The first marine fish extinction of the modern era

A new study has recently confirmed the extinction of the smooth handfish, the very first marine fish species to be declared officially extinct in the modern era. So what went wrong for these bottom-dwelling fish? And what lessons can we learn from their untimely demise?

spotted handfish 2
The spotted handfish is believed to be the closest living relative of the now extinct smooth handfish

Unfortunately, extinctions of marine species are nothing new in our oceans. In modern times several species have come to a swift end at the hands of humanity including the Caribbean monk seal and Steller’s sea cow. As we have continued to exploit the marine world, particularly for food and other valuable resources, many fish populations have also seen sharp declines, such as Atlantic cod and bluefin tuna. However until recently no marine fish species had been officially declared extinct on the highly influential IUCN Red List.

This is in part due to the limitations involved in accurately studying fish species, because of their wide geographic ranges and variable depths. However a recent study from researchers in Australia have confirmed that the bottom-dwelling smooth handfish (Sympterichthys unipennis) have now completely and permanently disappeared from the seafloor. It is a timely reminder that our oceans are not limitless or immune from human activity. It also highlights that unless changes are made soon, more species will be unnecessarily lost forever.

Smooth handfish

The smooth handfish were one of 14 (now 13) species of handfish, a group of bottom-dwelling fish with hand-like pectoral fins that are closely related to deep-sea anglerfish. Often described as a ‘missing-link’ type creature, these uniquely patterned fish are found exclusively on the seafloor where they walk around on their modified fins. The spotted handfish (Sympterichthys unipennis) were discovered in the early 1800’s in the region of south-eastern Australia where they were endemic. They were once so concentrated here that they were one of the first Australian marine species to be described by European scientists. However they have now not been seen in Australia for over a century, with everything we know about them coming from a single specimen (known as a holotype) collected over 200 years ago. This has led scientists working on behalf of the IUCN Red List to declare them as officially extinct earlier this year.

smooth handfish holotype
The only ever collected specimen of the smooth handfish. Almost everything we know about the species comes from this one specimen, known as a holotype

What went wrong?

Given how long it has been since anyone has seen a smooth handfish in the wild, it is likely that they were actually wiped out a long time ago. In addition to the fact we have only ever collected a single specimen and know so little about them, determining exactly what killed them off is a challenge. However the researchers involved believe the most likely culprit was habitat destruction by humans. Handfish are particularly vulnerable to habitat destruction, because unlike most other fish species they do not have a larval stage. Instead handfish mothers give birth to live young on the seafloor, meaning that they are highly localised to a single spot. Therefore the most likely scenario is that the early 20th century scallop fisheries in the area destroyed their habitat and wiped out the smooth handfish in the process.

Red handfish
A red handfish walks around the seafloor on its modified pectoral fins, because of its life as a bottom-dweller they are extremely susceptible to habitat destruction

Given their unique lifestyles, the other 13 species of handfish are also considered to be at extreme risk of following their relatives into extinction. Only 4 species have been seen in the wild since the turn of the century and all are listed as at least threatened on the IUCN red list. It is not too late for them yet, but unless the areas they reside in become fully protected by destructive fishing methods it may only be a matter of time until all the handfish disappear forever.

The first, but not the last

Although the smooth handfish now carries the title of the first marine fish species to become officially extinct, it is very unlikely that this is likely to be the case. Many researchers suspect that many other species that have not been seen for decades (including other handfish) have also likely perished. In addition to this there are likely many more niche species that were wiped out before we even got a chance to discover them. Given their limited geographical range, poorly understood history and the fact they haven’t been seen alive for over a century, it may seem like the disappearance of these species is somewhat insignificant. However many researchers would strongly disagree.

Ziebell's handfish
Ziebell’s handfish is another species that has not been seen for over a decade and is threatened by extinction

“I think people should be concerned about the extinction of any species, especially ones that humans are likely to have caused” says Jemina Stuart-Smith, a research fellow at the Institute for Marine and Antarctic Studies and manager of the Handfish Conservation Project , speaking to Mongabay earlier this year. “We don’t know enough about handfish to know what their ecological role is [and if extinction] will impact the ecosystems that they are a part [of], or whether it [the underlying causes] will lead to other extinctions. The Smooth handfish became extinct before we had a chance to study them”. It is therefore vital that we not only protect threatened marine species, but also learn as much about them as we can in case they disappear forever.

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