Marine Mammal Research

What are Marine Mammals? Marine mammals are some of the largest animals that inhabit the oceans and are very similar to mammals that are above land sharing many different traits. We are focusing our research on whales in the Bahamas specifically around Eleuthera. Our question is which whales are utilizing this area and where are they distributed and what is the Population density of marine mammals of different marine species surrounding the Eleutheran ecosystem? So far in our research we have utilized four different sources thus far in our research to better understand these marine mammals. These sources are scholarly articles and scientific journals including “An Entire group of whales have somehow escaped human attention”(reading note 1), “Global climate change, range changes and potential implications for the conservation of marine cetaceans: a review and synthesis” (reading note 2), “Sonars and Strandings: Are Beaked Whales the Aquatic Acoustic Canary?” (reading note 3), and “Challenges of implementing mark-recapture studies on poorly marked gregarious delphinids” (reading note 4). With this research under our team’s belt we have synthesized a working hypothesis which is how cetacean distribution in the Exuma sound is determined or influenced by water depth and other abiotic environmental variables such as PH, salinity, and SST. 

In order to conduct reliable and trustworthy research we have to ensure that our methods are consistent and free from bias. In saying that, we repeat the same procedure every time we go out on the water to collect data. We scout for marine mammals on transects which are repeated lines from one GPS location to another in order to have a consistent path. By using these transects we are able to scan the horizon for dorsal fins and other indications of marine life. Then when we see any marine life we record the coordinates and bearing off of our bow (out of 360º), and the distance from the boat in meters to have even more consistency. Throughout the transects every 15 minutes we also record the data of the PH, salinity, and SST (sea surface temperature) to determine if any of these factors are contributing to the cetaceans distribution. 

Throughout this research, there are many types of data that our team collects and this includes the independent or dependent variables and continuous or categorical data. Some of the Independent variables include abiotic factors such as environmental factors including ph, water salinity, water temperature, and weather conditions. The dependent variable is the actual presence of the different species of marine mammals in the ocean. Some of the continuous data that the team is collecting numerical data on a scale such as pH, levels, and water quality. The categorical data includes the coordinates of our transect, the number of specific species, and the different species present. 

The project design of our research was created to reduce collection bias in order to increase the validity of the results. Every week, when we go out on the boat we travel on the same transect so that there is no bias. By going off course to the places where we think we will see more cetaceans could lead to false data. Also doing fieldwork more consistently allows more replicates which will help us identify anomalies and outliers to exclude from our analysis. This will also help us minimize our standard deviation. This means that when we average the data, we will get a more accurate mean that is closer to the true value of the data. 

With the data that our team collects we are able to pursue many paths of research to help and better understand marine mammal species. Using the data we collect, then can be used to better understand marine mammals and to compare recurring cetaceans in the same area.  Utilizing the hydrophone data we can record the effect of marine noise on cetaceans and how these cetaceans communicate with each other. The informational data from the ph, salinity, and temperature are used to determine if any of these factors contribute to the distribution of the cetaceans. The distribution allows us to use this data to see how the population of whales increases or decreases over time and make sure they have a sustainable future.  

References (reading notes)

Gilbert, Sophie L., et al. "Conservation triage at the trailing edge of climate envelopes." Conservation Biology 34.1 (2020): 289-292.

Hupman, Krista, et al. "Challenges of implementing Mark-recapture studies on poorly marked gregarious delphinids." PloS one 13.7 (2018): e0198167.

Ketten, Darlene R. "Sonars and strandings: are beaked whales the aquatic acoustic canary." Acoustics Today 10.3 (2014): 46-56.

Mackinnon, James Bernard. “Beaked Whales Are Holding Their Breath Right Now.” The Atlantic, 20 Mar. 2021, www.theatlantic.com/science/archive/2021/03/beaked-whales-holding-their-breath/618455.

MacLeod, Colin D. "Global climate change, range changes and potential implications for the conservation of marine cetaceans: a review and synthesis." Endangered Species Research 7.2 (2009): 125-136.

Moors-Murphy, Hilary B. "Submarine canyons as important habitat for cetaceans, with special reference to the Gully: a review." Deep Sea Research Part II: Topical Studies in Oceanography 104 (2014): 6-19.