the surrounding water. This is a completely reversed situation from the freshwater environment because the fish now faces the problem of losing water passively to their environment. Salmonids try to compensate for this loss by actively drinking water from their environment and reducing water loss in the kidneys. However, they also have to actively rid themselves of the high amount of salt intake to reach an equal concentration level. For the intense osmoregulation that occurs freshwater and saltwater, salmonids use three main osmoregulatory structures, the gills, intestine, kidney and the bladder which exchange water and ions with the surrounding environment (Franklin 1989). Of these three structures, the gills are plausibly the most important as the gill epithelium represents more than 70 percent of the total body surface as well as being a site for chloride cells which are involved with the active uptake or excretion of monovalent ions (Franklin 1989).
However, the role of kidneys in osmoregulation is not to be overlooked, because it is able work cohesively with the gills to filter undesirable materials out of the blood and adjust the body water content by adjusting urine volumes. In order to not lose its electrolyte balance, it reabsorbs important ions and solutes before releasing the urine and major nitrogenous products such as ammonia and urea are excreted via the gills. Thus kidneys play an extremely important role in osmoregulation, crucial for survival in sea water. . In order to achieve proper osmoregulation in saltwater, physiological changes have to take place.
This occurs through the release of hormones from the endocrine system, involving parts of the body such as the thyroid, kidneys and gills. Two important such hormones are thyroxin (T4) and triiodothyronine (T3) which are produced by the thyroid after the pituitary releases a thyroid stimulating hormone. They affect growth, skin color and osmoregulation, as a result, saltwater survival may also be attributed to how much T4 and T3 increase is complete before saltwater entry. Another important hormone involved is prolactin, secreted by the pituitary gland, it increases ion uptake and inhibits salt secretion by causing the reduction of water permeability of the gills and other membranes, such as the skin and renal system in the kidney (McCormick 2001, Bjornsson et al 2011). In this way, prolactin helps the fish balance its electrolytes and water, conserving and reducing water loading in the fresh water environment.
These mechanisms help salmonids survive in freshwater, thus, prolactin is a very important hormone for freshwater osmoregulation. On the other hand, the cortisol hormone promotes saltwater survival. This is because cortisol reduces glomerular activity which is used to excrete large volumes of water in freshwater but since the fish is a hypo-osmotic regulator in the marine environment, the glomeruli’s importance reduces. Thus, secreted from the tissues of the anterior kidney, cortisol is often referred to as the “salt-water adapting hormone” because it reduces glomerular filtration rate, increasing renal sodium retention, preparing salmonids to enter salt water. It also plays a major role in osmoregulation by increasing the activity of the enzyme Na+/K+ ATPase, also known as the sodium pump. The increase of the sodium pump is directly correlated to an increase in gill chloride cells that help assist internal ion regulation by actively removing salt ions in the gill lamella when the fish is in the saltwater environment.
Growth hormones are also elevated during smoltification and are secreted from the pituitary gland, positively interacting with cortisol to promote salt secretion (McCormick 2001). In order to combat the physiological changes occurring during smoltification in freshwater, prolactin is used to enable freshwater survival even though the fish now has the mechanisms to survive in saltwater. Thus, prolactin is known to increase early in smolt development and decreases at the peak of smolting where the fish would be making its way to salt water supporting the fish while in freshwater. However, this osmoregulatory development that allows smolts to maintain high seawater tolerance while still in fresh water makes them more susceptible to external stressors which could lead to mortality (Bjornsson et al 2011). There are many factors that could result in mortality because of the intricate systems in place for salmonids require to successfully transition into sea water. For example, high cortisol could lead to early entry into the sea water before its physiological systems are ready, which puts the smolt at risk of mortality. As a result, morality rates of salmon are highest during migration downstream to salt water largely due to osmoregulatory unpreparedness (Cooke 2011).
There are also many changes to the physical body as salmonids mature. One such change is the silvering of the body from darker parr patterns is one of the most noticeable morphological changes. Another important change is the growth in size, larger fish have the tendency to have greater success and thus, scientist have found that there is a critical body size in order for smoltification to occur. Body size growth is also stimulated by the elevated levels of growth hormones produced by the pituitary glands during smolting which helps to increase physical robustness. These growth hormones also stimulate length growth more than weight growth, decreasing surface area to volume ratio contributing to osmoregulation (Stefansson 2008).
When salmonids are larger they also have been shown to have higher Na+/K+ ATPase activity as well as higher thyroxin (T4) and triiodothyronine (T3) levels compared to smaller fish. Teeth also begin to emerge from the gums as juvenile salmonids becomes molts, this helps prepare the fish for a change in diet in the marine water, where they can exploit the rich food supply. It is important to note that all of these changes in morphology can be manipulated by both temperature and photoperiod, which is the day in length, this is important as it can either advance or retard maturity in salmonids (Franklin 1989).
Behavioral changes are generally very different between parr and smolts. In a water column, parrs tend to occupy the bottom, feeding from and defending a territory. On the other hand, smolts will instead abandon the bottom for the top, this is assisted by an increase in swim bladder and size due to growing bigger. As they swim higher in the water column, they expose themselves to current which aids their migration towards the marine environment. Smolts also are less aggressive than parr, becoming more open to schooling which helps reduce risk of predation in open waters (Stefansson 2008). Parrs at the bottom of a water column also actively swim against the water current, keeping their position in freshwater, whilst smolts develop increased buoyancy with a preference to move downstream out of freshwater. Such behavior helps salmonids enter saltwater at the right time (Stefansson 2008). However, at the same time, many of these physiological, morphological and behavioral changes can be detrimental for freshwater residence if fish are unable to enter saltwater during the smolt ‘window’ where smoltification completes, giving that all these changes are reversible, desmoltification may occur, reducing its chances to survive in saltwater (Stefansson 2008).
Once anadromous salmonids enter saltwater, they proceed to feed and grow in a marine environment rich in resources and this is where formation of gametes appear. In the early summer of their maturing year they head begin heading back to their natal streams. They do so by olfactory imprinting. It is still uncertain exactly how salmon manage to navigate back to their spawning grounds, but there is evidence to believe they do so by olfactory imprinting (Bett 2016). Salmon generally stop feeding as they enter fresh water, their osmoregulation has to then transition once again. However, as salmon transition from the marine environment back to freshwater research studies have shown that osmoregulation in freshwater may be less of a challenge or mechanisms needed for freshwater osmoregulation is able to adapt more quickly than in salt water (Bystrainsky 2011). Mature salmonids migrating to their spawning grounds live solely on the stored up lipids for energy that they accumulated during their salt water residence.
This helps them fight their way upstream against rapids, falls and obstructions in the form of fallen logs and rocks until they reach their spawning grounds where they complete the cycle. This is where the female digs a redd using her tail for her eggs, preferably near a riffle, a rocky or shallow part of a stream or river with rough water, where the fast-running water will provide an ample supply of oxygen for the eggs. She may lay up to 8000 eggs in the redd which will then be fertilized by a male salmon. Covering the eggs with gravel, the female then remains on the redd to defend against other fish until her death several days later. However, not all salmon die after spawning, the atlantic salmon, cutthroat trout and rainbow trout are able to live a few more years and spawn a few more times before dying. In summary the life of an anadromous salmonid follows the life cycle of eggs to alevins, to fry, to parr to smolts and finally to mature salmonids.
The spectacular life it spawns in fresh water and undergoes parr to smolt transformation to give its species the best chance of survival by reducing its predators as juvenile salmonids but using the rich resources of the marine environment shows how. The many factors and processes required for smoltification and survival in saltwater goes to show how complex the life of an anadromous salmonid is.