7/22/2013: Bait Plumes

In a previous post I talked about how unreliable traps can be at catching fish. This is one reason we use video cameras, to help determine the reason fish may not have been captured in a particular trap & to “capture” information about those fish that do not enter traps. However, there is another variable to include when considering the unreliability of traps, bait plumes. The trap goes in the water baited with some variety of oily, smelly fish to attract piscivorous fishes (fish that eat other fish), which most snappers and groupers are. However, if there is a current in the water, the smell of the bait will basically travel in one direction. The fish that are attracted to the bait will swim toward the source (toward higher concentration of smell). If the mouth of the trap is on the down-current side of the trap, the fish will reach this side of the trap first when following the smell. However, if the trap lands facing the other direction, the fish will arrive at the end of the trap with no opening, and only the most hungry or most industrious will venture around the trap to get to the side where they can get at the bait. The others will mill around outside the trap on the other side, either too confused or not curious enough to figure out how to get inside.  This is exactly what we saw on some of our fish traps today. At least 5 red snapper were captured on video on the opposite side of the trap; however, only one was industrious enough to venture inside and get caught. 

Example of a bait plume

I also got the chance to talk to Jim, one of the NOAA corps officers onboard this afternoon.. We discovered that I was a deckhand on a trip aboard the S/V Spirit of Massachusetts while he was a college student on a semester at sea program.  He seemed to have a parallel story to mine. We both went to sea for the first time during college, and became absolutely captivated by it. We have both spent basically all of our time on the water since those formative experiences. He has worked on boats for non-profits and is now in the NOAA corps driving their ships. I have worked either as a scientist, science teacher, or sailor on the water since my first experience at sea in 1997. I remember when I was a student on my first trip, one of the crew members saying to me, “Some people get bit. Some people don’t.”  I have experienced this first-hand and can say that people who share the sea passion are really one of a kind.

7/21/2013: A ship as an island

So, I’ve talked a lot about the mission of this research trip. However, I have not discussed any of the people who make it possible. The entire ship’s company of this research vessel is 34 people. There are 12 scientists aboard along with over 20 people working on the boat.There is a chief officer (captain) and 3 watch-standing mates who are all a part of the NOAA corps. They are assigned to vessels for a few years and then move on to assignments onshore in various capacities. There are also several folks who work on the deck. They deploy and retrieve all of the research gear so that the scientists can work on data collections. A ship of this size also has several engineers to maintain the generators, engines, reverse osmosis system to make fresh water from the salt water around us, sewage systems, freezers, etc. There are two people who deal with computers. The ship is filled with computers that perform almost every job imaginable, in addition to the wifi which keeps us connected to the outside world via satellites at all times. There are 2 cooks who keep us all fed. One thing that I enjoy about going to sea is that it tends to miniaturize my world. In the “real world” I don’t know all of the people who maintain my electricity, keep the sewers from backing up, prepare meals at the restaurants frequent, drives the bus, maintains the cable & internet connections, etc. Aboard a ship, you know all of these people, and you can see how each of their jobs matters. Being aboard a ship constantly reminds me to stop & consider the monumental effort it takes for modern life to be as comfortable as we have made it. It also makes me mindful of each of the resources that I use. 

I just spent some time talking to the chief engineer for this cruise. His name is Victor & he is a very interesting guy as well. He is originally from Portugal & has worked aboard tuna fishing boats and the NOAA ship Bigelow in New England along with this vessel. He is filling in as chief engineer for a few months on the Pisces while they find a permanent chief engineer.  His next assignment will be aboard a new vessel that NOAA is building in connection with SCRIPPS. It will be stationed in San Diego & do work off of the west coast. One thing I am constantly impressed by about the crews of research ships is how interested they get in the research taking place aboard their vessel. It would be easy to just do your job & ignore the crazy scientists onboard. However, few people do that. Victor asked me questions about my work, what we are hoping to gain from this data (the numbers of groupers and snappers in the area), whether we are comparing to a long time series (no. We have no long time series in this area), and how the video reading works. He also told me about working aboard the Bigelow doing trawl surveys in the North Atlantic. Then he described for me the trip they went on where the vessel was doing deep water trawling. He couldn’t believe how far they had traveled to get to the areas they were interested in sampling. He said that they made it almost to the Azores. He was impressed by the large size of the nets they fished, the small size of the mesh, and the diameter of cable needed to successfully fish the trawl and get it back to the boat. He told me about how it took 3 hours to bring the nets back onboard and how there were not many fish down that deep, but that there were lots of different invertebrates. Many of these folks have had very interesting experiences working at sea and have seen many things that I can only imagine. It’s great to get to interact closely with so many different people who have a single commonality, a love of the ocean. 

By the way: you can follow our location at this website if you are so inclined. Under "Pick a ship" just select Pisces.

7/20/2013: Great video, but few trapped fish

I’m going to talk a little more about the video cameras and the videos in today’s blog. I already explained how the cameras are mounted on the traps and why we use cameras a little bit, but I wanted to get a little more into the specifics of my job & show a few examples of the types of habitat we are putting the traps on.

My job is primarily to deal with the data that comes in via videos. I load the SD cards into the cameras & track which card is in which camera on which trap (so we know when we bring it up exactly where it was located on the bottom of the ocean by GPS coordinates). I then mount the cameras on the traps & start them recording when we are about to deploy the traps. Once the traps are back onboard, I take the cameras out of the housings, download the videos from the SD cards & name their file with the collection number.

Sandy bottom. But still someone home

Mixy bottom

Shelly bottom. Not a lot...

Finger sponges poking through

A nice ledge

Some nice flat bottom

These videos serve two purposes. First, they give immediate feedback to the crew who was performing mapping. When they see a picture of what was on the bottom, they can better interpret the signals they are receiving from the acoustic equipment. We know that most reef fish prefer to live in areas where there are lots of rocks and that there is a higher diversity of fish in these areas. Fishermen also tend to target these areas, because this fact is well known. However, there are very large areas which have none of these features.Some areas are completely sandy, while others are flat with a sand veneer, but have algae or sponges attached to the hard rock underneath. These mixed habitats can hold some of the fish that anglers & scientist are interested in studying as well.

The ledge w/ only 20 fish caught

Another view of the same ledge

The second purpose of the videos is for scientists to get a better understanding of the fish assemblage in the area. Although traps are good at catching certain types of fish, there are many others which are either not interested in entering the traps, or actively avoid them. When a trap comes to the surface without a video camera, the scientists get no information about the species which avoided the trap. With a video camera attached, the scientists can go back & watch the video, noting all of the species of fish which were around, but didn’t go into the trap. There can be a lot of fish around that don’t like traps. For example, here’s a picture of a ledge. Watching the video, there are at least 15 different species of fish present, many in large numbers.  This trap came to the surface with a total of 20 fish from two species. Obviously, the traps are missing a fair amount of what is available within the habitat.