By Abigail Lynch

Fish are the most diverse group of vertebrates on earth – almost 28,000 species — more than half of all living vertebrate species.  So, perhaps, it isn’t surprising that fish have the record for both the shortest and longest vertebrate lifespan.  While a pet Goldfish (Carassius auratus) has a typical lifespan of 6-7 years, they have been reported to live as long as 30 years (Lorenzoni et al. 2007).  Still your average aquarium fish cannot compare to these short-lived and long-lived species!

Shortest-lived

The record for shortest recorded vertebrate lifespan goes to the Coral Reef Pygmy Goby (Eviota sigillata).  This little Indo-West Pacific reef fish, less than an inch long, has a lifetime which isn’t much longer.  It spends three weeks as larvae, quickly metamorphoses within one to two weeks, and settles on a nearby reef where it will spend its entire adult lifespan of less than a month (Depczynski and Bellwood 2005).  There is no record of Coral Reef Pygmy Gobies surviving even to 60 days.

The previous “record holder,” the Turquoise Killifish (Notobranchius furzeri), was documented surviving a lengthy 12 weeks (Valdesalici and Cellerino 2003).  These fish are found in vernal pools that pop up in the rainy season of equatorial Africa and have evolved to complete their full reproductive cycle before the pools dry up.   For both the Turquoise Killifish and Coral Reef Pygmy Goby, taking a ‘live fast, die young’ approach to life is an evolutionary advantage to ensure survival of the species.  They are small fish with high mortality rates and reproducing as quickly as possible is their best chance to pass along their genes.

Longest-lived

Some of the best documented examples of long-lived fish come from pets that have survived generations of owners.    Åle, as one example, was a European eel (Anguilla anguilla) that lived in a well in Brantevik, Sweden.  The eel was believed to have been placed in the well in 1859 and lived there a comfortable 155 years!  Koi (Cyprinus carpio haematopterus) are another long-lived pet fish.  While most don’t live more than 70 years (a commendable feat on its own), the oldest recorded Koi, “Hanako,” was born in 1751 and lived for 226 years!   She lived in three centuries, through multiple world wars, and major evolutions and revolutions in human society.  At the time of her death in 1977, Hanako was older than United States!

While these centenarians have impressive records, they don’t even come close to the longest-lived fish (and longest-lived vertebrate).  Greenland Sharks (Somniosus microcephalus) have an average lifespan of at least 272 years with the oldest recorded at 392 – almost four centuries!  Nielsen and colleagues (2016) radiocarbon dated (the same process used for archeological digs) the eye lenses of 28 Greenland Sharks caught as bycatch in arctic and subarctic ground fisheries.  Because Greenland Sharks are very slow growing and reproducing (not reaching sexual maturity until at least 156 years old), they may be susceptible to overfishing.

It’s pretty mind-boggling to think of all of the changes that have occurred in within the lifespan of a Greenland Shark born 400 years ago…wonder what will happen within the lifespan of a Greenland Shark born today??!?