The word ‘mola’ is derived from the Latin for millstone, a large round stone which was used to grind grain. This is mostly due to the fact that their bodies are disc shaped and appear, at first sight, to be cumbersome in the water. The reality could not be further from the truth. Sunfish are very strong swimmers and they regularly breach surface waters when startled or scared.
Presently, the IUCN Red list has them classified as ‘vulnerable’ which means that the species is likely to become endangered unless the circumstances threatening its survival and reproduction improve. Outside of natural predation, the greatest threat to sunfish are commercial fisheries. Making up between 70 to 95 percent of Mediterranean bycatch, these animals are frequently caught whilst fishing for swordfish and discarded. Most will perish throughout this encounter.
Recently, a report was made about a large sunfish which had been caught on the rocks during an outgoing tide. It had become stranded and needed assistance. A local Nautilus Project volunteer, 13-year-old Alexander, sprang into action once informed by a member of the public. The sunfish was tired and confused. The waves were in danger of stranding it again and Alexander gently climbed into the water to prevent it washing up again.
But what use is a sunfish to us anyway? We don’t eat them as they are discarded as bycatch, so why are they even required? Summer 2018 saw swathes of jellyfish washing up on our shores. The issue was so bad that swimming was nearly impossible on a large number of days. Interestingly, the sunfish is one of the largest consumers of gelatinous organisms which include plankton, salps and jellyfish.
Throughout that summer, waves of jellyfish swamped the coastline and NEMO sightings, a local citizen science platform, helped demonstrate that a few days after their arrival, the sunfish numbers within local waters increased. The connection is unmistakeable even though anecdotal. The predators were moving in to consume the abundant prey items around our coastline. We need more friends like that these days!
This data, collected by an ever-growing community of spotters, has really helped to build up a picture of sunfish patterns within Gibraltar waters, and for the first time is helping to inform good decision making. An important step indeed for a species listed as vulnerable. But local data collection does not stop there. Sunfish have been spotted many times since the original NEMO app release in June 2018. A small photo library is quickly building up which is opening up the potential to monitor individuals for the first time. Community citizen science monitoring really helps to multiply the eyes and ears out on the water and increases the chances of spotting something which might otherwise have been missed.
Sunfish have very distinguishable markings which differentiate individuals from one another. These markings can also be used to identify regular visitors to local waters and garner a better understanding of how each one is growing and their general condition. For the first time we are beginning to understand sunfish annual cycles and if indeed these ‘oceanic’ sunfish tend to remain coastal.
Crucially, this year alone we have witnessed a number of young individuals found dead on the surface. The suspected cause of these deaths was fishing bycatch but plastic pollution is also a very real contender.
Recently, we had the chance to speak to a UK-based dive club who had visited Gibraltar for some training exercises. Whilst chatting about local marine flora and fauna one of the divers excitedly shared that he had seen his first Mola mola ever. It was very striking to watch as all the others recounted this as their highlight also. Pondering on it made me realise that we often take for granted many local species as we are habituated to encounters with them. The reality is that our coastline has many amazing species to behold and situations like these serve to remind us of that fact.
In the case of our stranded sunfish it is good news that the animal has not washed up on our shoreline. That would have been confirmation that it was beyond help and in its dying throes. Although she was cut up pretty badly from the rocks, these animals tend to have a very robust immune response and it is probable that a full recovery is being made. Rather than being a millstone around our necks, these animals are a fantastic icon of local Gibraltarian marine biodiversity.