The Eggs that Stick Together, Stay Together!
Fishes have long fascinated biologists that study the science behind reproduction, as we discussed in Episode 4. However, how fishes reproduce is not the end of the story. The process from birth to individual survivial is as equally varied as the ways fishes reproduce. The majority of fishes lay eggs in the water column, which may be sticky so they can be deposited on some form of shelter, such as a drifting log or piece of kelp (e.g., flyingfish, killifishes, clownfishes). Others give birth to live young (e.g., guppies, dogsharks, coelacanths). Following birth, the juvenile fishes of many species find themselves on their own, fighting to survive. These larval and juvenile fishes may be morphologically similar to their adult forms (e.g, minnows, cichlids), or their anatomy may dramatically differ as the larval forms of many marine fishes find themselves inhabiting completely different habitats than those they will occupy when they are adults. Other fishes actually protect their young, such as the famous example of seahorses and seadragons, where males shelter and care for the eggs in modified poches until they hatch. Stranger still, is the marine engineer goby (Pholidichthys), where two adult fish live in a colony with their juvenile offspring. The juveniles have been observed gathering food during the day and bringing the nutrients back to the reproductive adults that are burrowed deeply underground, that then proceed to feed off of "slime" covering the bodies of the juveniles. No one ever said parenting was glamorous, even for a fish!
So long, and thanks for all the fish!