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.