Friday, September 19, 2008

Blog #11: Why we use handheld nets

Going on this trip has so far been fun because of the numerous dives, delicious food, and enjoyable company. In addition to all of that I found out that there is quite a process that starts with a diver splashing into 85 degree Bahamian water and ends with someone being able to look through the glass of the Giant Ocean Tank (GOT) and observe a complex and beautiful ecosystem.


An example of dinner on the Coral Reef II (taken during the May, 2008 expedition)



I should first mention a couple of reasons why the New England Aquarium chooses to catch their exhibit fish with hand held nets. The first one is that this biannual trip provides an engaging and educational vacation for the participants. In fact, five out of the eight participants on this trip are repeat participants from previous trips! Secondly, when it comes to collecting fish, this method allows us to take just the right number of fish and species that we need without harm to any other fish or the environment. Catching by hand allows us to be very specific with what we want without taking any bycatch. In addition, using nets gives the fish a fair fighting chance--in fact most of the time they win and the divers are left shouting unheard expletives into the open water.


Expedition members using hand held nets

However, if we are fortunate enough and we catch a fish with our nets we are careful to bring the fish up. We do this by clipping our catch bag to a barrel underwater and slowly bring up the barrel (5 feet every 10 minutes). This allows their swim bladders to slowly adjust and reduces stress to the fish. Once they are at the surface everyone is involved in a mad dash to place the fish in a bucket, find out the species of fish, count them all and then place them in the correct tank (of which there are about 25).

Then to take care of the fish the staff wake up, before the sun, and do a full system check. This involves observing the fish (right now there are about 200) for aggressive behavior, checking the amount of dissolved oxygen and the temperature of all of the tanks, and backwashing the system to help improve water flow. Most of the animals are fed chopped up shrimp or, if they are tiny animals, brine shrimp (otherwise known as sea monkeys). Thinking back on all of the responsibilities we have during the day to take care of these 200 fish it really makes me appreciate all the work our aquarists do back at the New England Aquarium - they have almost 30,000 animals of around 800 different species to look after! Well, it has been a full day I better get some rest so that I can do even more tomorrow.

- Megan Moore

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Monday, May 5, 2008

Blog #2: Bahamian Grunt Roundup

Temp: 85
Skies: Clear
Seas: Calm
Underwater visibility: Fantastic!

After a check-in dive (to get familiar with the local waters) and a teach-in on the ins and outs of catching fish with vinyl nets on a stick (somewhat like using a butterfly net while 25 feet underwater), we headed to Three Sisters Rock just offshore from Bimini for the major event of the day. The goal: to round up several dozen French grunts (Haemulon flavolineatum) and smallmouth grunts (Haemulon chrysargyreum shown at right).

This was an unbelievable experience for a diver like me, since I was only recently certified. The basic strategy goes like this:

Four to five divers station themselves around the perimeter of a barrier net (somewhat like a seine net). Then another group of divers wielding vinyl box nets in outstretched arms attempt to herd a large--make that very large--school of grunts in the barrier net. It looks kind of like the old safari movies when the "beaters" drive the big game into the sights of the waiting hunters, except our task really is to bring 'em back alive.

Once the grunts are in place, the divers gradually encircle the fish with the net. Then, using the vinyl box nets, five to 10 fish at a time are transferred to the nearby "grunt hotel," about 10 yards away. The experts then select the desired species to share with our visitors back in Boston, while gently letting the others go.

And a good day it was. The tally for the dive: 38 French grunts and 17 small mouth grunts. And a special bonus: one spotted spiny lobster (Panulirus guttatus) and one Caribbean spiny lobster (Panulirus argus) Both are clawless version of the Homarus americanus we're all used to in back home in New England.

There was another terrific treat upon returning to the boat. We discovered chef Mat had prepared crab rangoon for our afternoon snack. (From sustainable sources, of course!) Very tasty!

Captain John then fired up the engines for the 7 hour trip to the Berry Islands, 80 miles east of Bimini. We look forward to a great day tomorrow, and we'll keep you posted on the "catch."

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