NOAA Teacher at Sea
David Riddle
Onboard NOAA Ship Albatross IV July 13 – 28, 2006
Mission: Sea scallop survey Geographical Area: New England Date: July 25, 2006
Science and Technology Log
Science-wise, catches of scallops have been variable. Sometimes we’ve hauled in huge numbers; other times almost none. We’re still sorting and counting and measuring fish from every catch, and as we move back northward, a little east of our starting point now, the fish species have begun to change. We’ve even caught a few lobsters.
I’ve been trained to do several different jobs so far. I’ve monitored the computer station while collecting the CTD data, determining salinity by lowering the device over the side that measures conductivity, temperature, and density within 5-10 meters of the bottom. I’ve also helped download the data from the inclinometer, which results in a graph showing the angle of the dredge relative to the bottom during the tow.
I’ve learned the procedures for measuring and collecting additional data on little skates. They’re the fish that look like stingrays. We measure, length, width, weight, and determine degree of sexual maturity.
Now I’m doing the starfish count, every third tow. My job is to collect a random bucket full of the by-catch (the leftovers) after everything else countable has been removed, then sort, count, and weigh the starfish according to species. Sometimes the whole catch is mostly starfish, so there’s plenty to keep me busy.
Sightings: This afternoon I saw the dorsal fins of two ocean sunfish (Mola mola). I would have assumed they were sharks, since all that was visible was the fin, but the fishermen said you could tell by the shape of the fin and the way it moved through the water. The Peterson Guide to Atlantic Coast Fishes says they’re among the largest of the marine bony fishes. (Whale sharks and basking sharks are larger, but sharks have cartilage instead of bony skeletons.) Sunfishes can be as large as 3 meters long and 3.3 meters tall, and they may weigh over two tons.
Personal Log
Several days have passed since my last log entry. I’ve been making some hand-written notes, but they’re mostly about our encounter with the fringes of Tropical Storm Beryl and my re-encounter with seasickness. Everyone has been very understanding, and I’ve appreciated it. I’m feeling back to normal now.
NOAA Teacher at Sea
David Riddle
Onboard NOAA Ship Albatross IV July 13 – 28, 2006
Mission: Sea scallop survey Geographical Area: New England Date: July 17, 2006
A seahorse that came up with the dredge
Science and Technology Log
It’s almost halfway through my watch now, and I have a little down time. The day started with several stations that were close together, which kept us busy. Now the sampling stations are farther apart, and I’ve had time to work on some photographs of shells.
Our catches turn up lots of interesting creatures. Some I recognize from my college invertebrate zoology course (oh, so many years ago!) Others I’ve only seen pictures of. There are occasional sea squirts, bulbous little creatures that squirt a stream of water when squeezed. We find an occasional “sea mouse”, a polychaete worm, bristly-looking on the backside and shaped sort of like, well, a mouse. Underneath you can see the segments. Hermit crabs are abundant; many of them simply abandon their shells when they’re dumped onto the deck. This is probably not a good survival strategy, since they get dumped back overboard only to drift slowly to the bottom without any protection at all. Oh well, most everything in the ocean is somebody else’s lunch anyway. We find other species of crabs as well. The larger ones are set aside and are sitting in a bucket which has seawater continually being pumped through it to keep them alive. I wonder whose lunch they’ll turn out to be? We’ve caught a few small dogfish sharks, under two feet in length. I’m told on some of the ground fish surveys they catch tons of them (literally). Considerably smaller were two needlefish, about 6 inches long and ••• inch wide.
I find myself wondering things like, “What must it be like to be that small, living in this huge ocean?” Them I’m reminded of our little planet’s location in our galaxy, and the Milky Way’s tiny place in a universe with millions of other galaxies. OK. Humility is a good thing.
Then too, I’m reminded that small is not always equivalent to unimportant. Do you like breathing? Well, consider that roughly 3 out of every 4 breaths you take come to you courtesy of the phytoplankton in the oceans of the world. There they are, soaking up the sunshine and the carbon dioxide and pumping out huge quantities of oxygen every single daylight hour. They’re microscopic, but their importance in the overall scheme of life on this planet is enormous. I suppose it would be helpful to remember, while we’re busy saving the whales, we should take care of the little guys too. But then, how would “Save the Plankton” look on a T-shirt or bumper sticker?
On a more practical note, we’re due to reach our turn-around point in 5 more stations. We will have reached our southernmost latitude, which will put us due east of the North Carolina-Virginia border. Then we’ll begin making our way back up the coast, stopping at the stations in shallower waters. I flew to Boston from my home in western NC to take part in this Teacher at Sea experience. So this is the closest to home I’ll be for the next 12 days.
I keep thinking I’m done with my log for the day and then something else happens. At station 99 we caught a seahorse! The depth was 24 fathoms, and I seriously doubt it was on the bottom, but when the dredge came up, there it was on deck.
Sightings: The osprey was still here this morning, but as of late afternoon it was gone.
NOAA Teacher at Sea
David Riddle
Onboard NOAA Ship Albatross IV July 13 – 28, 2006
Mission: Sea scallop survey Geographical Area: New England Date: July 15, 2006
Not all scallop shells are pretty, but these were outstanding!
Science and Technology Log
We’re in an area now with an abundance of scallops, and most of them are large. When the catch is emptied from the net onto the deck, it takes 6 to 8 people working steadily, on hands and knees, to separate the scallops from the rest of the catch. We’ve gotten up to 16 bushels so far in one 15 minute tow, using an 8 foot dredge. If the next station is nearby, we just have time to get the measurements completed and clean up before it’s time to start again. But it’s not always that busy. If the next station is several miles away, we get time to sit for a few minutes and relax.
During one of my relaxing moments, I photographed some of the fish that were caught along with scallops and starfish and everything else. We catch small skates, which are shaped like stingrays, with a broad, diamond-shaped body and an elongated narrow tail. We also catch goosefish, sometimes called angler fish, with mouths agape, showing rows of needle-like teeth. We catch flounder too. All of these are bottom-dwellers, probably too slow to swim away from the net, or else when they feel the net coming they just hunker down in their standard defensive posture, which unfortunately is no help when the thing that’s coming after you weighs nearly a ton and is being dragged at between 3 and 4 knots.
Scallop eyes are visible as rows of dots inside the shell margin.
As we have moved farther south today, I’ve begun noticing scallops with different patterns on their shells. Some look like sunbursts; some are striped. I’ve collected a few to take home. I want to get some photos of live scallops also. When they open their shells you can see the row of eyes along the margin of the gills. Scallops can swim, which is unusual for a bivalve. The powerful muscle (the part we eat) which holds the shells together, opens and closes the shell in rapid succession. This draws water in between the shells and forces it out the back near the hinge in little concentrated jets. Scallops swim by jet propulsion! Prior to sailing, we saw a brief film clip showing a group of scallops swimming, in a jerky, erratic motion.
Sightings: An osprey landed on the mast about 11:00am. The fishermen say we’re about 20 miles offshore, so I imagine he/she is pretty tired. Maybe it will hang around for a while. Later…It’s 9:00 pm now and the osprey is still perched on the mast. I expect it will still be here in the morning. Another small songbird showed up later in the afternoon. I didn’t see it, so I don’t know the species. The fishermen offered it some fresh water, but it didn’t drink. They say it probably won’t survive this far out, if it won’t drink. Even so, some birds seem quite at home this far out.
Personal Log
Midnight notes: We did 18 stations in 12 hours; several were back to back. Do you think I’m ready for a shower and bed? Does a scallop live in the ocean?
This watch began, again, with fish waiting on the deck. We processed that catch just as we had all the others. While we were processing, another catch of fish were being collected. A CTD was also performed. When the fish catch has been processed, it is necessary to return the processed organisms to the sea. There is a shoot in the wetlab designed for this purpose. The shoot has not been working properly so far on this cruise. During our watch it backed up completely. Water was rising up through the drain in the floor. Clearing the blockage took several hours.
The catch was sitting on the deck and we had no reason to believe that we would get the shoot clear any time soon. The Watch Leader elected to process the catch “dry” so we separated and identified the species without the benefit of water to clean the organisms. Following this catch, the shoot was cleared and the lab was cleaned. We are now making our way south to assess the Texas Gulf Coast shrimp prior to the beginning of their season..
Personal Log
What a mess! Each organism had to be dipped into water just so that we could be sure it was identified properly. We found hundreds of little shrimp that are not even harvested for food purposes.
Question of the Day
Where do the shrimp live? Answer: In the mud on the bottom of the sea.
Our first real shift for the DELAWARE II Ocean Clam Survey began this morning off the coast of Long Island. The shift stated at midnight, so we were awaked at 11: 15. Our first dredge occurred at 2:15 AM. We are working in a crew of six. Two of us input data into the FSCS computer as the deck crew coordinates with the boatswain in charge of the winch. Safety is a big issue on the NOAA vessel, and scientists are not allowed on deck while the dredge is being lowered off the stern. A high voltage cable is fed out along with the winch cable, and no one is allowed ion the deck until the dredge is in position for tow. Our job upstairs is to coordinate with the Officer of the Day when each step is being done and input his into the computer. Each actual tow takes five minutes, but the entire process of lowering the dredge, dredging and raising the dredge onto the deck takes about 25 minutes. When the dredge is brought up, our job begins.
Measuring a larger clam
We often start by places a smaller mesh screen at the front of the dredge in order tot capture the contents and releasing the dredge into a tow to wash away some of the debris and substrate soil. When the dredge is brought in the second time it is hauled up to an enormous table where the contents are released for inspection of our crew. It is then our task to sort through large amounts of shell hash, rock and substrate and find the living organisms. Our trawl today has been averaging at depths of 60 meters (180ft. or 30 fathoms in you want to be really cool and nautical). This is Ocean Quahog territory. True to form, our first three station trawls resulted in large numbers of Ocean quahogs as well as the assorted species. For commercial fisherman, these other species are often referred to as discard. These are unwanted species, or at least not the targeted stock. Today along with the quahogs, we caught several varieties of clams. These smaller clams were varieties such as Asterias, Astarte, Astrope, and Razor. We also collected Sea Scallops and Horse mussels. We Few fish are caught in bottom dredges, but we did catch one small Sea Robin and a small Skate. At first, I thought the unwanted species were called bycatch, but through interviews with on board fishermen and scientists I was informed that the term bycatch more commonly refers to sea mammals, reptiles or marine birds that are accidentally caught or killed in commercial fishing.
Sea stars caught in the dredge
For example, in the area of scallop dredging, there has been a great deal of controversy surrounding the bycatch of endangered species of Sea Turtles. After each tow the catch was sorted, measured for length, and weight and catalogued into the computer database. What used to be done by pencil and paper is now done via electronic scans and scales. For quahogs under 40 mm, or above 110 mm in length, we conducted meat weigh measurements as well. This is hard work, and the ship conducts non-stop tows and data collection 24 hours a day. We are learning fast and having fun. The six-hour shift flew by and I was exhausted. A great morning, in bed by 7AM, and ready for the next shift at 11:30 AM. What a weird schedule. We have all been at it for a day and a half, and no one seems to know what day it is. As part of today’s log, I need to share what I have learned about the mysterious Ocean Quahog. The IO\Ocean Quahog, (Antica Islandica) is found from Newfoundland to Cape Hatteras. They are usually found in depths from 8 to 256 meters. They are a relatively cold-water species and are rarely found in waters above 16 degrees Celsius.
Their population densities are greater in off shore waters and they prefer a substrate of fine sand. In Maine they are found in shallower waters, but the populations are small, and the species grows at a slower rate. The average size is about 70mm. But today we had one at 110mm. What are really incredible about Ocean Quahogs are their ages. The scientists we interviewed today estimated that most of the many of bushels of quahogs we captured were in the 45 year old range. Quahogs can be in excess of 170 years old. Their most dramatic growth occurs in their first twenty years of life and the growth process slows significantly. Their ages are incredible, I may have to feel guilty the next time I spoon into clam chowder. Marine biologists have been finding that the Ocean Quahog, like the Atlantic Surf Clam, has shifting population strata. Surveys conducted over the past two decades and commercial fishing statistics show a pattern in which the Surf Clams are establishing themselves in deeper areas where quahogs previously predominated, and that the quahog populations are showing patterns of migration further offshore and further to the North.
One scientist onboard speculated that clam and quahog surveys might be important in the study of global warming. Ocean Quahogs have a commercial market value. The principal commercial fishing for the species occurs off the Delmarva Peninsula, New Jersey, Long Island and even Southern New England. In 1993, the commercial harvest of Quahogs reached its zenith at 25,000 metric tons. In 2000, the harvest had diminished to 14,000 metric tons. The decline in the fishery has been in part due to increased regulations under the Surf Clam- Ocean Quahog Fishery Management Plan (FPM), but also due to a decrease in the number of clamming boats and a depressed commercial market. Despite the reduction in total landings, the Quahog stock may be in jeopardy. The total landings are less than two percent of the total environmental stock, but any greater landings may threaten replacement levels and sustainability of this slow growing species.
Personal Log
Things were going along well until electrical problems with the dredge shut us down. Time to go to work on a different sort of problem.
