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Journals 2008/2009

Maria Gomez
Dr. Theodore Alexander Science Center School, Los Angeles, California

"Sound Localization in Plainfin Midshipman Fish"
Bodega Bay Marine lab, Bodega Bay, California
July 17 - July 26, 2009
Journal Index:
July 17-18 - 19 - 20 - 21 - 22
       23 - 24 - 25 - 26

July 20, 2008
Nick's Cove Beach

Wow, the alarm seemed to ring awfully early. I woke up before 5:00 a.m. to head off to our first collection site because low tide was at 5:30. The whole team, Dr. Joe, Andrew, Peter, Daphne and I got into the van and drove about 30 miles to our site. Dr. Bass, Midge, and a post grad student from UCLA followed us in their car. After we arrived to the site, we all put on our boots, gloves, and each of us helped take down the buckets that were used to collect the fish. We walked down to the edge of the shore and there were many rocks and boulders strewn about in the mud among a variety of mussels and other shells. All of us helped pick up the rocks and look for the fish that were there in the nests. Midshipmen fish mate at night in the intertidal zone. If the female is attracted to the humming of the male she then makes her way into the nest and one by one lays over 100-200 eggs that night. The male then ejects his sperm over the eggs and fertilizes them. The female leaves and the male then takes on the responsibility of caring for the eggs until they break out of their egg sacs and swim into the ocean near the shore. It usually takes about a month for the eggs to hatch. Dr. Sisneros wanted us to collect three different types of midshipmen fish; the #1 male, the #2 "sneaker" male, and the female. The #1 male has a large head, is a silver color and is much larger than the female. The female is smaller and has a golden color on her underside. The #2 male resembles the female in size and often uses his small size as a means of tricking the larger male into letting him into the larger male's nest where the "sneaker" fish then uses his sperm to fertilize the eggs that had been laid by the female fish. All of these fish have a line of markings along their underbody that resemble the buttons of the midshipmen's uniform. As we walked along the beach we helped each other pick up the rocks and check to see what we would find under the rock. Sometimes we wouldn't find anything, but most of the time we found a #1 male hiding in a shallow amount of water. Under some rocks we found all three types of the fish. Other times we found a #1 fish in the nest and large masses of eggs that had been laid by the female still attached to the rock's underside. We spent over two hours collecting the specimens and putting them into the large buckets. Afterwards we headed back to the lab as the fish had to be maintained in the proper environment until they could be tested that later that evening. Once back at the lab, we carried the fish and placed them in large containers that had ocean water pumped in continuously through the night and day. Once that was completed we had the rest of the day to ourselves. We spent the time sleeping since we knew that we would be up past midnight later that night for the first experiment. After our group dinner and meeting we all went back to the marine lab around 9:00 p.m.. The group spent about an hour getting all the gear and equipment into place for the experiment. Then at around 10:00 the experiments began. We tested 13 females, 7 #2 males and a variety of #1 males. Of the 13 females, five of them responded to the correct area. After the experiment ended, Dr. we went back to Dr. Sisneros's lab where he dissected 4fourof the non-responders to verify if they had eggs or not. At this point Dr. Sisneros took us back to our dorm area to get some sleep before our rising at 6:00 in the morning.

Collecting Midshipmen Fish at Nick's Cove

You never know what you might find under these big rocks!