Tag: lobster trap

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Maggie Flanagan, July 10, 2007

NOAA Teacher at Sea
Maggie Flanagan
Onboard NOAA Ship Oscar Elton Sette
June 12 – July 12, 2007

Mission: Lobster Survey
Geographical Area: Pacific Ocean; Necker Island
Date: July 10, 2007

NOAA Teacher at Sea Maggie Flanagan measures a lobster carapace.
Maggie Flanagan measures a lobster carapace.

Science and Technology Log – Lobster Lessons 

We’ve hauled back our last string of traps and have begun the transit back to Pearl Harbor. Our Northwestern Hawaiian Island (NWHI) lobster survey has provided the 2007 data for a record that goes back 30 years. Our Chief Scientist, Bob Moffitt, is a biologist with the National Marine Fisheries Service within NOAA. Bob completed his first lobster survey in 1977, and has been continually involved with the project. The model we still use was established in 1985-86, and there has been survey data nearly every year since then.  The two sites we monitor are Necker Island (Mokumanamana, in Hawaiian) and Maro Reef (Nalukakala, in Hawaiian).  Necker Island is closer to the Main Hawaiian Islands, 430 miles from Honolulu.  Maro Reef is farther out the NWHI, 850 miles from Honolulu.  Target species are spiny lobsters (Panulirus marginatus) and slipper lobsters (Scyllarides squammosus).

Initial analysis of the data includes computing our catch per unit effort (CPUE), which is the total number of lobsters in traps divided by the number of traps.  The data are separated by site, by species – spiny or slipper lobster, and by number of traps in the string, – 8 or 20. (Strings of 20 are often set in deeper water.)  The mean for all strings of a type in a year is used for comparisons.  Bob works up the numbers each evening to keep us posted.  

You can’t draw conclusions from just a few numbers, but a sample of CPUE information is below.

In 2007, Necker Island sampling was suspended for several days and the data may be biased towards historically less productive quadrants.
In 2007, Necker Island sampling was suspended for several days and the data may be biased towards historically less productive quadrants.

Graphing the entire data set reveals that Necker Island experienced a sharp decline in the presence of both types of lobsters during the mid to late 1990’s, and the numbers have remained low.  Graphs of Maro Reef data show a more complex story.  There, spiny lobsters dropped dramatically in 1989. Spiny lobster numbers remained low, as slipper lobster numbers increased. It’s proposed that as spiny lobsters were decreasing, slipper lobsters could access more resources, such as food and habitat, which expanded their numbers.  The spiny lobster has had more commercial value because it looks prettier, and so was probably targeted more by fisherman.

Teacher at Sea Maggie Flanagan holds spiny lobsters while “cracking” – recovering lobsters from traps.
Maggie Flanagan holds spiny lobsters while “cracking” – recovering lobsters from traps.

Commercial fishing for lobsters in the Northwestern Hawaiian Islands began with multi-purpose vessels which would keep the lobsters live for market. About 1981, fisherman started landing only the lobster tail, which was frozen at sea.  This greatly increased the capacity for the taking of lobsters. Data showed decline, fisheries scientists became concerned, and the fishery was closed in 1993, then opened with very low quotas.  By 1997, research data still showed decline and the NWHI commercial lobster fishery was closed again in 2000.  Models at that time showed that NWHI lobster overfishing (meaning the size and take of the fleet) wasn’t problematic and research that focused on the lobsters themselves would be needed.

When lobsters are tiny, in the phylosome stage, they are transported by currents.  Spiny lobsters spend 12 months in this stage and have been caught in plankton tows 60 miles out at sea.  So, lobsters can settle in sites far away from their parents.  This recruitment may or may not influence the population numbers of lobsters in the NWHI, but as a real possibility, is a topic for research. Bob Moffitt’s data, with that of other NWHI scientists, could contribute to a metapopulation model that could estimate the density of lobsters throughout all the NWHI over time.  This could be designed to scientifically predict the affects of fishing and recruitment.  DNA analysis could also reveal information on the transportation of lobsters when juvenile.

In 2006, all the NWHI were included in the creation of the Papahānaumokuākea Marine National Monument, which will be closed to all fishing.  The Monument is the largest marine protected area in the U.S., but the research questions on what will help Hawaiian lobster populations still remain to be answered.  Ocean currents in the area generally run to the west and south, and if juvenile lobsters are transported, they would be traveling those currents. But the marine protected area is already west of the Main Hawaiian Islands, so recruitment out to restore other areas seems unlikely, though not yet tested.    There is reason to celebrate our new Marine National Monument, but there is no conclusive scientific evidence that it will help lobster populations recover.

A slipper lobster as compared to a pencil.
A slipper lobster as compared to a pencil.

Personal Log 

With all fisheries closed in the NWHI, what will happen to the fisheries research that has  contributed much to the understanding of marine populations?  Will scientists be allowed to continue pursuing research questions, or will they be considered irrelevant?  Approval for access to the NWHI under the Monument status now involves an arduous permit process, even for scientists.  Bob Moffitt’s work has provided an extensive time series of data, and is considered worth continuing as ecosystem monitoring.  Hopefully in the future, scientific work will continue and guide policy making for protected areas.  

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Chris Monsour, June 23, 2007

NOAA Teacher at Sea
Chris Monsour
Onboard NOAA Ship Oscar Elton Sette
June 12 – July 12, 2007

Mission: Lobster Survey
Geographical Area: Northwestern Hawaiian Islands
Date: June 23, 2007

NOAA Teacher at Sea Chris Monsour is all smiles as he pulls up two Ehu during bottom fishing. This was the first time Monsour ever bottom fished.
Chris Monsour is all smiles as he pulls up two Ehu during his first bottom fishing experience.

Science and Technology Log 

Today was our last day at Maro Reef and now we are making the 36-hour trip to Necker Island 350 miles to the east southeast.  We finished up trapping today early as the number of lobsters collected was greatly reduced by the time we got to the sets of 20’s.  I had the job of assisting in the lab today. I would collect the lobsters from the buckets, identify the sex, and then hold in place so they could be measured.  In the morning, we collected a lot of slipper lobsters, sometimes as many as 19 or 20 in a trap. There were some spiny, but not nearly as many as the slipper. After lunch we collected the sets of 20 and found quite a difference. Instead of lobsters, we were collecting hermit crabs, spider crabs, sea anemone, and other types of crabs.  The differences may have to do with the sandy bottom or the greater deep of the traps.  I have tomorrow off to do whatever, which may include finishing up the book I started 8 days ago.

In this log I am going to talk about bottom fishing, which is one of the activities we get to do during the evening. Bottom fishing is the name given to line-fishing with baited hooks on or very close to the sea bottom. This is a fishing method, which catches predatory fish that feed on bottom-living crustaceans, fish, etc. One or more hooks may be used. Deep-bottom fishing has been known for many years in the Pacific region, and has been practiced for generations in some of the remote island communities of the Pacific. In the old days fishing was carried out from paddling canoes using gear made from locally-available materials, and was a challenge to even the most experienced fisherman.  We however have the luxury of modern bottom fishing gear such as a winch to help bring up our catch.

One of the reasons for the popularity in the fish that are caught by bottom fishing is the species caught never carry ciguatera fish poisoning. This is a type of natural toxicity, which originates from reef and lagoon fish that feed on toxic reef algae. Ciguatera fish poisoning causes illness and makes the affected person unable to eat seafood for a long time. The possible presence of ciguatera is a major cause of concern for many consumers of reef and lagoon fish. The fact that it never occurs in deepwater fish, due to their diet, makes these fish all the more valuable.  Some of the fish we have caught include Ehu, Uku, Opakapaka, Kahala, Butaguchi and Gindai. (have fun pronouncing these).

Deep-bottom fishing gear can be made from a range of materials, but the basic structure  is generally the same:

  • a mainline, several hundred meters long, to lower the hooks to the bottom.
  •  a terminal rig, usually 2–5 m in length, with attachment points for the mainline,  several hooks, and a sinker. The terminal rig can be made of nylon, or steel cable to resist cutting by the sharp teeth of fish or rough rocks and corals on the sea floor. The attachment points may be loops made on the ends of the terminal rig and at intervals along its length, or may be swivels knotted or crimped into the rig.
  •  several hooks, each fixed to a short trace , which can be connected to or disconnected from the attachment points along the terminal rig. This allows the traces to be changed quickly and easily when damaged or when the size of the fish being caught calls for smaller or larger hooks.
  • a heavy sinker, 0.5–2 kg in weight depending on the strength of the current, to get the rig down to the bottom quickly. I do enjoy the bottom fishing and to date I have caught 3 bottom fish, 1 Kahala and 2 Ehu. In fact I have the record on the boat for the largest Ehu at 54.6 centimeters!
Teacher at Sea Chris Monsour holds up two examples of fish caught during bottom fishing on board OSCAR ELTON SETTE. The fish on the left is a Ehu and the fish on the right is a Uku.
Chris Monsour holds up two fish caught during bottom fishing; Ehu (left) and Uku (right).

Personal Log 

I am glad to have tomorrow off so to speak.  It will be good to sleep in and catch up on all the e-mails I have gotten.  As mentioned before, Necker Island in the past has been slow because of its proximity to the inhabited islands. The bottom fish we are collecting are being used to get an idea of the health of the reefs.  During the processing of the fish, we collect weight, length, gonads, liver, fin, and bones from the skull.  Ryan is collecting these for his research. It is a very interesting process and bloody one too.

Animals Seen Today 

Spiny lobster, Slipper lobster, Ridgeback lobster (type of spiny), Sea anemone, Hermit Crab, and Spider Crab.

Questions of the Day 

  1. What can we learn from Hawaiian values and practices to guide our interactions  with the land and sea today?
  2. What can we do to help restore declining fish populations?

A hui hou,… Chris

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Chris Monsour, June 21, 2007

NOAA Teacher at Sea
Chris Monsour
Onboard NOAA Ship Oscar Elton Sette
June 12 – July 12, 2007

Mission: Lobster Survey
Geographical Area: Northwestern Hawaiian Islands
Date: June 21, 2007

A juvenile spiny lobster is a welcome sign on the board OSCAR ELTON SETTE. This was the smallest spiny lobster caught to date.
A juvenile spiny lobster is a welcome sign on the board OSCAR ELTON SETTE. This was the smallest spiny lobster caught to date.

Science and Technology Log 

We have been trapping for 5 days now and I have been the cracker twice, runner, and setter twice. The days are going by very quick and I find it harder and harder to write because by the time I get done, I am exhausted and then it is time to bottom fish.  We have been having good days in terms of the number of lobsters we are collecting and returning. Just by what I have seen, the slipper lobster is the most numerous and I really can’t seem to find the answer to why.  I do know that I would rather tangle with a slipper lobster than a spiny.  The focus of this log will be on the spiny lobster and what makes it such an interesting organism. As with most lobsters, the spiny lobster is important in the reef community.  I have learned that the spiny lobsters are usually found under ledges or in caves with only their antennae sticking out. The term stridulation comes from the lobster’s ability to rub its antennae to warn other animals away.  I finally understand why we are setting the traps at night. Lobsters remain in their shelters during the day and emerge at night to forage over the reef and in our case for mackerel within the traps.

Teacher at Sea Chris Monsour captured this image of spiny and slipper lobsters waiting to be processed on board OSCAR ELTON SETTE. All of the lobsters were released back to a spot near to where they were captured.
Chris Monsour captured this image of spiny and slipper lobsters waiting to be processed. All of the lobsters were released near the spot where they were captured.

The spiny lobster does not have the large chelipeds that the Maine lobster has.  The first thing I asked about was what do we do about the crusher and pincher (terms used to describe the front appendages of Maine lobster and crayfish). The spiny lobster does not have them; instead they have the spines that point forward that cover their antennae and dorsal surface.  During the reproductive period, which occurs during summer, male lobsters seek out females.  The males attach a sticky packet of sperm near the female’s reproductive opening and her eggs are fertilized as they leave her body.  The female attaches the fertilized eggs to the delicate limbs on the underside of her abdomen.  She aerates the developing embryos by fanning her abdominal limbs through the water.  Females with eggs are called “berried” females because the eggs resemble tiny, reddish or blackish berries. The embryos hatch months later and take up life in the plankton as wafer-thin phyllosome larvae.  The larvae spend up to 9 months in the plankton before settling out to begin life on the bottom.

As I have found through discussion with members of the crew, spiny lobsters are a popular food item in Hawaii.  Just as we have been doing, the commercial fishermen catch them using baited wire traps set on the seafloor.  Recreational fishermen, scuba divers, and snorkelers around the main Hawaiian Islands can only capture lobsters by hand (no nets or spears are allowed), and because of the long reproductive period, it is illegal to catch spiny lobsters during the summer months (May through August).  Females with eggs are protected throughout the year.

Teacher at Sea Chris Monsour holds up a Grey Reef Shark that was caught during the lobster cruise. Data such as the stomach contents will be used to further understand the dynamics that occur on the Maro Reef. Two of Chris’ shipmates, Ryan and Garrett show their excitement over Chris’s first shark encounter.
Chris Monsour holds up a Grey Reef Shark that was caught during the lobster cruise. Stomach contents will be used to further understand what occurs on the Maro Reef. Two of Chris’ shipmates show their excitement over Chris’s first shark encounter.

Personal Log 

As mentioned earlier I am worn out by the end of the day, but it is nice that I have gotten into a routine. We have 2 more days left here at Maro Reef then it is onto Necker Island for 2 weeks. I have been told that Necker Island is not as exciting because it was where more of the trapping occurred in the past and so the numbers are not as high. We will see what happens.

Animals Seen Today 

Uku albatross Ehu terns Reef sharks frigate birds Galopogos Sharks lemonhead eel Spiny Lobster conger eel Slipper lobster Hermit crab Spider crab Sponge crab

Questions of the Day 

  1. How does human debris have a negative impact on marine life, and what can we do       to solve this problem?
  2. What can we learn from a bolus about seabirds and human impact on their habitat?
  3. How do products we use on land affect our ocean and beaches?
  4. How effective are some alternative products that have less impact on the environment?

A hui hou… (Until we meet again) Chris

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Chris Monsour, June 18, 2007

NOAA Teacher at Sea
Chris Monsour
Onboard NOAA Ship Oscar Elton Sette
June 12 – July 12, 2007

Mission: Lobster Survey
Geographical Area: Northwestern Hawaiian Islands
Date: June 18, 2007

Teacher at Sea Chris Monsour, holds up one of the large Uku that was caught. The fish will be used for bottomfish studies.
Teacher at Sea Chris Monsour, holds up one of the large Uku that was caught. The fish will be used for bottomfish studies.

Science and Technology Log 

Yesterday and today were very busy days on board OSCAR ELTON SETTE as we set our first traps, cut bait and then pulled up traps and collected the lobsters, eels, sharks, and whatever else made it into the traps. Yesterday we set 160 traps off of Maro Reef. We set 10 lines of 8 traps and 4 lines of 20 traps. Each trap was assembled and 2 mackerel, which had been cut into thirds, was placed into the baiter. The baiter is a small container within the trap that holds the bait. The bait was cut earlier in the day. I volunteered to cut bait and I spent about an hour slicing and dicing the mackerel. Once the traps were baited we spent about an hour setting the traps. The traps were stacked into groups of fours and I would hand a trap to a fisherman who was standing on the stern and watch as the traps were pushed off into the water. I wish I could say my day was done but there was still a lot to do before tomorrow, including getting more bait.

Every night about 2100, the “crackers” for the next day go into a walk in freezer and pull out 13 boxes of frozen mackerel to thaw.  (The term “cracker” comes from the job of opening up the traps when they are pulled out of the water, one has to crack open the lobster trap and pull out whatever is in side.)  The next morning I got up at 0545 to cut the bait. The other cracker for the day was Matt and we spent a good hour cutting up the mackerel. I did learn that it is much easier to cut a half frozen mackerel as opposed to a thawed out mackerel.  The knives were kind of dull and the mackerel were full of blood and eggs and there were a few times where the mackerel ended up on my shirt.  No problems though.

Teacher at Sea Chris Monsour sorts through a trap that was brought up off the Maro Reef.
Teacher at Sea Chris Monsour sorts through a trap that was brought up off the Maro Reef.

The processing of pulling up 160 lobster pots takes up the good portion of the day so I will keep it simple.  Once the pots are pulled from the water and end up on the deck they first come to the crackers.  The crackers open the pots and remove all organisms from inside. Today, this included slipper lobsters, spiny lobsters, eels, sharks, crabs, fish and one octopus. The most difficult had to be the octopus, it just refused to come put and its tentacles stuck to every surface.  It took both Matt and me to pry the octopus from the trap. We both tried to avoid the mouth because they do have a beak like structure and neither of us wanted to see if it could remove a finger.  The spiny lobsters were also difficult because one, they are covered with spines but are a lot stronger than one would think. They would kick back with their tail and one time my pinky got caught by tail and blood was drawn. The slipper lobsters are easier to handle and taking them out the trap was not a problem because their bodies lack the spines.  Most of the lobsters that were pulled out were the slipper lobster, which are also the easiest to handle.  The worst part of the job as cracker is constantly being wet and having to dunk my hands in the bait buckets which are full of mackerel blood and organs.  The smell of the mackerel has found its way into my shoes, gloves, hair, and skin. I don’t think I will ever be able get rid of it. My job as cracker ended and tomorrow I start as a runner. Everyone who has done this cruise before says cracker is the best job. I guess I will soon find out.

Personal Log 

I would be lying if I said I was not tired. The job of cracker is not the hardest job, but when one has his hand in a trap that has eels, sharks, and spiny lobsters in it, it can be stressful. On top of emptying the traps, the old bait has to be removed and new bait placed in, all the while, a new trap is making its way down the table. So after eating dinner at 1630, I am ready to call it a day. By keeping so busy I have not had as much time to sit on the observation deck and look for whales and dolphins, but I have come face to face with some really amazing animals.  I am really fascinated by the eels.  They are very aggressive and strong animals. I almost had one get real personal with me when I was emptying a lobster pot and the eel had managed to hide on the bottom.  As I was picking up spiny lobster, this eel pops it head up by my hand and all I could say was EEL! EEL!  Everyone had a good laugh. We ended the day with a feeding frenzy in which all of the old bait is dumped over the side and the Galapagos Shark’s come in. It is an amazing sight to see and to be that close to such a great animal.  I am sure there will be many more moments like that to come.

Animals Seen Today 

Spiny lobster
Crabs
Slipper lobster
Lemon Head Eel
Galapagos Shark
Uku
Reef Shark
Hermit Crab

Question of the Day

Looking at the food web of The Papahānaumokuākea Marine National Monument, what would happen if a large predator like the Galapagos Shark was removed? Would there be another animal that could replace it in the web?

Aloha… Chris

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Chris Monsour, June 15, 2007

NOAA Teacher at Sea
Chris Monsour
Onboard NOAA Ship Oscar Elton Sette
June 12 – July 12, 2007

Mission: Lobster Survey
Geographical Area: Northwestern Hawaiian Islands
Date: June 15, 2007

Frigate bird
Frigatebird

Science and Technology Log 

Yesterday we entered The Papahānaumokuākea Marine National Monument (formerly the Northwestern Hawaiian Islands Marine National Monument). I found from talking to the crew it is the largest Marine Protected Area in the world. The new native Hawaiian name, Papahānaumokuākea reflects Hawaiian traditions relating to the birth of the Islands. Papahanaumoku is the goddess who birthed the islands.

I spent most of today on the observation deck above the bridge looking for birds and waiting for French Frigate Shoals to appear on the horizon.  A part of our mission was to deliver supplies to Fish and Wildlife personal on Tern Island, which is part of the shoal. Tern Island was formed into a runway to serve as a refueling stop for planes enroute to Midway during World War II. Some of the buildings remain and could be seen with a pair of binoculars.

This image of La Pérouse Pinnacle was taken by Teacher at Sea Chris Monsour as OSCAR ELTON SETTE approached the French Frigate Shoals to deliver supplies.
This image of La Pérouse Pinnacle was taken by Teacher at Sea Chris Monsour as OSCAR ELTON SETTE approached the French Frigate Shoals to deliver supplies.

I found through some investigating that French Frigate Shoals is an open atoll consisting of a large, crescent-shaped reef surrounding numerous small, sandy islets. The first object that stands out as soon as one reaches the shoal is the steep-sided pinnacle that sticks up out of the water. It is the first land I have seen in 3 days so it may not seem like much, but it was a welcome sight. The pinnacle is named “La Pérouse Pinnacle” after Compte de La Pérouse, who visited the atoll in 1786. As I did some research on the shoals I found that in the moonlight the pinnacle so resembled a full-rigged sailing ship that it lured more than one vessel to her doom on the shoals.

On deck we were preparing the tables and traps for tomorrow as we will set traps tomorrow at 1700 (or at 5:00 p.m.)  I asked Garrett who has been on this trip 5 times if I could get bait duty first. This consists of taking a Mackerel and making three cuts so that the muscle is exposed to attract the lobsters and any other organism that may venture into the trap. We will then collect the traps at 0800 Sunday morning.  We have set up an assembly line on the side of the ship, which consists of several tables end to end.  As a trap comes up, the cracker will open up the trap and take out the organisms that made it in and the old bait. The trap is then rebaited and sent toward the back of the ship.  The organisms that were collected will be placed in a bucket and sent to the wet lab to be measured and processed.  All of the lobsters that are collected will be returned after data such as carapace length are recorded.  The lobsters are not just tossed off the side of the boat, but are placed in a special cage and dropped to the bottom.  This prevents any predators from eating the lobster before they make it back to the bottom.

Personal Log 

The days have been going by pretty quickly.  I am ready to do some work though.  The major event of the past two days has been the meals and watching movies.  The food is excellent so I m sure my plan of losing weight on the trip will not come to be.  The good part now is that I have the chance to get to know the people I’m living with a lot better.  My roommate Mike is a student at the University in Hawaii and knows a great deal about sharks and I learned quite a bit about the behavior of the shark and especially about some of the sharks we may see.  I am learning to tie knots that will not come undone when we have large waves and I got to put on my survival suit for the first time during the abandon ship drill. I hope to have a picture to share of that.

It has become a common sight for Teacher at Sea Chris Monsour to see in the skies large, black birds, hovering lazily in place.  This is the frigatebird. The name “frigatebird” calls to mind the sails of ships and, indeed, frigatebirds sail gracefully in the air currents overhead. Their wingspan is some 7.5 feet and their deeply forked scissor-like tails afford them ultimate maneuverability. Their other common name, however, the “man-o’-war” bird, reflects the way in which they use their flying and maneuvering skill. Frigatebirds are pirates who harass incoming birds until the victim is so upset that it disgorges its catch. The frigatebird then drops with amazing speed and plucks the bolus out of the water, or even catches it before it hits.

Animals Seen Today 

Terns, Frigate birds, Shearwaters, and Dolphins.

Question of the Day 

During World War II what impact might the battles (Midway) that were fought near these islands have had on the ecosystem? Could there still be impact today?

Aloha… Chris