The following is a semi-formal lab report of my project thus far. This is the most tangible form of data, analysis, planning, and procedure that I can provide on my website. The report involves detailed explanations for why my project was conducted, plans for the future, and the results that have been collected to-date. Please keep in mind that this tagging project is ongoing and that a substantial amount of research and work is to be done beginning in April and continuing through the summer of 2019.
Sustaining the Martha’s Vineyard Channeled Whelk Populations and Fisheries Through Drilling and Tagging Practices
By Victoria Scott
Abstract
For the past several years the populations of channeled whelk (Busycotypus canaliculatus) in the waters surrounding Martha’s Vineyard have significantly declined, threatening both the species and its abundance as well as the whelk fishery. This research project is ongoing and focuses on developing and possibly implementing a new method of tagging and protecting large female whelk that involves drilling small holes into their outer shells. Thus far, eight local female whelk have been drilled, placed in a tank alongside a control group of eight other females, their behavior has been monitored, and they have been released into the outer Vineyard Haven Harbor where they will be recaptured in the spring of 2019. After several months of observing the tagged female whelk it was concluded that their behavior did not differ from that of the control group, and that the holes in their shells did not appear to have an impact on their ability to survive. This preliminary research established that drilled holes have the potential to be effective and feasible tags that could be used to protect large female channeled whelk.
Introduction
For generations the island of Martha’s Vineyard has been home to fishermen who make their living by catching and selling local channeled whelk (Busycotypus canaliculatus.) However, in recent years there has been a noticeable decline in the populations of channeled whelk in Martha's Vineyard waters, and as a result the Massachusetts Division of Marine Fisheries has increased the minimum gauge size to keep a caught specimen, and has recently proposed a new regulation that would increase the minimum size by 1/8th of an inch every year for the next ten years, eventually making the final gauge size 3 ⅞’’.
Though these changes are meant to protect the younger individuals in the populations so that they have a more likely chance of reaching sexual maturity, the MDMF has received severe backlash from whelk fishermen throughout Massachusetts. Increasing the minimum gauge size would not only dramatically decrease the sizes of the catches for the fishermen (who already feel as though their businesses are beginning to struggle with the current size), but it would also increase the amount of large, fertile female whelks that are being harvested.
Female whelks are significantly larger than males, so much so that this proposed gauge increase has the potential to ensure that fishermen would be catching and keeping females almost exclusively. This is a major source of concern for many biologists and experts, primarily because of the popular opinion that female whelks that are especially large have a greater capacity to carry eggs. Under this theory, by putting extra fishing pressure on these large females the fishermen would essentially be harvesting the individuals that are the greatest contributors to the population.
This project focuses on protecting such females. Beginning in October of 2018 a tagging project began that involves drilling two small holes in the outer shells of several large female whelk, and then observing their behavior alongside a control group. If using holes as a tagging method is proven not to negatively impact the behaviors and survival rates of these whelk, it could potentially be brought to the Massachusetts Division of Marine Fisheries which could pass a regulation that would protect any caught whelk with holes in their shells from being harvested, much like the lobster V-notching project.
Over the course of several months, eight drilled female whelks in a tank at the Martha’s Vineyard Shellfish Group headquarters were closely monitored. The tagged specimens were compared to the eight untagged whelk which were in the same tank, separated by a divider.
Although this project is ongoing, this preliminary research trial was expected to be successful. Since there has been no past research which would suggest otherwise, it was predicted that the holes in the shells of the whelk would not impede the use of their feet (the lower parts of their bodies which come out of the shell) to move or feed.
Materials and Methods
Results
Figure 1: A graph which displays the relationship between declining temperatures of the water in the tank and the declining amounts of recorded movement of the eight tagged whelk in the tank between October 20 and December 5 of 2018.
Figure 2: A chart displays that over the course of two months the rates of survival rates of both the control group of eight whelks and the tagged group of eight whelks remained unaffected - 100% of the whelks in both groups survived while they were observed in the saltwater tanks.
On October 11, 2018 eight female channeled whelk were drilled, tagged, and placed in a saltwater tank alongside a control group of eight female whelk at the Shellfish Hatchery. They remained in the tank under video surveillance and weekly monitoring until December 5, 2018. Throughout this time period there was a dramatic decline in the temperature of the water in the tank the whelk were being kept in (due to seasonal temperature changes.) Figure 1 demonstrates that this decline in the temperature in the tank corresponded with a decrease in tagged whelk movements that were captured on time lapse video footage. For the duration of the observational period none of the food provided (quahogs and scallops) to the whelk was consumed by any of the individuals in the control or tagged side of the tank. Quahogs were placed in the tank initially and after one week of being left uneaten it was decided that one quahog from each side of the tank would be partially crushed and placed back into the water. This was an attempt to intensify the scent of the quahog and to allow for the whelk to access the meat of the clam more easily. Despite this attempt, all of the quahogs remained uneaten and they were replaced with scallops under the impression that the shells of scallops may have been easier for the whelk to pry open. This had no effect on the eating habits of the control or experimental whelk, and throughout their entire time in the tank none of them consumed any food, giving no indication as to whether or not the drilling of the observed whelks had any impact on their feeding habits or abilities.
It is suspected that both the lack of feeding and declining movements of the whelk can be attributed to the decline in water temperatures (fig. 1) that was observed throughout the study. In the winter months, wild whelk typically bury themselves into the sand or mud on the seafloor, where they stay relatively dormant until the water temperature begins to rise again. Due to the fact that the observational period was during the time of year in which the whelk would normally be in this dormant state, it would be reasonable to link their disinterest in the food provided and their increasing lethargy to the coldness of the tank water.
Although it can’t be concluded whether or not the drilled holes affect the eating habits of the whelk, Figure 2 establishes that throughout the study there were no mortalities within the control or the tagged groups. The identical survival rates of the whelk after their two month period in the tank indicate that drilling the holes did not have an immediate effect on the ability of the treated group to survive. Additionally, the time lapse footage that was captured provides evidence that the holes in the shells of the whelk in the treated group did not have any apparent impact on their ability to move.
Although there was not a substantial amount of data that could be collected over the course of the observational period, the results of this primary study are encouraging. No evidence was collected that would indicate that the use of holes as a method of tagging female channeled whelk has a short-term effect on their ability to thrive.
Discussion
This project is ongoing and it is planned that in April of 2019 there will be efforts to attempt to recapture the whelks that were tagged and released in order to determine whether or not the holes had a long-term impact on their survival in the wild. The status of the holes themselves will also be evaluated. It is expected that the shells of the whelk will begin to fill in around the holes after some time, so the amount of time for which a tagged whelk can be protected will depend upon the amount of time it takes for the holes in its shell to fill in. Throughout the spring and summer of 2019 there will be continued efforts to obtain more control and treated groups of female channeled whelk which will be observed in order to gather more conclusive data.
Ideally, future research will allow for it to be concluded that using drilling as a tagging method does not harm female channeled whelk in any way, and that it could be a new method of protecting those individuals that contribute the most to their population. With the help of the Massachusetts Division of Marine Fisheries, drilled tags could become a legal means of sustaining both the whelk populations and the whelk fishery on Martha’s Vineyard.
The preliminary results of this study establish that using holes as a tagging method has no immediate impact on the survival of the whelks, which is both encouraging and provides motive to conduct future research to truly determine if this method could be put into use on the Vineyard.
References
Busycotypus canaliculatus. (n.d.). Retrieved February 22, 2019, from http://www.exoticsguide.org/busycotypus_canaliculatus
Michael C. Bell, Fiona Matheson (2014, December 9). V-notching in the Orkney lobster fishery, 2013. Retrieved from https://www.orkneyfisheries.com/copy-of-green-development-project
Nelson, Gary & H Wilcox, Steve & Glenn, Robert & L Pugh, Tracy. (2018). A Stock Assessment of Channeled Whelk (Busycotypus canaliculatus) in Nantucket Sound, Massachusetts. Retrieved from https://www.researchgate.net/publication/324058768_A_Stock_Assessment_of_Channeled_Whelk_Busycotypus_canaliculatus_in_Nantucket_Sound_Massachusetts
Rhode Island Sea Grant. (2014, July 21). Retrieved March 15, 2019, from https://seagrant.gso.uri.edu/the-secret-life-of-whelks/
Sustaining the Martha’s Vineyard Channeled Whelk Populations and Fisheries Through Drilling and Tagging Practices
By Victoria Scott
Abstract
For the past several years the populations of channeled whelk (Busycotypus canaliculatus) in the waters surrounding Martha’s Vineyard have significantly declined, threatening both the species and its abundance as well as the whelk fishery. This research project is ongoing and focuses on developing and possibly implementing a new method of tagging and protecting large female whelk that involves drilling small holes into their outer shells. Thus far, eight local female whelk have been drilled, placed in a tank alongside a control group of eight other females, their behavior has been monitored, and they have been released into the outer Vineyard Haven Harbor where they will be recaptured in the spring of 2019. After several months of observing the tagged female whelk it was concluded that their behavior did not differ from that of the control group, and that the holes in their shells did not appear to have an impact on their ability to survive. This preliminary research established that drilled holes have the potential to be effective and feasible tags that could be used to protect large female channeled whelk.
Introduction
For generations the island of Martha’s Vineyard has been home to fishermen who make their living by catching and selling local channeled whelk (Busycotypus canaliculatus.) However, in recent years there has been a noticeable decline in the populations of channeled whelk in Martha's Vineyard waters, and as a result the Massachusetts Division of Marine Fisheries has increased the minimum gauge size to keep a caught specimen, and has recently proposed a new regulation that would increase the minimum size by 1/8th of an inch every year for the next ten years, eventually making the final gauge size 3 ⅞’’.
Though these changes are meant to protect the younger individuals in the populations so that they have a more likely chance of reaching sexual maturity, the MDMF has received severe backlash from whelk fishermen throughout Massachusetts. Increasing the minimum gauge size would not only dramatically decrease the sizes of the catches for the fishermen (who already feel as though their businesses are beginning to struggle with the current size), but it would also increase the amount of large, fertile female whelks that are being harvested.
Female whelks are significantly larger than males, so much so that this proposed gauge increase has the potential to ensure that fishermen would be catching and keeping females almost exclusively. This is a major source of concern for many biologists and experts, primarily because of the popular opinion that female whelks that are especially large have a greater capacity to carry eggs. Under this theory, by putting extra fishing pressure on these large females the fishermen would essentially be harvesting the individuals that are the greatest contributors to the population.
This project focuses on protecting such females. Beginning in October of 2018 a tagging project began that involves drilling two small holes in the outer shells of several large female whelk, and then observing their behavior alongside a control group. If using holes as a tagging method is proven not to negatively impact the behaviors and survival rates of these whelk, it could potentially be brought to the Massachusetts Division of Marine Fisheries which could pass a regulation that would protect any caught whelk with holes in their shells from being harvested, much like the lobster V-notching project.
Over the course of several months, eight drilled female whelks in a tank at the Martha’s Vineyard Shellfish Group headquarters were closely monitored. The tagged specimens were compared to the eight untagged whelk which were in the same tank, separated by a divider.
Although this project is ongoing, this preliminary research trial was expected to be successful. Since there has been no past research which would suggest otherwise, it was predicted that the holes in the shells of the whelk would not impede the use of their feet (the lower parts of their bodies which come out of the shell) to move or feed.
Materials and Methods
- On October 9, sixteen large female whelks were obtained from Tom Turner, a local fisherman from Katama, and brought to the Martha’s Vineyard Shellfish Group, inc.
- Super glue was used to tag each whelk with small numbered tags on the whorls of their shell - this was for identification purposes.
- After the initial tagging, the lengths and gauge sizes of each whelk were measured and recorded; the whelks were all roughly equal in size.
- The sixteen whelk were then randomly divided into two equal groups of eight, one group to serve as a control and the other to later be tagged.
- A large saltwater tank was used to hold the whelks at the Shellfish Hatchery. A wooden divider with holes was placed in the middle of the tank in order to separate the two groups while maintaining equal conditions (flow rate, water temperature, etc.) between them. The two groups were then placed on either side of the divider.
- Several days later, one group of eight whelk were taken to Tom Turner’s house. An industrial-grade drill was used to drill two small holes (approximately 2.5 cm diameter) in the outer ridges of the shells of each whelk.
- Large yellow tags were then looped through the two holes of each whelk, it was attempted to make the tags as minimally-invasive as possible (avoiding the foot of the animal, etc.)
- The whelk were then taken back to the MV Shellfish Group and placed on their designated sides of the holding tank.
- One week later a time lapse camera was set up using zip ties and a small ladder to capture footage of the side of the tank that held the experimental (drilled) group of whelk.
- Five quahogs (two small and three large) were placed on both sides of the tank.
- The temperature of the water in the tank was measured on either side of the divider.
- One week later all sixteen whelks were checked and remained alive. The time lapse footage was also checked and the camera was set up once again.
- All ten of the quahogs remained uneaten. A cinder block was used to partially smash two large quahogs. One of the smashed quahogs was placed on either side of the divider in the tank. This was done in order to intensify the scent of the clams and possibly attract more attention to them from the whelk.
- The water temperatures on both sides of the tank were measured once again.
- One week later the whelk were checked on again and all sixteen remained alive. The time lapse footage was checked and the camera was set back up.
- All ten of the quahogs remained uneaten. They were removed from the tank and replaced with three large bay scallops on either side of the divider. Bay scallops were used because they may have been easier for the whelks to pry open and consume.
- The temperature of the water on both sides of the tank was measured once again.
- Four days later the whelks were checked on again and the water temperature was measured. All of the whelks remained alive and all of the scallops remained uneaten.
- The flow rate of the water was reduced on both sides of the tank. This was done to warm the temperature and reduce the flow of the water, which would intensify the scent of the scallops and potentially make it easier for the whelks to locate the scallops.
- For the next several weeks the whelks, water temperature, and time lapse footage was monitored on a weekly basis.
- On December 5 all of the whelks remained alive in the tank and none of the scallops had been eaten. The sixteen whelks were then placed in buckets and driven to the lagoon in Vineyard Haven.
- The whelks were loaded into a small fishing boat and driven from the lagoon, under the drawbridge, and into the outer Vineyard Haven Harbor.
- A buoy about twenty yards offshore was used as a marker, and all sixteen whelks were thrown off the side of the boat into the harbor.
- In April, snorkels and kayaks will be used to attempt to recapture the tagged whelk and observe their survival and the status of the holes in their shells.
Results
Figure 1: A graph which displays the relationship between declining temperatures of the water in the tank and the declining amounts of recorded movement of the eight tagged whelk in the tank between October 20 and December 5 of 2018.
Figure 2: A chart displays that over the course of two months the rates of survival rates of both the control group of eight whelks and the tagged group of eight whelks remained unaffected - 100% of the whelks in both groups survived while they were observed in the saltwater tanks.
On October 11, 2018 eight female channeled whelk were drilled, tagged, and placed in a saltwater tank alongside a control group of eight female whelk at the Shellfish Hatchery. They remained in the tank under video surveillance and weekly monitoring until December 5, 2018. Throughout this time period there was a dramatic decline in the temperature of the water in the tank the whelk were being kept in (due to seasonal temperature changes.) Figure 1 demonstrates that this decline in the temperature in the tank corresponded with a decrease in tagged whelk movements that were captured on time lapse video footage. For the duration of the observational period none of the food provided (quahogs and scallops) to the whelk was consumed by any of the individuals in the control or tagged side of the tank. Quahogs were placed in the tank initially and after one week of being left uneaten it was decided that one quahog from each side of the tank would be partially crushed and placed back into the water. This was an attempt to intensify the scent of the quahog and to allow for the whelk to access the meat of the clam more easily. Despite this attempt, all of the quahogs remained uneaten and they were replaced with scallops under the impression that the shells of scallops may have been easier for the whelk to pry open. This had no effect on the eating habits of the control or experimental whelk, and throughout their entire time in the tank none of them consumed any food, giving no indication as to whether or not the drilling of the observed whelks had any impact on their feeding habits or abilities.
It is suspected that both the lack of feeding and declining movements of the whelk can be attributed to the decline in water temperatures (fig. 1) that was observed throughout the study. In the winter months, wild whelk typically bury themselves into the sand or mud on the seafloor, where they stay relatively dormant until the water temperature begins to rise again. Due to the fact that the observational period was during the time of year in which the whelk would normally be in this dormant state, it would be reasonable to link their disinterest in the food provided and their increasing lethargy to the coldness of the tank water.
Although it can’t be concluded whether or not the drilled holes affect the eating habits of the whelk, Figure 2 establishes that throughout the study there were no mortalities within the control or the tagged groups. The identical survival rates of the whelk after their two month period in the tank indicate that drilling the holes did not have an immediate effect on the ability of the treated group to survive. Additionally, the time lapse footage that was captured provides evidence that the holes in the shells of the whelk in the treated group did not have any apparent impact on their ability to move.
Although there was not a substantial amount of data that could be collected over the course of the observational period, the results of this primary study are encouraging. No evidence was collected that would indicate that the use of holes as a method of tagging female channeled whelk has a short-term effect on their ability to thrive.
Discussion
This project is ongoing and it is planned that in April of 2019 there will be efforts to attempt to recapture the whelks that were tagged and released in order to determine whether or not the holes had a long-term impact on their survival in the wild. The status of the holes themselves will also be evaluated. It is expected that the shells of the whelk will begin to fill in around the holes after some time, so the amount of time for which a tagged whelk can be protected will depend upon the amount of time it takes for the holes in its shell to fill in. Throughout the spring and summer of 2019 there will be continued efforts to obtain more control and treated groups of female channeled whelk which will be observed in order to gather more conclusive data.
Ideally, future research will allow for it to be concluded that using drilling as a tagging method does not harm female channeled whelk in any way, and that it could be a new method of protecting those individuals that contribute the most to their population. With the help of the Massachusetts Division of Marine Fisheries, drilled tags could become a legal means of sustaining both the whelk populations and the whelk fishery on Martha’s Vineyard.
The preliminary results of this study establish that using holes as a tagging method has no immediate impact on the survival of the whelks, which is both encouraging and provides motive to conduct future research to truly determine if this method could be put into use on the Vineyard.
References
Busycotypus canaliculatus. (n.d.). Retrieved February 22, 2019, from http://www.exoticsguide.org/busycotypus_canaliculatus
Michael C. Bell, Fiona Matheson (2014, December 9). V-notching in the Orkney lobster fishery, 2013. Retrieved from https://www.orkneyfisheries.com/copy-of-green-development-project
Nelson, Gary & H Wilcox, Steve & Glenn, Robert & L Pugh, Tracy. (2018). A Stock Assessment of Channeled Whelk (Busycotypus canaliculatus) in Nantucket Sound, Massachusetts. Retrieved from https://www.researchgate.net/publication/324058768_A_Stock_Assessment_of_Channeled_Whelk_Busycotypus_canaliculatus_in_Nantucket_Sound_Massachusetts
Rhode Island Sea Grant. (2014, July 21). Retrieved March 15, 2019, from https://seagrant.gso.uri.edu/the-secret-life-of-whelks/