If you have snorkeled or dove on coral reefs you may have witnessed a curious sight. Normally, a large predatory fish swimming through a school of small potentially edible fish or near a crustacean such as a crab or shrimp causes those animals to scatter or hide. Perhaps think of a drone video you may have seen of a large shark swimming through a school of bait fish – there is a noticeable ring of clear water around the shark that moves with it. The fish are moving out of its way and trying not to be made into a meal. Yet if you look closely, sometimes these large fish stop in a certain area of a coral reef and rather than small fish or crustaceans swimming away, certain species swim closer and in fact sometimes swim right into the large fish's mouth! This is called a cleaning symbiosis and the locations on reefs are called cleaning stations. If you watch the whole encounter, you will see that the large fish swims slowly up to a certain point, opens its mouth, and waits patiently. Often the cleaner fish will do what might be called a little dance – signaling its intentions to the larger fish, effectively saying "Hey, don't eat me, I want to help you." The cleaner fish will go over the large fish's body, removing dead skin, and any parasites, and even swimming into its large mouth and doing the same. The small fish gets some food, and the large fish leaves healthier and there is some indication that the process is actually enjoyable for the larger fish.
We often hear about "nature red in tooth and claw" but it is becoming increasingly clear that cooperation and symbiosis have played as much of a role in shaping the world as competition. Maybe we liked the story of competition better since it allows us to live in certain ways that may be to our individual advantage.
My first foray into studying these relationships was in the Bahamas where I spent six weeks in the Exuma Cays Land and Sea Park studying grouper behavior. We wanted to find out how these fish were spending their time and the role of cleaning stations in impacting their movement and behavior. We mapped out an area of coral reef into grids and knew the location of a cleaning station in the area. We watched the fish to see what they did and where they did it, then removed the cleaning station to see if that changed anything – it did. The fish spent less time in that area and their behavior changed as a result. Just a simple test, but a step towards understanding the wider impact of these stations on fish behavior and movement patterns.
The next adventure learning about cleaner wrasse was on a trip to Thailand. The divemaster who I hired as a dive buddy was excited to be with me since he usually had a gaggle of tourist divers to lead around the reef and couldn't take a lot of time to just sit and watch. The methodology was simply to observe an individual cleaner wrasse for 15 minutes and count and record the number of seconds that it spent cleaning and which species it was cleaning. You might end up with a record of 10 different fish species which the cleaner wrasse had spent cleaning for a certain amount of seconds on average. This provided significant time to just watch, and I highly recommend this to those wanting to go into the field of marine biology. New technology is really helping us to do bigger and more complex work than we could ever have done before – but you still need to understand the places and the species. Sometimes people come up with explanations for their technological results and you can tell they have never or rarely spent any time on a coral reef or watching a particular species. Time in the water is precious!
And what to do about the mimic cleaner wrasse? This species looks virtually identical to the real thing except for the two large fangs. This species wiggles the same way as the real thing, the large fish stops and expects to be cleaned like it’s the real thing, and then next thing you know, a chunk of scale, flesh, or gill is taken. At one point I would have tried to explain this in light of the fall of humanity and that this must not have been a part of the original plan. However, these species were doing this, as best we can tell from the fossil record, long before humans came to be. I had always interpreted, or really been told, that death entering the world in the Genesis stories was a physical death. Biology and ecology made a whole lot more sense when I began to interact with Christian theologians who showed persuasively that this is not necessarily the case. It makes a lot more sense theologically to read those passages of Scripture in a different way and that what is being talked about is the separation between humans and God. Similarly, I had always interpreted, or really been told, that the word “good” in Genesis 1 meant “perfect.” Again, as I began to interact with a wider range of Christian theologians I learned that that word could and they would argue should mean something more like “fit for purpose.” God made a world that seems to need death to be creative. It doesn’t fit with what we might hope for in a God, but if it is a better explanation of reality and is consistent with the Scriptures, not what we hope they say, then we need to accept that and love God for who He is not what we wish Him to be. Perhaps we are all a little more like Voldemort than we would like, assuming death is the worst possible thing that can happen to us.