Scientists Seek Approval to Kill Sharks
enn.com — Federal scientists want permission to kill Galapagos sharks in the Northwestern Hawaiian Islands in an effort to save the endangered Hawaiian monk seal. Scientists argue that the monk seal is globally endangered but the sharks are not.
I can understand if scientists want to save the monk seal from extinction, but killing other species to, later, put them in danger of extinction is what I don't get. The reason the monk seals are in danger is because of human hands. According to the National Marine Fisheries Service (NMFS), mothers take care of their pups for six weeks. During that entire time, they do not leave the beach even to eat. Instead, they live off of fat that they have stored up over the previous year and feed their pups with a fat rich milk. Usually seals can be found with their pups on very remote beaches. However, recent births have been reported in the main Hawaiian Islands including Oahu, Kawai, and Molokai. Human disturbance has been identified as the primary factor in the decline of the species. In fact, if humans come too near a mother seal too often, she will abandon her pup and go out to sea. Unfortunately, this usually means death for the pup. Also, seals often get tangled in fishermen's nets and other trash in the oceans. It has been found that the fish that seals eat have been overfished by fishermen.
We need to keep in mind that sharks are essentials predators which help maintain the balance throughout the ecosystem. Eliminating sharks would have wider effects than just the monk seal. There are other ways we can prevent the extinction of the monk seal. The main threat to monk seals seems to be human intrusion into habitats and over-fishing. Certain beaches can be closed, so people do not get too close to seals raising pups or impose stiffer penalties for disturbing seals. The numbers of fish that can be caught in the areas where we have monk seals can be limit. We have to look at the bigger picture and find other ways to save the monk seals without the unintended consequences of unnecessary killing off a different species.
1 comment:
Aloha Lucy-
First thanks for blogging on this topic. Any chance to get dialog going on these issues is great. It needs to happen more often.
I am the Leader of the Hawaiian Monk Seal Research Program. And it is my team and our partners that are in charge of many of the efforts to research and recover monk seals across the Hawaiian Archipelago including the shark work you discuss here. Let me tell you, there’s been a lot of thought, discussion and debate that has gone into this work.
You have a lot of good information in the blog, but some of the conclusions that are drawn are either based on a faulty source of information or some incorrect assumptions. I just want to clarify a few points in case this conversation continues further.
First some background (an excerpt taken from a permit application):
Recent studies have shown that shark predation has been a significant factor contributing to early pup mortality at FFS, particularly at Trig Island. A significant number of pup deaths or disappearances related to shark predation have been either directly observed or inferred from previous events associated with shark predation on pups. Intense predation on preweaned pups and recently weaned pups was first detected at Trig and neighboring Whaleskate Island in the late 1990s, when 18-28 mortalities were documented each year from 1997-99. This equated to 38-69% of the annual cohort born at those sites. Atoll-wide, there have been 8-12 shark predation losses each of the last 7 years, equating to 15-21% of the annual cohort born at FFS. Last year (2007), 8 of the 43 pups born at FFS were believed lost due to shark predation. One other severely bitten pup was expected to die post season, and an additional weaned pup was reported missing prior to the start of the field season and may have been a shark predation mortality. This predation on pre-weaned pups is believed to involve a small number of persistent predators that first adopted the behavior after being attracted to the site by unusually high numbers of pup carcasses associated with two years of adult male seal aggression at Trig.
1. “I can understand if scientists want to save the monk seal from extinction, but killing other species to, later, put them in danger of extinction is what I don't get”.
After monitoring the sharks behavior and extensive discussions with shark experts and resource managers in the NWHI, two things were concluded. It was a small subset of G. sharks that were coming into the shallows to take pups and this type of behavior was extremely unusual for G. sharks. Nowhere else in the world do G. sharks swim into waters this shallow. It was also felt that if removal of this sharks was the course of action, the relatively small number of sharks would have no population level effects. In other words it would not “put them in danger of danger of extinction”.
2. “Human disturbance has been identified as the primary factor in the decline of the species.”
It would be great if we could point the finger at one factor to explain the decline of the seals. In reality the causes of the decline are numerous and differ in time in space. In other words, what is a major factor for seal mortality in one population or in one year, could be very different in another place or year. There are several human-RELATED issues that contribute to the decline or general risks to the seal (marine debris, fisheries, disturbance) but there are also natural factors that we are just as worried about (predation, disease, and competition for resources between monk seals and other top predators).
3. “We need to keep in mind that sharks are essentials predators which help maintain the balance throughout the ecosystem.”
You are absolutely correct on this point and it was one of the foundations in our decision-making process on these and other matters. However, “eliminating sharks would have wider effects than just the monk seal.” Is not a serious possibility. As stated previously we are not talking about the wholesale removal of sharks from the population (if that were the option followed).
4. “There are other ways we can prevent the extinction of the monk seal.”
Yes there are and we are developing the tools to deal with them and include captive feeding and protection of young seals, relocation to areas of higher survival, elimination of parasite loads to help animals maximize the energy they get from their food, and more. One thing you fail to mention in the blog is that we are also trying to find other ways to deal with the shark predation problem. This past year we didn’t attempt any removals of G. Sharks but tried using a number of deterrents to keep sharks away. If we can find another solution, we will take it. There is an article about our efforts in the Honolulu Advertiser from earlier in the year, however, it is in the archives so you have to buy it if you want to read it.
5. “The main threat to monk seals seems to be human intrusion into habitats and over-fishing.”
This is not accurate and oversimplifies an extremely complex conservation issue.
6. “Certain beaches can be closed, so people do not get too close to seals raising pups or impose stiffer penalties for disturbing seals. The numbers of fish that can be caught in the areas where we have monk seals can be limit. “
There is a whole other discussion that could go along with these points; and to a degree they are very valid. But you must consider what about the rights of the beach users, how do you balance that? Stiffer penalties are okay. The marine mammal protection act has very stiff penalties already, but it is very hard to prosecute. Fishing regulations… A clear link between monk seals and current fisheries has yet to be reasonably established, but if it is these types of discussions will take place. One important point is, that these suggestion only impact the 10% of the population that is in the main Hawaiian Islands. What about the 1000 seals that are in the NWHI? The population where less than 1 in 5 pups born will live to be an adult.
Sorry this was so long. I tried to just give you the tip of the iceberg of the information driving our decision-making. if you or your readers have any questions feel free to email me at charles.littnan AT noaa.gov
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