As we all know, fisheries are an important food sources to us, especially those who live in the coastal areas. There are industrial fisheries that work on large spatial scales of marine ecosystems, as well as small scale industries, which are on more local spatial scales. Such animals that are fished be fisheries include: salmon, cod, tuna, mullets, squid, oysters, scallops, crabs, lobsters, shrimps, and many more marine species. Sometimes because of our fishing activities we have caused much environmental problems to the marine ecosystems including overfishing, and accidental bycatch which has cause population declines in target species as well as non-target species. Such population declines of various species can disrupt the marine food web and cause problems in trophic cascades. This can overall, decrease the biodiversity of such marine ecosystems. In this news article, scientists of the University of Exeter, have been studying how the fisheries of the Mediterranean Sea impact the bottlenose dolphins, as well as how the dolphins impact the fishing business.
Most of the Fishing business of the Mediterranean sea are small scale operations, which has cost them thousands of euros to fix the damage the dolphins caused on their fishing nets. They seemed to have learned to associate the nets with the fish they catch. So, lately they have been stealing the fishes from the nets as an easy food source, instead of actually hunting for the fish themselves, as said by lead author Robin Snape, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus. Such problems have probably resulted in low fish stocks, which in turn have lead low catches due to the dolphins. However, even though the dolphins seem to be taking advantage of the nets and tearing them up, there is still the risk of such organisms being entangled and drowning. The authors have estimated that about ten dolphins in the Mediterranean die due to entanglement and drowning from the nets. Much of the funding for this study came from the Society for the Protection of Turtles.
Dolphins tear up nets as fish numbers fall
Tyler,
ReplyDeleteGreat post! I never thought about how fisheries might make it easier for predators to find food. I wonder if there are other organisms that feed from these nets. I also wonder what kinds of other animals get entangled in these nets, and how often this occurs.
As someone who lived near the Mediterranean for a few years, I saw firsthand house important local fishing businesses are to the coastal communities there. Dolphins have been shown before to be highly intelligent and I think it is fascinating that they have adapted this feeding strategy. I do not know much about the process of commercial fishing, but I wonder if there is a way that the fishermen could provide the dolphins with the bycatch fish? With their intelligence, it may be possible to "train" the dolphins to be patient and wait for the fishermen to toss fish overboard rather than having to expend the effort of tearing through nets. This way, the dolphins would still receive food without the profits of the fishermen being harmed; it could also reduce the risk of dolphins becoming entangled.
ReplyDeleteI like how you incorporated your post into this week's lecture! I think that the problem of bycatch is very interesting, being that it seems like a problem that could be avoided easily (although this isn't the case). I would like to see more follow up from lecture and your post on how the different techniques preventing bycatch are working!
ReplyDeleteThis feeding strategy used by these dolphins is interesting! It is amazing how they have adapted to learning how to use these nets to their advantage. I wonder if this strategy has other disadvantages besides getting caught in the net though. I wonder if having this easier access to fish has increased their dependency and decreased their natural ability to hunt for fish instead. Studies investigating what impact taking away this easy access to fish on the dolphin's hunting behavior would be interesting.
ReplyDeleteI thought this was incredibly interesting because it is just one example of how industrious and intelligent dolphins are. Many of us know that they are one of the smartest animals in the animal kingdom, yet such adaptability and logic was unbeknownst to me. I think it is also an amazing example of how animals are adopting to human influence and destruction. Despite low fish numbers from over fishing, dolphins have found a way to cope and adapt to these anthropological disasters.
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