August 23, 2022
...not an easy life
Sunday, June 18, will be Father’s Day in many parts of the world. It’s a day to show some respect to all the fathers who support and care for their families – not as big a deal as Mother’s Day, perhaps, but a special occasion all the same.
Among sea creatures, there is not much family life as people know it. Only the birds have real two-parent families, in which the jobs of making a home, getting food and looking after the children are shared between mother and father. The marine mammals – whales, dolphins and manatees – do look after their one or two offspring for a long time after birth, but that’s almost entirely the job of the mothers. Fathers provide some general protection for the group, but when the chips are down the mothers are the fiercest fighters.
For sea turtles, crocodiles and most fish, the rules of species survival are simple – make big strong babies and make a lot of them, since most will be eaten before or soon after the eggs hatch. There are ways to improve the odds. Mother sea turtles and crocodiles carefully choose and hide their nesting sites, mother octopus lay eggs in a den and watch over them until they hatch, mother lobsters carry their eggs around until they are ready to hatch, and sharks and stingrays have live young that can take care of themselves from the moment they’re born.
Some fathers do take on the egg-tending job. Male sergeant majors darken their silver and yellow stripes to a uniform slate blue and stand guard aggressively over their bright purple eggs. Male jawfish carry eggs in their huge mouths until they hatch. And male seahorses actually get pregnant. The male seahorse has a brood pouch on his abdomen (like a kangaroo) where the female deposits her eggs. The male fertilizes them and carries them in the pouch for 10–45 days, depending on species. When the eggs hatch, he “gives birth” to hundreds of very small but perfectly formed new seahorses.
Male damselfish do some home-making. They stake out a territory, defend it aggressively, and may even “farm” the algae and soft corals they like to eat. At spawning time these males build rocky nests, and the ones who defend the best feeding territories and build the best nests have the most mothers coming to lay eggs.
Most fish that spawn in large swarms spend the rest of the year hunting alone or in small groups. The loneliest fathers of all are probably the sea turtles. They live fifty years or more and spend all of that time at sea, most of it alone. However, for a couple of days every year or two there may be a female to chase, and with the never-ending search for food and the ever-present need to avoid becoming food, there’s no time to be bored.
Among the fish that normally spend their lives in groups, some of the fathers were once mothers. Most wrasses and parrotfish begin as females, and most of them stay that way. However, if a group loses its dominant male or doesn’t have enough males for good balance, one of the adult females can become – in a matter of weeks – a fully functional male complete with distinctive bright colours and body shape.
Whatever their family structure, all these sea creatures have the same basic needs – clean, safe places for adults to breed and babies to grow. The Special Fisheries Conservation Areas (fish sanctuaries) in the Marine Park help to fill this need. We’re already seeing larger schools of some fast-maturing smaller fish, and where these exist in large numbers the big hunters won’t be far behind. Our marine life may be a small fraction of what it once was, but it’s not gone. We can save what’s left, and we can grow more.
