The Adult and Sub Adult Squonkfish Population - Assignment Example

Go fish lab al Affiliation 6. Briefly describe the adult and sub adult squonkfish population dynamics during the 30 year period The population for the sub adults was slightly higher than the adults due to the fact that the fishing nets was selective and was designed to harvest more of the adults than the sub adults. The environmental factors such as El Niño killed many fish and also uncontrolled fishing contributed to the decrease in fish. What are the highest and lowest approximate numbers for each (in tons)? The approximate number for the sub adults Highest 140tons Lowest 29tons The approximate number for adults Highest 280tons Lowest 20tons 7. Did the squonfish population collapse or in danger of collapse? The population of fish is in danger of collapse according to the data because the number of fish limit initially is higher than the estimation after the fish harvesting 12. What happened to the squonkfish during the population during the 30 year of fishing did the population collapse? If not were there any discernible effects from fishing (compared to the population dynamics from part 1) The population of fish during the 30 years of fishing decreased as the number of fish harvested more so the adult fish. Fish harvesting is the most notorious ways to reduce the population. The dynamics caused by natural calamities such as el nino are not constant thus they don’t claim a big number like fishing 15. using the spread sheet calculate the sum harvest of sub adults and adults in tons in the first 10 years of harvesting. Similarly calculate the 30 year old harvesting by combining the whole row For ten years The sub adults: 10 x 6 =60tons The adults: 10 x 12 = 120tons (60 +120) =180 tons For 30 years Sub adults: 99tons Adults 203tons 99 + 203= 302 tons 302+180=482tons Calculate the average 10 year harvest 180/10 =18 Calculate the average for 30 years 302/30= 10.06 tons The probability for collapse in 30 years 9.9 + 20.3= 30.2 In your opinion with the catch limit of 6 tons for sub adult and 12 tons for adults is the risk of collapse acceptable? Justify your answer In this case the risk of collapse is not acceptable because the sub adults which later become adult are harvested in small numbers. Due to the fact that the adults are the last generation in the population it is of help that it is reduced at a controlled number so as to reduce the possibility of extinct as a result of competition. Try at least 3 runs with your new catch limits and calculate the average 30 year and 10 harvests and calculate the probability of collapse Using the limits of 4 and 8 the following is the result Average for 10 year 32/10= 3.2 tons for sub adults 64/10=6.4tons for adults 9.8 tons is the total average Average for 30 36/30=1.2tons for sub adults 72/30=2.4 tons of adult 36/30=1.2 tons Total average Probability of collapse 1.2/2.4= 1/2 34. Calculate and record the average 10 year and 30 year harvest and the probability of harvest Trawl width 50, trawl length 90 The average for 10 years Run 1 41/10= 4.1tons for sub adults 112/10= 11.2 tons for adult Run 2 51/10= 5.1 tons for sub adults 100/10= 10 tons for adults Run 3 29/10= 2.9 tons for sub adults 71/10= 7.1 tons for adults The total average 4.1 +5.1+ 2.9=12.1tons for sub adults Total average for adult fish 10+11.2+7.1=28.3 tons Total 12.1+28.3=40.4tons The average for 30 years Run 1 122/30=4.0666tons for sub adults 219/30=7.3tons for adults Run 2 51/30= 1.7 tons for sub adults 100/30= 3.333 tons for adults Run 3 33/30= 1.1 tons for sub adults 101/30=3.366 tons for adults Total average for sub adults 4.066+1.7+1.1=6.866/3 2.288tons Total average for adult fish 3.366+3.33+7.3=13.996/3 4.665 tons The total average 2.288+4.665=6.95tons Probability of collapse 2.88/4.66=0.6 23. Calculate the average 10 year harvest 35. do at least three runs for each effort level Trawl width 50 length 50 Run 1 87/30= 2.9tons for sub adults 205/30=6.8tons for adults 9.7tons Run 2 107/30= 3.56tons for sub adults 224/30=7.46tons for adults 11.02tons Run 3 120/30=4tons for sub adults 239/30= 7.96tons for adults Total= 11.9 tons Trawl 35width 25 length Run 1 120/30=4tons sub adults 239/30=7.96tons adults 11.96 Run 2 54/30= 1.8tons sub adults 104/30=3.46tons adults 5.26tons Run 3 46/30=1.53tons sub adults 106/30=3.5tons adults 5.3tons Trawl 30 width 30 length Run 1 39/30=1.3tons 129/3=4.3 Run 2 51/30= 1.7tons 123/30= 4.1tons Run 3 50/30= 1.66tons 123/30= 4.1tons 36. Which effort level( of those you tried) yields the best 30-year harvest while still protecting the squonkfish population Trawl 30width 30 lengths. This is because the value is maintained to mean that there is no much change in the population of the fish sampled. This means there is neither increase nor decrease. 37. In general how does the catch limit strategy compare with the constant effort strategy, in terms of harvest and risk of collapse in 30 years? Why do you think the strategy worked better? The constant effort strategy is better because it involves as fixed schedule and a constant way of operation which does not give space for increase or decrease in the population of the fish. 38.How your answers to would questions 30 and 36 change if you based your answer on 10 year instead of 30year long term harvest data briefly discuss the ramifications in terms of economic profitability and risk of collapse in using long, short term predictions to make decisions 10 year is a short term period, however for this case the catch limit strategy will result to the reduced harvest of fish and also the economic profit margin will reduce. For the constant effort there will be less change as there is set mechanisms which are not affected by the time length thereby there will be no change in the profit margin. 50. In the space below describe the adaptive technique you tried . Describe your most promising adaptive strategy. Why is it the best? The adaptive strategies used included adaptive effort strategy which calls for the use of a more efficient trawl area. This trawl area is a specific one which should be on a uniform dimension for an exact estimate. There is also the use of the mixed strategy which involves all the earlier used strategies. This is of more significance as it maintains the economic profit margin as well as keeping the population of fish from collapsing. thus, the later adaptive strategy is the best. 52. How does you adaptive compare with the best catch limit strategy and the best constant effort strategy. Explain why you think the difference occurs. For the best catch limit strategy. The mix strategy is better as it gives space for the adjustment of the profit margin thereby more profitable. For the best constant strategy the mixed strategy is better as it does not lead to large amount decrease in fish population as in the case of constant effort 53. Select the single most promising long term strategy for parts 2, 3, 4 of this lab. Describe the strategy here. the constant effort strategy is the best as it involves minimum reduction in the population of the fish at the same time it there is no adjustments in the profit margin by the harvesters. This means that the fish population is controlled. 55. Compare your fishing strategy to those of your classmates. Which strategy resulted in the best yield in the 30 years without the arm to the squonkfish population? My strategy is the best because it met the requirement of this lab test whose aim was to ensure the ecological balance and the profit expansion as far as fish harvesting is concerned. 57. What happens when adults are harvested exclusively compared with harvesting adults and sub adults? Why might this difference if you discovered any? How can this are used in fish harvesting strategy The adults are responsible for the reproduction of much small fish in the bank, harvesting adult fish exclusively will lead to reduce in the number of small fish thus there will be no movement in fish generations and reduced fish production. Again the profit margin will be reduced among the fish harvesters. In addition the population of the fish in a short run will be higher which will result into increased competition for resources such as food due to reduced number of adults. This strategy is important if there is need for control in the fish population especially if it is realized that they ca pose ecological threat with increased number Work Cited Lewis, N. D. C. (2004). Operational risk with Excel and VBA: Applied statistical methods for risk management. Hoboken, N.J: Wiley. Read More