Document Type

Honors Thesis

Publication Date

Spring 5-2017

Abstract

A dynamic model originally developed to model lobster shell shedding mortality was used to describe the impacts of Gaffkemia, a disease previously common in American lobster (Homarus americanus). The model illustrated that as the mortality due to Gaffkemia increased, annual lobster catch and the net income per fisherman would decrease.

This model was also used to estimate the impact that the absence of Gaffkemia had on the lobster population boom in the Gulf of Maine. With the removal of 6% Gaffkemia mortality, the model estimates a 2016 catch of approximately 146 million pounds of lobster from the population. This is larger than the official catch for 2016 which was 130,844,773 pounds.

The second compounded situation, using a simple compounded model, estimates that if Gaffkemia operated at a 5% mortality rate, its reduction would result in a 2016 catch of approximately 92 million pounds while 8% mortality reduction would result in a catch of approximately 176 million pounds. The removal of 6% Gaffkemia mortality most closely mimics what was seen in real life landings data.

An exponential fit to existing Gaffkemia mortality vs temperature data was developed to allow for the modeling of mean time to death (in days) for lobsters under various ocean water temperature scenarios. This equation could be used to predict a mean time to death for lobsters with Gaffkemia at any temperature.

Download

Share