Lobster Supply Chain Summer Blog
Update #1: Lobster Supply Chain Project is RAMPing up for the summer
Hello! My name is Addie and I am Cassie’s intern for the summer and will help out with her Lobster Supply Chain project. This summer we will focus on lobster’s behavioral reflexes and their reflex impairment scores and how this relates to mortality events. This summer on Mondays we will be monitoring seven different lobster reflexes in order to build a reflex action mortality predictor (RAMP) model. To do this, each week we will get a crate or two of lobsters and observe their reflexes. In theory, the loss of these reflexes coincides with the likelihood of lobster mortality, and together they create a RAMP curve. By monitoring the loss of these reflexes and at various transition points within the supply chain; Boat/Wharf, Wharf/Truck, Truck/Dealer, and collecting data from points, Cassie’s project aims to monitor lobster health and indicators of poor lobster health in order to reduce mortality within the supply chain and economic losses within the industry.
Last week we were in the planning and preparation stages of the project. Cassie worked on setting up our sites for the summer; distributors, where we are going to be holding lobsters and testing their reflexes and mortality rates, and transitions points where we will be observing reflexes through the supply chain. We calibrated various pieces of equipment that we will be using such as HOBO + Conductivity meters and Lowell Instrument Tilt & Current Meter (TCM), also known as a Seahorse.
This week we started to go into the field. On Tuesday we deployed a Seahorse and a HOBO + Conductivity meter. These two instruments will remain anchored for the duration of the summer to collect data and demonstrate how aspects of water quality change throughout the summer. This information, combined with the RAMP, will then be used to determine if these conditions have a negative impact on lobster health.
Update #2: C-HATs
One piece of equipment that Cassie had planned on using within her project was a C-HAT; crustacean heart and activity tracker. This device measures the heart rate of a lobster using infrared sensors. The device itself is powered by a lithium battery and information is stored on an SD card, all of this is stored within a waterproof go-pro case. The device, however, is still in development and needs to have a ‘saddle’ designed to accurately track heart rates, as the go-pro does not sit correctly and stay put on the lobster’s carapace, as it is curved. In an effort to troubleshoot this problem, I was tasked with creating a lobster saddle for the C-HAT to sit atop.
So far I have made three iterations of this saddle. All iterations have been made with hot glue and a can as a form. After testing the first two of the three iterations on a lobster at the DMC, we succeeding in getting some great data. The data showed a “normal” heart rate at the end and beginning of the C-HAT test duration, leading Cassie and I to think that the device only worked when out of the water. What was really occurring, however, was data that apparently looked warped, but was not, as a result of the water absorbing the light the infrared sensors can detect. When the plots that were made from the data were blown up, it was clear that the device was working perfectly fine. Now we just have to convert the underwater section of data, this can be done using software such as R that can count the number of peaks within a minute time frame (each peak representing a beat). After discovering that the saddles were effective, I fitted each of the seven C-HATs with one; four C-HATs have a hot glue saddle and three have a saddle made of moldable plastic. Now I will test out each saddle on the lobster we have here to see if they all work or if they still need some tweaking.
Update #4: End of Summer update
This summer the lobster supply chain project had a lot of successes! So far we have completed close to ten RAMPs at our Boothbay and South Portland locations. We have assessed over 750 lobsters so far and of those fourteen have died. With these results Cassie has started the process of creating the RAMP curve. So far it shows that a lobster’s reflex impairment score is an indicator of mortality, which is a success! The RAMP curve also demonstrates that the sum of individual injuries, and size influences mortality. The RAMP curve is still in the process of being finalized and more lobsters need to be assessed in order for this to happen.
This summer we have also been collecting data from the Mocklobsters. These devices track what a lobster would experience from trap to dealer and they are given to the lobstermen we are working with to put in their traps. Though there have been some hiccups with the Mocklobstes, such as water getting into the device, we have still had a number of successful runs and have collected helpful data.
In the future of the project Mocklobsters will continue to be set, though now they will only be set in shallower water to hopefully prevent any more from leaking. We are also fashioning a retainer out of threaded rods and acrylic to help keep the lid more secure. RAMPs will continue to be done until the number of lobsters assessed has reached 1,000. At this point there will likely be more dead’s to ensure the accuracy of the RAMP itself.
Update #3
Last week we were finally able to begin collecting data so Cassie could start to build her RAMP. After a a few weeks of uncertainty, Cassie was able to secure a location to do the RAMP. Starting last Monday we went to Boothbay each morning of the work week. On Monday we did our first day of RAMP reflex testing and Tuesday-Friday we went in the morning to see if any lobsters had died. We did have a few deaths, which for Cassie’s project is necessary, as she wants to be able to use the absence of certain reflexes to determine the percent chance of delayed mortality. Before this “RAMP” (reflex and mortality predictor) can be made, we need to sample at least 300 lobsters. This means we will be going to Boothbay everyday for the next 4-6 weeks.
Last week on Thursday the 17th we were also able to do a RAMP at a transition point within the supply chain. We only looked at 22 lobsters as we did not want to impose more stress on the lobsters by having them out of the water and in the sun for an extended duration of time.
