With the final leg of Operation Toxic Gulf 2014 being the return of the RV Odyssey to her home port of Key West, FL., and with numerous crew members on tight schedules with flights to catch, there were always time limits on how much we could achieve along the way. As part of our schedule, we had only one full day on the traditional sites southwest of Pensacola where we normally search for whales. As any crewmember could tell you, one day is never enough.
There has been a consistent theme across these “Leg summaries,” all centered around how to describe the emotions when we find a whale against the odds. As before during this highly successful campaign, experience, patience and a vessel perfectly suited to finding and tracking whales proved a tough combination to beat. Sure enough, around midday on our first and only day in the traditional sperm whale habitat we had quiet clicks, then loud clicks, then blows, then a biopsy.
As we tracked the whales–an adult female and a large juvenile, we were subjected to an extraordinary show, its rarity only exceeded by its spectacular nature. The juvenile whale performed two bouts of full breaching, each with 4-5 breaches, with the second bout occurring only 100 metres from the vessel. To see the massive hulking body of a sperm whale erupting from the waves in an explosion of muscle and foam was quite indescribable. How lucky we all are!
With these biopsies achieved, the Odyssey left the whale grounds overnight, heading for the continental shelf that runs parallel north-south with the west coast of Florida, approximately 100 miles off. In the past, as we go further south the likelihood of finding whales decreases, though we’d heard there supposedly exists a mysterious population of sperm whales northwest of the Dry Tortugas. After two nights and one day with no clicks, we regarded the chance of finding whales as increasingly unlikely as we ventured into waters further south than we have ever found whales before. Lo and behold, at 6 a.m. on the third day a lone whale seemed to come completely out of nowhere. Five minutes after being detected acoustically it was spotted, and half an hour later we added another biopsy to our data set.
Later on that afternoon, even further south, another set of clicks beamed through the boat. They seemed far too frequent and numerous to be bottlenose dolphins and as we got closer it became apparent that it was in fact a large group of whales!
As we headed even further south, well in to the afternoon another sound came over the array–clicking, but seemingly too numerous, too rapid, and too far south to be sperm whales. Large dolphins perhaps–Risso’s or bottlenose? As we got closer, something seemed amiss. The clicks, whilst very frequent, were too robust and steady for dolphins.
As it turned out, we had just run directly into the largest group of sperm whales we have encountered all summer–anywhere from 5-15 animals in a couple of square kilometres. It was almost certainly a group from the evasive population northwest of the Dry Tortugas. Five years of searching, and the final sperm whales to be encountered! The samples obtained on this last day are incredibly important, as the levels of toxicants within can be compared with those from the northern Gulf. Over five years we have now found whales from as far west as the Texas/Louisiana border, all along the continental shelf to the deep water northwest of the Dry Tortugas. Do the continuous, if sporadic, locations of whales along the shelf suggest that connections between these populations are more common than previously believed? Who knows, but this exciting discovery raises important questions that need answering.
As the day drew to a close with the sun’s light fading, our deadline for arrival in to Key West officially ending this campaign’s quest for biopsies, a sentimentality grew over the crew. In the backdrop of a magnificent sunset, the dinghy was put in the water to get some last photos of the Odyssey after a highly successful fifth and final season. As the dinghy sped around the Odyssey with the light fading fast, the shapes of some bottlenose dolphins became apparent bowriding the dinghy. A final farewell from those creatures we are striving to protect.
-Andy Rogan, Scientific Director for Operation Toxic Gulf 2014