A semelparous fish species, Salmo pandemica, has genetically-based variation in the size at which it reproduces. Consider two genetic morphs of the fish. Morph A matures at 30 cm size and produces on average 1000 eggs per individual during spawning. Morph B matures at 50 cm and produces on average 3000 eggs per individual during spawning. Assume that in the absence of fishing, the survivorship of both morphs is identical and individuals are only harvested when they exceed 40 cm in length. What is the minimum level of harvest mortality in morph B above which natural selection will favor Morph A

Question

Bennett Wu

Biology

8 March, 06:46

A semelparous fish species, Salmo pandemica, has genetically-based variation in the size at which it reproduces. Consider two genetic morphs of the fish. Morph A matures at 30 cm size and produces on average 1000 eggs per individual during spawning. Morph B matures at 50 cm and produces on average 3000 eggs per individual during spawning. Assume that in the absence of fishing, the survivorship of both morphs is identical and individuals are only harvested when they exceed 40 cm in length. What is the minimum level of harvest mortality in morph B above which natural selection will favor Morph A

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Sandra Mendez · Answer 1

the minimum level of mortality by harvest of Morph B is: 75%

Explanation:

The exercise teaches us that there are 2 apparently very similar types of fish, with a size difference of A of 30 centimeters and B 50 centimeters, but they are harvesting only those that exceed a size of 40 centimeters, and fish A is left out. because it will not reach this size, being favored by natural selection and consequently we will observe that the minimum level of mortality of B will be:

Morph A favors and the minimum level of mortality by harvest of Morph B is: 75%