Ocean Sunfish Necropsy on Sandy Neck, Barnstable MA.
Friday, December 30, 2011
Ocean Sunfish Necropsy on Sandy Neck, Barnstable MA.
Written by Michael O'Neill and Krill Carson
On Friday, December 23rd, a fresh ocean sunfish carcass washed up on Sandy Neck Beach in Barnstable MA. NECWA was notified of this carcass a few days later and a team of volunteers headed down to the Cape Cod on Tuesday, December 27th. Our goal was to try and relocate and necropsy this animal. If we were successful, this would be the latest date for any fresh carcass to wash ashore. The NECWA team included Tammy, Patty, Nick, Michael and Krill.
When we arrived at the gatehouse at Sandy Neck Beach Park (click here for website) we met Ranger Matthew and Ranger Nina. Both were super helpful in learning more about this carcass and its location on the beach. Ranger Matthew offered to drive us and all our gear to the site of the carcass and assist if needed during the examinations. We really appreciated that offer since we were not familiar with this barrier beach area that includes over 4,700 acres of dunes, maritime forest and marshes.
As we drove down the beach, we marveled at the excellent and unseasonably warm weather were were blessed with. Did this have anything to do with this late date stranding of a relatively fresh carcass? We found the carcass where Ranger Matthew had last seen it the day before. Luckily it was above the high tide line so it had not moved even with the strong winds from the night before.
It was amazing to see an animal in as good a condition as this one was, even after 4 days on the beach. Typically scavengers can do quite a bit of damage to a fresh carcass and the eyes of the animal are one of the first things to go, but this sunfish had everything intact, with only a few minor external patches of scavenger damage.
Our first order of business was to erect NECWA's new portable weighing tripod and get an accurate weight for this animal. It was the first time that most of the team had seen and used the tripod. It took us a few tries rigging the carcass in the straps so the body lifted evenly above the sandy beach. When all parts of the carcass were above the sand, the scale recorded 364 pounds!
This isn't the heaviest carcass that we have weighed this season, but it is only the third fresh carcass that has been weighed to date. Thanks again to David Clapp and Sam McGee for helping put this is amazing tripod together. And thanks to our NECWA supporters for your donations allowed us to make this dream a reality.
Our next task was to conduct a Level A examination that includes photographing/videotaping the external features of the animal and collecting a series of body measurements. The team worked very hard to collect accurate measurements that will be added to our database. Nick took the lead on videotaping the necropsy as well as helping to cut when needed. We hope to use this video footage in the future to create a "how to" guide to necropsying ocean sunfish.
Since we began this project in 2005, NECWA has worked hard to collect
one of the largest databases on ocean sunfish of any research group in the area. Recently, researchers from England, Japan and Sweden have contact us asking if we would be willing to collaborate on a variety of research studies. We said "Yes," of course!
Once we completed the Level A examination, Tammy took the lead on the necropsy. Her first job was to locate the gonad in order to determine the sex of this animal. To do this, Tammy through the skin and into the thick layer of reticulated collagen that complete encases the insides of this animal.
We are still not sure what function the reticulated collagen plays, but one thing that we noticed is that its thickness does vary in different areas of the body. The image above shows us measuring the thickness of the reticulated collagen just above the pectoral fin.
The sex of this ocean sunfish was determined male and we collected sections of the teste for future analysis back at the lab. So far, our data indicates an even number of males and females stranding each fall on our New England beaches.
Since this was Michael's and Ranger Matthew's first ocean sunfish necropsy, we spent more time than usual examining the internal organs and structures of this fascinating creature. We even measured the entire GI tract and recorded a length of 430 cm from the beginning of the stomach to the end of the intestine.
We also examined the gill structure where we found several large parasitic copepods (see photo above). After looking at the gills we also checked out the eye of the sunfish and the rows of pharyngeal teeth in the fish's throat (photo directly above).
Our experienced necropsy technicians, Nick and Krill, then worked on the difficult task of removing the entire spinal column from the carcass. This is made more complicated by the thick layer of collagen present under the skin of the fish, as well as the desire to keep the entire spine intact. Because NECWA can use bioartifacts like the sunfish's vertebrae for public education and research, it was extremely important not to accidentally cut through the vertebrae while trying to remove it from the carcass.
While all of these events were going on, our diligent photographer and data logger Patty was documenting every aspect of the necropsy with photos and notes. This is a vital aspect of the necropsy process because detailed notes and photos allow us to examine the information more accurately and prevent the loss of any valuable information that we may have missed out in the field.
Once the necessary samples had been taken, and our examination of the carcass was complete we buried all the parts of the animal that we had removed. Now that the remaining carcass was considerably lighter, Nick, Mike, and Tammy dragged the carcass down the beach to the ocean where the incoming tide quickly swept it away. Ranger Matthew was then kind enough to drive us and our gear back to the entrance of the beach park so we could load up our gear and head for home!
A very successful day on Sandy Neck Beach. Let's hope this is the last ocean sunfish stranding for the season. Happy holidays to everyone and we wish you the best in the coming new year!
Sunday, December 18, 2011
Sunday, December 11, 2011
December 10, 2011
Yesterday, Zack and Jamie helped Krill find a decomposed ocean sunfish that had washed up on the shores of Loagy Bay in Wellfleet MA. Thanks guys for helping locate this carcass that was originally reported to NECWA by Kirsten, a Wellfleet resident.
Over the past few weeks, NECWA has not received any reports of fresh ocean sunfish carcasses on the beaches of Cape Cod. We are very glad about this for it signals the probable end of the ocean sunfish stranding season for 2011. But please continue to look for carcasses. Last year, our last fresh carcasses stranded on Mant's beach in Brewster on December 5th. And with this unseasonably warm weather, you just never know.
Thanks to Kirsten from Wellfleet for the original report of this carcass. Although this carcass was far too decomposed to necropsy, every carcass is vital to our understanding of this amazing species.
So keep sending NECWA your reports. Go to the NEBShark website at www.nebshark.org and send in your sighting information. And please keep an eye out for sea turtles as this is the season that they strand along Cape Cod beaches as well. Sea turtle strandings are reported to Mass Audubon at Wellfleet Bay. If you find a live or dead sea turtle on a beach, call 508-349-2615.
Monday, December 5, 2011
This week, our very own Nicholas Schomburg was awarded a $100 gift certificate to Dick’s Sporting Goods in Colony Place, Plymouth. Nicholas has interned with the New England Coastal Wildlife Alliance (NECWA) since the summer of 2009 and is currently a senior at Plymouth South High School. The gift certificate was part of a larger program known as “$100 for 100”, which was sponsored by Joyal Capital Management, Dunkin Donuts, The Pacific Life Foundation/Insurance, First American Insurance, Heidrea, and The Bulfinch Group.
Nicholas was nominated for this reward based on his academic achievement and extracurricular activities associated with NECWA. As a NECWA intern, Nicholas has been involved in a variety of projects and programs related to research, education and conservation in the field of marine biology. He has acted as a Research Assistant and Naturalist aboard Captain John Boats, operating out of Plymouth Harbor.
Nicholas has participated in necropsies of ocean sunfish, seals and dolphins that stranded dead on Cape Cod beaches. And he has been very involved in educational outreach activities for both children and adults. Nicholas’s guidance counselor felt that these types of extracurricular activities helped Nicholas stand out among the rest of his high school peers and therefore, was a key factor in his winning this award.
Congratulations Nicholas from all of us at NECWA!
Hot off the press and just arrived!
Our new Key Tag for ocean sunfish and sea turtle strandings on Cape Cod.
NECWA and MA Audubon at Wellfleet Bay have partnered on a key tag for beachwalkers. The front has information for beachwalkers who come upon a stranded sea turtle and the back has information on ocean sunfish.
What a great way to keep important numbers with you as you walk local beaches. If you would like one, send a self-addressed, stamped envelope to NECWA at 11 Clarence Soule Drive, Middleboro, MA 02346.
Sunday, December 4, 2011
Holiday Gift Idea from NECWA
Marine Wildlife Adoptions for that Someone Special!
Marine Wildlife Adoptions for that Someone Special!
Need a unique gift for that someone special this holiday season? Then consider adopting a humpback whale, great white shark, gray seal, Atlantic white-sided dolphin or any of our adoption animals.
Click HERE to learn more about NECWA's Marine Wildlife Adoption program.
Sunday, November 20, 2011
On Saturday, November 5, 2011, Northbrook Academy parents and students helped staff from the New England Coastal Wildlife Alliance (NECWA) examine a dead ocean sunfish that stranded on the shores of Monument Beach. This carcass was recently reported to NECWA’s Ocean Sunfish Stranding Network and the carcass looked as if it was only a few days old.
This ocean fish carcass was missing the majority of its dorsal fin. Since the cut completely severed the top of the dorsal fin, we assume that the injury was the result of a collision with a large vessel. The tissue at the site of the injury was raw and red, indicating that the injury was relatively recent.
Ocean sunfish are the heaviest bony fish in the world and are common visitors to our New England waters, during the summer and fall. These large fish migrate great distances to feed in our cold waters on jellyfish, ctenophores and other gelatinous critters. As winter approaches, ocean sunfish begin their migrations south to spend their winters in warmer, more tropical waters.
|Measuring the carcass.|
But some individuals become trapped in the arm of Cape Cod. As water temperatures continue to drop, ocean sunfish become cold-stunned and are unable to swim or function normally. Many of these cold-stunned individuals will offshore and wash up on our local beaches.
The death of these beautiful giants is a sad occurrence, but the examination of each carcass provides insights into their biology and ecology. Last year, NECWA responded to over 18 ocean sunfish strandings and now has one of the largest databases on this species. Ocean sunfish that strand alive are pushed back into the water. Those that strand dead are studied and examined in order to further our knowledge of these unique coastal pelagic fish.
One piece of information that NECWA is now able to collect is the total body weight of each carcass. With the help of colleagues David Clapp and Sam McGee, NECWA created a portable weighing tripod that can be broken down and then re-assembled on a beach. Hanging from the center of the tripod is an electronic crane scale that provides an accurate body weight.
|Northbrook parent, Chip, and Krill work to secure the carcass.|
Northbrook parents and students were instrumental in helping NECWA examine and weigh this carcass. The team first weighed the carcass when it was partially submerged. Fearing that the water was interferring with the collection of an accurate weight measurement, it was decided to relocate the carcass to higher ground and re-weigh this fish.
|Team effort in moving this carcass to a better location.|
|Northbrook Academy students and parents as well as local residents|
helping NECWA staff relocate the carcass to higher ground.
After relocating the carcass, the teamed weighed this ocean sunfish once again and we were able to collect a weight of 650 pounds! This is the heaviest ocean sunfish carcass that NECWA has weighed so far using this portable tripod apparatus.
|Northbrook Academy parent Chip, Krill and Foster|
working on the tripod.
|Foster and Jessica helping Krill with the tripod.|
|Northbrook Academy student Jessica and Lindsay helping out.|
|Northbrook parents Stuart and Chip helping rig the carcass.|
|Stuart adjusting the straps on the tripod.|
As the team continued their efforts, Belinda experimented with tags in an attempt to find a tag that we could use in the future on live ocean sunfish that NECWA relocates to deeper water. Unfortunately, the dorsal fin of this animal was too thick for the tags that Belinda was using, but even failures like this provide valuable information that will allow us to determine the best tag for this species.
|Krill and Belinda experimenting with tags.|
Krill and Belinda then worked together to begin the internal examination of this animal. By cutting through the thin skin and then the thick reticulated collagen, they were able to access the reproductive tissues to determine that this individual was a female.
|Cutting through the thick reticulated collagen.|
|Krill trying to locate the sex organ.|
|Ovary removed from this ocean sunfish.|
Ocean sunfish have one gonad (reproductive organ) so they either have one ovary or one teste. The ovary of this fish was quite large and contained thousands of eggs.
|Foster examining the whole ovary of this carcass.|
|Sectioned ovary of the ocean sunfish.|
Next the team worked together to examine the animal’s internal structures and they determined that this animal was a female. The team also collected a series of tissues, including a section of the vertebra that will be used for aging studies.
As Krill continued examining the internal structures of this animal, Belinda and Foster worked together to remove the large and beautiful eye of this animal.
|The eye of this beautiful species.|
|Belinda and her son Foster |
working together to examine the eye.
|Examining the eye of the ocean sunfish.|
Krill, Belinda and Patty, all volunteer staff members with NECWA, want to thank Northbrook Academy parents and students for their amazing help and assistance. This was truly a team effort and it was one of the most successful necropsies NECWA has accomplished to date. Thanks to Patty from NECWA and Chip Warburton from Northbrook Academy for the amazing photos collected during the necropsy.
|Krill lifting the sunfish with the chain lift.|