13.05.2019 – The plastic challenge

There is no doubt; plastic is highly destructive for our oceans. It poisons, starves and suffocates marine life and is non-biodegradable, breaking down in time to micro-plastics that accumulate up the food chain and have recently been found in human stool samples. As a company we try to do our part in this area; we organise beach clean ups, write blogs and clean up during our trips on the ocean to help raise awareness amongst our guests and local communities on the detrimental effect of trash on our environment. But there is no better representation for this problem than a live one by the animals facing this challenge in our oceans.

Our tour began with a basking Loggerhead turtle (Caretta caretta) that was making the most out of the calm water conditions to regain its strengths at the surface in the warmth of the suns rays. Before long, our captain discovered a group of large, curious Bottlenose dolphins (Tursiops truncatus), that instantly approached our bow and glanced up at us beneath the crystal clear waters of the Atlantic. The clear water also allowed us to locate a white plastic bag on the fluke of a dolphin and, while we were already wondering how to remove it, the animal suddenly started playing with it and tossing it to one of its peers. While the plastic bag serves as a toy to the intelligent dolphin, the short-term memory of sea turtles means they will never learn to not munch at a plastic bag that they easily mix up with their frequent prey, jellyfish. Even I mistook a small piece of plastic for a jellyfish from the boat; for a turtle that may be a fatal mistake. The playful nature of dolphins can also get them in trouble with plastic: little juveniles, for example, could get their beaks stuck in the handles of the bag, inhibiting them from hunting and feeding.

Our tour continued with two interactive groups of the charismatic Short-beaked common dolphins (Delphinus delphis), a species frequently encountered during our tours at this time of the year. Amidst the playful dolphins and the cheery admiration for the animals on the side of our guests, were several Siphonophore Jellyfish including several Portuguese Man O’ Wars (Physalia physalis) as well as a handful of By-the-wind-sailors (Velella velella). The mix-up of plastic bags with jellyfish can also be reversed. In todays plastic age, with 8 million tons of plastic waste entering our oceans on an annual basis, most of us tend to expect more sightings of plastic than marine organisms. This is one reason why it is no surprise that the Portuguese Man O’Wars are often mistaken for drifting plastic waste at the surface or on beaches, stinging diligent people trying to remove waste from the ocean and coastline.

As mentioned before, our team always tries to remove as much waste as possible from the ocean and our captain managed to remove the white plastic bag that served as a toy for the Bottlenose dolphins as well as a large plastic container that served as a hiding place for several Grey Triggerfish (Balistes capriscus), with one wedged nicely into one of its corners. As with most drifting objects, the container also served as a substrate for several colonising goose barnacles that show that the ocean even manages to bring out the beauty in plastic.

By Paula Thake

Sightings of the day

Stenella

15:00 Bottlenose dolphins, Short-beaked common dolphins