Every organism on Earth is part of the Red Queen’s race. As stated by Van Valen, organisms have to adapt to a forever changing environment. Otherwise, if they do not adapt they put themselves and feature generations at risk from perishing. Organisms that are closer to the poles have to worry about surviving lower temperatures, therefore they must develop strategies that will help them cope with winter. Generally, organisms have a choice between hibernation, migration, resistance, or tolerance. One strategy is not better than another, it all depends on the constraints placed by nature for a given species. For instance, a wingless insect would probably not migrate because the absence of wings would limit its movement. Similarly, hibernation requires organisms to increase their body lipid content which also wouldn’t favor an insect because of their small bodies. Instead, a wingless insect can evolve to either tolerate or resist winter. But if coping with winter wasn’t enough, extant species now have to face another threat, global warming. The rise in temperatures is causing G1 pressure on many species that live on land, or water, however, not all species are beingG2 affected at the same rate. An example of an organism that is being affected both by winter and global warming is the Striped Bass or G3 Morone saxatilis.G4 G5 G6
Striped bass are found in many places in North America but for the purpose of this essay, I will focus primarily on those that are found along the Atlantic Coast. This species is anadromous, meaning that they G7 travel from the ocean into freshwater to spawn. In the Atlantic Coast, G8 there are three major spawning sites for striped bass; the main one is the Chesapeake Bay, followed by the Hudson River, andG9 the Delaware Bay. Spawning takes place in early spring and not every mature female will reproduce every year. Striped bass usually take 2 years to reach sexual maturity and once this is reached they leave their freshwater homes to venture out into the ocean with other populations of striped bass (Baker et al. 2016). Furthermore, this species is migratory. Annually, adult striped bass participate in a spring migration and a fall migration.
Migration is the winter strategy used by adult striped bass. As stated earlier, this species has a winter and fall migration in which they travel together as groups, however, fish that exceed the G10 average size of the population tend to travel alone. During the spring striped bass migrate north, some make stops in order to spawn, later they continue their journey north of the Atlantic Coast. They remain in northern waters during the summer but as soon as they sense a drop in water temperature they prepare to migrate south. Interestingly, weather events such as hurricanes and wind currents can have an impact on the temperature of the ocean and this may hint striped bass to start migrating earlier than usual. Swimming hundreds of miles tG11 o reach their winter homes is no easy task. Stripers just like any other organism require a lot of energy to travel great distances. It is this time of the year where striped bass get very excited and begin to feed in large amounts to meet their energy demand placed by winter migration. They aggregate in large groups and attack schools of smaller fish, such aggregations are known as boils. Boils are easily spotted by people because the fish move very excitedly splashing water around, also hundreds of seabirds fly above trying to feast on fish. G12 G13
Furthermore, research has shown that adult stripers are usually not found in main spawning ranges for the duration of winter, instead, theyG14 ms15 ms16 ms17 remain in warmer ocean waters (Waldman et al. 2012 and Clark, 1968: McLaren et al. 1981). Striped bass found in the Mid-Atlantic regions during the summer have been found as far as North Carolina (Waldman et al. 2012). To keep track of where striped bass are going they are usually caught, tagged, and then released by organizations such as NOAA. When surveys are conducted and they catch fish that been tagged they can refer to where it’s been tagged and how much it has moved. Fish surveys are also conducted in order to calculate the density of a given marine species. Moreover, in a different survey done in 2005 by the NMFS during the winter and fall in the Mid-Atlantic coast they found a sharp decline of stripers in the ocean but during the spring the populations of adults increased (Able et al 2012). The two studies seem to agree that stripers do migrate to the south during the winter.
On the other hand, juvenile fish that are on average younger than 2 years old have a different strategy. They do not migrate like their adult relatives. Instead, they stay relatively near their freshwater birth sites (Baker et al. 2016). In a study done by T. P. Hurts, and D.O. Conover, they discovered that it is essential for juveniles to remain in freshwater bodies as opposed to out in the ocean where adults may be found (T.P. Hurts & D.O. Conover 2002). For their study, they collected juvenile fish or what they called “young-of-the-year” from the Hudson River and brought them into a labG18 and split them into different tanks. They tested how temperature and salt concentration affected this species by gradually controlling salinity levels and temperature levels. Finally, they concluded that salinity concentration is directly related to the fish survival. When the tanks that had higher salt concentrations were exposed to low temperatures the mortality rates of the striped juveniles reduced. Therefore, juveniles tend to not be found along the coasts of the ocean during the winters because salinity concentrations have an effect in thG19 G20 eir survival during the winter but the cause why that has not been studied extensively. In a different study, aG21 survey of stripers was conducted along the coastal ocean in the Mid-Atlantic. The study showed that stripers that were 20 or fewer centimeterG22 G23 s that were assumed to be juveniles were barely found along the coast. However, there was a greater number of individuals collected from the Delaware River and Hudson River (Able et al. 2012). The absence of juveniles along the ocean coast during the winter could be explained that younger fish indeed evolved to stay in freshwater during the winter because the higher the salinity of the water the lower their survival.G24 G25 G26 G27
At the same time, species that live in the ocean are being affected by the rise of temperature due to global warming. The striped bass is not the exception.it might not be greatly affected at the beginning. Kleisner and his colleagues published a study in which they state that the ocean temperature has increased and will continue to increase throughout the years which has been predicted by global climate models together with data that has been collected throughout the years.G28 But along with ocean temperatures getting warmer, data suggests that there is a movement G29 of habitat expressed by marine species such as the striped bass and many other, which are situated along the Atlantic Coast. Furthermore, those species that are already located above the Mid-Atlantic will have a much harder time because they won’t be able to keep moving north, instead, it has been suggested that they will seek deeper water in search for a better habitatG30 . Kleisner also included information obtained by NOAA Northeast Fisheries Science Center about surveys of fish throughout many years. The valuable information that the previous organization has collected is very interesting because it shows how the distribution of striped bass has changed in 50 years. Their data agrees with what Kleisner and his colleges have stated about species such as the striped bass moving their habitats north. Fortunately, computerized models have predicted that stripers should do well for the next 80 years because there is still space left for them to keep moving up the Atlantic coast. G31
Ultimately, global warming doesn’t just affect marine life, it also affects us, humans. Kleisner also included a section in his research paper about how the shift in the habitat G32 G33 of many species will have an economic effect on the general human population. To illustrate G34 Kleisner’s point, imagine that you’re a fisherman who normally fishes for striped bass around the waters of North Carolina but now due to global warming you have to travel a greater distance in search for these fishes. The cost of fuel will increase, also the price of the product for the consumers which eventually will lead to a company going out of business.G35 G36