VOLUNTARY SWIMMING SPEEDS AND RESPIRATION RATES OF 



A FILTER-FEEDING PLANKTIVORE, THE ATLANTIC MENHADEN, 



BREVOORTIA TYRANNUS (PISCES: CLUPEIDAE) 



Ann G. Durbin/ Edward G. Durbin,' Peter G. Verity,* and Thomas J. Smayda^ 



ABSTRACT 



Voluntary swimming speeds and respiration rates of a group of adult Atlantic menhaden (mean wet 

 weight = 302 g) were measured before, during, and after a 7-hour feeding period, during which the 

 diatom Ditylum brightwelli was made available at a constant rate. Total ration for the 12 fish ranged 

 between 9.60 and 94.79 g dry weight. Temperature was 20°±1° C. In the absence of food, the routine 

 swimming speeds and respiration rates of the menhaden were: mean ± 95% confidence limits = 

 12.2 ± 1.6 cm per second (0.47 ±0.06 body lengths per second), and 0.10±0.009 m.g Oj per gram per hour. 

 During feeding the fish increased their voluntary swimming speed 2.4- to 3.5-fold, and their respiration 

 rates 2.2- to 5.4-fold above the routine rates, depending on the concentration of plankton in the water. 

 There was a linear relationship between logio respiration rate and mean swimming speed during the 

 feeding and the postfeeding periods. During feeding, the metabolic cost per increment in swimming 

 speed was about 2.5 times higher than the cost of swimming in other species; this is believed to reflect a 

 high energetic cost of filter feeding. There was an approximately hyperbolic relationship between the 

 voluntary swimming speed of the Atlantic menhaden, and the phytoplankton chlorophyll a concentra- 

 tion in the water The swimming speed and respiration rate of the fish remained constant as long as the 

 input of phytoplankton into the tank continued at a constant rate. After feeding, the activity levels and 

 respiration rates of the menhaden quickly returned to prefeeding routine rates. 



The Atlantic menhaden, Breuoor^ia tyrannus, is a 

 schoohng, filter- feeding planktivore (Peck 1894; 

 Durbin and Durbin 1975) which supports a major 

 commercial fishery along the Atlantic coast of the 

 United States. 



The present study investigates voluntary 

 swimming speeds and oxygen consumption rates 

 of Atlantic menhaden before, during, and after a 

 7-h period during which the fish were fed a ration 

 of the diatom Ditylum brightwelli. During this 

 period the plankton was made available at a con- 

 stant rate, so that feeding was continuous and the 

 ingestion rate was constant. The prolonged feed- 

 ing was designed to reproduce, as much as possi- 

 ble, natural feeding conditions for menhaden. 

 During these experiments ammonia and dissolved 

 organic nitrogen excretion rates, feces production 

 rates, and assimilation efficiencies were also mea- 

 sured and will be reported in a second paper. These 

 studies are part of a larger effort to determine the 

 energy budget of Atlantic menhaden in Narragan- 

 sett Bay, R.I. 



'Graduate School of Oceanography, University of Rhode Is- 

 land, Kingston, RI 02881. 



^Department of Oceanography, University of Washington, 

 Seattle WA 98195. 



METHODS 



Adult Atlantic menhaden were dipnetted from a 

 commercial purse seine, 2-3 min after it had been 

 set around a school. These fish were transferred to 

 a round, 1.2 m diameter tank and brought in good 

 condition to the laboratory. There the fish were 

 maintained outdoors, in a circular fiber glass tank 

 1.85 m in diameter and 0.76 m deep, supplied with 

 flowing unfiltered seawater. The tank was pro- 

 tected by a large fiber glass canopy. 



Five days after capture, the number offish in the 

 tank was reduced to 25. Once a day the fish were 

 fed a ration of RangenV salmon feed, size 00 pow- 

 der, equivalent to 3% of their dry body weight per 

 day. Within 3 wk all fish fed readily in the tank. 

 The fish were held for 6 wk before use in experi- 

 ments. During this period, the tank was cleaned 

 every day, and preliminary trials were carried out. 

 This enabled the fish to become accustomed to 

 routine sampling procedures, to the presence of 

 observers near the tank, and also to the presence of 

 a clear Plexiglas cover, which was lowered onto the 

 surface of the tank water during respiration mea- 



Manuscript accepted March 1980. 



FISHERY BULLETIN: VOL. 78. NO. 4, 1981. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



877 



