Juvenile Fish Are Wielding Sea Anemones Like Shields Against Predators

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Juvenile Fish Are Wielding Sea Anemones Like Shields Against Predators

Small fish off the coast of Tahiti have evolved a large adaptation in order to avoid becoming prey. Divers captured a silver half-dollar shaped fish known as Myers’ Pomfret with its scientific name Brama myers (19459006) “riding” an anthozoan larvae, or sea anemone. Divers hypothesize, with the invertebrate neatly tucked between the fishes’ pelvic fins, that the little fish is using the sea anemone to defend itself against predators. Fish and Anemones – A Symbiotic Relationship Rich Collins, Image Credit

This is not the first time that this type of relationship has been observed between larval anemones and juvenile fish. Newly hatched species of fish have been seen in Florida’s West Palm Beach carrying larvae anemones in their mouths and encasing them with sharp teeth. It is well documented that anemones and fish have a symbiotic relationship. Just ask fans of Finding Nemo (19459005). The anemone, which is venomous, protects its fishy host, and the inhabitant fish provides nutrition to it. The photographs published recently in Journal of Fish Biologyshow that the anemone and fish relationship is much more complex than thought.

Stinging shield

Young bamidae with an anemone. Rich Collins, consultant and diver at Florida Museum of Natural History said that some vulnerable juvenile or larval fishes use invertebrate animals for defense. Diverse took photos during nighttime blackwater drift dives. This is when divers are drifting into open, deep water to take pictures of marine life between the hours of 7:30 pm and 10:00 pm. Diverse captured images in depths up to 60 feet. All of the photos were taken at the epipelagic zones, which is where sunlight still penetrates the deepest parts.

A variety of fish were observed associating anemones – filefish, driftfish and young jacks all carried larval button polyps or tube anemones in their mouths. The marine anthozoans, which include corals, sea fan, and anemones, lack any bones. The invertebrates have stinging nematocysts (microscopically small harpoon cells) and polyps. Gabriel Alfonso said that the sting of a larval stinging anemone would not kill an would-be predator but it would make the sting “unpalatable.” The anemone could benefit by being moved to a new area. The authors of the study wrote: “Fishes at an early developmental stage have different survival strategies in their interactions with invertebrates. They may hide within them or mimic invertebrate species that are venomous or unpalatable or those low in nutrition. Or they might swim alongside or form associations between the fishes, the anthozoans, and the epipelagic water. These images, collected by citizen scientists and community scientists, highlight the importance of emerging blackwater photography as well as how it can improve our understanding of oceans around the globe. The authors concluded that “this novel data source offers many insights previously unavailable through scientific specimens, such as color, behavior and associations with other planktonic animals.” We highlight the importance of community science in the advancement of Ichthyology, by emphasizing its relationship with the Blackwater Divers community.