The colorful world of the coral reefs hides an incredible menagerie of complex life forms, and they are at risk as most corals around the world are under threat from climate change. But the Goby fish, one of the smallest of denizens of this vast kingdom, could be one of its saviors.
The goby fish is just about a tiny two inches long but is capable of maintaining the diversity and productivity of the coral reef community that stands out at tiny oases in the vast oceans with its increasing dead zones. This tiny fish variety is the most important link in the food chain and provides an endless supply of food to the bigger species.
Scientists have, for close to 2 centuries, have wondered about the ‘Darwin Paradox,’ the enduring mystery of the ability of coral reefs to thrive in tropical waters which are short on nutrients.
The Unique Relationship Between Coral Reefs And Goby Fish
The reefs teem with life amidst the aquatic wastelands, and it is the tiny colorful fish that are the biggest source of food for the bigger fish. These fishes are called ‘cryptobenthic’ due to their tendency to live on or near the seafloor or hide in crevices.
These fishes, including the goby fish, reproduce fast and die early, eaten by the larger fish within the first few weeks of their life.
Simon Brandl of Simon Fraser University, British Columbia, says that they are similar to a gummy balls jar. Every other fish has a go at these tiny morsels of food.
Brandl and his colleagues discovered that this fish species that has for long been ignored by the scientific community, is the cornerstone of the coral biosphere.
Despite the constant predation, the goby fish and also the cardinalfish and the blennies manage to thrive in the coral reefs. Through the study of the larva of the Goby fish, scientists were able to get to the bottom of this enduring mystery. The larvae of other fish species disperse into the open ocean, where they have a lower chance of survival.
But the larvae of the goby fish do not drift away but remain near the parents’ reefs. This vastly increases the percentage of survivors. These fish reproduce overwhelmingly and quickly replace the adult goby fish that have been eaten by predators.
Goby Fish Is Vital To The Balance
This source of food sustains the larger life forms in the coral reefs. Co-author of the study, Carole Baldwin, and a curator at the Smithsonian’s National Museum of Natural History said that bottom-dwelling fishes, like the goby fish, are a constant source of food but have never been recognized for their value.
These cryptobenthic fish dominate the lower rung of life around the coral reefs. The team comprising science from France, Canada, Australia, and the US, studied the goby fish and other members of the cryptobenthic fish in French Polynesia, Belize, and Australia.
The combed vast data on the coral fish varieties throws light on the unknown productivity of these bottom-dwelling reef fishes, and they contribute almost two-third of the larvae that are present near the reef.
The abundance of goby fish and other similar varieties such as the cardinal and the blennies, provide an incredible 57% of consumable biomass in the reefs. They also supply the basic food source for the larger varieties of reef fish which are a vital source of food for millions of pf people worldwide.
People diving or snorkeling among the coral reefs will see these tiny fish only as flashes of white, red, yellow, or orange as they move away to safety. And they are rarely seen. These tiny fish with their short life span reinforce the coral reef’s high productivity and supply an unlimited quantity of fresh fish that sustain an incredible array of life forms. These incredible pools of life and in stark contrast to vast expanses in the tropical oceans of the planet that are mostly barren of life forms.
And within these vast areas of barrenness, the coral reefs support these regions with a rich and exceptional biological variety. Naturalist Charles Darwin was aware of this stark contrast between the vast stretches of barren oceans interspersed by these tropical havens of rich life forms. He had commented on this phenomenon while voyaging through the atolls and islands of the Pacific Ocean.
The Darwin’s Paradox Still Exists
But even Darwin was not able to fully explain the reason these outposts of rich life could survive and even flourish in these low-productive tropical oceans with their low nutrient levels. this ecological dilemma came to be termed the ‘Darwin’s Paradox,’ and has continued to intrigue scientists for 2 centuries.
Brandl says that the work by his team does not claim to fully explain the paradox. But the discovery of the role of fishes like the goby fish throws some light on the reasons that are behind the ability of the coral reefs to support such a rich a diverse marine ecology.
The goby fish and other cryptobenthic varieties stay hidden in the crevasses, canyons, grottos, and other hidden nooks and crannies within reef rocks and coral heads. This has made any research on them difficult.
Their lifespan is also quite short, with some living for a mere 59 days, with just 25 of them as adults. But given their rapid growth and high vulnerability and mortality, it is difficult to understand how the goby fish manage to survive and maintain their population.
Even the largest fish species in the food chain, the sharks and the barracudas depend on a complex food chain that starts with the goby fish and similar varieties.
These incredible creatures manage to reproduce larvae at a rate faster than which they are devoured. The goby fish highlights the importance of the smallest of fish species for the survival of the species at the top of the food chain. Brandl says that these fishes need to be more closely studied to understand the coral reefs more thoroughly, especially as they are going through rapid alterations due to climate changes.