Written by Dr. Michelle Heupel
I learned something new last year. I love learning new things, but I sort of wish I didn’t have to learn this. The International Union for Conservation of Nature (IUCN) has something they call the Red List. This is a list of all the species of plant and animal (or as close as we can get to all of them) and their conservation status. Scientists volunteer their time to assess species and the results are listed with IUCN. An analysis of the IUCN data for sharks, skates and rays last year revealed that 5 of the 7 most threatened families were rays, not sharks. And on top of that there are more threatened ray (107) than shark (74) species. Wow, who knew?
This result was published in a paper by Nick Dulvy and a slew of us who contributed to the listings (http://elifesciences.org/content/3/e00590). I think all of us were stunned to see that the rays were so much more threatened than the sharks. So what does this mean in the real world? It means we have been catching and removing a lot of rays without realising the damage we are doing to their populations.
How did this happen? Great question. Skates and rays are not as well studied as sharks. Maybe they aren’t as cool? Maybe they aren’t as obvious? The reasons why vary, but the reality is not many people have or do study them. One reason these species aren’t well studied is that they have never really been the target of fisheries. They are typically taken as bycatch, meaning they just come up in the nets or lines when fishers are trying to catch something else. Historically bycatch species were usually not well studied because they weren’t high value or important species. Many of the rays that are killed each year may not even be harvested for food. They may simply be caught in nets, die during the fishing process and get tossed overboard. This means we haven’t really understood how many were being affected by fishing. Another, and possibly very important factor, is money. It is easier to get research money to study a target or high value species, it is much more difficult to get money to study bycatch, although that is changing as we grow more and more aware of the importance of bycatch species.
A giant shovelnose ray, one of the species with high value fins.
We haven’t done a good job of keeping track of what is happening with rays for a variety of reasons. In the meantime some rays have become pretty important to fisheries. For example, sawfish and guitarfish have some of the most valuable fins in the shark fin market. This means there is a lot of money to be made which provides incentive to fish these species, especially guitarfish. Sawfish, unfortunately are one of the groups that is worst off. These are amazing animals. A slightly flattened shark with a hedge trimmer for a nose! They use their nose, or saw, to whack fish and stun them or grub around in the mud for food. They are truly bizarre and beautiful. This really cool saw, however, means they get tangled up in nets very easily. Fishermen in the Gulf of Mexico used to kill them to get the out of their nets. And then there are the people who want the saw for a trophy. It’s surprising how many sawfish saws I have seen hanging on walls in bars, marinas, etc. When we viewed our current house the previous owner had a sawfish saw hung on one of the walls! All 5 species of sawfish are listed by the IUCN Red List as Endangered or Critically Endangered and their populations have declined around the globe. Australia is one of the remaining strongholds for many of these species, and in the US the smalltooth sawfish was the first elasmobranch included under the Endangered Species Act after their populations had declined by 95%. Recovery from such a large decline will be very long.
Dr Colin Simpfendorfer releasing a smalltooth sawfish in the Florida Everglades.
So, we need to start doing a better job conserving ray species. They need to become a priority research area. We know very little about even the basic biology of many species and under the current circumstances that isn’t good enough. We can, and should, do better. So while campaigning for better conservation and management of sharks spare a thought for the rays. They need our help too.