Introduction
Fishing has been a popular industry, especially in those maritime countries. And of course to make a sustainable future, harvesting has to be restricted somehow to maintain the fish population at certain acceptable levels but at the same time sustains this industry.
To look into the problem, a lot of factors have to be taken into considerations - birth rate, death rate, immigration and emigration rate, etc. Differentiation – one important convention of calculus, is of good practical use in the real life. It provides powerful tools for explaining the behavior of dynamically process. By modeling a fish population system with the basis of differentiation, it can help the government to regulate in order to achieve a fishery optimal
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So the net rate of change in the fish population per year is N. For now we only consider birth rate and death rate, we will have
N’ = Birth rate - Death rate - Immigration rate + Emigration rate
According to a lot of observations of many species for a long-time period, we can make the assumption that birth rate and death rate are both roughly proportional to the size of the population, so we have
Birth rate at time :
Death rate at time :
Where b and d are both positive proportionality constants. If now we assume the birth rate is bigger than the death rate, which is a basic standard for species to live on. That means b is larger than d, then we have
which means that the fish population will keep increasing all the time, and that never happens in the real life. So that we have to bring in a new factor – overcrowding. Since a fixed habitat has its maximum capacity for species, as the population increases, the death rate will accelerate so that it can’t be accounted for by a single constant coefficient d. In order to model a more accurate system, we will then change death rate to
Death rate at time : in which we use term cf(t) to account for overcrowding. Now we
Plankton Activity Postlab 1) Apply 2.5: Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales. Explain how the abundance of phytoplankton in the pond depends on the abundance of an abiotic resource such as nitrogen. - Phytoplankton are the producers in the pond. Species of organisms in ecosystems have their own carrying capacity relative to other species, and carrying capacities are determined by particular abiotic and biotic resources in an ecosystem. An increase in nitrogen levels in the pond (e.g. from fertilizers) will result in a dramatic increase in phytoplankton levels, but once phytoplankton population reaches its carrying capacity (determined by availability of other resources besides nitrogen, [DO] levels, predation etc.),
The anchovies are then eaten by tertiary consumers, which are the bigger fish. The last link in the food chain are humans. We then eat the bigger fish (Food Web). Now, if the algae and bay grass population decreases, then all of the other organisms population in the
Students started off with a population of ten Skittlefish (skittles) on an orange reef (construction paper). The skittles had varying colors, and the adaptive trait being examined was the ability to blend in with the reef so the predators would not find them. The hypothesis that was thought up was that individuals’ survival was based on their location and coloring. The first year began with two of each color, and 5 Skittlefish were eaten that “year”. The ones eaten were two green, two purple, and one red.
"An Enviro's Case for Seal Hunt" (2013) is an opinionated article by author and journalist Terry Glavin, arguing against the controversy and negativity surrounding the Canadian seal hunt. The author states that not only is sealing humane, it is also sustainable. Glavin bases his article on his experiences and research with various environmental organizations such as "the Sierra Club, the David Suzuki Foundation, Greenpeace, etc." (Glavin, 2013, p. 166). Because of his personal experiences with environmental issues, Glavin's article presents a strong bias.
How to Kill Silverfish If you’ve notice the silvery torpedo-shaped insect scurrying out of a bookcase or your pantry, “how to kill silverfish” is probably a question and priority in your mind. Nobody wants their homes invaded by insects and especially ones that cause damage to food products and sometimes, precious books or manuscripts. Nocturnal Habits & Diet Silverfish are creatures of the night and possibly the only time you might come across one in the daytime hours is if you happen to move objects they are hiding under.
The European demography experienced its most significant transformation between the 18th and 19th century which can be illustrated using the Demographic Transition Model (DTM) . This model correlates to a country’s development: as it moves from a pre-industrialised to an industrialised system, the population growth rate moves from high birth and mortality rates to low birth and mortality rates. 1700 to 1900 Europe saw three phases of this model – the pre-industrialized phase saw high birth rates and high mortality rates due to high fertility and spread of epidemics. The first stage of the DTM can further be elucidated by the Malthusian theory. According to the Malthusian theory, population increased geometrically while food production grew
There are several causes of overfishing, such as fishing vessel in large number in one area, using a mesh net in a small size and high demand of fish. One example of overfishing was happened in Canada. Since 17th century, local fisherman in Canada has caught cod fish using a simple fishing gear. Simple fishing gear makes limited the volume of their harvest, limited the size and the age of fish. Because the demand of cod fish was in a high level, the industries were also decided to run the infiltrations in order to overcome that.
Discussions and Findings What impact are chemicals currently having on Corals and fish species on the Great Barrier Reef? The impacts of chemicals on the Great Barrier Reef are far beyond what is first expected. The reef is subject to effects of sediment, nutrients and chemical pollutants that currently effect 25% of the worlds coral reefs (Amelia S. Wenger, 2015), including the Great Barrier Reef. These three effects result in a decline in water quality, which is due to an increase in nutrients caused by fertilisers, herbicides, insecticides and sewage.
In 2013, a documentary called Blackfish was released to the public. This film was produced, written, and directed by a lady named Gabriela Cowperthwaite, as a way to show the world how poorly whales are treated and why they do not belong in captivity. Blackfish also shows how little people really know about the beautiful and highly intelligent orca whale itself. Her film was seen by many, and touched the hearts of a lot people, taking the debate of the topic to a higher level. The movie hits on a lot of main issues about captivity, told by reliable people, along with proven statistics to go along with them.
1. If overfishing continues hundreds of thousands of fish farmers and medium scale fisheries, often very poor, that depend on aquaculture and fishing, will be out of work. According to the Food and Agriculture